[PATCH v2] drm/exynos: fimd: clear channel before enabling iommu

[Daniel Kurtz]

On Tue, Apr 29, 2014 at 9:38 AM, Inki Dae <inki.dae at samsung.com> wrote:

> From: Akshu Agrawal <akshu.a at samsung.com>
>
> If any fimd channel was already active, initializing iommu will result
> in a PAGE FAULT (e.e. u-boot could have turned on the display and
> not disabled it before the kernel starts). This patch checks if any
> channel is active before initializing iommu and disables it.
>
> Changelog v2:
> - consider SoC without SHADOWCON register
>
> Signed-off-by: Akshu Agrawal <akshu.a at samsung.com>
> Signed-off-by: Prathyush K <prathyush.k at samsung.com>
> Signed-off-by: Inki Dae <inki.dae at samsung.com>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_fimd.c |   70
> +++++++++++++++++++++---------
>  1 file changed, 50 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> index 40fd6cc..ef21ce4 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> @@ -143,6 +143,48 @@ static inline struct fimd_driver_data
> *drm_fimd_get_driver_data(
>         return (struct fimd_driver_data *)of_id->data;
>  }
>
> +static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
> +{
> +       struct fimd_context *ctx = mgr->ctx;
> +
> +       if (ctx->suspended)
> +               return;
> +
>

Hi Inki,

I think you need this to guarantee that the irq is actually enabled:

drm_vblank_get(ctx->drm_dev, ctx->pipe);

+       atomic_set(&ctx->wait_vsync_event, 1);
> +
> +       /*
> +        * wait for FIMD to signal VSYNC interrupt or return after
> +        * timeout which is set to 50ms (refresh rate of 20).
> +        */
> +       if (!wait_event_timeout(ctx->wait_vsync_queue,
> +                               !atomic_read(&ctx->wait_vsync_event),
> +                               HZ/20))
> +               DRM_DEBUG_KMS("vblank wait timed out.\n");
>

drm_vblank_put(ctx->drm_dev, ctx->pipe);


> +}
> +
> +
> +static void fimd_clear_channel(struct exynos_drm_manager *mgr)
> +{
> +       struct fimd_context *ctx = mgr->ctx;
> +       int win, ch_enabled = 0;
> +
> +       DRM_DEBUG_KMS("%s\n", __FILE__);
> +
> +       /* Check if any channel is enabled. */
> +       for (win = 0; win < WINDOWS_NR; win++) {
> +               u32 val = readl(ctx->regs + SHADOWCON);
> +               if (val & SHADOWCON_CHx_ENABLE(win)) {
> +                       val &= ~SHADOWCON_CHx_ENABLE(win);
> +                       writel(val, ctx->regs + SHADOWCON);
> +                       ch_enabled = 1;
> +               }
> +       }
> +
> +       /* Wait for vsync, as disable channel takes effect at next vsync */
> +       if (ch_enabled)
> +               fimd_wait_for_vblank(mgr);
> +}
> +
>  static int fimd_mgr_initialize(struct exynos_drm_manager *mgr,
>                         struct drm_device *drm_dev, int pipe)
>  {
> @@ -169,8 +211,15 @@ static int fimd_mgr_initialize(struct
> exynos_drm_manager *mgr,
>         drm_dev->vblank_disable_allowed = true;
>
>         /* attach this sub driver to iommu mapping if supported. */
> -       if (is_drm_iommu_supported(ctx->drm_dev))
> +       if (is_drm_iommu_supported(ctx->drm_dev)) {
> +               /*
> +                * If any channel is already active, iommu will throw
> +                * a PAGE FAULT when enabled. So clear any channel if
> enabled.
> +                */
> +               if (ctx->driver_data->has_shadowcon)
> +                       fimd_clear_channel(mgr);
>

We already disable all overlays at the end of fimd_probe() by calling
fimd_clear_win().
Perhaps all that was missing was just waiting until the next vblank to
ensure that these clears have all completed?

Best Regards,
-Daniel

                drm_iommu_attach_device(ctx->drm_dev, ctx->dev);
> +       }
>
>         return 0;
>  }
> @@ -324,25 +373,6 @@ static void fimd_disable_vblank(struct
> exynos_drm_manager *mgr)
>         }
>  }
>
> -static void fimd_wait_for_vblank(struct exynos_drm_manager *mgr)
> -{
> -       struct fimd_context *ctx = mgr->ctx;
> -
> -       if (ctx->suspended)
> -               return;
> -
> -       atomic_set(&ctx->wait_vsync_event, 1);
> -
> -       /*
> -        * wait for FIMD to signal VSYNC interrupt or return after
> -        * timeout which is set to 50ms (refresh rate of 20).
> -        */
> -       if (!wait_event_timeout(ctx->wait_vsync_queue,
> -                               !atomic_read(&ctx->wait_vsync_event),
> -                               HZ/20))
> -               DRM_DEBUG_KMS("vblank wait timed out.\n");
> -}
> -
>  static void fimd_win_mode_set(struct exynos_drm_manager *mgr,
>                         struct exynos_drm_overlay *overlay)
>  {
> --
> 1.7.9.5
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/dri-devel/attachments/20140430/c1d69d45/attachment.html>