Subject: [PATCH V2 05/10] firmware: tegra: add BPMP support

From: [email-masked] (Sivaram Nair)
Date: Fri, 8 Jul 2016 10:55:23 -0700

On Tue, Jul 05, 2016 at 05:04:26PM +0800, Joseph Lo wrote:
> The Tegra BPMP (Boot and Power Management Processor) is designed for the
> booting process handling, offloading the power management tasks and
> some system control services from the CPU. It can be clock, DVFS,
> thermal/EDP, power gating operation and system suspend/resume handling.
> So the CPU and the drivers of these modules can base on the service that
> the BPMP firmware driver provided to signal the event for the specific PM
> action to BPMP and receive the status update from BPMP.
> 
> Comparing to the ARM SCPI, the service provided by BPMP is message-based
> communication but not method-based. The BPMP firmware driver provides the
> send/receive service for the users, when the user concerns the response
> time. If the user needs to get the event or update from the firmware, it
> can request the MRQ service as well. The user needs to take care of the
> message format, which we call BPMP ABI.
> 
> The BPMP ABI defines the message format for different modules or usages.
> For example, the clock operation needs an MRQ service code called
> MRQ_CLK with specific message format which includes different sub
> commands for various clock operations. This is the message format that
> BPMP can recognize.
> 
> So the user needs two things to initiate IPC between BPMP. Get the
> service from the bpmp_ops structure and maintain the message format as
> the BPMP ABI defined.
> 
> Based-on-the-work-by:
> Sivaram Nair <[email-masked]>
> 
> Signed-off-by: Joseph Lo <[email-masked]>
> ---
> Changes in V2:
> - None
> ---
>  drivers/firmware/tegra/Kconfig  |   12 +
>  drivers/firmware/tegra/Makefile |    1 +
>  drivers/firmware/tegra/bpmp.c   |  713 +++++++++++++++++
>  include/soc/tegra/bpmp.h        |   29 +
>  include/soc/tegra/bpmp_abi.h    | 1601 +++++++++++++++++++++++++++++++++++++++
>  5 files changed, 2356 insertions(+)
>  create mode 100644 drivers/firmware/tegra/bpmp.c
>  create mode 100644 include/soc/tegra/bpmp.h
>  create mode 100644 include/soc/tegra/bpmp_abi.h
> 
> diff --git a/drivers/firmware/tegra/Kconfig b/drivers/firmware/tegra/Kconfig
> index 1fa3e4e136a5..ff2730d5c468 100644
> --- a/drivers/firmware/tegra/Kconfig
> +++ b/drivers/firmware/tegra/Kconfig
> @@ -10,4 +10,16 @@ config TEGRA_IVC
>  	  keeps the content is synchronization between host CPU and remote
>  	  processors.
>  
> +config TEGRA_BPMP
> +	bool "Tegra BPMP driver"
> +	depends on ARCH_TEGRA && TEGRA_HSP_MBOX && TEGRA_IVC
> +	help
> +	  BPMP (Boot and Power Management Processor) is designed to off-loading
> +	  the PM functions which include clock/DVFS/thermal/power from the CPU.
> +	  It needs HSP as the HW synchronization and notification module and
> +	  IVC module as the message communication protocol.
> +
> +	  This driver manages the IPC interface between host CPU and the
> +	  firmware running on BPMP.
> +
>  endmenu
> diff --git a/drivers/firmware/tegra/Makefile b/drivers/firmware/tegra/Makefile
> index 92e2153e8173..e34a2f79e1ad 100644
> --- a/drivers/firmware/tegra/Makefile
> +++ b/drivers/firmware/tegra/Makefile
> @@ -1 +1,2 @@
> +obj-$(CONFIG_TEGRA_BPMP)	+= bpmp.o
>  obj-$(CONFIG_TEGRA_IVC)		+= ivc.o
> diff --git a/drivers/firmware/tegra/bpmp.c b/drivers/firmware/tegra/bpmp.c
> new file mode 100644
> index 000000000000..24fda626610e
> --- /dev/null
> +++ b/drivers/firmware/tegra/bpmp.c
> @@ -0,0 +1,713 @@
> +/*
> + * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/mailbox_client.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_device.h>
> +#include <linux/platform_device.h>
> +#include <linux/semaphore.h>
> +
> +#include <soc/tegra/bpmp.h>
> +#include <soc/tegra/bpmp_abi.h>
> +#include <soc/tegra/ivc.h>
> +
> +#define BPMP_MSG_SZ		128
> +#define BPMP_MSG_DATA_SZ	120

These should come from bpmp_abi.h (MSG_MIN_SZ & MSG_MIN_DATA_SZ).

> +
> +#define __MRQ_ATTRS		0xff000000
> +#define __MRQ_INDEX(id)		((id) & ~__MRQ_ATTRS)
> +
> +#define DO_ACK			BIT(0)
> +#define RING_DOORBELL		BIT(1)
> +
> +struct tegra_bpmp_soc_data {
> +	u32 ch_index;		/* channel index */
> +	u32 thread_ch_index;	/* thread channel index */
> +	u32 cpu_rx_ch_index;	/* CPU Rx channel index */
> +	u32 nr_ch;		/* number of total channels */
> +	u32 nr_thread_ch;	/* number of thread channels */
> +	u32 ch_timeout;		/* channel timeout */
> +	u32 thread_ch_timeout;	/* thread channel timeout */
> +};
> +
> +struct channel_info {
> +	u32 tch_free;
> +	u32 tch_to_complete;
> +	struct semaphore tch_sem;
> +};
> +
> +struct mb_data {
> +	s32 code;
> +	s32 flags;

These should be u32?

> +	u8 data[BPMP_MSG_DATA_SZ];
> +} __packed;
> +
> +struct channel_data {
> +	struct mb_data *ib;
> +	struct mb_data *ob;
> +};
> +
> +struct mrq {
> +	struct list_head list;
> +	u32 mrq_code;
> +	bpmp_mrq_handler handler;
> +	void *data;
> +};
> +
> +struct tegra_bpmp {
> +	struct device *dev;
> +	const struct tegra_bpmp_soc_data *soc_data;
> +	void __iomem *tx_base;
> +	void __iomem *rx_base;
> +	struct mbox_client cl;
> +	struct mbox_chan *chan;
> +	struct ivc *ivc_channels;
> +	struct channel_data *ch_area;
> +	struct channel_info ch_info;
> +	struct completion *ch_completion;
> +	struct list_head mrq_list;
> +	struct tegra_bpmp_ops *ops;
> +	spinlock_t lock;
> +	bool init_done;
> +};
> +
> +static struct tegra_bpmp *bpmp;
> +
> +static int bpmp_get_thread_ch(int idx)
> +{
> +	return bpmp->soc_data->thread_ch_index + idx;
> +}
> +
> +static int bpmp_get_thread_ch_index(int ch)
> +{
> +	if (ch < bpmp->soc_data->thread_ch_index ||
> +	    ch >= bpmp->soc_data->cpu_rx_ch_index)
> +		return -1;
> +	return ch - bpmp->soc_data->thread_ch_index;
> +}
> +
> +static int bpmp_get_ob_channel(void)
> +{
> +	return smp_processor_id() + bpmp->soc_data->ch_index;
> +}
> +
> +static struct completion *bpmp_get_completion_obj(int ch)
> +{
> +	int i = bpmp_get_thread_ch_index(ch);
> +
> +	return i < 0 ? NULL : bpmp->ch_completion + i;
> +}
> +
> +static int bpmp_valid_txfer(void *ob_data, int ob_sz, void *ib_data, int ib_sz)
> +{
> +	return ob_sz >= 0 && ob_sz <= BPMP_MSG_DATA_SZ &&
> +	       ib_sz >= 0 && ib_sz <= BPMP_MSG_DATA_SZ &&
> +	       (!ob_sz || ob_data) && (!ib_sz || ib_data);
> +}
> +
> +static bool bpmp_master_acked(int ch)
> +{
> +	struct ivc *ivc_chan;
> +	void *frame;
> +	bool ready;
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	frame = tegra_ivc_read_get_next_frame(ivc_chan);
> +	ready = !IS_ERR_OR_NULL(frame);
> +	bpmp->ch_area[ch].ib = ready ? frame : NULL;
> +
> +	return ready;
> +}
> +
> +static int bpmp_wait_ack(int ch)
> +{
> +	ktime_t t;

You could consider adding a bpmp_master_acked() check here. It will be
an extra call, but you might avoid executing the next line many times.

> +
> +	t = ns_to_ktime(local_clock());
> +
> +	do {
> +		if (bpmp_master_acked(ch))
> +			return 0;
> +	} while (ktime_us_delta(ns_to_ktime(local_clock()), t) <
> +		 bpmp->soc_data->ch_timeout);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static bool bpmp_master_free(int ch)
> +{
> +	struct ivc *ivc_chan;
> +	void *frame;
> +	bool ready;
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	frame = tegra_ivc_write_get_next_frame(ivc_chan);
> +	ready = !IS_ERR_OR_NULL(frame);
> +	bpmp->ch_area[ch].ob = ready ? frame : NULL;
> +
> +	return ready;
> +}
> +
> +static int bpmp_wait_master_free(int ch)
> +{
> +	ktime_t t;

Similarly doing an extra bpmp_master_free() check here, is worth
considering.

> +
> +	t = ns_to_ktime(local_clock());
> +
> +	do {
> +		if (bpmp_master_free(ch))
> +			return 0;
> +	} while (ktime_us_delta(ns_to_ktime(local_clock()), t)
> +		 < bpmp->soc_data->ch_timeout);
> +
> +	return -ETIMEDOUT;
> +}
> +
> +static int __read_ch(int ch, void *data, int sz)
> +{
> +	struct ivc *ivc_chan;
> +	struct mb_data *p;
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	p = bpmp->ch_area[ch].ib;
> +	if (data)
> +		memcpy_fromio(data, p->data, sz);
> +
> +	return tegra_ivc_read_advance(ivc_chan);
> +}
> +
> +static int bpmp_read_ch(int ch, void *data, int sz)
> +{
> +	unsigned long flags;
> +	int i, ret;
> +
> +	i = bpmp_get_thread_ch_index(ch);
> +
> +	spin_lock_irqsave(&bpmp->lock, flags);
> +	ret = __read_ch(ch, data, sz);
> +	bpmp->ch_info.tch_free |= (1 << i);
> +	spin_unlock_irqrestore(&bpmp->lock, flags);
> +
> +	up(&bpmp->ch_info.tch_sem);
> +
> +	return ret;
> +}
> +
> +static int __write_ch(int ch, int mrq_code, int flags, void *data, int sz)
> +{
> +	struct ivc *ivc_chan;
> +	struct mb_data *p;
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	p = bpmp->ch_area[ch].ob;
> +
> +	p->code = mrq_code;
> +	p->flags = flags;
> +	if (data)
> +		memcpy_toio(p->data, data, sz);
> +
> +	return tegra_ivc_write_advance(ivc_chan);
> +}
> +
> +static int bpmp_write_threaded_ch(int *ch, int mrq_code, void *data, int sz)
> +{
> +	unsigned long flags;
> +	int ret, i;
> +
> +	ret = down_timeout(&bpmp->ch_info.tch_sem,
> +			   usecs_to_jiffies(bpmp->soc_data->thread_ch_timeout));
> +	if (ret)
> +		return ret;
> +
> +	spin_lock_irqsave(&bpmp->lock, flags);
> +
> +	i = __ffs(bpmp->ch_info.tch_free);
> +	*ch = bpmp_get_thread_ch(i);
> +	ret = bpmp_master_free(*ch) ? 0 : -EFAULT;
> +	if (!ret) {
> +		bpmp->ch_info.tch_free &= ~(1 << i);
> +		__write_ch(*ch, mrq_code, DO_ACK | RING_DOORBELL, data, sz);
> +		bpmp->ch_info.tch_to_complete |= (1 << *ch);
> +	}
> +
> +	spin_unlock_irqrestore(&bpmp->lock, flags);
> +
> +	return ret;
> +}
> +
> +static int bpmp_write_ch(int ch, int mrq_code, int flags, void *data, int sz)
> +{
> +	int ret;
> +
> +	ret = bpmp_wait_master_free(ch);
> +	if (ret)
> +		return ret;
> +
> +	return __write_ch(ch, mrq_code, flags, data, sz);
> +}
> +
> +static int bpmp_send_receive_atomic(int mrq_code, void *ob_data, int ob_sz,
> +				    void *ib_data, int ib_sz)
> +{
> +	int ch, ret;
> +
> +	if (WARN_ON(!irqs_disabled()))
> +		return -EPERM;
> +
> +	if (!bpmp_valid_txfer(ob_data, ob_sz, ib_data, ib_sz))
> +		return -EINVAL;
> +
> +	if (!bpmp->init_done)
> +		return -ENODEV;
> +
> +	ch = bpmp_get_ob_channel();
> +	ret = bpmp_write_ch(ch, mrq_code, DO_ACK, ob_data, ob_sz);
> +	if (ret)
> +		return ret;
> +
> +	ret = mbox_send_message(bpmp->chan, NULL);
> +	if (ret < 0)
> +		return ret;
> +	mbox_client_txdone(bpmp->chan, 0);

mbox_send_message() & mbox_client_txdone() are always used in pair - so
why don't we move these two into a helper function?

> +
> +	ret = bpmp_wait_ack(ch);
> +	if (ret)
> +		return ret;
> +
> +	return __read_ch(ch, ib_data, ib_sz);
> +}
> +
> +static int bpmp_send_receive(int mrq_code, void *ob_data, int ob_sz,
> +			     void *ib_data, int ib_sz)
> +{
> +	struct completion *comp_obj;
> +	unsigned long timeout;
> +	int ch, ret;
> +
> +	if (WARN_ON(irqs_disabled()))
> +		return -EPERM;
> +
> +	if (!bpmp_valid_txfer(ob_data, ob_sz, ib_data, ib_sz))
> +		return -EINVAL;
> +
> +	if (!bpmp->init_done)
> +		return -ENODEV;
> +
> +	ret = bpmp_write_threaded_ch(&ch, mrq_code, ob_data, ob_sz);
> +	if (ret)
> +		return ret;
> +
> +	ret = mbox_send_message(bpmp->chan, NULL);
> +	if (ret < 0)
> +		return ret;
> +	mbox_client_txdone(bpmp->chan, 0);
> +
> +	comp_obj = bpmp_get_completion_obj(ch);
> +	timeout = usecs_to_jiffies(bpmp->soc_data->thread_ch_timeout);
> +	if (!wait_for_completion_timeout(comp_obj, timeout))
> +		return -ETIMEDOUT;
> +
> +	return bpmp_read_ch(ch, ib_data, ib_sz);
> +}
> +
> +static struct mrq *bpmp_find_mrq(u32 mrq_code)
> +{
> +	struct mrq *mrq;
> +
> +	list_for_each_entry(mrq, &bpmp->mrq_list, list) {
> +		if (mrq_code == mrq->mrq_code)
> +			return mrq;
> +	}
> +
> +	return NULL;
> +}
> +
> +static void bpmp_mrq_return_data(int ch, int code, void *data, int sz)
> +{
> +	int flags = bpmp->ch_area[ch].ib->flags;
> +	struct ivc *ivc_chan;
> +	struct mb_data *frame;
> +	int ret;
> +
> +	if (WARN_ON(sz > BPMP_MSG_DATA_SZ))
> +		return;
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	ret = tegra_ivc_read_advance(ivc_chan);
> +	WARN_ON(ret);
> +
> +	if (!(flags & DO_ACK))
> +		return;
> +
> +	frame = tegra_ivc_write_get_next_frame(ivc_chan);
> +	if (IS_ERR_OR_NULL(frame)) {
> +		WARN_ON(1);
> +		return;
> +	}
> +
> +	frame->code = code;
> +	if (data != NULL)
> +		memcpy_toio(frame->data, data, sz);
> +	ret = tegra_ivc_write_advance(ivc_chan);
> +	WARN_ON(ret);
> +
> +	if (flags & RING_DOORBELL) {
> +		ret = mbox_send_message(bpmp->chan, NULL);
> +		if (ret < 0) {
> +			WARN_ON(1);
> +			return;
> +		}
> +		mbox_client_txdone(bpmp->chan, 0);
> +	}
> +}
> +
> +static void bpmp_mail_return(int ch, int ret_code, int val)
> +{
> +	bpmp_mrq_return_data(ch, ret_code, &val, sizeof(val));
> +}
> +
> +static void bpmp_handle_mrq(int mrq_code, int ch)
> +{
> +	struct mrq *mrq;
> +
> +	spin_lock(&bpmp->lock);
> +
> +	mrq = bpmp_find_mrq(mrq_code);
> +	if (!mrq) {
> +		spin_unlock(&bpmp->lock);
> +		bpmp_mail_return(ch, -EINVAL, 0);
> +		return;
> +	}
> +
> +	mrq->handler(mrq_code, mrq->data, ch);
> +
> +	spin_unlock(&bpmp->lock);
> +}
> +
> +static int bpmp_request_mrq(int mrq_code, bpmp_mrq_handler handler, void *data)
> +{
> +	struct mrq *mrq;
> +	unsigned long flags;
> +
> +	if (!handler)
> +		return -EINVAL;
> +
> +	mrq = devm_kzalloc(bpmp->dev, sizeof(*mrq), GFP_KERNEL);
> +	if (!mrq)
> +		return -ENOMEM;
> +
> +	spin_lock_irqsave(&bpmp->lock, flags);
> +
> +	mrq->mrq_code = __MRQ_INDEX(mrq_code);
> +	mrq->handler = handler;
> +	mrq->data = data;

The last three lines can be outside the lock area.

> +	list_add(&mrq->list, &bpmp->mrq_list);
> +
> +	spin_unlock_irqrestore(&bpmp->lock, flags);
> +
> +	return 0;
> +}
> +
> +static void bpmp_mrq_handle_ping(int mrq_code, void *data, int ch)
> +{
> +	int challenge;
> +	int reply;
> +
> +	challenge = *(int *)bpmp->ch_area[ch].ib->data;
> +	reply = challenge << (smp_processor_id() + 1);
> +	bpmp_mail_return(ch, 0, reply);

We should use struct mrq_ping_response here...

> +}
> +
> +static int bpmp_mailman_init(void)
> +{
> +	return bpmp_request_mrq(MRQ_PING, bpmp_mrq_handle_ping, NULL);
> +}
> +
> +static int bpmp_ping(void)
> +{
> +	unsigned long flags;
> +	ktime_t t;
> +	int challenge = 1;
> +	int reply = 0;
> +	int ret;
> +
> +	t = ktime_get();
> +	local_irq_save(flags);
> +	ret = bpmp_send_receive_atomic(MRQ_PING, &challenge, sizeof(challenge),
> +				       &reply, sizeof(reply));

...and struct mrq_ping_request here.

> +	local_irq_restore(flags);
> +	t = ktime_sub(ktime_get(), t);
> +
> +	if (!ret)
> +		dev_info(bpmp->dev,
> +			 "ping ok: challenge: %d, reply: %d, time: %lld\n",
> +			 challenge, reply, ktime_to_us(t));
> +
> +	return ret;
> +}
> +
> +static int bpmp_get_fwtag(void)
> +{
> +	unsigned long flags;
> +	void *vaddr;
> +	dma_addr_t paddr;
> +	u32 addr;
> +	int ret;
> +
> +	vaddr = dma_alloc_coherent(bpmp->dev, BPMP_MSG_DATA_SZ, &paddr,
> +				   GFP_KERNEL);
> +	if (!vaddr)
> +		return -ENOMEM;
> +	addr = paddr;
> +
> +	local_irq_save(flags);
> +	ret = bpmp_send_receive_atomic(MRQ_QUERY_TAG, &addr, sizeof(addr),
> +				       NULL, 0);
> +	local_irq_restore(flags);
> +
> +	if (!ret)
> +		dev_info(bpmp->dev, "fwtag: %s\n", (char *)vaddr);
> +
> +	dma_free_coherent(bpmp->dev, BPMP_MSG_DATA_SZ, vaddr, paddr);
> +
> +	return ret;
> +}
> +
> +static void bpmp_signal_thread(int ch)
> +{
> +	int flags = bpmp->ch_area[ch].ob->flags;
> +	struct completion *comp_obj;
> +
> +	if (!(flags & RING_DOORBELL))
> +		return;
> +
> +	comp_obj = bpmp_get_completion_obj(ch);
> +	if (!comp_obj) {
> +		WARN_ON(1);
> +		return;
> +	}
> +
> +	complete(comp_obj);
> +}
> +
> +static void bpmp_handle_rx(struct mbox_client *cl, void *data)
> +{
> +	int i, rx_ch;
> +
> +	rx_ch = bpmp->soc_data->cpu_rx_ch_index;
> +
> +	if (bpmp_master_acked(rx_ch))
> +		bpmp_handle_mrq(bpmp->ch_area[rx_ch].ib->code, rx_ch);
> +
> +	spin_lock(&bpmp->lock);
> +
> +	for (i = 0; i < bpmp->soc_data->nr_thread_ch &&
> +			bpmp->ch_info.tch_to_complete; i++) {
> +		int ch = bpmp_get_thread_ch(i);
> +
> +		if ((bpmp->ch_info.tch_to_complete & (1 << ch)) &&
> +		    bpmp_master_acked(ch)) {
> +			bpmp->ch_info.tch_to_complete &= ~(1 << ch);
> +			bpmp_signal_thread(ch);
> +		}
> +	}
> +
> +	spin_unlock(&bpmp->lock);
> +}
> +
> +static void bpmp_ivc_notify(struct ivc *ivc)
> +{
> +	int ret;
> +
> +	ret = mbox_send_message(bpmp->chan, NULL);
> +	if (ret < 0)
> +		return;
> +
> +	mbox_send_message(bpmp->chan, NULL);
> +}

This will be called by the ivc framework at different times including
after reading a frame - causing multiple/redundant interrupts asserted
to bpmp --- since you are already doing the required from
bpmp_send_receive_atomic, bpmp_send_receive() & bpmp_mrq_return_data().
I think you should stub this out, and call mbox_send_message() and
mbox_client_txdone() after each tegra_ivc_channel_notified() in
bpmp_msg_chan_init()

> +
> +static int bpmp_msg_chan_init(int ch)
> +{
> +	struct ivc *ivc_chan;
> +	u32 hdr_sz, msg_sz, que_sz;
> +	uintptr_t rx_base, tx_base;
> +	int ret;
> +
> +	msg_sz = tegra_ivc_align(BPMP_MSG_SZ);
> +	hdr_sz = tegra_ivc_total_queue_size(0);
> +	que_sz = tegra_ivc_total_queue_size(msg_sz);
> +
> +	rx_base =  (uintptr_t)(bpmp->rx_base + que_sz * ch);
> +	tx_base =  (uintptr_t)(bpmp->tx_base + que_sz * ch);
> +
> +	ivc_chan = bpmp->ivc_channels + ch;
> +	ret = tegra_ivc_init(ivc_chan, rx_base, DMA_ERROR_CODE, tx_base,
> +			     DMA_ERROR_CODE, 1, msg_sz, bpmp->dev,
> +			     bpmp_ivc_notify);
> +	if (ret) {
> +		dev_err(bpmp->dev, "%s fail: ch %d returned %d\n",
> +			__func__, ch, ret);
> +		return ret;
> +	}
> +
> +	/* reset the channel state */
> +	tegra_ivc_channel_reset(ivc_chan);

A minor optimization would be to ring the doorbell here...

> +
> +	/* sync the channel state with BPMP */
> +	while (tegra_ivc_channel_notified(ivc_chan))
> +		;

... and keep this while loop outside this per-channel function (after
all the message channels are initialized in probe). That way, we don't
have to sync each channel before starting to initialize the next one.

> +
> +	return 0;
> +}
> +
> +struct tegra_bpmp_ops *tegra_bpmp_get_ops(void)
> +{
> +	if (bpmp->init_done && bpmp->ops)
> +		return bpmp->ops;
> +	return NULL;
> +}
> +EXPORT_SYMBOL(tegra_bpmp_get_ops);
> +
> +static struct tegra_bpmp_ops bpmp_ops = {
> +	.send_receive = bpmp_send_receive,
> +	.send_receive_atomic = bpmp_send_receive_atomic,
> +	.request_mrq = bpmp_request_mrq,
> +	.mrq_return = bpmp_mail_return,
> +};
> +
> +static const struct tegra_bpmp_soc_data soc_data_tegra186 = {
> +	.ch_index = 0,
> +	.thread_ch_index = 6,
> +	.cpu_rx_ch_index = 13,
> +	.nr_ch = 14,
> +	.nr_thread_ch = 7,
> +	.ch_timeout = 60 * USEC_PER_SEC,
> +	.thread_ch_timeout = 600 * USEC_PER_SEC,

This is too large - you can bring these down to 1 sec. I also wonder if
these should be moved to DT?

> +};
> +
> +static const struct of_device_id tegra_bpmp_match[] = {
> +	{ .compatible = "nvidia,tegra186-bpmp", .data = &soc_data_tegra186 },
> +	{ }
> +};
> +
> +static int tegra_bpmp_probe(struct platform_device *pdev)
> +{
> +	const struct of_device_id *match;
> +	struct resource shmem_res;
> +	struct device_node *shmem_np;
> +	int i, ret;
> +
> +	bpmp = devm_kzalloc(&pdev->dev, sizeof(*bpmp), GFP_KERNEL);
> +	if (!bpmp)
> +		return -ENOMEM;
> +	bpmp->dev = &pdev->dev;
> +
> +	match = of_match_device(tegra_bpmp_match, &pdev->dev);
> +	if (!match)
> +		return -EINVAL;

I am curious: is this check really required (tegra_bpmp_match is part of
tegra_bpmp_driver)?

> +	bpmp->soc_data = match->data;
> +
> +	shmem_np = of_parse_phandle(pdev->dev.of_node, "shmem", 0);
> +	of_address_to_resource(shmem_np, 0, &shmem_res);
> +	bpmp->tx_base = devm_ioremap_resource(&pdev->dev, &shmem_res);
> +	if (IS_ERR(bpmp->tx_base))
> +		return PTR_ERR(bpmp->tx_base);
> +
> +	shmem_np = of_parse_phandle(pdev->dev.of_node, "shmem", 1);
> +	of_address_to_resource(shmem_np, 0, &shmem_res);
> +	bpmp->rx_base = devm_ioremap_resource(&pdev->dev, &shmem_res);
> +	if (IS_ERR(bpmp->rx_base))
> +		return PTR_ERR(bpmp->rx_base);
> +
> +	bpmp->ivc_channels = devm_kcalloc(&pdev->dev, bpmp->soc_data->nr_ch,
> +					  sizeof(*bpmp->ivc_channels),
> +					  GFP_KERNEL);
> +	if (!bpmp->ivc_channels)
> +		return -ENOMEM;
> +
> +	bpmp->ch_area = devm_kcalloc(&pdev->dev, bpmp->soc_data->nr_ch,
> +				     sizeof(*bpmp->ch_area), GFP_KERNEL);
> +	if (!bpmp->ch_area)
> +		return -ENOMEM;
> +
> +	bpmp->ch_completion = devm_kcalloc(&pdev->dev,
> +					   bpmp->soc_data->nr_thread_ch,
> +					   sizeof(*bpmp->ch_completion),
> +					   GFP_KERNEL);
> +	if (!bpmp->ch_completion)
> +		return -ENOMEM;
> +
> +	/* mbox registration */
> +	bpmp->cl.dev = &pdev->dev;
> +	bpmp->cl.rx_callback = bpmp_handle_rx;
> +	bpmp->cl.tx_block = false;
> +	bpmp->cl.knows_txdone = false;
> +	bpmp->chan = mbox_request_channel(&bpmp->cl, 0);
> +	if (IS_ERR(bpmp->chan)) {
> +		if (PTR_ERR(bpmp->chan) != -EPROBE_DEFER)
> +			dev_err(&pdev->dev,
> +				"fail to get HSP mailbox, bpmp init fail.\n");
> +		return PTR_ERR(bpmp->chan);
> +	}
> +
> +	/* message channel initialization */
> +	for (i = 0; i < bpmp->soc_data->nr_ch; i++) {
> +		struct completion *comp_obj;
> +
> +		ret = bpmp_msg_chan_init(i);
> +		if (ret)
> +			return ret;
> +
> +		comp_obj = bpmp_get_completion_obj(i);
> +		if (comp_obj)
> +			init_completion(comp_obj);
> +	}
> +
> +	bpmp->ch_info.tch_free = (1 << bpmp->soc_data->nr_thread_ch) - 1;
> +	sema_init(&bpmp->ch_info.tch_sem, bpmp->soc_data->nr_thread_ch);
> +
> +	spin_lock_init(&bpmp->lock);
> +	INIT_LIST_HEAD(&bpmp->mrq_list);
> +	if (bpmp_mailman_init())
> +		return -ENODEV;
> +
> +	bpmp->init_done = true;
> +
> +	ret = bpmp_ping();
> +	if (ret)
> +		dev_err(&pdev->dev, "ping failed: %d\n", ret);
> +
> +	ret = bpmp_get_fwtag();
> +	if (ret)
> +		dev_err(&pdev->dev, "get fwtag failed: %d\n", ret);
> +
> +	/* BPMP is ready now. */
> +	bpmp->ops = &bpmp_ops;
> +
> +	return 0;
> +}
> +
> +static struct platform_driver tegra_bpmp_driver = {
> +	.driver = {
> +		.name = "tegra-bpmp",
> +		.of_match_table = tegra_bpmp_match,
> +	},
> +	.probe = tegra_bpmp_probe,
> +};
> +
> +static int __init tegra_bpmp_init(void)
> +{
> +	return platform_driver_register(&tegra_bpmp_driver);
> +}
> +core_initcall(tegra_bpmp_init);
> diff --git a/include/soc/tegra/bpmp.h b/include/soc/tegra/bpmp.h
> new file mode 100644
> index 000000000000..aaa0ef34ad7b
> --- /dev/null
> +++ b/include/soc/tegra/bpmp.h
> @@ -0,0 +1,29 @@
> +/*
> + * Copyright (c) 2016, NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#ifndef __TEGRA_BPMP_H

Missing #define __TEGRA_BPMP_H

> +
> +typedef void (*bpmp_mrq_handler)(int mrq_code, void *data, int ch);
> +
> +struct tegra_bpmp_ops {
> +	int (*send_receive)(int mrq_code, void *ob_data, int ob_sz,
> +			    void *ib_data, int ib_sz);
> +	int (*send_receive_atomic)(int mrq_code, void *ob_data, int ob_sz,
> +			    void *ib_data, int ib_sz);
> +	int (*request_mrq)(int mrq_code, bpmp_mrq_handler handler, void *data);
> +	void (*mrq_return)(int ch, int ret_code, int val);
> +};
> +
> +struct tegra_bpmp_ops *tegra_bpmp_get_ops(void);
> +
> +#endif /* __TEGRA_BPMP_H */
> diff --git a/include/soc/tegra/bpmp_abi.h b/include/soc/tegra/bpmp_abi.h
> new file mode 100644
> index 000000000000..0aaef5960e29
> --- /dev/null
> +++ b/include/soc/tegra/bpmp_abi.h
> @@ -0,0 +1,1601 @@
> +/*
> + * Copyright (c) 2014-2016, NVIDIA CORPORATION.  All rights reserved.
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef _ABI_BPMP_ABI_H_
> +#define _ABI_BPMP_ABI_H_
> +
> +#ifdef LK
> +#include <stdint.h>
> +#endif
> +
> +#ifndef __ABI_PACKED
> +#define __ABI_PACKED __attribute__((packed))
> +#endif
> +
> +#ifdef NO_GCC_EXTENSIONS
> +#define EMPTY char empty;
> +#define EMPTY_ARRAY 1
> +#else
> +#define EMPTY
> +#define EMPTY_ARRAY 0
> +#endif
> +
> +#ifndef __UNION_ANON
> +#define __UNION_ANON
> +#endif
> +/**
> + * @file
> + */
> +
> +
> +/**
> + * @defgroup MRQ MRQ Messages
> + * @brief Messages sent to/from BPMP via IPC
> + * @{
> + *   @defgroup MRQ_Format Message Format
> + *   @defgroup MRQ_Codes Message Request (MRQ) Codes
> + *   @defgroup MRQ_Payloads Message Payloads
> + *   @defgroup Error_Codes Error Codes
> + * @}
> + */
> +
> +/**
> + * @addtogroup MRQ_Format Message Format
> + * @{
> + * The CPU requests the BPMP to perform a particular service by
> + * sending it an IVC frame containing a single MRQ message. An MRQ
> + * message consists of a @ref mrq_request followed by a payload whose
> + * format depends on mrq_request::mrq.
> + *
> + * The BPMP processes the data and replies with an IVC frame (on the
> + * same IVC channel) containing and MRQ response. An MRQ response
> + * consists of a @ref mrq_response followed by a payload whose format
> + * depends on the associated mrq_request::mrq.
> + *
> + * A well-defined subset of the MRQ messages that the CPU sends to the
> + * BPMP can lead to BPMP eventually sending an MRQ message to the
> + * CPU. For example, when the CPU uses an #MRQ_THERMAL message to set
> + * a thermal trip point, the BPMP may eventually send a single
> + * #MRQ_THERMAL message of its own to the CPU indicating that the trip
> + * point has been crossed.
> + * @}
> + */
> +
> +/**
> + * @ingroup MRQ_Format
> + * @brief header for an MRQ message
> + *
> + * Provides the MRQ number for the MRQ message: #mrq. The remainder of
> + * the MRQ message is a payload (immediately following the
> + * mrq_request) whose format depends on mrq.
> + *
> + * @todo document the flags
> + */
> +struct mrq_request {
> +	/** @brief MRQ number of the request */
> +	uint32_t mrq;
> +	/** @brief flags for the request */
> +	uint32_t flags;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Format
> + * @brief header for an MRQ response
> + *
> + *  Provides an error code for the associated MRQ message. The
> + *  remainder of the MRQ response is a payload (immediately following
> + *  the mrq_response) whose format depends on the associated
> + *  mrq_request::mrq
> + *
> + * @todo document the flags
> + */
> +struct mrq_response {
> +	/** @brief error code for the MRQ request itself */
> +	int32_t err;
> +	/** @brief flags for the response */
> +	uint32_t flags;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Format
> + * Minimum needed size for an IPC message buffer
> + */
> +#define MSG_MIN_SZ	128
> +/**
> + * @ingroup MRQ_Format
> + *  Minimum size guaranteed for data in an IPC message buffer
> + */
> +#define MSG_DATA_MIN_SZ	120
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @name Legal MRQ codes
> + * These are the legal values for mrq_request::mrq
> + * @{
> + */
> +
> +#define MRQ_PING		0
> +#define MRQ_QUERY_TAG		1
> +#define MRQ_MODULE_LOAD		4
> +#define MRQ_MODULE_UNLOAD	5
> +#define MRQ_TRACE_MODIFY	7
> +#define MRQ_WRITE_TRACE		8
> +#define MRQ_THREADED_PING	9
> +#define MRQ_MODULE_MAIL		11
> +#define MRQ_DEBUGFS		19
> +#define MRQ_RESET		20
> +#define MRQ_I2C			21
> +#define MRQ_CLK			22
> +#define MRQ_QUERY_ABI		23
> +#define MRQ_PG_READ_STATE	25
> +#define MRQ_PG_UPDATE_STATE	26
> +#define MRQ_THERMAL		27
> +#define MRQ_CPU_VHINT		28
> +#define MRQ_ABI_RATCHET		29
> +#define MRQ_EMC_DVFS_LATENCY	31
> +#define MRQ_TRACE_ITER		64
> +
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @brief Maximum MRQ code to be sent by CPU software to
> + * BPMP. Subject to change in future
> + */
> +#define MAX_CPU_MRQ_ID		64
> +
> +/**
> + * @addtogroup MRQ_Payloads Message Payloads
> + * @{
> + *   @defgroup Ping
> + *   @defgroup Query_Tag Query Tag
> + *   @defgroup Module Loadable Modules
> + *   @defgroup Trace
> + *   @defgroup Debugfs
> + *   @defgroup Reset
> + *   @defgroup I2C
> + *   @defgroup Clocks
> + *   @defgroup ABI_info ABI Info
> + *   @defgroup MC_Flush MC Flush
> + *   @defgroup Powergating
> + *   @defgroup Thermal
> + *   @defgroup Vhint CPU Voltage hint
> + *   @defgroup MRQ_Deprecated Deprecated MRQ messages
> + *   @defgroup EMC
> + * @}
> + */
> +
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_PING
> + * @brief A simple ping
> + *
> + * * Platforms: All
> + * * Initiators: Any
> + * * Targets: Any
> + * * Request Payload: @ref mrq_ping_request
> + * * Response Payload: @ref mrq_ping_response
> + *
> + * @ingroup MRQ_Codes
> + * @def MRQ_THREADED_PING
> + * @brief A deeper ping
> + *
> + * * Platforms: All
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_ping_request
> + * * Response Payload: @ref mrq_ping_response
> + *
> + * Behavior is equivalent to a simple #MRQ_PING except that BPMP
> + * responds from a thread context (providing a slightly more robust
> + * sign of life).
> + *
> + */
> +
> +/**
> + * @ingroup Ping
> + * @brief request with #MRQ_PING
> + *
> + * Used by the sender of an #MRQ_PING message to request a pong from
> + * recipient. The response from the recipient is computed based on
> + * #challenge.
> + */
> +struct mrq_ping_request {
> +/** @brief arbitrarily chosen value */
> +	uint32_t challenge;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Ping
> + * @brief response to #MRQ_PING
> + *
> + * Sent in response to an #MRQ_PING message. #reply should be the
> + * mrq_ping_request challenge left shifted by 1 with the carry-bit
> + * dropped.
> + *
> + */
> +struct mrq_ping_response {
> +	/** @brief response to the MRQ_PING challege */
> +	uint32_t reply;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_QUERY_TAG
> + * @brief Query BPMP firmware's tag (i.e. version information)
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_query_tag_request
> + * * Response Payload: N/A
> + *
> + */
> +
> +/**
> + * @ingroup Query_Tag
> + * @brief request with #MRQ_QUERY_TAG
> + *
> + * Used by #MRQ_QUERY_TAG call to ask BPMP to fill in the memory
> + * pointed by #addr with BPMP firmware header.
> + *
> + * The sender is reponsible for ensuring that #addr is mapped in to
> + * the recipient's address map.
> + */
> +struct mrq_query_tag_request {
> +  /** @brief base address to store the firmware header */
> +	uint32_t addr;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_MODULE_LOAD
> + * @brief dynamically load a BPMP code module
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_module_load_request
> + * * Response Payload: @ref mrq_module_load_response
> + *
> + * @note This MRQ is disabled on production systems
> + *
> + */
> +
> +/**
> + * @ingroup Module
> + * @brief request with #MRQ_MODULE_LOAD
> + *
> + * Used by #MRQ_MODULE_LOAD calls to ask the recipient to dynamically
> + * load the code located at #phys_addr and having size #size
> + * bytes. #phys_addr is treated as a void pointer.
> + *
> + * The recipient copies the code from #phys_addr to locally allocated
> + * memory prior to responding to this message.
> + *
> + * @todo document the module header format
> + *
> + * The sender is responsible for ensuring that the code is mapped in
> + * the recipient's address map.
> + *
> + */
> +struct mrq_module_load_request {
> +	/** @brief base address of the code to load. Treated as (void *) */
> +	uint32_t phys_addr; /* (void *) */
> +	/** @brief size in bytes of code to load */
> +	uint32_t size;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Module
> + * @brief response to #MRQ_MODULE_LOAD
> + *
> + * @todo document mrq_response::err
> + */
> +struct mrq_module_load_response {
> +	/** @brief handle to the loaded module */
> +	uint32_t base;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_MODULE_UNLOAD
> + * @brief unload a previously loaded code module
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_module_unload_request
> + * * Response Payload: N/A
> + *
> + * @note This MRQ is disabled on production systems
> + */
> +
> +/**
> + * @ingroup Module
> + * @brief request with #MRQ_MODULE_UNLOAD
> + *
> + * Used by #MRQ_MODULE_UNLOAD calls to request that a previously loaded
> + * module be unloaded.
> + */
> +struct mrq_module_unload_request {
> +	/** @brief handle of the module to unload */
> +	uint32_t base;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_TRACE_MODIFY
> + * @brief modify the set of enabled trace events
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_trace_modify_request
> + * * Response Payload: @ref mrq_trace_modify_response
> + *
> + * @note This MRQ is disabled on production systems
> + */
> +
> +/**
> + * @ingroup Trace
> + * @brief request with #MRQ_TRACE_MODIFY
> + *
> + * Used by %MRQ_TRACE_MODIFY calls to enable or disable specify trace
> + * events.  #set takes precedence for any bit set in both #set and
> + * #clr.
> + */
> +struct mrq_trace_modify_request {
> +	/** @brief bit mask of trace events to disable */
> +	uint32_t clr;
> +	/** @brief bit mask of trace events to enable */
> +	uint32_t set;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Trace
> + * @brief response to #MRQ_TRACE_MODIFY
> + *
> + * Sent in repsonse to an #MRQ_TRACE_MODIFY message. #mask reflects the
> + * state of which events are enabled after the recipient acted on the
> + * message.
> + *
> + */
> +struct mrq_trace_modify_response {
> +	/** @brief bit mask of trace event enable states */
> +	uint32_t mask;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_WRITE_TRACE
> + * @brief Write trace data to a buffer
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_write_trace_request
> + * * Response Payload: @ref mrq_write_trace_response
> + *
> + * mrq_response::err depends on the @ref mrq_write_trace_request field
> + * values. err is -#BPMP_EINVAL if size is zero or area is NULL or
> + * area is in an illegal range. A positive value for err indicates the
> + * number of bytes written to area.
> + *
> + * @note This MRQ is disabled on production systems
> + */
> +
> +/**
> + * @ingroup Trace
> + * @brief request with #MRQ_WRITE_TRACE
> + *
> + * Used by MRQ_WRITE_TRACE calls to ask the recipient to copy trace
> + * data from the recipient's local buffer to the output buffer. #area
> + * is treated as a byte-aligned pointer in the recipient's address
> + * space.
> + *
> + * The sender is responsible for ensuring that the output
> + * buffer is mapped in the recipient's address map. The recipient is
> + * responsible for protecting its own code and data from accidental
> + * overwrites.
> + */
> +struct mrq_write_trace_request {
> +	/** @brief base address of output buffer */
> +	uint32_t area;
> +	/** @brief size in bytes of the output buffer */
> +	uint32_t size;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Trace
> + * @brief response to #MRQ_WRITE_TRACE
> + *
> + * Once this response is sent, the respondent will not access the
> + * output buffer further.
> + */
> +struct mrq_write_trace_response {
> +	/**
> +	 * @brief flag whether more data remains in local buffer
> +	 *
> +	 * Value is 1 if the entire local trace buffer has been
> +	 * drained to the outputbuffer. Value is 0 otherwise.
> +	 */
> +	uint32_t eof;
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct mrq_threaded_ping_request {
> +	uint32_t challenge;
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct mrq_threaded_ping_response {
> +	uint32_t reply;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_MODULE_MAIL
> + * @brief send a message to a loadable module
> + *
> + * * Platforms: All
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_module_mail_request
> + * * Response Payload: @ref mrq_module_mail_response
> + *
> + * @note This MRQ is disabled on production systems
> + */
> +
> +/**
> + * @ingroup Module
> + * @brief request with #MRQ_MODULE_MAIL
> + */
> +struct mrq_module_mail_request {
> +	/** @brief handle to the previously loaded module */
> +	uint32_t base;
> +	/** @brief module-specific mail payload
> +	 *
> +	 * The length of data[ ] is unknown to the BPMP core firmware
> +	 * but it is limited to the size of an IPC message.
> +	 */
> +	uint8_t data[EMPTY_ARRAY];
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Module
> + * @brief response to #MRQ_MODULE_MAIL
> + */
> +struct mrq_module_mail_response {
> +	/** @brief module-specific mail payload
> +	 *
> +	 * The length of data[ ] is unknown to the BPMP core firmware
> +	 * but it is limited to the size of an IPC message.
> +	 */
> +	uint8_t data[EMPTY_ARRAY];
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_DEBUGFS
> + * @brief Interact with BPMP's debugfs file nodes
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_debugfs_request
> + * * Response Payload: @ref mrq_debugfs_response
> + */
> +
> +/**
> + * @addtogroup Debugfs
> + * @{
> + *
> + * The BPMP firmware implements a pseudo-filesystem called
> + * debugfs. Any driver within the firmware may register with debugfs
> + * to expose an arbitrary set of "files" in the filesystem. When
> + * software on the CPU writes to a debugfs file, debugfs passes the
> + * written data to a callback provided by the driver. When software on
> + * the CPU reads a debugfs file, debugfs queries the driver for the
> + * data to return to the CPU. The intention of the debugfs filesystem
> + * is to provide information useful for debugging the system at
> + * runtime.
> + *
> + * @note The files exposed via debugfs are not part of the
> + * BPMP firmware's ABI. debugfs files may be added or removed in any
> + * given version of the firmware. Typically the semantics of a debugfs
> + * file are consistent from version to version but even that is not
> + * guaranteed.
> + *
> + * @}
> + */
> +/** @ingroup Debugfs */
> +enum mrq_debugfs_commands {
> +	CMD_DEBUGFS_READ = 1,
> +	CMD_DEBUGFS_WRITE = 2,
> +	CMD_DEBUGFS_DUMPDIR = 3,
> +	CMD_DEBUGFS_MAX
> +};
> +
> +/**
> + * @ingroup Debugfs
> + * @brief parameters for CMD_DEBUGFS_READ/WRITE command
> + */
> +struct cmd_debugfs_fileop_request {
> +	/** @brief physical address pointing at filename */
> +	uint32_t fnameaddr;
> +	/** @brief length in bytes of filename buffer */
> +	uint32_t fnamelen;
> +	/** @brief physical address pointing to data buffer */
> +	uint32_t dataaddr;
> +	/** @brief length in bytes of data buffer */
> +	uint32_t datalen;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Debugfs
> + * @brief parameters for CMD_DEBUGFS_READ/WRITE command
> + */
> +struct cmd_debugfs_dumpdir_request {
> +	/** @brief physical address pointing to data buffer */
> +	uint32_t dataaddr;
> +	/** @brief length in bytes of data buffer */
> +	uint32_t datalen;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Debugfs
> + * @brief response data for CMD_DEBUGFS_READ/WRITE command
> + */
> +struct cmd_debugfs_fileop_response {
> +	/** @brief always 0 */
> +	uint32_t reserved;
> +	/** @brief number of bytes read from or written to data buffer */
> +	uint32_t nbytes;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Debugfs
> + * @brief response data for CMD_DEBUGFS_DUMPDIR command
> + */
> +struct cmd_debugfs_dumpdir_response {
> +	/** @brief always 0 */
> +	uint32_t reserved;
> +	/** @brief number of bytes read from or written to data buffer */
> +	uint32_t nbytes;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Debugfs
> + * @brief request with #MRQ_DEBUGFS.
> + *
> + * The sender of an MRQ_DEBUGFS message uses #cmd to specify a debugfs
> + * command to execute. Legal commands are the values of @ref
> + * mrq_debugfs_commands. Each command requires a specific additional
> + * payload of data.
> + *
> + * |command            |payload|
> + * |-------------------|-------|
> + * |CMD_DEBUGFS_READ   |fop    |
> + * |CMD_DEBUGFS_WRITE  |fop    |
> + * |CMD_DEBUGFS_DUMPDIR|dumpdir|
> + */
> +struct mrq_debugfs_request {
> +	uint32_t cmd;
> +	union {
> +		struct cmd_debugfs_fileop_request fop;
> +		struct cmd_debugfs_dumpdir_request dumpdir;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Debugfs
> + */
> +struct mrq_debugfs_response {
> +	/** @brief always 0 */
> +	int32_t reserved;
> +	union {
> +		/** @brief response data for CMD_DEBUGFS_READ OR
> +		 * CMD_DEBUGFS_WRITE command
> +		 */
> +		struct cmd_debugfs_fileop_response fop;
> +		/** @brief response data for CMD_DEBUGFS_DUMPDIR command */
> +		struct cmd_debugfs_dumpdir_response dumpdir;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/**
> + * @addtogroup Debugfs
> + * @{
> + */
> +#define DEBUGFS_S_ISDIR	(1 << 9)
> +#define DEBUGFS_S_IRUSR	(1 << 8)
> +#define DEBUGFS_S_IWUSR	(1 << 7)
> +/** @} */
> +
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_RESET
> + * @brief reset an IP block
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_reset_request
> + * * Response Payload: N/A
> + */
> +
> +/**
> + * @ingroup Reset
> + */
> +enum mrq_reset_commands {
> +	CMD_RESET_ASSERT = 1,
> +	CMD_RESET_DEASSERT = 2,
> +	CMD_RESET_MODULE = 3,
> +	CMD_RESET_MAX, /* not part of ABI and subject to change */
> +};
> +
> +/**
> + * @ingroup Reset
> + * @brief request with MRQ_RESET
> + *
> + * Used by the sender of an #MRQ_RESET message to request BPMP to
> + * assert or or deassert a given reset line.
> + */
> +struct mrq_reset_request {
> +	/** @brief reset action to perform (@enum mrq_reset_commands) */
> +	uint32_t cmd;
> +	/** @brief id of the reset to affected */
> +	uint32_t reset_id;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_I2C
> + * @brief issue an i2c transaction
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_i2c_request
> + * * Response Payload: @ref mrq_i2c_response
> + */
> +
> +/**
> + * @addtogroup I2C
> + * @{
> + */
> +#define TEGRA_I2C_IPC_MAX_IN_BUF_SIZE	(MSG_DATA_MIN_SZ - 12)
> +#define TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE	(MSG_DATA_MIN_SZ - 4)
> +/** @} */
> +
> +/**
> + * @ingroup I2C
> + * @name Serial I2C flags
> + * Use these flags with serial_i2c_request::flags
> + * @{
> + */
> +#define SERIALI2C_TEN           0x0010
> +#define SERIALI2C_RD            0x0001
> +#define SERIALI2C_STOP          0x8000
> +#define SERIALI2C_NOSTART       0x4000
> +#define SERIALI2C_REV_DIR_ADDR  0x2000
> +#define SERIALI2C_IGNORE_NAK    0x1000
> +#define SERIALI2C_NO_RD_ACK     0x0800
> +#define SERIALI2C_RECV_LEN      0x0400
> +/** @} */
> +/** @ingroup I2C */
> +enum {
> +	CMD_I2C_XFER = 1
> +};
> +
> +/**
> + * @ingroup I2C
> + * @brief serializable i2c request
> + *
> + * Instances of this structure are packed (little-endian) into
> + * cmd_i2c_xfer_request::data_buf. Each instance represents a single
> + * transaction (or a portion of a transaction with repeated starts) on
> + * an i2c bus.
> + *
> + * Because these structures are packed, some instances are likely to
> + * be misaligned. Additionally because #data is variable length, it is
> + * not possible to iterate through a serialized list of these
> + * structures without inspecting #len in each instance.  It may be
> + * easier to serialize or deserialize cmd_i2c_xfer_request::data_buf
> + * manually rather than using this structure definition.
> +*/
> +struct serial_i2c_request {
> +	/** @brief I2C slave address */
> +	uint16_t addr;
> +	/** @brief bitmask of SERIALI2C_ flags */
> +	uint16_t flags;
> +	/** @brief length of I2C transaction in bytes */
> +	uint16_t len;
> +	/** @brief for write transactions only, #len bytes of data */
> +	uint8_t data[];
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup I2C
> + * @brief trigger one or more i2c transactions
> + */
> +struct cmd_i2c_xfer_request {
> +	/** @brief valid bus number from mach-t186/i2c-t186.h*/
> +	uint32_t bus_id;
> +
> +	/** @brief count of valid bytes in #data_buf*/
> +	uint32_t data_size;
> +
> +	/** @brief serialized packed instances of @ref serial_i2c_request*/
> +	uint8_t data_buf[TEGRA_I2C_IPC_MAX_IN_BUF_SIZE];
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup I2C
> + * @brief container for data read from the i2c bus
> + *
> + * Processing an cmd_i2c_xfer_request::data_buf causes BPMP to execute
> + * zero or more I2C reads. The data read from the bus is serialized
> + * into #data_buf.
> + */
> +struct cmd_i2c_xfer_response {
> +	/** @brief count of valid bytes in #data_buf*/
> +	uint32_t data_size;
> +	/** @brief i2c read data */
> +	uint8_t data_buf[TEGRA_I2C_IPC_MAX_OUT_BUF_SIZE];
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup I2C
> + * @brief request with #MRQ_I2C
> + */
> +struct mrq_i2c_request {
> +	/** @brief always CMD_I2C_XFER (i.e. 1) */
> +	uint32_t cmd;
> +	/** @brief parameters of the transfer request */
> +	struct cmd_i2c_xfer_request xfer;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup I2C
> + * @brief response to #MRQ_I2C
> + */
> +struct mrq_i2c_response {
> +	struct cmd_i2c_xfer_response xfer;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_CLK
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_clk_request
> + * * Response Payload: @ref mrq_clk_response
> + * @addtogroup Clocks
> + * @{
> + */
> +
> +/**
> + * @name MRQ_CLK sub-commands
> + * @{
> + */
> +enum {
> +	CMD_CLK_GET_RATE = 1,
> +	CMD_CLK_SET_RATE = 2,
> +	CMD_CLK_ROUND_RATE = 3,
> +	CMD_CLK_GET_PARENT = 4,
> +	CMD_CLK_SET_PARENT = 5,
> +	CMD_CLK_IS_ENABLED = 6,
> +	CMD_CLK_ENABLE = 7,
> +	CMD_CLK_DISABLE = 8,
> +	CMD_CLK_GET_ALL_INFO = 14,
> +	CMD_CLK_GET_MAX_CLK_ID = 15,
> +	CMD_CLK_MAX,
> +};
> +/** @} */
> +
> +#define MRQ_CLK_NAME_MAXLEN	40
> +#define MRQ_CLK_MAX_PARENTS	16
> +
> +/** @private */
> +struct cmd_clk_get_rate_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +struct cmd_clk_get_rate_response {
> +	int64_t rate;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_set_rate_request {
> +	int32_t unused;
> +	int64_t rate;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_set_rate_response {
> +	int64_t rate;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_round_rate_request {
> +	int32_t unused;
> +	int64_t rate;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_round_rate_response {
> +	int64_t rate;
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_get_parent_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +struct cmd_clk_get_parent_response {
> +	uint32_t parent_id;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_set_parent_request {
> +	uint32_t parent_id;
> +} __ABI_PACKED;
> +
> +struct cmd_clk_set_parent_response {
> +	uint32_t parent_id;
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_is_enabled_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +struct cmd_clk_is_enabled_response {
> +	int32_t state;
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_enable_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_enable_response {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_disable_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_disable_response {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_get_all_info_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +struct cmd_clk_get_all_info_response {
> +	uint32_t flags;
> +	uint32_t parent;
> +	uint32_t parents[MRQ_CLK_MAX_PARENTS];
> +	uint8_t num_parents;
> +	uint8_t name[MRQ_CLK_NAME_MAXLEN];
> +} __ABI_PACKED;
> +
> +/** @private */
> +struct cmd_clk_get_max_clk_id_request {
> +	EMPTY
> +} __ABI_PACKED;
> +
> +struct cmd_clk_get_max_clk_id_response {
> +	uint32_t max_id;
> +} __ABI_PACKED;
> +/** @} */
> +
> +/**
> + * @ingroup Clocks
> + * @brief request with #MRQ_CLK
> + *
> + * Used by the sender of an #MRQ_CLK message to control clocks. The
> + * clk_request is split into several sub-commands. Some sub-commands
> + * require no additional data. Others have a sub-command specific
> + * payload
> + *
> + * |sub-command                 |payload                |
> + * |----------------------------|-----------------------|
> + * |CMD_CLK_GET_RATE            |-                      |
> + * |CMD_CLK_SET_RATE            |clk_set_rate           |
> + * |CMD_CLK_ROUND_RATE          |clk_round_rate         |
> + * |CMD_CLK_GET_PARENT          |-                      |
> + * |CMD_CLK_SET_PARENT          |clk_set_parent         |
> + * |CMD_CLK_IS_ENABLED          |-                      |
> + * |CMD_CLK_ENABLE              |-                      |
> + * |CMD_CLK_DISABLE             |-                      |
> + * |CMD_CLK_GET_ALL_INFO        |-                      |
> + * |CMD_CLK_GET_MAX_CLK_ID      |-                      |
> + *
> + */
> +
> +struct mrq_clk_request {
> +	/** @brief sub-command and clock id concatenated to 32-bit word.
> +	 * - bits[31..24] is the sub-cmd.
> +	 * - bits[23..0] is the clock id
> +	 */
> +	uint32_t cmd_and_id;
> +
> +	union {
> +		/** @private */
> +		struct cmd_clk_get_rate_request clk_get_rate;
> +		struct cmd_clk_set_rate_request clk_set_rate;
> +		struct cmd_clk_round_rate_request clk_round_rate;
> +		/** @private */
> +		struct cmd_clk_get_parent_request clk_get_parent;
> +		struct cmd_clk_set_parent_request clk_set_parent;
> +		/** @private */
> +		struct cmd_clk_enable_request clk_enable;
> +		/** @private */
> +		struct cmd_clk_disable_request clk_disable;
> +		/** @private */
> +		struct cmd_clk_is_enabled_request clk_is_enabled;
> +		/** @private */
> +		struct cmd_clk_get_all_info_request clk_get_all_info;
> +		/** @private */
> +		struct cmd_clk_get_max_clk_id_request clk_get_max_clk_id;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup Clocks
> + * @brief response to MRQ_CLK
> + *
> + * Each sub-command supported by @ref mrq_clk_request may return
> + * sub-command-specific data. Some do and some do not as indicated in
> + * the following table
> + *
> + * |sub-command                 |payload                 |
> + * |----------------------------|------------------------|
> + * |CMD_CLK_GET_RATE            |clk_get_rate            |
> + * |CMD_CLK_SET_RATE            |clk_set_rate            |
> + * |CMD_CLK_ROUND_RATE          |clk_round_rate          |
> + * |CMD_CLK_GET_PARENT          |clk_get_parent          |
> + * |CMD_CLK_SET_PARENT          |clk_set_parent          |
> + * |CMD_CLK_IS_ENABLED          |clk_is_enabled          |
> + * |CMD_CLK_ENABLE              |-                       |
> + * |CMD_CLK_DISABLE             |-                       |
> + * |CMD_CLK_GET_ALL_INFO        |clk_get_all_info        |
> + * |CMD_CLK_GET_MAX_CLK_ID      |clk_get_max_id          |
> + *
> + */
> +
> +struct mrq_clk_response {
> +	union {
> +		struct cmd_clk_get_rate_response clk_get_rate;
> +		struct cmd_clk_set_rate_response clk_set_rate;
> +		struct cmd_clk_round_rate_response clk_round_rate;
> +		struct cmd_clk_get_parent_response clk_get_parent;
> +		struct cmd_clk_set_parent_response clk_set_parent;
> +		/** @private */
> +		struct cmd_clk_enable_response clk_enable;
> +		/** @private */
> +		struct cmd_clk_disable_response clk_disable;
> +		struct cmd_clk_is_enabled_response clk_is_enabled;
> +		struct cmd_clk_get_all_info_response clk_get_all_info;
> +		struct cmd_clk_get_max_clk_id_response clk_get_max_clk_id;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_QUERY_ABI
> + * @brief check if an MRQ is implemented
> + *
> + * * Platforms: All
> + * * Initiators: Any
> + * * Targets: Any
> + * * Request Payload: @ref mrq_query_abi_request
> + * * Response Payload: @ref mrq_query_abi_response
> + */
> +
> +/**
> + * @ingroup ABI_info
> + * @brief request with MRQ_QUERY_ABI
> + *
> + * Used by #MRQ_QUERY_ABI call to check if MRQ code #mrq is supported
> + * by the recipient.
> + */
> +struct mrq_query_abi_request {
> +	/** @brief MRQ code to query */
> +	uint32_t mrq;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup ABI_info
> + * @brief response to MRQ_QUERY_ABI
> + */
> +struct mrq_query_abi_response {
> +	/** @brief 0 if queried MRQ is supported. Else, -#BPMP_ENODEV */
> +	int32_t status;
> +} __ABI_PACKED;
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_PG_READ_STATE
> + * @brief read the power-gating state of a partition
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_pg_read_state_request
> + * * Response Payload: @ref mrq_pg_read_state_response
> + * @addtogroup Powergating
> + * @{
> + */
> +
> +/**
> + * @brief request with #MRQ_PG_READ_STATE
> + *
> + * Used by MRQ_PG_READ_STATE call to read the current state of a
> + * partition.
> + */
> +struct mrq_pg_read_state_request {
> +	/** @brief ID of partition */
> +	uint32_t partition_id;
> +} __ABI_PACKED;
> +
> +/**
> + * @brief response to MRQ_PG_READ_STATE
> + * @todo define possible errors.
> + */
> +struct mrq_pg_read_state_response {
> +	/** @brief read as don't care */
> +	uint32_t sram_state;
> +	/** @brief state of power partition
> +	 * * 0 : off
> +	 * * 1 : on
> +	 */
> +	uint32_t logic_state;
> +} __ABI_PACKED;
> +
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_PG_UPDATE_STATE
> + * @brief modify the power-gating state of a partition
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_pg_update_state_request
> + * * Response Payload: N/A
> + * @addtogroup Powergating
> + * @{
> + */
> +
> +/**
> + * @brief request with mrq_pg_update_state_request
> + *
> + * Used by #MRQ_PG_UPDATE_STATE call to request BPMP to change the
> + * state of a power partition #partition_id.
> + */
> +struct mrq_pg_update_state_request {
> +	/** @brief ID of partition */
> +	uint32_t partition_id;
> +	/** @brief secondary control of power partition
> +	 *  @details Ignored by many versions of the BPMP
> +	 *  firmware. For maximum compatibility, set the value
> +	 *  according to @logic_state
> +	 * *  0x1: power ON partition (@ref logic_state == 0x3)
> +	 * *  0x3: power OFF partition (@ref logic_state == 0x1)
> +	 */
> +	uint32_t sram_state;
> +	/** @brief controls state of power partition, legal values are
> +	 * *  0x1 : power OFF partition
> +	 * *  0x3 : power ON partition
> +	 */
> +	uint32_t logic_state;
> +	/** @brief change state of clocks of the power partition, legal values
> +	 * *  0x0 : do not change clock state
> +	 * *  0x1 : disable partition clocks (only applicable when
> +	 *          @ref logic_state == 0x1)
> +	 * *  0x3 : enable partition clocks (only applicable when
> +	 *          @ref logic_state == 0x3)
> +	 */
> +	uint32_t clock_state;
> +} __ABI_PACKED;
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_THERMAL
> + * @brief interact with BPMP thermal framework
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: Any
> + * * Request Payload: TODO
> + * * Response Payload: TODO
> + *
> + * @addtogroup Thermal
> + *
> + * The BPMP firmware includes a thermal framework. Drivers within the
> + * bpmp firmware register with the framework to provide thermal
> + * zones. Each thermal zone corresponds to an entity whose temperature
> + * can be measured. The framework also has a notion of trip points. A
> + * trip point consists of a thermal zone id, a temperature, and a
> + * callback routine. The framework invokes the callback when the zone
> + * hits the indicated temperature. The BPMP firmware uses this thermal
> + * framework interally to implement various temperature-dependent
> + * functions.
> + *
> + * Software on the CPU can use #MRQ_THERMAL (with payload @ref
> + * mrq_thermal_host_to_bpmp_request) to interact with the BPMP thermal
> + * framework. The CPU must It can query the number of supported zones,
> + * query zone temperatures, and set trip points.
> + *
> + * When a trip point set by the CPU gets crossed, BPMP firmware issues
> + * an IPC to the CPU having mrq_request::mrq = #MRQ_THERMAL and a
> + * payload of @ref mrq_thermal_bpmp_to_host_request.
> + * @{
> + */
> +enum mrq_thermal_host_to_bpmp_cmd {
> +	/**
> +	 * @brief Check whether the BPMP driver supports the specified
> +	 * request type.
> +	 *
> +	 * Host needs to supply request parameters.
> +	 *
> +	 * mrq_response::err is 0 if the specified request is
> +	 * supported and -#BPMP_ENODEV otherwise.
> +	 */
> +	CMD_THERMAL_QUERY_ABI = 0,
> +
> +	/**
> +	 * @brief Get the current temperature of the specified zone.
> +	 *
> +	 * Host needs to supply request parameters.
> +	 *
> +	 * mrq_response::err is
> +	 * *  0: Temperature query succeeded.
> +	 * *  -#BPMP_EINVAL: Invalid request parameters.
> +	 * *  -#BPMP_ENOENT: No driver registered for thermal zone..
> +	 * *  -#BPMP_EFAULT: Problem reading temperature measurement.
> +	 */
> +	CMD_THERMAL_GET_TEMP = 1,
> +
> +	/**
> +	 * @brief Enable or disable and set the lower and upper
> +	 *   thermal limits for a thermal trip point. Each zone has
> +	 *   one trip point.
> +	 *
> +	 * Host needs to supply request parameters. Once the
> +	 * temperature hits a trip point, the BPMP will send a message
> +	 * to the CPU having MRQ=MRQ_THERMAL and
> +	 * type=CMD_THERMAL_HOST_TRIP_REACHED
> +	 *
> +	 * mrq_response::err is
> +	 * *  0: Trip successfully set.
> +	 * *  -#BPMP_EINVAL: Invalid request parameters.
> +	 * *  -#BPMP_ENOENT: No driver registered for thermal zone.
> +	 * *  -#BPMP_EFAULT: Problem setting trip point.
> +	 */
> +	CMD_THERMAL_SET_TRIP = 2,
> +
> +	/**
> +	 * @brief Get the number of supported thermal zones.
> +	 *
> +	 * No request parameters required.
> +	 *
> +	 * mrq_response::err is always 0, indicating success.
> +	 */
> +	CMD_THERMAL_GET_NUM_ZONES = 3,
> +
> +	/** @brief: number of supported host-to-bpmp commands. May
> +	 * increase in future
> +	 */
> +	CMD_THERMAL_HOST_TO_BPMP_NUM
> +};
> +
> +enum mrq_thermal_bpmp_to_host_cmd {
> +	/**
> +	 * @brief Indication that the temperature for a zone has
> +	 *   exceeded the range indicated in the thermal trip point
> +	 *   for the zone.
> +	 *
> +	 * BPMP needs to supply request parameters. Host only needs to
> +	 * acknowledge.
> +	 */
> +	CMD_THERMAL_HOST_TRIP_REACHED = 100,
> +
> +	/** @brief: number of supported bpmp-to-host commands. May
> +	 * increase in future
> +	 */
> +	CMD_THERMAL_BPMP_TO_HOST_NUM
> +};
> +
> +/*
> + * Host->BPMP request data for request type CMD_THERMAL_QUERY_ABI
> + *
> + * zone: Request type for which to check existence.
> + */
> +struct cmd_thermal_query_abi_request {
> +	uint32_t type;
> +} __ABI_PACKED;
> +
> +/*
> + * Host->BPMP request data for request type CMD_THERMAL_GET_TEMP
> + *
> + * zone: Number of thermal zone.
> + */
> +struct cmd_thermal_get_temp_request {
> +	uint32_t zone;
> +} __ABI_PACKED;
> +
> +/*
> + * BPMP->Host reply data for request CMD_THERMAL_GET_TEMP
> + *
> + * error: 0 if request succeeded.
> + *	-BPMP_EINVAL if request parameters were invalid.
> + *      -BPMP_ENOENT if no driver was registered for the specified thermal zone.
> + *      -BPMP_EFAULT for other thermal zone driver errors.
> + * temp: Current temperature in millicelsius.
> + */
> +struct cmd_thermal_get_temp_response {
> +	int32_t temp;
> +} __ABI_PACKED;
> +
> +/*
> + * Host->BPMP request data for request type CMD_THERMAL_SET_TRIP
> + *
> + * zone: Number of thermal zone.
> + * low: Temperature of lower trip point in millicelsius
> + * high: Temperature of upper trip point in millicelsius
> + * enabled: 1 to enable trip point, 0 to disable trip point
> + */
> +struct cmd_thermal_set_trip_request {
> +	uint32_t zone;
> +	int32_t low;
> +	int32_t high;
> +	uint32_t enabled;
> +} __ABI_PACKED;
> +
> +/*
> + * BPMP->Host request data for request type CMD_THERMAL_HOST_TRIP_REACHED
> + *
> + * zone: Number of thermal zone where trip point was reached.
> + */
> +struct cmd_thermal_host_trip_reached_request {
> +	uint32_t zone;
> +} __ABI_PACKED;
> +
> +/*
> + * BPMP->Host reply data for request type CMD_THERMAL_GET_NUM_ZONES
> + *
> + * num: Number of supported thermal zones. The thermal zones are indexed
> + *      starting from zero.
> + */
> +struct cmd_thermal_get_num_zones_response {
> +	uint32_t num;
> +} __ABI_PACKED;
> +
> +/*
> + * Host->BPMP request data.
> + *
> + * Reply type is union mrq_thermal_bpmp_to_host_response.
> + *
> + * type: Type of request. Values listed in enum mrq_thermal_type.
> + * data: Request type specific parameters.
> + */
> +struct mrq_thermal_host_to_bpmp_request {
> +	uint32_t type;
> +	union {
> +		struct cmd_thermal_query_abi_request query_abi;
> +		struct cmd_thermal_get_temp_request get_temp;
> +		struct cmd_thermal_set_trip_request set_trip;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/*
> + * BPMP->Host request data.
> + *
> + * type: Type of request. Values listed in enum mrq_thermal_type.
> + * data: Request type specific parameters.
> + */
> +struct mrq_thermal_bpmp_to_host_request {
> +	uint32_t type;
> +	union {
> +		struct cmd_thermal_host_trip_reached_request host_trip_reached;
> +	} __UNION_ANON;
> +} __ABI_PACKED;
> +
> +/*
> + * Data in reply to a Host->BPMP request.
> + */
> +union mrq_thermal_bpmp_to_host_response {
> +	struct cmd_thermal_get_temp_response get_temp;
> +	struct cmd_thermal_get_num_zones_response get_num_zones;
> +} __ABI_PACKED;
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_CPU_VHINT
> + * @brief Query CPU voltage hint data
> + *
> + * * Platforms: T186
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_cpu_vhint_request
> + * * Response Payload: N/A
> + *
> + * @addtogroup Vhint CPU Voltage hint
> + * @{
> + */
> +
> +/**
> + * @brief request with #MRQ_CPU_VHINT
> + *
> + * Used by #MRQ_CPU_VHINT call by CCPLEX to retrieve voltage hint data
> + * from BPMP to memory space pointed by #addr. CCPLEX is responsible
> + * to allocate sizeof(cpu_vhint_data) sized block of memory and
> + * appropriately map it for BPMP before sending the request.
> + */
> +struct mrq_cpu_vhint_request {
> +	/** @brief IOVA address for the #cpu_vhint_data */
> +	uint32_t addr; /* struct cpu_vhint_data * */
> +	/** @brief ID of the cluster whose data is requested */
> +	uint32_t cluster_id; /* enum cluster_id */
> +} __ABI_PACKED;
> +
> +/**
> + * @brief description of the CPU v/f relation
> + *
> + * Used by #MRQ_CPU_VHINT call to carry data pointed by #addr of
> + * struct mrq_cpu_vhint_request
> + */
> +struct cpu_vhint_data {
> +	uint32_t ref_clk_hz; /**< reference frequency in Hz */
> +	uint16_t pdiv; /**< post divider value */
> +	uint16_t mdiv; /**< input divider value */
> +	uint16_t ndiv_max; /**< fMAX expressed with max NDIV value */
> +	/** table of ndiv values as a function of vINDEX (voltage index) */
> +	uint16_t ndiv[80];
> +	/** minimum allowed NDIV value */
> +	uint16_t ndiv_min;
> +	/** minimum allowed voltage hint value (as in vINDEX) */
> +	uint16_t vfloor;
> +	/** maximum allowed voltage hint value (as in vINDEX) */
> +	uint16_t vceil;
> +	/** post-multiplier for vindex value */
> +	uint16_t vindex_mult;
> +	/** post-divider for vindex value */
> +	uint16_t vindex_div;
> +	/** reserved for future use */
> +	uint16_t reserved[328];
> +} __ABI_PACKED;
> +
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_ABI_RATCHET
> + * @brief ABI ratchet value query
> + *
> + * * Platforms: T186
> + * * Initiators: Any
> + * * Targets: BPMP
> + * * Request Payload: @ref mrq_abi_ratchet_request
> + * * Response Payload: @ref mrq_abi_ratchet_response
> + * @addtogroup ABI_info
> + * @{
> + */
> +
> +/**
> + * @brief an ABI compatibility mechanism
> + *
> + * BPMP_ABI_RATCHET_VALUE may increase for various reasons in a future
> + * revision of this header file.
> + * 1. That future revision deprecates some MRQ
> + * 2. That future revision introduces a breaking change to an existing
> + *    MRQ or
> + * 3. A bug is discovered in an existing implementation of the BPMP-FW
> + *    (or possibly one of its clients) which warrants deprecating that
> + *    implementation.
> + */
> +#define BPMP_ABI_RATCHET_VALUE 3
> +
> +/**
> + * @brief request with #MRQ_ABI_RATCHET.
> + *
> + * #ratchet should be #BPMP_ABI_RATCHET_VALUE from the ABI header
> + * against which the requester was compiled.
> + *
> + * If ratchet is less than BPMP's #BPMP_ABI_RATCHET_VALUE, BPMP may
> + * reply with mrq_response::err = -#BPMP_ERANGE to indicate that
> + * BPMP-FW cannot interoperate correctly with the requester. Requester
> + * should cease further communication with BPMP.
> + *
> + * Otherwise, err shall be 0.
> + */
> +struct mrq_abi_ratchet_request {
> +	/** @brief requester's ratchet value */
> +	uint16_t ratchet;
> +};
> +
> +/**
> + * @brief response to #MRQ_ABI_RATCHET
> + *
> + * #ratchet shall be #BPMP_ABI_RATCHET_VALUE from the ABI header
> + * against which BPMP firwmare was compiled.
> + *
> + * If #ratchet is less than the requester's #BPMP_ABI_RATCHET_VALUE,
> + * the requster must either interoperate with BPMP according to an ABI
> + * header version with BPMP_ABI_RATCHET_VALUE = ratchet or cease
> + * communication with BPMP.
> + *
> + * If mrq_response::err is 0 and ratchet is greater than or equal to the
> + * requester's BPMP_ABI_RATCHET_VALUE, the requester should continue
> + * normal operation.
> + */
> +struct mrq_abi_ratchet_response {
> +	/** @brief BPMP's ratchet value */
> +	uint16_t ratchet;
> +};
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_EMC_DVFS_LATENCY
> + * @brief query frequency dependent EMC DVFS latency
> + *
> + * * Platforms: T186
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: N/A
> + * * Response Payload: @ref mrq_emc_dvfs_latency_response
> + * @addtogroup EMC
> + * @{
> + */
> +
> +/**
> + * @brief used by @ref mrq_emc_dvfs_latency_response
> + */
> +struct emc_dvfs_latency {
> +	/** @brief EMC frequency in kHz */
> +	uint32_t freq;
> +	/** @brief EMC DVFS latency in nanoseconds */
> +	uint32_t latency;
> +} __ABI_PACKED;
> +
> +#define EMC_DVFS_LATENCY_MAX_SIZE	14
> +/**
> + * @brief response to #MRQ_EMC_DVFS_LATENCY
> + */
> +struct mrq_emc_dvfs_latency_response {
> +	/** @brief the number valid entries in #pairs */
> +	uint32_t num_pairs;
> +	/** @brief EMC <frequency, latency> information */
> +	struct emc_dvfs_latency pairs[EMC_DVFS_LATENCY_MAX_SIZE];
> +} __ABI_PACKED;
> +
> +/** @} */
> +
> +/**
> + * @ingroup MRQ_Codes
> + * @def MRQ_TRACE_ITER
> + * @brief manage the trace iterator
> + *
> + * * Platforms: All
> + * * Initiators: CCPLEX
> + * * Targets: BPMP
> + * * Request Payload: N/A
> + * * Response Payload: @ref mrq_trace_iter_request
> + * @addtogroup Trace
> + * @{
> + */
> +enum {
> +	/** @brief (re)start the tracing now. Ignore older events */
> +	TRACE_ITER_INIT = 0,
> +	/** @brief clobber all events in the trace buffer */
> +	TRACE_ITER_CLEAN = 1
> +};
> +
> +/**
> + * @brief request with #MRQ_TRACE_ITER
> + */
> +struct mrq_trace_iter_request {
> +	/** @brief TRACE_ITER_INIT or TRACE_ITER_CLEAN */
> +	uint32_t cmd;
> +} __ABI_PACKED;
> +
> +/** @} */
> +
> +/*
> + *  4. Enumerations
> + */
> +
> +/*
> + *   4.1 CPU enumerations
> + *
> + * See <mach-t186/system-t186.h>
> + *
> + *   4.2 CPU Cluster enumerations
> + *
> + * See <mach-t186/system-t186.h>
> + *
> + *   4.3 System low power state enumerations
> + *
> + * See <mach-t186/system-t186.h>
> + */
> +
> +/*
> + *   4.4 Clock enumerations
> + *
> + * For clock enumerations, see <mach-t186/clk-t186.h>
> + */
> +
> +/*
> + *   4.5 Reset enumerations
> + *
> + * For reset enumerations, see <mach-t186/reset-t186.h>
> + */
> +
> +/*
> + *   4.6 Thermal sensor enumerations
> + *
> + * For thermal sensor enumerations, see <mach-t186/thermal-t186.h>
> + */
> +
> +/**
> + * @defgroup Error_Codes
> + * Negative values for mrq_response::err generally indicate some
> + * error. The ABI defines the following error codes. Negating these
> + * defines is an exercise left to the user.
> + * @{
> + */
> +/** @brief No such file or directory */
> +#define BPMP_ENOENT	2
> +/** @brief No MRQ handler */
> +#define BPMP_ENOHANDLER	3
> +/** @brief I/O error */
> +#define BPMP_EIO	5
> +/** @brief Bad sub-MRQ command */
> +#define BPMP_EBADCMD	6
> +/** @brief Not enough memory */
> +#define BPMP_ENOMEM	12
> +/** @brief Permission denied */
> +#define BPMP_EACCES	13
> +/** @brief Bad address */
> +#define BPMP_EFAULT	14
> +/** @brief No such device */
> +#define BPMP_ENODEV	19
> +/** @brief Argument is a directory */
> +#define BPMP_EISDIR	21
> +/** @brief Invalid argument */
> +#define BPMP_EINVAL	22
> +/** @brief Timeout during operation */
> +#define BPMP_ETIMEDOUT  23
> +/** @brief Out of range */
> +#define BPMP_ERANGE	34
> +/** @} */
> +/** @} */
> +#endif
> -- 
> 2.9.0
> 
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