diff mbox series

[v2,20/22] drm: mxsfb: Merge mxsfb_set_pixel_fmt() and mxsfb_set_bus_fmt()

Message ID 20200530031015.15492-21-laurent.pinchart@ideasonboard.com (mailing list archive)
State New, archived
Headers show
Series drm: mxsfb: Add i.MX7 support | expand

Commit Message

Laurent Pinchart May 30, 2020, 3:10 a.m. UTC 
The mxsfb_set_pixel_fmt() and mxsfb_set_bus_fmt() functions both deal
with format configuration, are always called in a row from
mxsfb_crtc_mode_set_nofb(), and set fields from the LCDC_CTRL register.
This requires a read-modify-update cycle in mxsfb_set_bus_fmt(). Make
this more efficient by merging them together.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Stefan Agner <stefan@agner.ch>
---
 drivers/gpu/drm/mxsfb/mxsfb_kms.c | 47 +++++++++++++------------------
 1 file changed, 19 insertions(+), 28 deletions(-)

Comments

Emil Velikov June 5, 2020, 2:58 p.m. UTC | #1 
Hi Laurent,

With the previous disclaimer in mind, the series is:
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

There's a small suggestion inline, for future work.

On Sat, 30 May 2020 at 04:11, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:

>         switch (bus_format) {
>         case MEDIA_BUS_FMT_RGB565_1X16:
> -               reg |= CTRL_BUS_WIDTH_16;
> +               ctrl |= CTRL_BUS_WIDTH_16;
>                 break;
>         case MEDIA_BUS_FMT_RGB666_1X18:
> -               reg |= CTRL_BUS_WIDTH_18;
> +               ctrl |= CTRL_BUS_WIDTH_18;
>                 break;
>         case MEDIA_BUS_FMT_RGB888_1X24:
> -               reg |= CTRL_BUS_WIDTH_24;
> +               ctrl |= CTRL_BUS_WIDTH_24;
>                 break;
>         default:
>                 dev_err(drm->dev, "Unknown media bus format %d\n", bus_format);
>                 break;

Off the top of my head, the default case should be handled in the
atomic_check() hook.
That is, unless I'm missing something and one can change the bus
format in between atomic_check() and atomic_enable(). Which would
sound like a very odd thing to do.

-Emil
Laurent Pinchart June 6, 2020, 11:01 p.m. UTC | #2 
Hi Emil,

On Fri, Jun 05, 2020 at 03:58:53PM +0100, Emil Velikov wrote:
> Hi Laurent,
> 
> With the previous disclaimer in mind, the series is:
> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>

Sorry, which disclaimer is that ?

> There's a small suggestion inline, for future work.
> 
> On Sat, 30 May 2020 at 04:11, Laurent Pinchart wrote:
> 
> >         switch (bus_format) {
> >         case MEDIA_BUS_FMT_RGB565_1X16:
> > -               reg |= CTRL_BUS_WIDTH_16;
> > +               ctrl |= CTRL_BUS_WIDTH_16;
> >                 break;
> >         case MEDIA_BUS_FMT_RGB666_1X18:
> > -               reg |= CTRL_BUS_WIDTH_18;
> > +               ctrl |= CTRL_BUS_WIDTH_18;
> >                 break;
> >         case MEDIA_BUS_FMT_RGB888_1X24:
> > -               reg |= CTRL_BUS_WIDTH_24;
> > +               ctrl |= CTRL_BUS_WIDTH_24;
> >                 break;
> >         default:
> >                 dev_err(drm->dev, "Unknown media bus format %d\n", bus_format);
> >                 break;
> 
> Off the top of my head, the default case should be handled in the
> atomic_check() hook.
> That is, unless I'm missing something and one can change the bus
> format in between atomic_check() and atomic_enable(). Which would
> sound like a very odd thing to do.

I agree, this should go to the atomic check. There are still quite a few
things to improve in this driver, one step at a time :-)
Emil Velikov June 15, 2020, 7:31 p.m. UTC | #3 
i Laurent,

On Sun, 7 Jun 2020 at 00:02, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Emil,
>
> On Fri, Jun 05, 2020 at 03:58:53PM +0100, Emil Velikov wrote:
> > Hi Laurent,
> >
> > With the previous disclaimer in mind, the series is:
> > Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
>
> Sorry, which disclaimer is that ?
>
"I don't know much about the hardware" from earlier. Even then, the
refactor that is 1-21 is spot on.


> > There's a small suggestion inline, for future work.
> >
> > On Sat, 30 May 2020 at 04:11, Laurent Pinchart wrote:
> >
> > >         switch (bus_format) {
> > >         case MEDIA_BUS_FMT_RGB565_1X16:
> > > -               reg |= CTRL_BUS_WIDTH_16;
> > > +               ctrl |= CTRL_BUS_WIDTH_16;
> > >                 break;
> > >         case MEDIA_BUS_FMT_RGB666_1X18:
> > > -               reg |= CTRL_BUS_WIDTH_18;
> > > +               ctrl |= CTRL_BUS_WIDTH_18;
> > >                 break;
> > >         case MEDIA_BUS_FMT_RGB888_1X24:
> > > -               reg |= CTRL_BUS_WIDTH_24;
> > > +               ctrl |= CTRL_BUS_WIDTH_24;
> > >                 break;
> > >         default:
> > >                 dev_err(drm->dev, "Unknown media bus format %d\n", bus_format);
> > >                 break;
> >
> > Off the top of my head, the default case should be handled in the
> > atomic_check() hook.
> > That is, unless I'm missing something and one can change the bus
> > format in between atomic_check() and atomic_enable(). Which would
> > sound like a very odd thing to do.
>
> I agree, this should go to the atomic check. There are still quite a few
> things to improve in this driver, one step at a time :-)
>
Agreed - simply mentioning for completeness-sake. Doing that at misc
later point is perfectly fine.

HTH
Emil
diff mbox series

Patch

diff --git a/drivers/gpu/drm/mxsfb/mxsfb_kms.c b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
index 19b937b383cf..f81f8c222c13 100644
--- a/drivers/gpu/drm/mxsfb/mxsfb_kms.c
+++ b/drivers/gpu/drm/mxsfb/mxsfb_kms.c
@@ -42,13 +42,23 @@  static u32 set_hsync_pulse_width(struct mxsfb_drm_private *mxsfb, u32 val)
 		mxsfb->devdata->hs_wdth_shift;
 }
 
-/* Setup the MXSFB registers for decoding the pixels out of the framebuffer */
-static void mxsfb_set_pixel_fmt(struct mxsfb_drm_private *mxsfb)
+/*
+ * Setup the MXSFB registers for decoding the pixels out of the framebuffer and
+ * outputting them on the bus.
+ */
+static void mxsfb_set_formats(struct mxsfb_drm_private *mxsfb)
 {
 	struct drm_device *drm = mxsfb->drm;
 	const u32 format = mxsfb->crtc.primary->state->fb->format->format;
+	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
 	u32 ctrl, ctrl1;
 
+	if (mxsfb->connector->display_info.num_bus_formats)
+		bus_format = mxsfb->connector->display_info.bus_formats[0];
+
+	DRM_DEV_DEBUG_DRIVER(drm->dev, "Using bus_format: 0x%08X\n",
+			     bus_format);
+
 	ctrl = CTRL_BYPASS_COUNT | CTRL_MASTER;
 
 	/* CTRL1 contains IRQ config and status bits, preserve those. */
@@ -69,40 +79,23 @@  static void mxsfb_set_pixel_fmt(struct mxsfb_drm_private *mxsfb)
 		break;
 	}
 
-	writel(ctrl1, mxsfb->base + LCDC_CTRL1);
-	writel(ctrl, mxsfb->base + LCDC_CTRL);
-}
-
-static void mxsfb_set_bus_fmt(struct mxsfb_drm_private *mxsfb)
-{
-	struct drm_device *drm = mxsfb->drm;
-	u32 bus_format = MEDIA_BUS_FMT_RGB888_1X24;
-	u32 reg;
-
-	reg = readl(mxsfb->base + LCDC_CTRL);
-
-	if (mxsfb->connector->display_info.num_bus_formats)
-		bus_format = mxsfb->connector->display_info.bus_formats[0];
-
-	DRM_DEV_DEBUG_DRIVER(drm->dev, "Using bus_format: 0x%08X\n",
-			     bus_format);
-
-	reg &= ~CTRL_BUS_WIDTH_MASK;
 	switch (bus_format) {
 	case MEDIA_BUS_FMT_RGB565_1X16:
-		reg |= CTRL_BUS_WIDTH_16;
+		ctrl |= CTRL_BUS_WIDTH_16;
 		break;
 	case MEDIA_BUS_FMT_RGB666_1X18:
-		reg |= CTRL_BUS_WIDTH_18;
+		ctrl |= CTRL_BUS_WIDTH_18;
 		break;
 	case MEDIA_BUS_FMT_RGB888_1X24:
-		reg |= CTRL_BUS_WIDTH_24;
+		ctrl |= CTRL_BUS_WIDTH_24;
 		break;
 	default:
 		dev_err(drm->dev, "Unknown media bus format %d\n", bus_format);
 		break;
 	}
-	writel(reg, mxsfb->base + LCDC_CTRL);
+
+	writel(ctrl1, mxsfb->base + LCDC_CTRL1);
+	writel(ctrl, mxsfb->base + LCDC_CTRL);
 }
 
 static void mxsfb_enable_controller(struct mxsfb_drm_private *mxsfb)
@@ -213,7 +206,7 @@  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);
 
-	mxsfb_set_pixel_fmt(mxsfb);
+	mxsfb_set_formats(mxsfb);
 
 	clk_set_rate(mxsfb->clk, m->crtc_clock * 1000);
 
@@ -255,8 +248,6 @@  static void mxsfb_crtc_mode_set_nofb(struct mxsfb_drm_private *mxsfb)
 
 	writel(vdctrl0, mxsfb->base + LCDC_VDCTRL0);
 
-	mxsfb_set_bus_fmt(mxsfb);
-
 	/* Frame length in lines. */
 	writel(m->crtc_vtotal, mxsfb->base + LCDC_VDCTRL1);