Subject: Re: [PATCH 5/7] remoteproc/k3-r5: Add a remoteproc driver for R5F subsystem

From: Mathieu Poirier <[email-masked]>
Date: Thu, 9 Apr 2020 15:25:01 -0600

On Tue, Mar 24, 2020 at 03:18:17PM -0500, Suman Anna wrote:
> The TI K3 family of SoCs typically have one or more dual-core Arm Cortex
> R5F processor clusters/subsystems (R5FSS). This R5F subsystem/cluster
> can be configured at boot time to be either run in a LockStep mode or in
> an Asymmetric Multi Processing (AMP) fashion in Split-mode. This subsystem
> has 64 KB each Tightly-Coupled Memory (TCM) internal memories for each
> core split between two banks - TCMA and TCMB (further interleaved into
> two banks). The subsystem does not have an MMU, but has a Region Address
> Translater (RAT) module that is accessible only from the R5Fs for providing
> translations between 32-bit CPU addresses into larger system bus addresses.
> 
> Add a remoteproc driver to support this subsystem to be able to load and
> boot the R5F cores primarily in LockStep mode. The code also includes the
> base support for Split mode. Error Recovery and Power Management features
> are not currently supported. Loading support includes the internal TCMs
> and DDR. RAT support is left for a future patch, and as such the reserved
> memory carveout regions are all expected to be using memory regions within
> the first 2 GB.
> 
> The R5F remote processors do not have an MMU, and so require fixed memory
> carveout regions matching the firmware image addresses. Support for this
> is provided by mandating multiple memory regions to be attached to the
> remoteproc device. The first memory region will be used to serve as the
> DMA pool for all dynamic allocations like the vrings and vring buffers.
> The remaining memory regions are mapped into the kernel at device probe
> time, and are used to provide address translations for firmware image
> segments without the need for any RSC_CARVEOUT entries. Any firmware
> image using memory outside of the supplied reserved memory carveout
> regions will be errored out.
> 
> The R5F processors on TI K3 SoCs require a specific sequence for booting
> and shutting down the processors. This sequence is also dependent on the
> mode (LockStep or Split) the R5F cluster is configured for. The R5F cores
> have a Memory Protection Unit (MPU) that has a default configuration that
> does not allow the cores to run out of DDR out of reset. This is resolved
> by using the TCMs for boot-strapping code that applies the appropriate
> executable permissions on desired DDR memory. The loading into the TCMs
> requires that the resets be released first with the cores in halted state.
> The Power Sleep Controller (PSC) module on K3 SoCs requires that the cores
> be in WFI/WFE states with no active bus transactions before the cores can
> be put back into reset. Support for this is provided by using the newly
> introduced .prepare() and .unprepare() ops in the remoteproc core. The
> .prepare() ops is invoked before any loading, and the .unprepare() ops
> is invoked after the remoteproc resource cleanup. The R5F core resets
> are deasserted in .prepare() and asserted in .unprepare(), and the cores
> themselves are started and halted in .start() and .stop() ops. This
> ensures symmetric usage and allows the R5F cores state machine to be
> maintained properly between using the sysfs 'state' variable, bind/unbind
> and regular module load/unload flows.
> 
> The subsystem is represented as a single remoteproc in LockStep mode, and
> as two remoteprocs in Split mode. The driver uses various TI-SCI interfaces
> to talk to the System Controller (DMSC) for managing configuration, power
> and reset management of these cores. IPC between the A53 cores and the R5
> cores is supported through the virtio rpmsg stack using shared memory and
> OMAP Mailboxes.
> 
> The AM65x SoCs typically have a single R5FSS in the MCU voltage domain. The
> J721E SoCs uses a slightly revised IP and typically have three R5FSSs, with
> one cluster present within the MCU voltage domain (MCU_R5FSS0), and the
> remaining two clusters present in the MAIN voltage domain (MAIN_R5FSS0 and
> MAIN_R5FSS1). The integration of these clusters on J721E SoC is also
> slightly different in that these IPs do support an actual local reset line,
> while they are a no-op on AM65x SoCs.
> 
> Signed-off-by: Suman Anna <[email-masked]>
> ---
>  drivers/remoteproc/Kconfig               |   16 +
>  drivers/remoteproc/Makefile              |    1 +
>  drivers/remoteproc/ti_k3_r5_remoteproc.c | 1346 ++++++++++++++++++++++
>  3 files changed, 1363 insertions(+)
>  create mode 100644 drivers/remoteproc/ti_k3_r5_remoteproc.c
> 
> diff --git a/drivers/remoteproc/Kconfig b/drivers/remoteproc/Kconfig
> index de3862c15fcc..073048b4c0fb 100644
> --- a/drivers/remoteproc/Kconfig
> +++ b/drivers/remoteproc/Kconfig
> @@ -224,6 +224,22 @@ config STM32_RPROC
>  
>  	  This can be either built-in or a loadable module.
>  
> +config TI_K3_R5_REMOTEPROC
> +	tristate "TI K3 R5 remoteproc support"
> +	depends on ARCH_K3
> +	select MAILBOX
> +	select OMAP2PLUS_MBOX
> +	help
> +	  Say y here to support TI's R5F remote processor subsystems
> +	  on various TI K3 family of SoCs through the remote processor
> +	  framework.
> +
> +	  You want to say y here in order to offload some processing
> +	  tasks to these processors
> +
> +	  It's safe to say N here if you're not interested in utilizing
> +	  a slave processor
> +
>  endif # REMOTEPROC
>  
>  endmenu
> diff --git a/drivers/remoteproc/Makefile b/drivers/remoteproc/Makefile
> index e30a1b15fbac..00ba826818af 100644
> --- a/drivers/remoteproc/Makefile
> +++ b/drivers/remoteproc/Makefile
> @@ -28,3 +28,4 @@ qcom_wcnss_pil-y			+= qcom_wcnss_iris.o
>  obj-$(CONFIG_ST_REMOTEPROC)		+= st_remoteproc.o
>  obj-$(CONFIG_ST_SLIM_REMOTEPROC)	+= st_slim_rproc.o
>  obj-$(CONFIG_STM32_RPROC)		+= stm32_rproc.o
> +obj-$(CONFIG_TI_K3_R5_REMOTEPROC)	+= ti_k3_r5_remoteproc.o
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> new file mode 100644
> index 000000000000..655f8f14c37d
> --- /dev/null
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -0,0 +1,1346 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * TI K3 R5F (MCU) Remote Processor driver
> + *
> + * Copyright (C) 2017-2020 Texas Instruments Incorporated - http://www.ti.com/
> + *	Suman Anna <[email-masked]>
> + */
> +
> +#include <linux/dma-mapping.h>
> +#include <linux/err.h>
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mailbox_client.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/of_address.h>
> +#include <linux/of_reserved_mem.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/remoteproc.h>
> +#include <linux/omap-mailbox.h>
> +#include <linux/reset.h>
> +#include <linux/soc/ti/ti_sci_protocol.h>
> +
> +#include "omap_remoteproc.h"
> +#include "remoteproc_internal.h"
> +#include "ti_sci_proc.h"
> +
> +/* This address can either be for ATCM or BTCM with the other at address 0x0 */
> +#define K3_R5_TCM_DEV_ADDR	0x41010000
> +
> +/* R5 TI-SCI Processor Configuration Flags */
> +#define PROC_BOOT_CFG_FLAG_R5_DBG_EN			0x00000001
> +#define PROC_BOOT_CFG_FLAG_R5_DBG_NIDEN			0x00000002
> +#define PROC_BOOT_CFG_FLAG_R5_LOCKSTEP			0x00000100
> +#define PROC_BOOT_CFG_FLAG_R5_TEINIT			0x00000200
> +#define PROC_BOOT_CFG_FLAG_R5_NMFI_EN			0x00000400
> +#define PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE		0x00000800
> +#define PROC_BOOT_CFG_FLAG_R5_BTCM_EN			0x00001000
> +#define PROC_BOOT_CFG_FLAG_R5_ATCM_EN			0x00002000
> +
> +/* R5 TI-SCI Processor Control Flags */
> +#define PROC_BOOT_CTRL_FLAG_R5_CORE_HALT		0x00000001
> +
> +/* R5 TI-SCI Processor Status Flags */
> +#define PROC_BOOT_STATUS_FLAG_R5_WFE			0x00000001
> +#define PROC_BOOT_STATUS_FLAG_R5_WFI			0x00000002
> +#define PROC_BOOT_STATUS_FLAG_R5_CLK_GATED		0x00000004
> +#define PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED	0x00000100
> +
> +/**
> + * struct k3_r5_mem - internal memory structure
> + * @cpu_addr: MPU virtual address of the memory region
> + * @bus_addr: Bus address used to access the memory region
> + * @dev_addr: Device address from remoteproc view
> + * @size: Size of the memory region
> + */
> +struct k3_r5_mem {
> +	void __iomem *cpu_addr;
> +	phys_addr_t bus_addr;
> +	u32 dev_addr;
> +	size_t size;
> +};
> +
> +enum cluster_mode {
> +	CLUSTER_MODE_SPLIT = 0,
> +	CLUSTER_MODE_LOCKSTEP,
> +};
> +
> +/**
> + * struct k3_r5_cluster - K3 R5F Cluster structure
> + * @dev: cached device pointer
> + * @mode: Mode to configure the Cluster - Split or LockStep
> + * @cores: list of R5 cores within the cluster
> + */
> +struct k3_r5_cluster {
> +	struct device *dev;
> +	enum cluster_mode mode;
> +	struct list_head cores;
> +};
> +
> +/**
> + * struct k3_r5_core - K3 R5 core structure
> + * @elem: linked list item
> + * @dev: cached device pointer
> + * @rproc: rproc handle representing this core
> + * @mem: internal memory regions data
> + * @num_mems: number of internal memory regions
> + * @reset: reset control handle
> + * @tsp: TI-SCI processor control handle
> + * @ti_sci: TI-SCI handle
> + * @ti_sci_id: TI-SCI device identifier
> + * @atcm_enable: flag to control ATCM enablement
> + * @btcm_enable: flag to control BTCM enablement
> + * @loczrama: flag to dictate which TCM is at device address 0x0
> + */
> +struct k3_r5_core {
> +	struct list_head elem;
> +	struct device *dev;
> +	struct rproc *rproc;
> +	struct k3_r5_mem *mem;
> +	int num_mems;
> +	struct reset_control *reset;
> +	struct ti_sci_proc *tsp;
> +	const struct ti_sci_handle *ti_sci;
> +	u32 ti_sci_id;
> +	u32 atcm_enable;
> +	u32 btcm_enable;
> +	u32 loczrama;
> +};
> +
> +/**
> + * struct k3_r5_rproc - K3 remote processor state
> + * @dev: cached device pointer
> + * @cluster: cached pointer to parent cluster structure
> + * @mbox: mailbox channel handle
> + * @client: mailbox client to request the mailbox channel
> + * @rproc: rproc handle
> + * @core: cached pointer to r5 core structure being used
> + * @rmem: reserved memory regions data
> + * @num_rmems: number of reserved memory regions
> + */
> +struct k3_r5_rproc {
> +	struct device *dev;
> +	struct k3_r5_cluster *cluster;
> +	struct mbox_chan *mbox;
> +	struct mbox_client client;
> +	struct rproc *rproc;
> +	struct k3_r5_core *core;
> +	struct k3_r5_mem *rmem;
> +	int num_rmems;
> +};
> +
> +/**
> + * k3_r5_rproc_mbox_callback() - inbound mailbox message handler
> + * @client: mailbox client pointer used for requesting the mailbox channel
> + * @data: mailbox payload
> + *
> + * This handler is invoked by the OMAP mailbox driver whenever a mailbox
> + * message is received. Usually, the mailbox payload simply contains
> + * the index of the virtqueue that is kicked by the remote processor,
> + * and we let remoteproc core handle it.
> + *
> + * In addition to virtqueue indices, we also have some out-of-band values
> + * that indicate different events. Those values are deliberately very
> + * large so they don't coincide with virtqueue indices.
> + */
> +static void k3_r5_rproc_mbox_callback(struct mbox_client *client, void *data)
> +{
> +	struct k3_r5_rproc *kproc = container_of(client, struct k3_r5_rproc,
> +						client);
> +	struct device *dev = kproc->rproc->dev.parent;
> +	const char *name = kproc->rproc->name;
> +	u32 msg = omap_mbox_message(data);
> +
> +	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
> +
> +	switch (msg) {
> +	case RP_MBOX_CRASH:
> +		/*
> +		 * remoteproc detected an exception, but error recovery is not
> +		 * supported. So, just log this for now
> +		 */
> +		dev_err(dev, "K3 R5F rproc %s crashed\n", name);
> +		break;
> +	case RP_MBOX_ECHO_REPLY:
> +		dev_info(dev, "received echo reply from %s\n", name);
> +		break;
> +	default:
> +		/* silently handle all other valid messages */
> +		if (msg >= RP_MBOX_READY && msg < RP_MBOX_END_MSG)
> +			return;
> +		if (msg > kproc->rproc->max_notifyid) {
> +			dev_dbg(dev, "dropping unknown message 0x%x", msg);
> +			return;
> +		}
> +		/* msg contains the index of the triggered vring */
> +		if (rproc_vq_interrupt(kproc->rproc, msg) == IRQ_NONE)
> +			dev_dbg(dev, "no message was found in vqid %d\n", msg);
> +	}
> +}
> +
> +/* kick a virtqueue */
> +static void k3_r5_rproc_kick(struct rproc *rproc, int vqid)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct device *dev = rproc->dev.parent;
> +	mbox_msg_t msg = (mbox_msg_t)vqid;
> +	int ret;
> +
> +	/* send the index of the triggered virtqueue in the mailbox payload */
> +	ret = mbox_send_message(kproc->mbox, (void *)msg);
> +	if (ret < 0)
> +		dev_err(dev, "failed to send mailbox message, status = %d\n",
> +			ret);
> +}
> +
> +static int k3_r5_split_reset(struct k3_r5_core *core)
> +{
> +	int ret;
> +
> +	ret = reset_control_assert(core->reset);
> +	if (ret) {
> +		dev_err(core->dev, "local-reset assert failed, ret = %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	ret = core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> +						   core->ti_sci_id);
> +	if (ret) {
> +		dev_err(core->dev, "module-reset assert failed, ret = %d\n",
> +			ret);
> +		if (reset_control_deassert(core->reset))
> +			dev_warn(core->dev, "local-reset deassert back failed\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static int k3_r5_split_release(struct k3_r5_core *core)
> +{
> +	int ret;
> +
> +	ret = core->ti_sci->ops.dev_ops.get_device(core->ti_sci,
> +						   core->ti_sci_id);
> +	if (ret) {
> +		dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	ret = reset_control_deassert(core->reset);
> +	if (ret) {
> +		dev_err(core->dev, "local-reset deassert failed, ret = %d\n",
> +			ret);
> +		if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> +							 core->ti_sci_id))
> +			dev_warn(core->dev, "module-reset assert back failed\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static int k3_r5_lockstep_reset(struct k3_r5_cluster *cluster)
> +{
> +	struct k3_r5_core *core;
> +	int ret;
> +
> +	/* assert local reset on all applicable cores */
> +	list_for_each_entry(core, &cluster->cores, elem) {
> +		ret = reset_control_assert(core->reset);
> +		if (ret) {
> +			dev_err(core->dev, "local-reset assert failed, ret = %d\n",
> +				ret);
> +			core = list_prev_entry(core, elem);
> +			goto unroll_local_reset;
> +		}
> +	}
> +
> +	/* disable PSC modules on all applicable cores */
> +	list_for_each_entry(core, &cluster->cores, elem) {
> +		ret = core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> +							   core->ti_sci_id);
> +		if (ret) {
> +			dev_err(core->dev, "module-reset assert failed, ret = %d\n",
> +				ret);
> +			goto unroll_module_reset;
> +		}
> +	}
> +
> +	return 0;
> +
> +unroll_module_reset:
> +	list_for_each_entry_continue_reverse(core, &cluster->cores, elem) {
> +		if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> +							 core->ti_sci_id))
> +			dev_warn(core->dev, "module-reset assert back failed\n");
> +	}
> +	core = list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> +unroll_local_reset:
> +	list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> +		if (reset_control_deassert(core->reset))
> +			dev_warn(core->dev, "local-reset deassert back failed\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static int k3_r5_lockstep_release(struct k3_r5_cluster *cluster)
> +{
> +	struct k3_r5_core *core;
> +	int ret;
> +
> +	/* enable PSC modules on all applicable cores */
> +	list_for_each_entry_reverse(core, &cluster->cores, elem) {

Out of curiosity, any HW specific reason to start with the last core?

> +		ret = core->ti_sci->ops.dev_ops.get_device(core->ti_sci,
> +							   core->ti_sci_id);
> +		if (ret) {
> +			dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> +				ret);
> +			core = list_next_entry(core, elem);
> +			goto unroll_module_reset;
> +		}
> +	}
> +
> +	/* deassert local reset on all applicable cores */
> +	list_for_each_entry_reverse(core, &cluster->cores, elem) {
> +		ret = reset_control_deassert(core->reset);
> +		if (ret) {
> +			dev_err(core->dev, "module-reset deassert failed, ret = %d\n",
> +				ret);
> +			goto unroll_local_reset;
> +		}
> +	}
> +
> +	return 0;
> +
> +unroll_local_reset:
> +	list_for_each_entry_continue(core, &cluster->cores, elem) {
> +		if (reset_control_assert(core->reset))
> +			dev_warn(core->dev, "local-reset assert back failed\n");
> +	}
> +	core = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> +unroll_module_reset:
> +	list_for_each_entry_from(core, &cluster->cores, elem) {
> +		if (core->ti_sci->ops.dev_ops.put_device(core->ti_sci,
> +							 core->ti_sci_id))
> +			dev_warn(core->dev, "module-reset assert back failed\n");
> +	}
> +
> +	return ret;
> +}
> +
> +static inline int k3_r5_core_halt(struct k3_r5_core *core)
> +{
> +	return ti_sci_proc_set_control(core->tsp,
> +				       PROC_BOOT_CTRL_FLAG_R5_CORE_HALT, 0);
> +}
> +
> +static inline int k3_r5_core_run(struct k3_r5_core *core)
> +{
> +	return ti_sci_proc_set_control(core->tsp,
> +				       0, PROC_BOOT_CTRL_FLAG_R5_CORE_HALT);
> +}
> +
> +/*
> + * The R5F cores have controls for both a reset and a halt/run. The code
> + * execution from DDR requires the initial boot-strapping code to be run
> + * from the internal TCMs. This function is used to release the resets on
> + * applicable cores to allow loading into the TCMs. The .prepare() ops is
> + * invoked by remoteproc core before any firmware loading, and is followed
> + * by the .start() ops after loading to actually let the R5 cores run.
> + */
> +static int k3_r5_rproc_prepare(struct rproc *rproc)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct k3_r5_core *core = kproc->core;
> +	struct device *dev = kproc->dev;
> +	int ret;
> +
> +	ret = cluster->mode ? k3_r5_lockstep_release(cluster) :
> +			      k3_r5_split_release(core);
> +	if (ret)
> +		dev_err(dev, "unable to enable cores for TCM loading, ret = %d\n",
> +			ret);
> +
> +	return ret;
> +}
> +
> +/*
> + * This function implements the .unprepare() ops and performs the complimentary
> + * operations to that of the .prepare() ops. The function is used to assert the
> + * resets on all applicable cores for the rproc device (depending on LockStep
> + * or Split mode). This completes the second portion of powering down the R5F
> + * cores. The cores themselves are only halted in the .stop() ops, and the
> + * .unprepare() ops is invoked by the remoteproc core after the remoteproc is
> + * stopped.
> + */
> +static int k3_r5_rproc_unprepare(struct rproc *rproc)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct k3_r5_core *core = kproc->core;
> +	struct device *dev = kproc->dev;
> +	int ret;
> +
> +	ret = cluster->mode ? k3_r5_lockstep_reset(cluster) :
> +			      k3_r5_split_reset(core);
> +	if (ret)
> +		dev_err(dev, "unable to disable cores, ret = %d\n", ret);
> +
> +	return ret;
> +}
> +
> +/*
> + * The R5F start sequence includes two different operations
> + * 1. Configure the boot vector for R5F core(s)
> + * 2. Unhalt/Run the R5F core(s)
> + *
> + * The sequence is different between LockStep and Split modes. The LockStep
> + * mode requires the boot vector to be configured only for Core0, and then
> + * unhalt both the cores to start the execution - Core1 needs to be unhalted
> + * first followed by Core0. The Split-mode requires that Core0 to be maintained
> + * always in a higher power state that Core1 (implying Core1 needs to be started
> + * always only after Core0 is started).
> + */
> +static int k3_r5_rproc_start(struct rproc *rproc)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct mbox_client *client = &kproc->client;
> +	struct device *dev = kproc->dev;
> +	struct k3_r5_core *core;
> +	u32 boot_addr;
> +	int ret;
> +
> +	client->dev = dev;
> +	client->tx_done = NULL;
> +	client->rx_callback = k3_r5_rproc_mbox_callback;
> +	client->tx_block = false;
> +	client->knows_txdone = false;
> +
> +	kproc->mbox = mbox_request_channel(client, 0);
> +	if (IS_ERR(kproc->mbox)) {
> +		ret = -EBUSY;
> +		dev_err(dev, "mbox_request_channel failed: %ld\n",
> +			PTR_ERR(kproc->mbox));
> +		return ret;
> +	}

Does this needs to be done every time a remote processor is booted or could it
be done just once in k3_r5_core_of_init()?

> +
> +	/*
> +	 * Ping the remote processor, this is only for sanity-sake for now;
> +	 * there is no functional effect whatsoever.
> +	 *
> +	 * Note that the reply will _not_ arrive immediately: this message
> +	 * will wait in the mailbox fifo until the remote processor is booted.
> +	 */
> +	ret = mbox_send_message(kproc->mbox, (void *)RP_MBOX_ECHO_REQUEST);
> +	if (ret < 0) {
> +		dev_err(dev, "mbox_send_message failed: %d\n", ret);
> +		goto put_mbox;
> +	}
> +
> +	boot_addr = rproc->bootaddr;
> +	/* TODO: add boot_addr sanity checking */
> +	dev_err(dev, "booting R5F core using boot addr = 0x%x\n", boot_addr);

s/dev_err()/dev_dbg()

> +
> +	/* boot vector need not be programmed for Core1 in LockStep mode */
> +	core = kproc->core;
> +	ret = ti_sci_proc_set_config(core->tsp, boot_addr, 0, 0);
> +	if (ret)
> +		goto put_mbox;
> +
> +	/* unhalt/run all applicable cores */
> +	if (cluster->mode) {
> +		list_for_each_entry_reverse(core, &cluster->cores, elem) {
> +			ret = k3_r5_core_run(core);
> +			if (ret)
> +				goto unroll_core_run;
> +		}
> +	} else {
> +		ret = k3_r5_core_run(core);
> +		if (ret)
> +			goto put_mbox;
> +	}
> +
> +	return 0;
> +
> +unroll_core_run:
> +	list_for_each_entry_continue(core, &cluster->cores, elem) {
> +		if (k3_r5_core_halt(core))
> +			dev_warn(core->dev, "core halt back failed\n");
> +	}
> +put_mbox:
> +	mbox_free_channel(kproc->mbox);
> +	return ret;
> +}
> +
> +/*
> + * The R5F stop function includes the following operations
> + * 1. Halt R5F core(s)
> + *
> + * The sequence is different between LockStep and Split modes, and the order
> + * of cores the operations are performed are also in general reverse to that
> + * of the start function. The LockStep mode requires each operation to be
> + * performed first on Core0 followed by Core1. The Split-mode requires that
> + * Core0 to be maintained always in a higher power state that Core1 (implying
> + * Core1 needs to be stopped first before Core0).
> + *
> + * Note that the R5F halt operation in general is not effective when the R5F
> + * core is running, but is needed to make sure the core won't run after
> + * deasserting the reset the subsequent time. The asserting of reset can
> + * be done here, but is preferred to be done in the .unprepare() ops - this
> + * maintains the symmetric behavior between the .start(), .stop(), .prepare()
> + * and .unprepare() ops, and also balances them well between sysfs 'state'
> + * flow and device bind/unbind or module removal.
> + */
> +static int k3_r5_rproc_stop(struct rproc *rproc)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct k3_r5_core *core = kproc->core;
> +	int ret;
> +
> +	/* halt all applicable cores */
> +	if (cluster->mode) {
> +		list_for_each_entry(core, &cluster->cores, elem) {
> +			ret = k3_r5_core_halt(core);
> +			if (ret) {
> +				core = list_prev_entry(core, elem);
> +				goto unroll_core_halt;
> +			}
> +		}
> +	} else {
> +		ret = k3_r5_core_halt(core);
> +		if (ret)
> +			goto out;
> +	}
> +
> +	mbox_free_channel(kproc->mbox);
> +
> +	return 0;
> +
> +unroll_core_halt:
> +	list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> +		if (k3_r5_core_run(core))
> +			dev_warn(core->dev, "core run back failed\n");
> +	}
> +out:
> +	return ret;
> +}
> +
> +/*
> + * Internal Memory translation helper
> + *
> + * Custom function implementing the rproc .da_to_va ops to provide address
> + * translation (device address to kernel virtual address) for internal RAMs
> + * present in a DSP or IPU device). The translated addresses can be used
> + * either by the remoteproc core for loading, or by any rpmsg bus drivers.
> + */
> +static void *k3_r5_rproc_da_to_va(struct rproc *rproc, u64 da, size_t len)
> +{
> +	struct k3_r5_rproc *kproc = rproc->priv;
> +	struct k3_r5_core *core = kproc->core;
> +	void __iomem *va = NULL;
> +	phys_addr_t bus_addr;
> +	u32 dev_addr, offset;
> +	size_t size;
> +	int i;
> +
> +	if (len == 0)
> +		return NULL;
> +
> +	/* handle both R5 and SoC views of ATCM and BTCM */
> +	for (i = 0; i < core->num_mems; i++) {
> +		bus_addr = core->mem[i].bus_addr;
> +		dev_addr = core->mem[i].dev_addr;
> +		size = core->mem[i].size;
> +
> +		/* handle R5-view addresses of TCMs */
> +		if (da >= dev_addr && ((da + len) <= (dev_addr + size))) {
> +			offset = da - dev_addr;
> +			va = core->mem[i].cpu_addr + offset;
> +			return (__force void *)va;
> +		}
> +
> +		/* handle SoC-view addresses of TCMs */
> +		if (da >= bus_addr && ((da + len) <= (bus_addr + size))) {
> +			offset = da - bus_addr;
> +			va = core->mem[i].cpu_addr + offset;
> +			return (__force void *)va;
> +		}
> +	}
> +
> +	/* handle static DDR reserved memory regions */
> +	for (i = 0; i < kproc->num_rmems; i++) {
> +		dev_addr = kproc->rmem[i].dev_addr;
> +		size = kproc->rmem[i].size;
> +
> +		if (da >= dev_addr && ((da + len) <= (dev_addr + size))) {
> +			offset = da - dev_addr;
> +			va = kproc->rmem[i].cpu_addr + offset;
> +			return (__force void *)va;
> +		}
> +	}
> +
> +	return NULL;
> +}
> +
> +static const struct rproc_ops k3_r5_rproc_ops = {
> +	.prepare	= k3_r5_rproc_prepare,
> +	.unprepare	= k3_r5_rproc_unprepare,
> +	.start		= k3_r5_rproc_start,
> +	.stop		= k3_r5_rproc_stop,
> +	.kick		= k3_r5_rproc_kick,
> +	.da_to_va	= k3_r5_rproc_da_to_va,
> +};
> +
> +static const char *k3_r5_rproc_get_firmware(struct device *dev)
> +{
> +	const char *fw_name;
> +	int ret;
> +
> +	ret = of_property_read_string(dev->of_node, "firmware-name",
> +				      &fw_name);
> +	if (ret) {
> +		dev_err(dev, "failed to parse firmware-name property, ret = %d\n",
> +			ret);
> +		return ERR_PTR(ret);
> +	}
> +
> +	return fw_name;
> +}
> +
> +static int k3_r5_rproc_configure(struct k3_r5_rproc *kproc)
> +{
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct device *dev = kproc->dev;
> +	struct k3_r5_core *core0, *core, *temp;
> +	u32 ctrl = 0, cfg = 0, stat = 0;
> +	u32 set_cfg = 0, clr_cfg = 0;
> +	u64 boot_vec = 0;
> +	bool lockstep_en;
> +	int ret;
> +
> +	core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> +	core = cluster->mode ? core0 : kproc->core;
> +
> +	ret = ti_sci_proc_get_status(core->tsp, &boot_vec, &cfg, &ctrl,
> +				     &stat);
> +	if (ret < 0)
> +		return ret;
> +
> +	dev_dbg(dev, "boot_vector = 0x%llx, cfg = 0x%x ctrl = 0x%x stat = 0x%x\n",
> +		boot_vec, cfg, ctrl, stat);
> +
> +	lockstep_en = !!(stat & PROC_BOOT_STATUS_FLAG_R5_LOCKSTEP_PERMITTED);
> +	if (!lockstep_en && cluster->mode) {
> +		dev_err(cluster->dev, "lockstep mode not permitted, force configuring for split-mode\n");
> +		cluster->mode = 0;
> +	}
> +
> +	/* always enable ARM mode and set boot vector to 0 */
> +	boot_vec = 0x0;
> +	if (core == core0) {
> +		clr_cfg = PROC_BOOT_CFG_FLAG_R5_TEINIT;
> +		/*
> +		 * LockStep configuration bit is Read-only on Split-mode _only_
> +		 * devices and system firmware will NACK any requests with the
> +		 * bit configured, so program it only on permitted devices
> +		 */
> +		if (lockstep_en)
> +			clr_cfg |= PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> +	}
> +
> +	if (core->atcm_enable)
> +		set_cfg |= PROC_BOOT_CFG_FLAG_R5_ATCM_EN;
> +	else
> +		clr_cfg |= PROC_BOOT_CFG_FLAG_R5_ATCM_EN;
> +
> +	if (core->btcm_enable)
> +		set_cfg |= PROC_BOOT_CFG_FLAG_R5_BTCM_EN;
> +	else
> +		clr_cfg |= PROC_BOOT_CFG_FLAG_R5_BTCM_EN;
> +
> +	if (core->loczrama)
> +		set_cfg |= PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE;
> +	else
> +		clr_cfg |= PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE;
> +
> +	if (cluster->mode) {
> +		/*
> +		 * work around system firmware limitations to make sure both
> +		 * cores are programmed symmetrically in LockStep. LockStep
> +		 * and TEINIT config is only allowed with Core0.
> +		 */
> +		list_for_each_entry(temp, &cluster->cores, elem) {
> +			ret = k3_r5_core_halt(core);
> +			if (ret)
> +				goto out;
> +
> +			if (temp != core) {
> +				clr_cfg &= ~PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> +				clr_cfg &= ~PROC_BOOT_CFG_FLAG_R5_TEINIT;
> +			}
> +			ret = ti_sci_proc_set_config(temp->tsp, boot_vec,
> +						     set_cfg, clr_cfg);
> +			if (ret)
> +				goto out;
> +		}
> +
> +		set_cfg = PROC_BOOT_CFG_FLAG_R5_LOCKSTEP;
> +		clr_cfg = 0;
> +		ret = ti_sci_proc_set_config(core->tsp, boot_vec,
> +					     set_cfg, clr_cfg);
> +	} else {
> +		ret = k3_r5_core_halt(core);
> +		if (ret)
> +			goto out;
> +
> +		ret = ti_sci_proc_set_config(core->tsp, boot_vec,
> +					     set_cfg, clr_cfg);
> +	}
> +
> +out:
> +	return ret;
> +}
> +
> +static int k3_r5_reserved_mem_init(struct k3_r5_rproc *kproc)
> +{
> +	struct device *dev = kproc->dev;
> +	struct device_node *np = dev->of_node;
> +	struct device_node *rmem_np;
> +	struct reserved_mem *rmem;
> +	int num_rmems;
> +	int ret, i;
> +
> +	num_rmems = of_property_count_elems_of_size(np, "memory-region",
> +						    sizeof(phandle));
> +	if (num_rmems <= 0) {
> +		dev_err(dev, "device does not have reserved memory regions, ret = %d\n",
> +			num_rmems);
> +		return -EINVAL;
> +	}
> +	if (num_rmems < 2) {
> +		dev_err(dev, "device needs atleast two memory regions to be defined, num = %d\n",
> +			num_rmems);
> +		return -EINVAL;
> +	}
> +
> +	/* use reserved memory region 0 for vring DMA allocations */
> +	ret = of_reserved_mem_device_init_by_idx(dev, np, 0);
> +	if (ret) {
> +		dev_err(dev, "device cannot initialize DMA pool, ret = %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	num_rmems--;
> +	kproc->rmem = kcalloc(num_rmems, sizeof(*kproc->rmem), GFP_KERNEL);
> +	if (!kproc->rmem) {
> +		ret = -ENOMEM;
> +		goto release_rmem;
> +	}
> +
> +	/* use remaining reserved memory regions for static carveouts */
> +	for (i = 0; i < num_rmems; i++) {
> +		rmem_np = of_parse_phandle(np, "memory-region", i + 1);
> +		if (!rmem_np) {
> +			ret = -EINVAL;
> +			goto unmap_rmem;
> +		}
> +
> +		rmem = of_reserved_mem_lookup(rmem_np);
> +		if (!rmem) {
> +			of_node_put(rmem_np);
> +			ret = -EINVAL;
> +			goto unmap_rmem;
> +		}
> +		of_node_put(rmem_np);
> +
> +		kproc->rmem[i].bus_addr = rmem->base;
> +		/* 64-bit address regions currently not supported */
> +		kproc->rmem[i].dev_addr = (u32)rmem->base;

Because the bus and the device addresses are the same I have to deduce the AP
and the R5 have the same view of the memory.  Please add a comment to assert
that is really the case.

> +		kproc->rmem[i].size = rmem->size;
> +		kproc->rmem[i].cpu_addr = ioremap_wc(rmem->base, rmem->size);
> +		if (!kproc->rmem[i].cpu_addr) {
> +			dev_err(dev, "failed to map reserved memory#%d at %pa of size %pa\n",
> +				i + 1, &rmem->base, &rmem->size);
> +			ret = -ENOMEM;
> +			goto unmap_rmem;
> +		}
> +
> +		dev_dbg(dev, "reserved memory%d: bus addr %pa size 0x%zx va %pK da 0x%x\n",
> +			i + 1, &kproc->rmem[i].bus_addr,
> +			kproc->rmem[i].size, kproc->rmem[i].cpu_addr,
> +			kproc->rmem[i].dev_addr);
> +	}
> +	kproc->num_rmems = num_rmems;
> +
> +	return 0;
> +
> +unmap_rmem:
> +	for (i--; i >= 0; i--) {
> +		if (kproc->rmem[i].cpu_addr)
> +			iounmap(kproc->rmem[i].cpu_addr);
> +	}
> +	kfree(kproc->rmem);
> +release_rmem:
> +	of_reserved_mem_device_release(dev);
> +	return ret;
> +}
> +
> +static void k3_r5_reserved_mem_exit(struct k3_r5_rproc *kproc)
> +{
> +	int i;
> +
> +	for (i = 0; i < kproc->num_rmems; i++)
> +		iounmap(kproc->rmem[i].cpu_addr);
> +	kfree(kproc->rmem);
> +
> +	of_reserved_mem_device_release(kproc->dev);
> +}
> +
> +static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
> +{
> +	struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +	struct k3_r5_rproc *kproc;
> +	struct k3_r5_core *core, *core1;
> +	struct device *cdev;
> +	const char *fw_name;
> +	struct rproc *rproc;
> +	int ret;
> +
> +	core1 = list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> +	list_for_each_entry(core, &cluster->cores, elem) {
> +		cdev = core->dev;
> +		fw_name = k3_r5_rproc_get_firmware(cdev);
> +		if (IS_ERR(fw_name)) {
> +			ret = PTR_ERR(fw_name);
> +			goto out;
> +		}
> +
> +		rproc = rproc_alloc(cdev, dev_name(cdev), &k3_r5_rproc_ops,
> +				    fw_name, sizeof(*kproc));
> +		if (!rproc) {
> +			ret = -ENOMEM;
> +			goto out;
> +		}
> +
> +		/* K3 R5s have a Region Address Translator (RAT) but no MMU */
> +		rproc->has_iommu = false;
> +		/* error recovery is not supported at present */
> +		rproc->recovery_disabled = true;
> +
> +		kproc = rproc->priv;
> +		kproc->cluster = cluster;
> +		kproc->core = core;
> +		kproc->dev = cdev;
> +		kproc->rproc = rproc;
> +		core->rproc = rproc;
> +
> +		ret = k3_r5_rproc_configure(kproc);
> +		if (ret) {
> +			dev_err(dev, "initial configure failed, ret = %d\n",
> +				ret);
> +			goto err_config;
> +		}
> +
> +		ret = k3_r5_reserved_mem_init(kproc);
> +		if (ret) {
> +			dev_err(dev, "reserved memory init failed, ret = %d\n",
> +				ret);
> +			goto err_config;
> +		}
> +
> +		ret = rproc_add(rproc);
> +		if (ret) {
> +			dev_err(dev, "rproc_add failed, ret = %d\n", ret);
> +			goto err_add;
> +		}
> +
> +		/* create only one rproc in lockstep mode */
> +		if (cluster->mode)
> +			break;
> +	}
> +
> +	return 0;
> +
> +err_split:
> +	rproc_del(rproc);
> +err_add:
> +	k3_r5_reserved_mem_exit(kproc);
> +err_config:
> +	rproc_free(rproc);
> +	core->rproc = NULL;
> +out:
> +	/* undo core0 upon any failures on core1 in split-mode */
> +	if (!cluster->mode && core == core1) {
> +		core = list_prev_entry(core, elem);
> +		rproc = core->rproc;
> +		kproc = rproc->priv;
> +		goto err_split;
> +	}
> +	return ret;
> +}
> +
> +static int k3_r5_cluster_rproc_exit(struct platform_device *pdev)
> +{
> +	struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> +	struct k3_r5_rproc *kproc;
> +	struct k3_r5_core *core;
> +	struct rproc *rproc;
> +
> +	/*
> +	 * lockstep mode has only one rproc associated with first core, whereas
> +	 * split-mode has two rprocs associated with each core, and requires
> +	 * that core1 be powered down first
> +	 */
> +	core = cluster->mode ?
> +		list_first_entry(&cluster->cores, struct k3_r5_core, elem) :
> +		list_last_entry(&cluster->cores, struct k3_r5_core, elem);
> +
> +	list_for_each_entry_from_reverse(core, &cluster->cores, elem) {
> +		rproc = core->rproc;
> +		kproc = rproc->priv;
> +
> +		rproc_del(rproc);
> +
> +		k3_r5_reserved_mem_exit(kproc);
> +
> +		rproc_free(rproc);
> +		core->rproc = NULL;
> +	}
> +
> +	return 0;
> +}
> +
> +static int k3_r5_core_of_get_internal_memories(struct platform_device *pdev,
> +					       struct k3_r5_core *core)
> +{
> +	static const char * const mem_names[] = {"atcm", "btcm"};
> +	struct device *dev = &pdev->dev;
> +	struct resource *res;
> +	int num_mems;
> +	int i, ret;
> +
> +	num_mems = ARRAY_SIZE(mem_names);
> +	core->mem = devm_kcalloc(dev, num_mems, sizeof(*core->mem), GFP_KERNEL);
> +	if (!core->mem)
> +		return -ENOMEM;
> +
> +	for (i = 0; i < num_mems; i++) {
> +		res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> +						   mem_names[i]);
> +		if (!res) {
> +			dev_err(dev, "found no memory resource for %s\n",
> +				mem_names[i]);
> +			ret = -EINVAL;
> +			goto fail;
> +		}
> +		if (!devm_request_mem_region(dev, res->start,
> +					     resource_size(res),
> +					     dev_name(dev))) {
> +			dev_err(dev, "could not request %s region for resource\n",
> +				mem_names[i]);
> +			ret = -EBUSY;
> +			goto fail;
> +		}
> +
> +		/*
> +		 * TCMs are designed in general to support RAM-like backing
> +		 * memories. So, map these as Normal Non-Cached memories. This
> +		 * also avoids/fixes any potential alignment faults due to
> +		 * unaligned data accesses when using memcpy() or memset()
> +		 * functions (normally seen with device type memory).
> +		 */
> +		core->mem[i].cpu_addr = devm_ioremap_wc(dev, res->start,
> +							resource_size(res));
> +		if (IS_ERR(core->mem[i].cpu_addr)) {
> +			dev_err(dev, "failed to map %s memory\n", mem_names[i]);
> +			ret = PTR_ERR(core->mem[i].cpu_addr);
> +			devm_release_mem_region(dev, res->start,
> +						resource_size(res));
> +			goto fail;
> +		}
> +		core->mem[i].bus_addr = res->start;
> +
> +		/*
> +		 * TODO:
> +		 * The R5F cores can place ATCM & BTCM anywhere in its address
> +		 * based on the corresponding Region Registers in the System
> +		 * Control coprocessor. For now, place ATCM and BTCM at
> +		 * addresses 0 and 0x41010000 (same as the bus address on AM65x
> +		 * SoCs) based on loczrama setting
> +		 */
> +		if (!strcmp(mem_names[i], "atcm")) {
> +			core->mem[i].dev_addr = core->loczrama ?
> +							0 : K3_R5_TCM_DEV_ADDR;
> +		} else {
> +			core->mem[i].dev_addr = core->loczrama ?
> +							K3_R5_TCM_DEV_ADDR : 0;
> +		}
> +		core->mem[i].size = resource_size(res);
> +
> +		dev_dbg(dev, "memory %8s: bus addr %pa size 0x%zx va %pK da 0x%x\n",
> +			mem_names[i], &core->mem[i].bus_addr,
> +			core->mem[i].size, core->mem[i].cpu_addr,
> +			core->mem[i].dev_addr);
> +	}
> +	core->num_mems = num_mems;
> +
> +	return 0;
> +
> +fail:
> +	for (i--; i >= 0; i--) {
> +		devm_iounmap(dev, core->mem[i].cpu_addr);
> +		devm_release_mem_region(dev, core->mem[i].bus_addr,
> +					core->mem[i].size);
> +	}
> +	if (core->mem)
> +		devm_kfree(dev, core->mem);
> +	return ret;
> +}
> +
> +static
> +struct ti_sci_proc *k3_r5_core_of_get_tsp(struct device *dev,
> +					  const struct ti_sci_handle *sci)
> +{
> +	struct ti_sci_proc *tsp;
> +	u32 temp[2];
> +	int ret;
> +
> +	ret = of_property_read_u32_array(dev->of_node, "ti,sci-proc-ids",
> +					 temp, 2);
> +	if (ret < 0)
> +		return ERR_PTR(ret);
> +
> +	tsp = kzalloc(sizeof(*tsp), GFP_KERNEL);
> +	if (!tsp)
> +		return ERR_PTR(-ENOMEM);
> +
> +	tsp->dev = dev;
> +	tsp->sci = sci;
> +	tsp->ops = &sci->ops.proc_ops;
> +	tsp->proc_id = temp[0];
> +	tsp->host_id = temp[1];
> +
> +	return tsp;
> +}
> +
> +static int k3_r5_core_of_init(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct k3_r5_core *core;
> +	int ret, ret1;
> +
> +	core = devm_kzalloc(dev, sizeof(*core), GFP_KERNEL);
> +	if (!core)
> +		return -ENOMEM;
> +
> +	core->dev = dev;
> +	core->atcm_enable = 0;
> +	core->btcm_enable = 1;
> +	core->loczrama = 1;
> +
> +	ret = of_property_read_u32(np, "atcm-enable", &core->atcm_enable);
> +	if (ret < 0 && ret != -EINVAL) {
> +		dev_err(dev, "invalid format for atcm-enable, ret = %d\n", ret);
> +		goto err_of;
> +	}
> +
> +	ret = of_property_read_u32(np, "btcm-enable", &core->btcm_enable);
> +	if (ret < 0 && ret != -EINVAL) {
> +		dev_err(dev, "invalid format for btcm-enable, ret = %d\n", ret);
> +		goto err_of;
> +	}
> +
> +	ret = of_property_read_u32(np, "loczrama", &core->loczrama);
> +	if (ret < 0 && ret != -EINVAL) {
> +		dev_err(dev, "invalid format for loczrama, ret = %d\n", ret);
> +		goto err_of;
> +	}
> +
> +	core->ti_sci = ti_sci_get_by_phandle(np, "ti,sci");
> +	if (IS_ERR(core->ti_sci)) {
> +		ret = PTR_ERR(core->ti_sci);
> +		if (ret != -EPROBE_DEFER) {
> +			dev_err(dev, "failed to get ti-sci handle, ret = %d\n",
> +				ret);
> +		}
> +		core->ti_sci = NULL;
> +		goto err_of;
> +	}
> +
> +	ret = of_property_read_u32(np, "ti,sci-dev-id", &core->ti_sci_id);
> +	if (ret) {
> +		dev_err(dev, "missing 'ti,sci-dev-id' property\n");
> +		goto err_sci_id;
> +	}
> +
> +	core->reset = reset_control_get_exclusive(dev, NULL);
> +	if (IS_ERR(core->reset)) {
> +		ret = PTR_ERR(core->reset);
> +		if (ret != -EPROBE_DEFER) {
> +			dev_err(dev, "failed to get reset handle, ret = %d\n",
> +				ret);
> +		}
> +		goto err_sci_id;
> +	}
> +
> +	core->tsp = k3_r5_core_of_get_tsp(dev, core->ti_sci);
> +	if (IS_ERR(core->tsp)) {
> +		dev_err(dev, "failed to construct ti-sci proc control, ret = %d\n",
> +			ret);
> +		ret = PTR_ERR(core->tsp);
> +		goto err_sci_proc;
> +	}
> +
> +	ret = ti_sci_proc_request(core->tsp);
> +	if (ret < 0) {
> +		dev_err(dev, "ti_sci_proc_request failed, ret = %d\n", ret);
> +		goto err_proc;
> +	}
> +
> +	ret = k3_r5_core_of_get_internal_memories(pdev, core);
> +	if (ret) {
> +		dev_err(dev, "failed to get internal memories, ret = %d\n",
> +			ret);
> +		goto err_intmem;
> +	}
> +
> +	platform_set_drvdata(pdev, core);
> +
> +	return 0;
> +
> +err_intmem:
> +	ret1 = ti_sci_proc_release(core->tsp);
> +	if (ret1)
> +		dev_err(dev, "failed to release proc, ret1 = %d\n", ret1);
> +err_proc:
> +	kfree(core->tsp);
> +err_sci_proc:
> +	reset_control_put(core->reset);
> +err_sci_id:
> +	ret1 = ti_sci_put_handle(core->ti_sci);
> +	if (ret1)
> +		dev_err(dev, "failed to put ti_sci handle, ret = %d\n", ret1);
> +err_of:
> +	devm_kfree(dev, core);
> +	return ret;
> +}
> +
> +/*
> + * free the resources explicitly since driver model is not being used
> + * for the child R5F devices
> + */
> +static int k3_r5_core_of_exit(struct platform_device *pdev)
> +{
> +	struct k3_r5_core *core = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +	int i, ret;
> +
> +	for (i = 0; i < core->num_mems; i++) {
> +		devm_release_mem_region(dev, core->mem[i].bus_addr,
> +					core->mem[i].size);
> +		devm_iounmap(dev, core->mem[i].cpu_addr);
> +	}
> +	if (core->mem)
> +		devm_kfree(dev, core->mem);
> +
> +	ret = ti_sci_proc_release(core->tsp);
> +	if (ret)
> +		dev_err(dev, "failed to release proc, ret = %d\n", ret);
> +
> +	kfree(core->tsp);
> +	reset_control_put(core->reset);
> +
> +	ret = ti_sci_put_handle(core->ti_sci);
> +	if (ret)
> +		dev_err(dev, "failed to put ti_sci handle, ret = %d\n", ret);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	devm_kfree(dev, core);
> +
> +	return ret;
> +}
> +
> +static int k3_r5_cluster_of_init(struct platform_device *pdev)
> +{
> +	struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct platform_device *cpdev;
> +	struct device_node *child;
> +	struct k3_r5_core *core, *temp;
> +	int ret;
> +
> +	for_each_available_child_of_node(np, child) {
> +		cpdev = of_find_device_by_node(child);
> +		if (!cpdev) {
> +			ret = -ENODEV;
> +			dev_err(dev, "could not get R5 core platform device\n");
> +			goto fail;
> +		}
> +
> +		ret = k3_r5_core_of_init(cpdev);
> +		if (ret) {
> +			dev_err(dev, "k3_r5_core_of_init failed, ret = %d\n",
> +				ret);
> +			put_device(&cpdev->dev);
> +			goto fail;
> +		}
> +
> +		core = platform_get_drvdata(cpdev);
> +		put_device(&cpdev->dev);
> +		list_add_tail(&core->elem, &cluster->cores);
> +	}
> +
> +	return 0;
> +
> +fail:
> +	list_for_each_entry_safe_reverse(core, temp, &cluster->cores, elem) {
> +		list_del(&core->elem);
> +		cpdev = to_platform_device(core->dev);
> +		if (k3_r5_core_of_exit(cpdev))
> +			dev_err(dev, "k3_r5_core_of_exit cleanup failed\n");
> +	}
> +	return ret;
> +}
> +
> +static int k3_r5_cluster_of_exit(struct platform_device *pdev)
> +{
> +	struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> +	struct device *dev = &pdev->dev;
> +	struct platform_device *cpdev;
> +	struct k3_r5_core *core, *temp;
> +	int ret;
> +
> +	list_for_each_entry_safe_reverse(core, temp, &cluster->cores, elem) {
> +		list_del(&core->elem);
> +		cpdev = to_platform_device(core->dev);
> +		ret = k3_r5_core_of_exit(cpdev);
> +		if (ret) {
> +			dev_err(dev, "k3_r5_core_of_exit failed, ret = %d\n",
> +				ret);
> +			break;
> +		}
> +	}
> +
> +	return ret;
> +}
> +
> +static int k3_r5_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct k3_r5_cluster *cluster;
> +	int ret, ret1;
> +	int num_cores;
> +
> +	cluster = devm_kzalloc(dev, sizeof(*cluster), GFP_KERNEL);
> +	if (!cluster)
> +		return -ENOMEM;
> +
> +	cluster->dev = dev;
> +	cluster->mode = CLUSTER_MODE_LOCKSTEP;
> +	INIT_LIST_HEAD(&cluster->cores);
> +
> +	ret = of_property_read_u32(np, "lockstep-mode", &cluster->mode);
> +	if (ret < 0 && ret != -EINVAL) {
> +		dev_err(dev, "invalid format for lockstep-mode, ret = %d\n",
> +			ret);
> +		return ret;
> +	}
> +
> +	num_cores = of_get_available_child_count(np);
> +	if (num_cores != 2) {
> +		dev_err(dev, "MCU cluster requires both R5F cores to be enabled, num_cores = %d\n",
> +			num_cores);
> +		return -ENODEV;
> +	}
> +
> +	platform_set_drvdata(pdev, cluster);
> +
> +	dev_dbg(dev, "creating child devices for R5F cores\n");
> +	ret = of_platform_populate(np, NULL, NULL, dev);
> +	if (ret) {
> +		dev_err(dev, "of_platform_populate failed, ret = %d\n", ret);
> +		return ret;
> +	}
> +
> +	ret = k3_r5_cluster_of_init(pdev);
> +	if (ret) {
> +		dev_err(dev, "k3_r5_cluster_of_init failed, ret = %d\n", ret);
> +		goto fail_of;
> +	}
> +
> +	ret = k3_r5_cluster_rproc_init(pdev);
> +	if (ret) {
> +		dev_err(dev, "k3_r5_cluster_rproc_init failed, ret = %d\n",
> +			ret);
> +		goto fail_rproc;
> +	}
> +
> +	return 0;
> +
> +fail_rproc:
> +	ret1 = k3_r5_cluster_of_exit(pdev);
> +	if (ret1)
> +		dev_err(dev, "k3_r5_cluster_of_exit failed, ret = %d\n", ret1);
> +fail_of:
> +	of_platform_depopulate(dev);
> +	return ret;
> +}
> +
> +static int k3_r5_remove(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +
> +	ret = k3_r5_cluster_rproc_exit(pdev);
> +	if (ret) {
> +		dev_err(dev, "k3_r5_cluster_rproc_exit failed, ret = %d\n",
> +			ret);
> +		goto fail;
> +	}
> +
> +	ret = k3_r5_cluster_of_exit(pdev);
> +	if (ret) {
> +		dev_err(dev, "k3_r5_cluster_of_exit failed, ret = %d\n", ret);
> +		goto fail;
> +	}
> +
> +	dev_dbg(dev, "removing child devices for R5F cores\n");
> +	of_platform_depopulate(dev);
> +
> +fail:
> +	return ret;
> +}
> +
> +static const struct of_device_id k3_r5_of_match[] = {
> +	{ .compatible = "ti,am654-r5fss", },
> +	{ .compatible = "ti,j721e-r5fss", },
> +	{ /* sentinel */ },
> +};
> +MODULE_DEVICE_TABLE(of, k3_r5_of_match);
> +
> +static struct platform_driver k3_r5_rproc_driver = {
> +	.probe = k3_r5_probe,
> +	.remove = k3_r5_remove,
> +	.driver = {
> +		.name = "k3_r5_rproc",
> +		.of_match_table = k3_r5_of_match,
> +	},
> +};
> +
> +module_platform_driver(k3_r5_rproc_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("TI K3 R5F remote processor driver");
> +MODULE_AUTHOR("Suman Anna <[email-masked]>");
> -- 
> 2.23.0
> 

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