Subject: [PATCH V14 9/9] vfio, platform: add QTI HIDMA reset driver

From: [email-masked] (Sinan Kaya)
Date: Fri, 26 Feb 2016 14:05:58 -0500

On 2/26/2016 12:52 PM, Eric Auger wrote:
> Hi Sinan,
> On 02/05/2016 05:34 AM, Sinan Kaya wrote:
>> In situations where the userspace driver is stopped abnormally and the
>> VFIO platform device is released, the assigned HW device currently is
>> left running. As a consequence the HW device might continue issuing IRQs
>> and performing DMA accesses.
>>
>> This patch is implementing a reset driver for HIDMA platform driver.
>> This gets called by the VFIO platform reset interface.
>>
>> Signed-off-by: Sinan Kaya <[email-masked]>
>> ---
>>  drivers/vfio/platform/reset/Kconfig                |  9 ++
>>  drivers/vfio/platform/reset/Makefile               |  2 +
>>  .../vfio/platform/reset/vfio_platform_qcomhidma.c  | 99 ++++++++++++++++++++++
>>  3 files changed, 110 insertions(+)
>>  create mode 100644 drivers/vfio/platform/reset/vfio_platform_qcomhidma.c
>>
>> diff --git a/drivers/vfio/platform/reset/Kconfig b/drivers/vfio/platform/reset/Kconfig
>> index 70cccc5..d02b3b5 100644
>> --- a/drivers/vfio/platform/reset/Kconfig
>> +++ b/drivers/vfio/platform/reset/Kconfig
>> @@ -13,3 +13,12 @@ config VFIO_PLATFORM_AMDXGBE_RESET
>>  	  Enables the VFIO platform driver to handle reset for AMD XGBE
>>  
>>  	  If you don't know what to do here, say N.
>> +
>> +config VFIO_PLATFORM_QCOMHIDMA_RESET
>> +	tristate "VFIO support for Qualcomm Technologies HIDMA reset"
>> +	depends on VFIO_PLATFORM
>> +	help
>> +	  Enables the VFIO platform driver to handle reset for Qualcomm Technologies
>> +	  HIDMA Channel.
>> +
>> +	  If you don't know what to do here, say N.
>> diff --git a/drivers/vfio/platform/reset/Makefile b/drivers/vfio/platform/reset/Makefile
>> index 93f4e23..ec7748a 100644
>> --- a/drivers/vfio/platform/reset/Makefile
>> +++ b/drivers/vfio/platform/reset/Makefile
>> @@ -1,7 +1,9 @@
>>  vfio-platform-calxedaxgmac-y := vfio_platform_calxedaxgmac.o
>>  vfio-platform-amdxgbe-y := vfio_platform_amdxgbe.o
>> +vfio-platform-qcomhidma-y := vfio_platform_qcomhidma.o
>>  
>>  ccflags-y += -Idrivers/vfio/platform
>>  
>>  obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o
>> +obj-$(CONFIG_VFIO_PLATFORM_QCOMHIDMA_RESET) += vfio-platform-qcomhidma.o
>>  obj-$(CONFIG_VFIO_PLATFORM_AMDXGBE_RESET) += vfio-platform-amdxgbe.o
>> diff --git a/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c b/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c
>> new file mode 100644
>> index 0000000..70d7eed
>> --- /dev/null
>> +++ b/drivers/vfio/platform/reset/vfio_platform_qcomhidma.c
>> @@ -0,0 +1,99 @@
>> +/*
>> + * Qualcomm Technologies HIDMA VFIO Reset Driver
>> + *
>> + * Copyright (c) 2016, The Linux Foundation. All rights reserved.
>> + *
>> + * This program is free software; you can redistribute it and/or modify
>> + * it under the terms of the GNU General Public License version 2 and
>> + * only version 2 as published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that 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/module.h>
>> +#include <linux/kernel.h>
>> +#include <linux/init.h>
>> +#include <linux/io.h>
>> +#include <linux/device.h>
>> +#include <linux/iopoll.h>
>> +
>> +#include "vfio_platform_private.h"
>> +
>> +#define TRCA_CTRLSTS_OFFSET		0x000
>> +#define EVCA_CTRLSTS_OFFSET		0x000
>> +
>> +#define CH_CONTROL_MASK		GENMASK(7, 0)
> nit: alignment
> 
> Besides it looks ok to me
> Reviewed-by: Eric Auger <[email-masked]>
> 
> If it better suits you maybe you can separate the upstream of your
> management/channel driver from the VFIO reset driver upstream.

Thanks, I wanted to keep things together. There were some review concerns
to whether I'm doing the right thing when it comes to virtualization. 

Patches 8 & 9 definitely needs to go in through another merge branch.

> 
> Best Regards
> 
> Eric
> 
>> +#define CH_STATE_MASK			GENMASK(7, 0)
>> +#define CH_STATE_BIT_POS		0x8
>> +
>> +#define HIDMA_CH_STATE(val)	\
>> +	((val >> CH_STATE_BIT_POS) & CH_STATE_MASK)
>> +
>> +#define EVCA_IRQ_EN_OFFSET		0x110
>> +
>> +#define CH_RESET			9
>> +#define CH_DISABLED			0
>> +
>> +int vfio_platform_qcomhidma_reset(struct vfio_platform_device *vdev)
>> +{
>> +	struct vfio_platform_region *trreg;
>> +	struct vfio_platform_region *evreg;
>> +	u32 val;
>> +	int ret;
>> +
>> +	if (vdev->num_regions != 2)
>> +		return -ENODEV;
>> +
>> +	trreg = &vdev->regions[0];
>> +	if (!trreg->ioaddr) {
>> +		trreg->ioaddr =
>> +			ioremap_nocache(trreg->addr, trreg->size);
>> +		if (!trreg->ioaddr)
>> +			return -ENOMEM;
>> +	}
>> +
>> +	evreg = &vdev->regions[1];
>> +	if (!evreg->ioaddr) {
>> +		evreg->ioaddr =
>> +			ioremap_nocache(evreg->addr, evreg->size);
>> +		if (!evreg->ioaddr)
>> +			return -ENOMEM;
>> +	}
>> +
>> +	/* disable IRQ */
>> +	writel(0, evreg->ioaddr + EVCA_IRQ_EN_OFFSET);
>> +
>> +	/* reset both transfer and event channels */
>> +	val = readl(trreg->ioaddr + TRCA_CTRLSTS_OFFSET);
>> +	val &= ~(CH_CONTROL_MASK << 16);
>> +	val |= CH_RESET << 16;
>> +	writel(val, trreg->ioaddr + TRCA_CTRLSTS_OFFSET);
>> +
>> +	ret = readl_poll_timeout(trreg->ioaddr + TRCA_CTRLSTS_OFFSET, val,
>> +				 HIDMA_CH_STATE(val) == CH_DISABLED, 1000,
>> +				 10000);
>> +	if (ret)
>> +		return ret;
>> +
>> +	val = readl(evreg->ioaddr + EVCA_CTRLSTS_OFFSET);
>> +	val &= ~(CH_CONTROL_MASK << 16);
>> +	val |= CH_RESET << 16;
>> +	writel(val, evreg->ioaddr + EVCA_CTRLSTS_OFFSET);
>> +
>> +	ret = readl_poll_timeout(evreg->ioaddr + EVCA_CTRLSTS_OFFSET, val,
>> +				 HIDMA_CH_STATE(val) == CH_DISABLED, 1000,
>> +				 10000);
>> +	if (ret)
>> +		return ret;
>> +
>> +	pr_info("HIDMA channel reset\n");
>> +	return 0;
>> +}
>> +module_vfio_reset_handler("qcom,hidma-1.0", "QCOM8061",
>> +			  vfio_platform_qcomhidma_reset);
>> +
>> +MODULE_LICENSE("GPL v2");
>> +MODULE_DESCRIPTION("Reset support for Qualcomm Technologies HIDMA device");
>>
> 

-- 
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project