Re: [PATCH v2 1/3] drm/exynos: fimd: ensure proper hw state in fimd_clear_channel()

[Inki Dae <inki.dae-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org>]

On 2015년 06월 03일 17:26, Marek Szyprowski wrote:
> One should not do any assumptions on the stare of the fimd hardware
> during driver initialization, so to properly reset fimd before enabling
> IOMMU, one should ensure that all power domains and clocks are really
> enabled. This patch adds pm_runtime and clocks management in the
> fimd_clear_channel() function to ensure that any access to fimd
> registers will be performed with clocks and power domains enabled.
> 
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Tested-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
>  drivers/gpu/drm/exynos/exynos_drm_fimd.c | 22 ++++++++++++++++++----
>  1 file changed, 18 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/gpu/drm/exynos/exynos_drm_fimd.c b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> index 96618534358e..3ec9d4299a86 100644
> --- a/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> +++ b/drivers/gpu/drm/exynos/exynos_drm_fimd.c
> @@ -242,12 +242,21 @@ static void fimd_enable_shadow_channel_path(struct fimd_context *ctx,
>  	writel(val, ctx->regs + SHADOWCON);
>  }
>  
> +static int fimd_enable_vblank(struct exynos_drm_crtc *crtc);
> +static void fimd_disable_vblank(struct exynos_drm_crtc *crtc);

You can remove abvoe declarations. See the below comment.

> +
>  static void fimd_clear_channel(struct fimd_context *ctx)
>  {
>  	unsigned int win, ch_enabled = 0;
>  
>  	DRM_DEBUG_KMS("%s\n", __FILE__);
>  
> +	/* Hardware is in unknown state, so ensure it gets enabled properly */
> +	pm_runtime_get_sync(ctx->dev);
> +
> +	clk_prepare_enable(ctx->bus_clk);
> +	clk_prepare_enable(ctx->lcd_clk);
> +
>  	/* Check if any channel is enabled. */
>  	for (win = 0; win < WINDOWS_NR; win++) {
>  		u32 val = readl(ctx->regs + WINCON(win));
> @@ -265,12 +274,17 @@ static void fimd_clear_channel(struct fimd_context *ctx)
>  
>  	/* Wait for vsync, as disable channel takes effect at next vsync */
>  	if (ch_enabled) {
> -		unsigned int state = ctx->suspended;
> -
> -		ctx->suspended = 0;
> +		ctx->suspended = false;
> +		fimd_enable_vblank(ctx->crtc);

I think you can call enable_vblank callback instead of
fimd_enable_vblank function because ctx object has exynos_crtc object.

i.e.,
		struct exynos_drm_crtc_ops *ops = ctx->crtc->ops;
		...
		if (ops->enable_vblank)
			ops->enable_vblank(ctx->crtc);
		...

>  		fimd_wait_for_vblank(ctx->crtc);
> -		ctx->suspended = state;
> +		fimd_disable_vblank(ctx->crtc);

Ditto.

Thanks,
Inki Dae

> +		ctx->suspended = true;
>  	}
> +
> +	clk_disable_unprepare(ctx->lcd_clk);
> +	clk_disable_unprepare(ctx->bus_clk);
> +
> +	pm_runtime_put(ctx->dev);
>  }
>  
>  static int fimd_iommu_attach_devices(struct fimd_context *ctx,
> 

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