From: alex.williamson@redhat.com (Alex Williamson)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH V9 6/9] vfio: platform: call _RST method when using ACPI
Date: Thu, 14 Jul 2016 16:04:39 -0600 [thread overview]
Message-ID: <20160714160439.5bafca73@t450s.home> (raw)
In-Reply-To: <1468461995-32676-7-git-send-email-okaya@codeaurora.org>
On Wed, 13 Jul 2016 22:06:32 -0400
Sinan Kaya <okaya@codeaurora.org> wrote:
> The device tree code checks for the presence of a reset driver and calls
> the of_reset function pointer by looking up the reset driver as a module.
>
> ACPI defines _RST method to perform device level reset. After the _RST
> method is executed, the OS can resume using the device. _RST method is
> expected to stop DMA transfers and IRQs.
>
> This patch introduces two functions as vfio_platform_acpi_has_reset and
> vfio_platform_acpi_call_reset. The has reset method is used to declare
> reset capability via the ioctl flag VFIO_DEVICE_FLAGS_RESET. The call
> reset function is used to execute the _RST ACPI method.
>
> Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
> ---
> drivers/vfio/platform/vfio_platform_common.c | 52 +++++++++++++++++++++++++++-
> 1 file changed, 51 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> index 03483c2..2d9c905 100644
> --- a/drivers/vfio/platform/vfio_platform_common.c
> +++ b/drivers/vfio/platform/vfio_platform_common.c
> @@ -28,6 +28,8 @@
> #define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>"
> #define DRIVER_DESC "VFIO platform base module"
>
> +#define VFIO_PLATFORM_IS_ACPI(vdev) ((vdev)->acpihid != NULL)
> +
> static LIST_HEAD(reset_list);
> static DEFINE_MUTEX(driver_lock);
>
> @@ -77,13 +79,55 @@ static int vfio_platform_acpi_probe(struct vfio_platform_device *vdev,
> #endif
> }
>
> +static inline
> +int vfio_platform_acpi_call_reset(struct vfio_platform_device *vdev,
> + const char **extra_dbg)
> +{
> +#ifdef CONFIG_ACPI
> + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> + struct device *dev = vdev->device;
> + acpi_handle handle = ACPI_HANDLE(dev);
> + acpi_status acpi_ret;
> +
> + acpi_ret = acpi_evaluate_object(handle, "_RST", NULL, &buffer);
> + if (ACPI_FAILURE(acpi_ret)) {
> + if (extra_dbg)
> + *extra_dbg = acpi_format_exception(acpi_ret);
> + return -EINVAL;
> + }
> +
> + return 0;
> +#else
> + return -ENOENT;
> +#endif
> +}
> +
> +static inline
> +bool vfio_platform_acpi_has_reset(struct vfio_platform_device *vdev)
> +{
> +#ifdef CONFIG_ACPI
> + struct device *dev = vdev->device;
> + acpi_handle handle = ACPI_HANDLE(dev);
> +
> + return acpi_has_method(handle, "_RST");
> +#else
> + return false;
> +#endif
> +}
What exactly is the rationale for making these inline? Clearly reset
is not a performance relevant path. Thanks,
Alex
> +
> static bool vfio_platform_has_reset(struct vfio_platform_device *vdev)
> {
> + if (VFIO_PLATFORM_IS_ACPI(vdev))
> + return vfio_platform_acpi_has_reset(vdev);
> +
> return vdev->of_reset ? true : false;
> }
>
> static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
> {
> + if (VFIO_PLATFORM_IS_ACPI(vdev))
> + return;
> +
> vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
> &vdev->reset_module);
> if (!vdev->of_reset) {
> @@ -95,6 +139,9 @@ static void vfio_platform_get_reset(struct vfio_platform_device *vdev)
>
> static void vfio_platform_put_reset(struct vfio_platform_device *vdev)
> {
> + if (VFIO_PLATFORM_IS_ACPI(vdev))
> + return;
> +
> if (vdev->of_reset)
> module_put(vdev->reset_module);
> }
> @@ -170,7 +217,10 @@ static void vfio_platform_regions_cleanup(struct vfio_platform_device *vdev)
> static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
> const char **extra_dbg)
> {
> - if (vdev->of_reset) {
> + if (VFIO_PLATFORM_IS_ACPI(vdev)) {
> + dev_info(vdev->device, "reset\n");
> + return vfio_platform_acpi_call_reset(vdev, extra_dbg);
> + } else if (vdev->of_reset) {
> dev_info(vdev->device, "reset\n");
> return vdev->of_reset(vdev);
> }
next prev parent reply other threads:[~2016-07-14 22:04 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 2:06 [PATCH V9 0/9] vfio, platform: add ACPI support Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 1/9] vfio: platform: rename reset function Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 2/9] vfio: platform: move reset call to a common function Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 3/9] vfio: platform: determine reset capability Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 4/9] vfio: platform: add support for ACPI probe Sinan Kaya
2016-07-14 21:41 ` Alex Williamson
2016-07-16 1:27 ` Sinan Kaya
2016-07-18 17:32 ` Alex Williamson
2016-07-18 21:23 ` Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 5/9] vfio: platform: add extra debug info argument to call reset Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 6/9] vfio: platform: call _RST method when using ACPI Sinan Kaya
2016-07-14 22:04 ` Alex Williamson [this message]
2016-07-16 1:09 ` Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 7/9] vfio, platform: make reset driver a requirement by default Sinan Kaya
2016-07-14 22:24 ` Alex Williamson
2016-07-16 1:07 ` Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 8/9] vfio: platform: check reset call return code during open Sinan Kaya
2016-07-14 2:06 ` [PATCH V9 9/9] vfio: platform: check reset call return code during release Sinan Kaya
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