Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
To:     Neil Armstrong <narmstrong@baylibre.com>
Cc:     linux-omap@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-kernel@vger.kernel.org, khilman@baylibre.com,
        Benoit Parrot <bparrot@ti.com>
References: <20210923070701.145377-1-narmstrong@baylibre.com>
 <20210923070701.145377-4-narmstrong@baylibre.com>
From:   Tomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Subject: Re: [PATCH v5 3/8] drm/omap: introduce omap_hw_overlay
Message-ID: <6e5980a6-218e-b585-3ad7-3e55350929b6@ideasonboard.com>
Date:   Tue, 12 Oct 2021 10:59:57 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.13.0
MIME-Version: 1.0
In-Reply-To: <20210923070701.145377-4-narmstrong@baylibre.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

On 23/09/2021 10:06, Neil Armstrong wrote:
> From: Benoit Parrot <bparrot@ti.com>
> 
> Split out the hardware overlay specifics from omap_plane.
> To start, the hw overlays are statically assigned to planes.
> 
> The goal is to eventually assign hw overlays dynamically to planes
> during plane->atomic_check() based on requested caps (scaling, YUV,
> etc). And then perform hw overlay re-assignment if required.
> 
> Signed-off-by: Benoit Parrot <bparrot@ti.com>
> Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
> ---
>   drivers/gpu/drm/omapdrm/Makefile       |  1 +
>   drivers/gpu/drm/omapdrm/omap_drv.c     |  9 ++-
>   drivers/gpu/drm/omapdrm/omap_drv.h     |  4 ++
>   drivers/gpu/drm/omapdrm/omap_overlay.c | 87 ++++++++++++++++++++++++++
>   drivers/gpu/drm/omapdrm/omap_overlay.h | 31 +++++++++
>   drivers/gpu/drm/omapdrm/omap_plane.c   | 42 ++++++-------
>   6 files changed, 151 insertions(+), 23 deletions(-)
>   create mode 100644 drivers/gpu/drm/omapdrm/omap_overlay.c
>   create mode 100644 drivers/gpu/drm/omapdrm/omap_overlay.h
> 
> diff --git a/drivers/gpu/drm/omapdrm/Makefile b/drivers/gpu/drm/omapdrm/Makefile
> index 21e8277ff88f..710b4e0abcf0 100644
> --- a/drivers/gpu/drm/omapdrm/Makefile
> +++ b/drivers/gpu/drm/omapdrm/Makefile
> @@ -9,6 +9,7 @@ omapdrm-y := omap_drv.o \
>   	omap_debugfs.o \
>   	omap_crtc.o \
>   	omap_plane.o \
> +	omap_overlay.o \
>   	omap_encoder.o \
>   	omap_fb.o \
>   	omap_gem.o \
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.c b/drivers/gpu/drm/omapdrm/omap_drv.c
> index f86e20578143..b994014b22e8 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.c
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.c
> @@ -583,10 +583,14 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev)
>   
>   	omap_gem_init(ddev);
>   
> +	ret = omap_hwoverlays_init(priv);
> +	if (ret)
> +		goto err_gem_deinit;
> +
>   	ret = omap_modeset_init(ddev);
>   	if (ret) {
>   		dev_err(priv->dev, "omap_modeset_init failed: ret=%d\n", ret);
> -		goto err_gem_deinit;
> +		goto err_free_overlays;
>   	}
>   
>   	/* Initialize vblank handling, start with all CRTCs disabled. */
> @@ -618,6 +622,8 @@ static int omapdrm_init(struct omap_drm_private *priv, struct device *dev)
>   	omap_fbdev_fini(ddev);
>   err_cleanup_modeset:
>   	omap_modeset_fini(ddev);
> +err_free_overlays:
> +	omap_hwoverlays_destroy(priv);
>   err_gem_deinit:
>   	omap_gem_deinit(ddev);
>   	destroy_workqueue(priv->wq);
> @@ -642,6 +648,7 @@ static void omapdrm_cleanup(struct omap_drm_private *priv)
>   	drm_atomic_helper_shutdown(ddev);
>   
>   	omap_modeset_fini(ddev);
> +	omap_hwoverlays_destroy(priv);
>   	omap_gem_deinit(ddev);
>   
>   	destroy_workqueue(priv->wq);
> diff --git a/drivers/gpu/drm/omapdrm/omap_drv.h b/drivers/gpu/drm/omapdrm/omap_drv.h
> index 591d4c273f02..b4d9c2062723 100644
> --- a/drivers/gpu/drm/omapdrm/omap_drv.h
> +++ b/drivers/gpu/drm/omapdrm/omap_drv.h
> @@ -24,6 +24,7 @@
>   #include "omap_gem.h"
>   #include "omap_irq.h"
>   #include "omap_plane.h"
> +#include "omap_overlay.h"
>   
>   #define DBG(fmt, ...) DRM_DEBUG_DRIVER(fmt"\n", ##__VA_ARGS__)
>   #define VERB(fmt, ...) if (0) DRM_DEBUG_DRIVER(fmt, ##__VA_ARGS__) /* verbose debug */
> @@ -57,6 +58,9 @@ struct omap_drm_private {
>   	unsigned int num_planes;
>   	struct drm_plane *planes[8];
>   
> +	unsigned int num_ovls;
> +	struct omap_hw_overlay *overlays[8];
> +
>   	struct drm_fb_helper *fbdev;
>   
>   	struct workqueue_struct *wq;
> diff --git a/drivers/gpu/drm/omapdrm/omap_overlay.c b/drivers/gpu/drm/omapdrm/omap_overlay.c
> new file mode 100644
> index 000000000000..2b1416d2aad2
> --- /dev/null
> +++ b/drivers/gpu/drm/omapdrm/omap_overlay.c
> @@ -0,0 +1,87 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2018 Texas Instruments Incorporated -  http://www.ti.com/
> + * Author: Benoit Parrot, <bparrot@ti.com>

Extra comma there, and similar case below.

> + */
> +
> +#include <drm/drm_atomic.h>
> +#include <drm/drm_atomic_helper.h>
> +#include <drm/drm_plane_helper.h>
> +
> +#include "omap_dmm_tiler.h"
> +#include "omap_drv.h"
> +
> +/*
> + * overlay funcs
> + */
> +static const char * const overlay_id_to_name[] = {
> +	[OMAP_DSS_GFX] = "gfx",
> +	[OMAP_DSS_VIDEO1] = "vid1",
> +	[OMAP_DSS_VIDEO2] = "vid2",
> +	[OMAP_DSS_VIDEO3] = "vid3",
> +};

I was expecting to see the name array to be removed from omap_plane.c as 
it's moved here, but that's not the case. Why is that? Especially as 
after this series these names make no sense with the planes.

> +static void omap_overlay_destroy(struct omap_hw_overlay *overlay)
> +{
> +	kfree(overlay);
> +}
> +
> +static struct omap_hw_overlay *omap_overlay_init(enum omap_plane_id overlay_id,
> +						 enum omap_overlay_caps caps)
> +{
> +	struct omap_hw_overlay *overlay;
> +
> +	overlay = kzalloc(sizeof(*overlay), GFP_KERNEL);
> +	if (!overlay)
> +		return ERR_PTR(-ENOMEM);
> +
> +	overlay->name = overlay_id_to_name[overlay_id];
> +	overlay->overlay_id = overlay_id;
> +	overlay->caps = caps;
> +	/*
> +	 * When this is called priv->num_crtcs is not known yet.
> +	 * Use a safe mask value to start with, it will get updated to the
> +	 * proper value after the first use.
> +	 */
> +	overlay->possible_crtcs = 0xff;

This sounds like a hack. Why do we need possible_crtcs anyway? If I'm 
not mistaken, on all DSS versions any overlay can be used on any ctrtc. 
On the DRM plane level we need the possible_crtc as the DRM framework 
needs that (i.e. we just always set all crtcs available for all planes), 
but why is it needed here?

> +	return overlay;
> +}
> +
> +int omap_hwoverlays_init(struct omap_drm_private *priv)
> +{
> +	static const enum omap_plane_id hw_plane_ids[] = {
> +			OMAP_DSS_GFX, OMAP_DSS_VIDEO1,
> +			OMAP_DSS_VIDEO2, OMAP_DSS_VIDEO3,
> +	};
> +	u32 num_overlays = dispc_get_num_ovls(priv->dispc);
> +	enum omap_overlay_caps caps;
> +	int i, ret;
> +
> +	for (i = 0; i < num_overlays; i++) {
> +		struct omap_hw_overlay *overlay;
> +
> +		caps = dispc_ovl_get_caps(priv->dispc, hw_plane_ids[i]);
> +		overlay = omap_overlay_init(hw_plane_ids[i], caps);
> +		if (IS_ERR(overlay)) {
> +			ret = PTR_ERR(overlay);
> +			dev_err(priv->dev, "failed to construct overlay for %s (%d)\n",
> +				overlay_id_to_name[i], ret);
> +			return ret;
> +		}

I think this leaks memory if omap_overlay_init() fails.

> +		overlay->idx = priv->num_ovls;
> +		priv->overlays[priv->num_ovls++] = overlay;
> +	}
> +
> +	return 0;
> +}
> +
> +void omap_hwoverlays_destroy(struct omap_drm_private *priv)
> +{
> +	int i;
> +
> +	for (i = 0; i < priv->num_ovls; i++) {
> +		omap_overlay_destroy(priv->overlays[i]);
> +		priv->overlays[i] = NULL;
> +	}
> +}
> diff --git a/drivers/gpu/drm/omapdrm/omap_overlay.h b/drivers/gpu/drm/omapdrm/omap_overlay.h
> new file mode 100644
> index 000000000000..892fecb67adb
> --- /dev/null
> +++ b/drivers/gpu/drm/omapdrm/omap_overlay.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2018 Texas Instruments Incorporated -  http://www.ti.com/
> + * Author: Benoit Parrot, <bparrot@ti.com>
> + */
> +
> +#ifndef __OMAPDRM_OVERLAY_H__
> +#define __OMAPDRM_OVERLAY_H__
> +
> +#include <linux/types.h>
> +
> +enum drm_plane_type;
> +
> +struct drm_device;
> +struct drm_mode_object;
> +struct drm_plane;
> +
> +/* Used to associate a HW overlay/plane to a plane */
> +struct omap_hw_overlay {
> +	int idx;

unsigned int.

> +
> +	const char *name;
> +	enum omap_plane_id overlay_id;

Perhaps just "id" is fine. You don't have "overlay_name" there either, 
but just "name".

  Tomi