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

From: Sinan Kaya
Date: Fri Feb 26 2016 - 14:06:10 EST

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 <okaya@xxxxxxxxxxxxxx>
>> ---
>> 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 <eric.auger@xxxxxxxxxx>
>
> 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