[PATCH 21/21] drm: mxsfb: Support the alpha plane

Laurent Pinchart laurent.pinchart at ideasonboard.com
Sat May 30 02:44:33 UTC 2020


Hi Stefan,

On Tue, Mar 24, 2020 at 12:48:17AM +0100, Stefan Agner wrote:
> On 2020-03-09 20:52, Laurent Pinchart wrote:
> > The LCDIF in the i.MX6SX and i.MX7 have a second plane called the alpha
> > plane. Support it.
> > 
> > Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
> > ---
> >  drivers/gpu/drm/mxsfb/mxsfb_drv.c  |   3 +
> >  drivers/gpu/drm/mxsfb/mxsfb_drv.h  |  16 ++--
> >  drivers/gpu/drm/mxsfb/mxsfb_kms.c  | 129 +++++++++++++++++++++++++----
> >  drivers/gpu/drm/mxsfb/mxsfb_regs.h |  22 +++++
> >  4 files changed, 149 insertions(+), 21 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> > b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> > index ed8e3f7bc27c..ab3a212375f1 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.c
> > @@ -49,6 +49,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = {
> >  		.next_buf	= LCDC_V3_NEXT_BUF,
> >  		.hs_wdth_mask	= 0xff,
> >  		.hs_wdth_shift	= 24,
> > +		.has_overlay	= false,
> >  	},
> >  	[MXSFB_V4] = {
> >  		.transfer_count	= LCDC_V4_TRANSFER_COUNT,
> > @@ -56,6 +57,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = {
> >  		.next_buf	= LCDC_V4_NEXT_BUF,
> >  		.hs_wdth_mask	= 0x3fff,
> >  		.hs_wdth_shift	= 18,
> > +		.has_overlay	= false,
> >  	},
> >  	[MXSFB_V6] = {
> >  		.transfer_count	= LCDC_V4_TRANSFER_COUNT,
> > @@ -63,6 +65,7 @@ static const struct mxsfb_devdata mxsfb_devdata[] = {
> >  		.next_buf	= LCDC_V4_NEXT_BUF,
> >  		.hs_wdth_mask	= 0x3fff,
> >  		.hs_wdth_shift	= 18,
> > +		.has_overlay	= true,
> >  	},
> >  };
> >  
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> > b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> > index 607a6a5e6be3..399d23e91ed1 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_drv.h
> > @@ -16,11 +16,12 @@
> >  struct clk;
> >  
> >  struct mxsfb_devdata {
> > -	unsigned int	 transfer_count;
> > -	unsigned int	 cur_buf;
> > -	unsigned int	 next_buf;
> > -	unsigned int	 hs_wdth_mask;
> > -	unsigned int	 hs_wdth_shift;
> > +	unsigned int	transfer_count;
> > +	unsigned int	cur_buf;
> > +	unsigned int	next_buf;
> > +	unsigned int	hs_wdth_mask;
> > +	unsigned int	hs_wdth_shift;
> 
> This seems an unrelated change, can you split that out?

OK.

> > +	bool		has_overlay;
> >  };
> >  
> >  struct mxsfb_drm_private {
> > @@ -32,7 +33,10 @@ struct mxsfb_drm_private {
> >  	struct clk			*clk_disp_axi;
> >  
> >  	struct drm_device		*drm;
> > -	struct drm_plane		plane;
> > +	struct {
> > +		struct drm_plane	primary;
> > +		struct drm_plane	overlay;
> > +	} planes;
> >  	struct drm_crtc			crtc;
> >  	struct drm_encoder		encoder;
> >  	struct drm_connector		*connector;
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > index f81f8c222c13..c9c394f7cbe2 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
> > @@ -169,9 +169,9 @@ static int mxsfb_reset_block(struct
> > mxsfb_drm_private *mxsfb)
> >  	return clear_poll_bit(mxsfb->base + LCDC_CTRL, CTRL_CLKGATE);
> >  }
> >  
> > -static dma_addr_t mxsfb_get_fb_paddr(struct mxsfb_drm_private *mxsfb)
> > +static dma_addr_t mxsfb_get_fb_paddr(struct drm_plane *plane)
> >  {
> > -	struct drm_framebuffer *fb = mxsfb->plane.state->fb;
> > +	struct drm_framebuffer *fb = plane->state->fb;
> >  	struct drm_gem_cma_object *gem;
> >  
> >  	if (!fb)
> > @@ -206,6 +206,9 @@ static void mxsfb_crtc_mode_set_nofb(struct
> > mxsfb_drm_private *mxsfb)
> >  	/* Clear the FIFOs */
> >  	writel(CTRL1_FIFO_CLEAR, mxsfb->base + LCDC_CTRL1 + REG_SET);
> >  
> > +	if (mxsfb->devdata->has_overlay)
> > +		writel(0, mxsfb->base + LCDC_AS_CTRL);
> > +
> >  	mxsfb_set_formats(mxsfb);
> >  
> >  	clk_set_rate(mxsfb->clk, m->crtc_clock * 1000);
> > @@ -313,7 +316,7 @@ static void mxsfb_crtc_atomic_enable(struct drm_crtc *crtc,
> >  	mxsfb_crtc_mode_set_nofb(mxsfb);
> >  
> >  	/* Write cur_buf as well to avoid an initial corrupt frame */
> > -	paddr = mxsfb_get_fb_paddr(mxsfb);
> > +	paddr = mxsfb_get_fb_paddr(crtc->primary);
> >  	if (paddr) {
> >  		writel(paddr, mxsfb->base + mxsfb->devdata->cur_buf);
> >  		writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
> > @@ -410,20 +413,85 @@ static int mxsfb_plane_atomic_check(struct
> > drm_plane *plane,
> >  						   false, true);
> >  }
> >  
> > -static void mxsfb_plane_atomic_update(struct drm_plane *plane,
> > -				      struct drm_plane_state *old_pstate)
> > +static void mxsfb_plane_primary_atomic_update(struct drm_plane *plane,
> > +					      struct drm_plane_state *old_pstate)
> >  {
> >  	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev);
> >  	dma_addr_t paddr;
> >  
> > -	paddr = mxsfb_get_fb_paddr(mxsfb);
> > +	paddr = mxsfb_get_fb_paddr(plane);
> >  	if (paddr)
> >  		writel(paddr, mxsfb->base + mxsfb->devdata->next_buf);
> >  }
> >  
> > -static const struct drm_plane_helper_funcs mxsfb_plane_helper_funcs = {
> > +static void mxsfb_plane_overlay_atomic_update(struct drm_plane *plane,
> > +					      struct drm_plane_state *old_pstate)
> > +{
> > +	struct mxsfb_drm_private *mxsfb = to_mxsfb_drm_private(plane->dev);
> > +	struct drm_plane_state *state = plane->state;
> > +	dma_addr_t paddr;
> > +	u32 ctrl;
> > +
> > +	paddr = mxsfb_get_fb_paddr(plane);
> > +	if (!paddr) {
> > +		writel(0, mxsfb->base + LCDC_AS_CTRL);
> > +		return;
> > +	}
> > +
> > +	/*
> > +	 * HACK: The hardware seems to output 64 bytes of data of unknown
> > +	 * origin, and then to proceed with the framebuffer. Until the reason
> > +	 * is understood, live with the 16 initial invalid pixels on the first
> > +	 * line and start 64 bytes within the framebuffer.
> > +	 */
> > +	paddr += 64;
> 
> Wow, that is interesting. Did you check/find downstream drivers which
> support this feature and have some kind of hint/work around?
>
> Also adding NXP folks, maybe you have some idea?

I've had a look at the fbdev driver (drivers/video/fbdev/mxsfb.c) in the
4.14-2.3.x-imx branch of https://github.com/Freescale/linux-fslc.git.
When enabling the overlay, the driver first disables the LCDIF
completely, clears the FIFOs, then enable the overlay, clears the FIFOs
again, and reenables the LCDIF. I really hope that whole sequence isn't
needed, as that would reduce the usability of the LCDIF even more, but
it looks quite like a FIFO issue. Feedback from NXP would be helpful,
the i.MX7D reference manual doesn't decribe how to operate the overlay
plane, it only lists the related registers.

> Otherwise I guess we live with this.
> 
> > +
> > +	writel(paddr, mxsfb->base + LCDC_AS_NEXT_BUF);
> > +
> > +	/*
> > +	 * If the plane was previously disabled, write LCDC_AS_BUF as well to
> > +	 * provide the first buffer.
> > +	 */
> > +	if (!old_pstate->fb)
> > +		writel(paddr, mxsfb->base + LCDC_AS_BUF);
> > +
> > +	ctrl = AS_CTRL_AS_ENABLE | AS_CTRL_ALPHA(255);
> > +
> > +	switch (state->fb->format->format) {
> > +	case DRM_FORMAT_XRGB4444:
> > +		ctrl |= AS_CTRL_FORMAT_RGB444 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
> > +		break;
> > +	case DRM_FORMAT_ARGB4444:
> > +		ctrl |= AS_CTRL_FORMAT_ARGB4444 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
> > +		break;
> > +	case DRM_FORMAT_XRGB1555:
> > +		ctrl |= AS_CTRL_FORMAT_RGB555 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
> > +		break;
> > +	case DRM_FORMAT_ARGB1555:
> > +		ctrl |= AS_CTRL_FORMAT_ARGB1555 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
> > +		break;
> > +	case DRM_FORMAT_RGB565:
> > +		ctrl |= AS_CTRL_FORMAT_RGB565 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
> > +		break;
> > +	case DRM_FORMAT_XRGB8888:
> > +		ctrl |= AS_CTRL_FORMAT_RGB888 | AS_CTRL_ALPHA_CTRL_OVERRIDE;
> > +		break;
> > +	case DRM_FORMAT_ARGB8888:
> > +		ctrl |= AS_CTRL_FORMAT_ARGB8888 | AS_CTRL_ALPHA_CTRL_EMBEDDED;
> > +		break;
> > +	}
> > +
> > +	writel(ctrl, mxsfb->base + LCDC_AS_CTRL);
> > +}
> > +
> > +static const struct drm_plane_helper_funcs mxsfb_plane_primary_helper_funcs = {
> > +	.atomic_check = mxsfb_plane_atomic_check,
> > +	.atomic_update = mxsfb_plane_primary_atomic_update,
> > +};
> > +
> > +static const struct drm_plane_helper_funcs mxsfb_plane_overlay_helper_funcs = {
> >  	.atomic_check = mxsfb_plane_atomic_check,
> > -	.atomic_update = mxsfb_plane_atomic_update,
> > +	.atomic_update = mxsfb_plane_overlay_atomic_update,
> >  };
> >  
> >  static const struct drm_plane_funcs mxsfb_plane_funcs = {
> > @@ -435,27 +503,58 @@ static const struct drm_plane_funcs mxsfb_plane_funcs = {
> >  	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> >  };
> >  
> > -static const uint32_t mxsfb_formats[] = {
> > +static const uint32_t mxsfb_primary_plane_formats[] = {
> > +	DRM_FORMAT_RGB565,
> > +	DRM_FORMAT_XRGB8888,
> > +};
> > +
> > +static const uint32_t mxsfb_overlay_plane_formats[] = {
> > +	DRM_FORMAT_XRGB4444,
> > +	DRM_FORMAT_ARGB4444,
> > +	DRM_FORMAT_XRGB1555,
> > +	DRM_FORMAT_ARGB1555,
> > +	DRM_FORMAT_RGB565,
> >  	DRM_FORMAT_XRGB8888,
> > -	DRM_FORMAT_RGB565
> > +	DRM_FORMAT_ARGB8888,
> >  };
> >  
> > +/*
> > -----------------------------------------------------------------------------
> > + * Initialization
> > + */
> > +
> >  int mxsfb_kms_init(struct mxsfb_drm_private *mxsfb)
> >  {
> >  	struct drm_encoder *encoder = &mxsfb->encoder;
> > -	struct drm_plane *plane = &mxsfb->plane;
> >  	struct drm_crtc *crtc = &mxsfb->crtc;
> >  	int ret;
> >  
> > -	drm_plane_helper_add(plane, &mxsfb_plane_helper_funcs);
> > -	ret = drm_universal_plane_init(mxsfb->drm, plane, 0, &mxsfb_plane_funcs,
> > -				       mxsfb_formats, ARRAY_SIZE(mxsfb_formats),
> > +	drm_plane_helper_add(&mxsfb->planes.primary,
> > +			     &mxsfb_plane_primary_helper_funcs);
> > +	ret = drm_universal_plane_init(mxsfb->drm, &mxsfb->planes.primary, 1,
> > +				       &mxsfb_plane_funcs,
> > +				       mxsfb_primary_plane_formats,
> > +				       ARRAY_SIZE(mxsfb_primary_plane_formats),
> >  				       NULL, DRM_PLANE_TYPE_PRIMARY, NULL);
> >  	if (ret)
> >  		return ret;
> >  
> > +	if (mxsfb->devdata->has_overlay) {
> > +		drm_plane_helper_add(&mxsfb->planes.overlay,
> > +				     &mxsfb_plane_overlay_helper_funcs);
> > +		ret = drm_universal_plane_init(mxsfb->drm,
> > +					       &mxsfb->planes.overlay, 1,
> > +					       &mxsfb_plane_funcs,
> > +					       mxsfb_overlay_plane_formats,
> > +					       ARRAY_SIZE(mxsfb_overlay_plane_formats),
> > +					       NULL, DRM_PLANE_TYPE_OVERLAY,
> > +					       NULL);
> > +		if (ret)
> > +			return ret;
> > +	}
> > +
> >  	drm_crtc_helper_add(crtc, &mxsfb_crtc_helper_funcs);
> > -	ret = drm_crtc_init_with_planes(mxsfb->drm, crtc, plane, NULL,
> > +	ret = drm_crtc_init_with_planes(mxsfb->drm, crtc,
> > +					&mxsfb->planes.primary, NULL,
> >  					&mxsfb_crtc_funcs, NULL);
> >  	if (ret)
> >  		return ret;
> > diff --git a/drivers/gpu/drm/mxsfb/mxsfb_regs.h
> > b/drivers/gpu/drm/mxsfb/mxsfb_regs.h
> > index 8ebb52bb1b46..55d28a27f912 100644
> > --- a/drivers/gpu/drm/mxsfb/mxsfb_regs.h
> > +++ b/drivers/gpu/drm/mxsfb/mxsfb_regs.h
> > @@ -27,6 +27,11 @@
> >  #define LCDC_VDCTRL4			0xb0
> >  #define LCDC_V4_DEBUG0			0x1d0
> >  #define LCDC_V3_DEBUG0			0x1f0
> > +#define LCDC_AS_CTRL			0x210
> > +#define LCDC_AS_BUF			0x220
> > +#define LCDC_AS_NEXT_BUF		0x230
> > +#define LCDC_AS_CLRKEYLOW		0x240
> > +#define LCDC_AS_CLRKEYHIGH		0x250
> >  
> >  #define CTRL_SFTRST			BIT(31)
> >  #define CTRL_CLKGATE			BIT(30)
> > @@ -90,6 +95,23 @@
> >  #define DEBUG0_HSYNC			BIT(26)
> >  #define DEBUG0_VSYNC			BIT(25)
> >  
> > +#define AS_CTRL_PS_DISABLE		BIT(23)
> > +#define AS_CTRL_ALPHA_INVERT		BIT(20)
> > +#define AS_CTRL_ALPHA(a)		(((a) & 0xff) << 8)
> > +#define AS_CTRL_FORMAT_RGB565		(0xe << 4)
> > +#define AS_CTRL_FORMAT_RGB444		(0xd << 4)
> > +#define AS_CTRL_FORMAT_RGB555		(0xc << 4)
> > +#define AS_CTRL_FORMAT_ARGB4444		(0x9 << 4)
> > +#define AS_CTRL_FORMAT_ARGB1555		(0x8 << 4)
> > +#define AS_CTRL_FORMAT_RGB888		(0x4 << 4)
> > +#define AS_CTRL_FORMAT_ARGB8888		(0x0 << 4)
> > +#define AS_CTRL_ENABLE_COLORKEY		BIT(3)
> > +#define AS_CTRL_ALPHA_CTRL_ROP		(3 << 1)
> > +#define AS_CTRL_ALPHA_CTRL_MULTIPLY	(2 << 1)
> > +#define AS_CTRL_ALPHA_CTRL_OVERRIDE	(1 << 1)
> > +#define AS_CTRL_ALPHA_CTRL_EMBEDDED	(0 << 1)
> > +#define AS_CTRL_AS_ENABLE		BIT(0)
> > +
> >  #define MXSFB_MIN_XRES			120
> >  #define MXSFB_MIN_YRES			120
> >  #define MXSFB_MAX_XRES			0xffff

-- 
Regards,

Laurent Pinchart


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