Patchwork [v3,09/11] powerpc/mpc5121: shared DIU framebuffer support

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Submitter Anatolij Gustschin
Date Feb. 5, 2010, 1:42 p.m.
Message ID <1265377377-29327-10-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/44639/
State Superseded
Delegated to: Grant Likely
Headers show

Comments

Anatolij Gustschin - Feb. 5, 2010, 1:42 p.m.
MPC5121 DIU configuration/setup as initialized by the boot
loader currently will get lost while booting Linux. As a
result displaying the boot splash is not possible through
the boot process.

To prevent this we reserve configured DIU frame buffer
address range while booting and preserve AOI descriptor
and gamma table so that DIU continues displaying through
the whole boot process. On first open from user space
DIU frame buffer driver releases the reserved frame
buffer area and continues to operate as usual.

The patch also moves drivers/video/fsl-diu-fb.h file to
include/linux as we use some DIU structures in platform
code.

'diu_ops' callbacks in platform code borrowed from John's
DIU code.

Signed-off-by: John Rigby <jrigby@gmail.com>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
Cc: Grant Likely <grant.likely@secretlab.ca>
---
No changes since v2

Changes since v1:
 - specify align attribute before "diu_shared_fb" variable
   name to fix checkpatch warning

 arch/powerpc/platforms/512x/mpc5121_ads.c     |    7 +
 arch/powerpc/platforms/512x/mpc5121_generic.c |   12 +
 arch/powerpc/platforms/512x/mpc512x.h         |    3 +
 arch/powerpc/platforms/512x/mpc512x_shared.c  |  283 +++++++++++++++++++++++++
 arch/powerpc/sysdev/fsl_soc.h                 |    1 +
 drivers/video/fsl-diu-fb.c                    |   40 +++-
 {drivers/video => include/linux}/fsl-diu-fb.h |    0
 7 files changed, 341 insertions(+), 5 deletions(-)
 rename {drivers/video => include/linux}/fsl-diu-fb.h (100%)

diff --git a/drivers/video/fsl-diu-fb.h b/include/linux/fsl-diu-fb.h
similarity index 100%
rename from drivers/video/fsl-diu-fb.h
rename to include/linux/fsl-diu-fb.h
Grant Likely - Feb. 16, 2010, 6:06 p.m.
On Fri, Feb 5, 2010 at 6:42 AM, Anatolij Gustschin <agust@denx.de> wrote:
> MPC5121 DIU configuration/setup as initialized by the boot
> loader currently will get lost while booting Linux. As a
> result displaying the boot splash is not possible through
> the boot process.
>
> To prevent this we reserve configured DIU frame buffer
> address range while booting and preserve AOI descriptor
> and gamma table so that DIU continues displaying through
> the whole boot process. On first open from user space
> DIU frame buffer driver releases the reserved frame
> buffer area and continues to operate as usual.
>
> The patch also moves drivers/video/fsl-diu-fb.h file to
> include/linux as we use some DIU structures in platform
> code.
>
> 'diu_ops' callbacks in platform code borrowed from John's
> DIU code.
>
> Signed-off-by: John Rigby <jrigby@gmail.com>
> Signed-off-by: Anatolij Gustschin <agust@denx.de>
> Cc: Grant Likely <grant.likely@secretlab.ca>
> ---
[...]
> diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
> index 72d68b3..29c7f31 100644
> --- a/drivers/video/fsl-diu-fb.c
> +++ b/drivers/video/fsl-diu-fb.c
> @@ -34,7 +34,7 @@
>  #include <linux/of_platform.h>
>
>  #include <sysdev/fsl_soc.h>
> -#include "fsl-diu-fb.h"
> +#include <linux/fsl-diu-fb.h>
>
>  /*
>  * These parameters give default parameters
> @@ -178,6 +178,21 @@ static struct fb_videomode __devinitdata fsl_diu_mode_db[] = {
>                .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
>                .vmode          = FB_VMODE_NONINTERLACED
>        },
> +       {
> +               .name           = "800x480-60",
> +               .refresh        = 60,
> +               .xres           = 800,
> +               .yres           = 480,
> +               .pixclock       = 31250,
> +               .left_margin    = 86,
> +               .right_margin   = 42,
> +               .upper_margin   = 33,
> +               .lower_margin   = 10,
> +               .hsync_len      = 128,
> +               .vsync_len      = 2,
> +               .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
> +               .vmode          = FB_VMODE_NONINTERLACED
> +       },
>  };

This hunk bothers me.  It looks like the type of data that belongs
either in some common shared .c file, or encoded into the device tree.
 It seems to be data about the display panel, instead of data about
the framebuffer driver.  I know that the driver already uses this
pattern, but before I merge this patch and further rely on that
pattern, I think it is worth discussing.

Kumar, York, thoughts?

g.
York Sun - Feb. 18, 2010, 4:15 p.m.
On Tue, 2010-02-16 at 11:06 -0700, Grant Likely wrote:
> [...]
> > diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
> > index 72d68b3..29c7f31 100644
> > --- a/drivers/video/fsl-diu-fb.c
> > +++ b/drivers/video/fsl-diu-fb.c
> > @@ -34,7 +34,7 @@
> >  #include <linux/of_platform.h>
> >
> >  #include <sysdev/fsl_soc.h>
> > -#include "fsl-diu-fb.h"
> > +#include <linux/fsl-diu-fb.h>
> >
> >  /*
> >  * These parameters give default parameters
> > @@ -178,6 +178,21 @@ static struct fb_videomode __devinitdata fsl_diu_mode_db[] = {
> >                .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
> >                .vmode          = FB_VMODE_NONINTERLACED
> >        },
> > +       {
> > +               .name           = "800x480-60",
> > +               .refresh        = 60,
> > +               .xres           = 800,
> > +               .yres           = 480,
> > +               .pixclock       = 31250,
> > +               .left_margin    = 86,
> > +               .right_margin   = 42,
> > +               .upper_margin   = 33,
> > +               .lower_margin   = 10,
> > +               .hsync_len      = 128,
> > +               .vsync_len      = 2,
> > +               .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
> > +               .vmode          = FB_VMODE_NONINTERLACED
> > +       },
> >  };
> 
> This hunk bothers me.  It looks like the type of data that belongs
> either in some common shared .c file, or encoded into the device tree.
>  It seems to be data about the display panel, instead of data about
> the framebuffer driver.  I know that the driver already uses this
> pattern, but before I merge this patch and further rely on that
> pattern, I think it is worth discussing.
> 
> Kumar, York, thoughts?
> 
> g.
> 

It is a hardware related configuration. It is only used during booting
before other configuration comes available.

I am OK to move it to anywhere as long as it doesn't get confused or
lost.

York
Anatolij Gustschin - Feb. 27, 2010, 9:58 p.m.
This patch series rework DIU support patch submitted
previously with the patch series for updating MPC5121
support in mainline. It doesn't add new panel timing data
to the framebuffer driver anymore. Instead we now allow
encoding this data in the device tree. First two patches
add this support.

The third patch for DIU support is rebased, but still
depends on patches for adding MPC5121 USB support (because
it touches shared platform code).

It is intended for inclusion in 2.6.34, since without
DIU support patch framebuffer doesn't work on mpc5121.

Anatolij Gustschin (3):
  video: add support for getting video mode from device tree
  fbdev: fsl-diu-fb.c: allow setting panel video mode from DT
  powerpc/mpc5121: shared DIU framebuffer support

 arch/powerpc/platforms/512x/mpc5121_ads.c     |    7 +
 arch/powerpc/platforms/512x/mpc5121_generic.c |   13 ++
 arch/powerpc/platforms/512x/mpc512x.h         |    3 +
 arch/powerpc/platforms/512x/mpc512x_shared.c  |  282 +++++++++++++++++++++++++
 arch/powerpc/sysdev/fsl_soc.h                 |    1 +
 drivers/video/Kconfig                         |    6 +
 drivers/video/Makefile                        |    1 +
 drivers/video/fsl-diu-fb.c                    |   88 +++++---
 drivers/video/fsl-diu-fb.h                    |  223 -------------------
 drivers/video/ofmode.c                        |   95 +++++++++
 drivers/video/ofmode.h                        |    6 +
 include/linux/fsl-diu-fb.h                    |  223 +++++++++++++++++++
 12 files changed, 693 insertions(+), 255 deletions(-)
 delete mode 100644 drivers/video/fsl-diu-fb.h
 create mode 100644 drivers/video/ofmode.c
 create mode 100644 drivers/video/ofmode.h
 create mode 100644 include/linux/fsl-diu-fb.h
Anatolij Gustschin - Feb. 27, 2010, 10:09 p.m.
On Tue, 16 Feb 2010 11:06:22 -0700
Grant Likely <grant.likely@secretlab.ca> wrote:

> [...]
> > diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
> > index 72d68b3..29c7f31 100644
> > --- a/drivers/video/fsl-diu-fb.c
> > +++ b/drivers/video/fsl-diu-fb.c
> > @@ -34,7 +34,7 @@
> >  #include <linux/of_platform.h>
> >
> >  #include <sysdev/fsl_soc.h>
> > -#include "fsl-diu-fb.h"
> > +#include <linux/fsl-diu-fb.h>
> >
> >  /*
> >  * These parameters give default parameters
> > @@ -178,6 +178,21 @@ static struct fb_videomode __devinitdata fsl_diu_mode_db[] = {
> >                .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
> >                .vmode          = FB_VMODE_NONINTERLACED
> >        },
> > +       {
> > +               .name           = "800x480-60",
> > +               .refresh        = 60,
> > +               .xres           = 800,
> > +               .yres           = 480,
> > +               .pixclock       = 31250,
> > +               .left_margin    = 86,
> > +               .right_margin   = 42,
> > +               .upper_margin   = 33,
> > +               .lower_margin   = 10,
> > +               .hsync_len      = 128,
> > +               .vsync_len      = 2,
> > +               .sync           = FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
> > +               .vmode          = FB_VMODE_NONINTERLACED
> > +       },
> >  };
> 
> This hunk bothers me.  It looks like the type of data that belongs
> either in some common shared .c file, or encoded into the device tree.
>  It seems to be data about the display panel, instead of data about
> the framebuffer driver.  I know that the driver already uses this
> pattern, but before I merge this patch and further rely on that
> pattern, I think it is worth discussing.

In the updated DIU patches I don't add panel timing data to the
framebuffer driver. It is encoded in the device tree now. If this
is acceptable, I'll send another patch adding the documentation
for added bindings.

Thanks,
Anatolij
Grant Likely - Feb. 28, 2010, 7:04 a.m.
Hi Anatolij,

On Sat, Feb 27, 2010 at 2:58 PM, Anatolij Gustschin <agust@denx.de> wrote:
> This patch series rework DIU support patch submitted
> previously with the patch series for updating MPC5121
> support in mainline. It doesn't add new panel timing data
> to the framebuffer driver anymore. Instead we now allow
> encoding this data in the device tree. First two patches
> add this support.

Thanks for this work.  I've made specific comments on the individual
patches.  There are some details to be worked out, but I think it is
moving in the right direction.

> It is intended for inclusion in 2.6.34, since without
> DIU support patch framebuffer doesn't work on mpc5121.

It's actually late for 2.6.34.  Unless it is a bug fix, I stop picking
up new patches somewhere in the -rc7 or -rc8 timerframe, and I am
definitely in bug-fix-only mode once the merge window has opened.  I
do this to ensure all patches receive a decent amount of linux-next
exposure before I ask Linus to pull them.

I'll being picking up new patches for 2.6.35 into my -next branch
after 2.6.34-rc1 is released.

g.

Patch

diff --git a/arch/powerpc/platforms/512x/mpc5121_ads.c b/arch/powerpc/platforms/512x/mpc5121_ads.c
index ee6ae12..aa4d5a8 100644
--- a/arch/powerpc/platforms/512x/mpc5121_ads.c
+++ b/arch/powerpc/platforms/512x/mpc5121_ads.c
@@ -42,6 +42,7 @@  static void __init mpc5121_ads_setup_arch(void)
 	for_each_compatible_node(np, "pci", "fsl,mpc5121-pci")
 		mpc83xx_add_bridge(np);
 #endif
+	mpc512x_setup_diu();
 }
 
 static void __init mpc5121_ads_init_IRQ(void)
@@ -60,11 +61,17 @@  static int __init mpc5121_ads_probe(void)
 	return of_flat_dt_is_compatible(root, "fsl,mpc5121ads");
 }
 
+void __init mpc5121_ads_init_early(void)
+{
+	mpc512x_init_diu();
+}
+
 define_machine(mpc5121_ads) {
 	.name			= "MPC5121 ADS",
 	.probe			= mpc5121_ads_probe,
 	.setup_arch		= mpc5121_ads_setup_arch,
 	.init			= mpc512x_init,
+	.init_early		= mpc5121_ads_init_early,
 	.init_IRQ		= mpc5121_ads_init_IRQ,
 	.get_irq		= ipic_get_irq,
 	.calibrate_decr		= generic_calibrate_decr,
diff --git a/arch/powerpc/platforms/512x/mpc5121_generic.c b/arch/powerpc/platforms/512x/mpc5121_generic.c
index a6c0e3a..c5ecb3d 100644
--- a/arch/powerpc/platforms/512x/mpc5121_generic.c
+++ b/arch/powerpc/platforms/512x/mpc5121_generic.c
@@ -48,10 +48,22 @@  static int __init mpc5121_generic_probe(void)
 	return board[i] != NULL;
 }
 
+void __init mpc512x_generic_init_early(void)
+{
+	mpc512x_init_diu();
+}
+
+void __init mpc512x_generic_setup_arch(void)
+{
+	mpc512x_setup_diu();
+}
+
 define_machine(mpc5121_generic) {
 	.name			= "MPC5121 generic",
 	.probe			= mpc5121_generic_probe,
 	.init			= mpc512x_init,
+	.init_early		= mpc512x_generic_init_early,
+	.setup_arch		= mpc512x_generic_setup_arch,
 	.init_IRQ		= mpc512x_init_IRQ,
 	.get_irq		= ipic_get_irq,
 	.calibrate_decr		= generic_calibrate_decr,
diff --git a/arch/powerpc/platforms/512x/mpc512x.h b/arch/powerpc/platforms/512x/mpc512x.h
index d72b2c7..1cfe9d5 100644
--- a/arch/powerpc/platforms/512x/mpc512x.h
+++ b/arch/powerpc/platforms/512x/mpc512x.h
@@ -17,4 +17,7 @@  extern int __init mpc5121_clk_init(void);
 void __init mpc512x_declare_of_platform_devices(void);
 extern void mpc512x_restart(char *cmd);
 extern void __init mpc5121_usb_init(void);
+extern void __init mpc512x_init_diu(void);
+extern void __init mpc512x_setup_diu(void);
+extern struct fsl_diu_shared_fb diu_shared_fb;
 #endif				/* __MPC512X_H__ */
diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 4de8175..65b0a5d 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -16,7 +16,11 @@ 
 #include <linux/io.h>
 #include <linux/irq.h>
 #include <linux/of_platform.h>
+#include <linux/fsl-diu-fb.h>
+#include <linux/bootmem.h>
+#include <sysdev/fsl_soc.h>
 
+#include <asm/cacheflush.h>
 #include <asm/machdep.h>
 #include <asm/ipic.h>
 #include <asm/prom.h>
@@ -57,6 +61,285 @@  void mpc512x_restart(char *cmd)
 		;
 }
 
+
+struct fsl_diu_shared_fb {
+	char		gamma[0x300];	/* 32-bit aligned! */
+	struct diu_ad	ad0;		/* 32-bit aligned! */
+	phys_addr_t	fb_phys;
+	size_t		fb_len;
+	bool		in_use;
+};
+
+unsigned int mpc512x_get_pixel_format(unsigned int bits_per_pixel,
+				      int monitor_port)
+{
+	unsigned int pix_fmt;
+
+	switch (bits_per_pixel) {
+	case 32:
+		pix_fmt = 0x88883316;
+		break;
+	case 24:
+		pix_fmt = 0x88082219;
+		break;
+	case 16:
+		pix_fmt = 0x65053118;
+		break;
+	default:
+		pix_fmt = 0x00000400;
+	}
+	return pix_fmt;
+}
+
+void mpc512x_set_gamma_table(int monitor_port, char *gamma_table_base)
+{
+}
+
+void mpc512x_set_monitor_port(int monitor_port)
+{
+}
+
+#define CCM_SCFR1	0x0000000c
+#define DIU_DIV_MASK	0x000000ff
+void mpc512x_set_pixel_clock(unsigned int pixclock)
+{
+	unsigned long bestval, bestfreq, speed_ccb, busfreq;
+	unsigned long minpixclock, maxpixclock, pixval;
+	struct device_node *np;
+	void __iomem *ccm;
+	u32 temp;
+	long err;
+	int i;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,mpc5121-clock");
+	if (!np) {
+		pr_err("Can't find clock control module.\n");
+		return;
+	}
+
+	ccm = of_iomap(np, 0);
+	if (!ccm) {
+		pr_err("Can't map clock control module reg.\n");
+		of_node_put(np);
+		return;
+	}
+	of_node_put(np);
+
+	busfreq = 200000000;
+	np = of_find_node_by_type(NULL, "cpu");
+	if (np) {
+		unsigned int size;
+		const unsigned int *prop =
+			of_get_property(np, "bus-frequency", &size);
+		if (prop)
+			busfreq = *prop;
+		of_node_put(np);
+	}
+
+	/* Pixel Clock configuration */
+	pr_debug("DIU: Bus Frequency = %lu\n", busfreq);
+	speed_ccb = busfreq * 4;
+
+	/* Calculate the pixel clock with the smallest error */
+	/* calculate the following in steps to avoid overflow */
+	pr_debug("DIU pixclock in ps - %d\n", pixclock);
+	temp = 1;
+	temp *= 1000000000;
+	temp /= pixclock;
+	temp *= 1000;
+	pixclock = temp;
+	pr_debug("DIU pixclock freq - %u\n", pixclock);
+
+	temp *= 5;
+	temp /= 100;  /* pixclock * 0.05 */
+	pr_debug("deviation = %d\n", temp);
+	minpixclock = pixclock - temp;
+	maxpixclock = pixclock + temp;
+	pr_debug("DIU minpixclock - %lu\n", minpixclock);
+	pr_debug("DIU maxpixclock - %lu\n", maxpixclock);
+	pixval = speed_ccb/pixclock;
+	pr_debug("DIU pixval = %lu\n", pixval);
+
+	err = 100000000;
+	bestval = pixval;
+	pr_debug("DIU bestval = %lu\n", bestval);
+
+	bestfreq = 0;
+	for (i = -1; i <= 1; i++) {
+		temp = speed_ccb / (pixval+i);
+		pr_debug("DIU test pixval i=%d, pixval=%lu, temp freq. = %u\n",
+			i, pixval, temp);
+		if ((temp < minpixclock) || (temp > maxpixclock))
+			pr_debug("DIU exceeds monitor range (%lu to %lu)\n",
+				minpixclock, maxpixclock);
+		else if (abs(temp - pixclock) < err) {
+			pr_debug("Entered the else if block %d\n", i);
+			err = abs(temp - pixclock);
+			bestval = pixval + i;
+			bestfreq = temp;
+		}
+	}
+
+	pr_debug("DIU chose = %lx\n", bestval);
+	pr_debug("DIU error = %ld\n NomPixClk ", err);
+	pr_debug("DIU: Best Freq = %lx\n", bestfreq);
+	/* Modify DIU_DIV in CCM SCFR1 */
+	temp = in_be32(ccm + CCM_SCFR1);
+	pr_debug("DIU: Current value of SCFR1: 0x%08x\n", temp);
+	temp &= ~DIU_DIV_MASK;
+	temp |= (bestval & DIU_DIV_MASK);
+	out_be32(ccm + CCM_SCFR1, temp);
+	pr_debug("DIU: Modified value of SCFR1: 0x%08x\n", temp);
+	iounmap(ccm);
+}
+
+ssize_t mpc512x_show_monitor_port(int monitor_port, char *buf)
+{
+	return snprintf(buf, PAGE_SIZE, "0 - 5121 LCD\n");
+}
+
+int mpc512x_set_sysfs_monitor_port(int val)
+{
+	return 0;
+}
+
+struct fsl_diu_shared_fb __attribute__ ((__aligned__(8))) diu_shared_fb;
+EXPORT_SYMBOL_GPL(diu_shared_fb);
+
+#if defined(CONFIG_FB_FSL_DIU) || \
+    defined(CONFIG_FB_FSL_DIU_MODULE)
+static inline void mpc512x_free_bootmem(struct page *page)
+{
+	__ClearPageReserved(page);
+	BUG_ON(PageTail(page));
+	BUG_ON(atomic_read(&page->_count) > 1);
+	atomic_set(&page->_count, 1);
+	__free_page(page);
+	totalram_pages++;
+}
+
+void mpc512x_release_bootmem(void)
+{
+	unsigned long addr = diu_shared_fb.fb_phys & PAGE_MASK;
+	unsigned long size = diu_shared_fb.fb_len;
+	unsigned long start, end;
+
+	if (diu_shared_fb.in_use) {
+		start = PFN_UP(addr);
+		end = PFN_DOWN(addr + size);
+
+		for (; start < end; start++)
+			mpc512x_free_bootmem(pfn_to_page(start));
+
+		diu_shared_fb.in_use = false;
+	}
+	diu_ops.release_bootmem	= NULL;
+}
+#endif
+
+/*
+ * Check if DIU was pre-initialized. If so, perform steps
+ * needed to continue displaying through the whole boot process.
+ * Move area descriptor and gamma table elsewhere, they are
+ * destroyed by bootmem allocator otherwise. The frame buffer
+ * address range will be reserved in setup_arch() after bootmem
+ * allocator is up.
+ */
+void __init mpc512x_init_diu(void)
+{
+	struct device_node *np;
+	void __iomem *diu_reg;
+	phys_addr_t desc;
+	void __iomem *vaddr;
+	unsigned long mode, pix_fmt, res, bpp;
+	unsigned long dst;
+
+	np = of_find_compatible_node(NULL, NULL, "fsl,diu");
+	if (!np) {
+		pr_err("No DIU node\n");
+		return;
+	}
+
+	diu_reg = of_iomap(np, 0);
+	of_node_put(np);
+	if (!diu_reg) {
+		pr_err("Can't map DIU\n");
+		return;
+	}
+
+	mode = in_be32(diu_reg + 0x1c);
+	if (mode != 1) {
+		pr_info("%s: DIU OFF\n", __func__);
+		goto out;
+	}
+
+	desc = in_be32(diu_reg);
+	vaddr = ioremap(desc, sizeof(struct diu_ad));
+	if (!vaddr) {
+		pr_err("Can't map DIU area desc.\n");
+		goto out;
+	}
+	memcpy(&diu_shared_fb.ad0, vaddr, sizeof(struct diu_ad));
+	/* flush fb area descriptor */
+	dst = (unsigned long)&diu_shared_fb.ad0;
+	flush_dcache_range(dst, dst + sizeof(struct diu_ad) - 1);
+
+	res = in_be32(diu_reg + 0x28);
+	pix_fmt = in_le32(vaddr);
+	bpp = ((pix_fmt >> 16) & 0x3) + 1;
+	diu_shared_fb.fb_phys = in_le32(vaddr + 4);
+	diu_shared_fb.fb_len = ((res & 0xfff0000) >> 16) * (res & 0xfff) * bpp;
+	diu_shared_fb.in_use = true;
+	iounmap(vaddr);
+
+	desc = in_be32(diu_reg + 0xc);
+	vaddr = ioremap(desc, sizeof(diu_shared_fb.gamma));
+	if (!vaddr) {
+		pr_err("Can't map DIU area desc.\n");
+		diu_shared_fb.in_use = false;
+		goto out;
+	}
+	memcpy(&diu_shared_fb.gamma, vaddr, sizeof(diu_shared_fb.gamma));
+	/* flush gamma table */
+	dst = (unsigned long)&diu_shared_fb.gamma;
+	flush_dcache_range(dst, dst + sizeof(diu_shared_fb.gamma) - 1);
+
+	iounmap(vaddr);
+	out_be32(diu_reg + 0xc, virt_to_phys(&diu_shared_fb.gamma));
+	out_be32(diu_reg + 4, 0);
+	out_be32(diu_reg + 8, 0);
+	out_be32(diu_reg, virt_to_phys(&diu_shared_fb.ad0));
+
+out:
+	iounmap(diu_reg);
+}
+
+void __init mpc512x_setup_diu(void)
+{
+	int ret;
+
+	if (diu_shared_fb.in_use) {
+		ret = reserve_bootmem(diu_shared_fb.fb_phys,
+				      diu_shared_fb.fb_len,
+				      BOOTMEM_EXCLUSIVE);
+		if (ret) {
+			pr_err("%s: reserve bootmem failed\n", __func__);
+			diu_shared_fb.in_use = false;
+		}
+	}
+
+#if defined(CONFIG_FB_FSL_DIU) || \
+    defined(CONFIG_FB_FSL_DIU_MODULE)
+	diu_ops.get_pixel_format	= mpc512x_get_pixel_format;
+	diu_ops.set_gamma_table		= mpc512x_set_gamma_table;
+	diu_ops.set_monitor_port	= mpc512x_set_monitor_port;
+	diu_ops.set_pixel_clock		= mpc512x_set_pixel_clock;
+	diu_ops.show_monitor_port	= mpc512x_show_monitor_port;
+	diu_ops.set_sysfs_monitor_port	= mpc512x_set_sysfs_monitor_port;
+	diu_ops.release_bootmem		= mpc512x_release_bootmem;
+#endif
+}
+
 void __init mpc512x_init_IRQ(void)
 {
 	struct device_node *np;
diff --git a/arch/powerpc/sysdev/fsl_soc.h b/arch/powerpc/sysdev/fsl_soc.h
index 19754be..346057d 100644
--- a/arch/powerpc/sysdev/fsl_soc.h
+++ b/arch/powerpc/sysdev/fsl_soc.h
@@ -30,6 +30,7 @@  struct platform_diu_data_ops {
 	void (*set_pixel_clock) (unsigned int pixclock);
 	ssize_t (*show_monitor_port) (int monitor_port, char *buf);
 	int (*set_sysfs_monitor_port) (int val);
+	void (*release_bootmem) (void);
 };
 
 extern struct platform_diu_data_ops diu_ops;
diff --git a/drivers/video/fsl-diu-fb.c b/drivers/video/fsl-diu-fb.c
index 72d68b3..29c7f31 100644
--- a/drivers/video/fsl-diu-fb.c
+++ b/drivers/video/fsl-diu-fb.c
@@ -34,7 +34,7 @@ 
 #include <linux/of_platform.h>
 
 #include <sysdev/fsl_soc.h>
-#include "fsl-diu-fb.h"
+#include <linux/fsl-diu-fb.h>
 
 /*
  * These parameters give default parameters
@@ -178,6 +178,21 @@  static struct fb_videomode __devinitdata fsl_diu_mode_db[] = {
 		.sync		= FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
 		.vmode		= FB_VMODE_NONINTERLACED
 	},
+	{
+		.name		= "800x480-60",
+		.refresh	= 60,
+		.xres		= 800,
+		.yres		= 480,
+		.pixclock	= 31250,
+		.left_margin	= 86,
+		.right_margin	= 42,
+		.upper_margin	= 33,
+		.lower_margin	= 10,
+		.hsync_len	= 128,
+		.vsync_len	= 2,
+		.sync		= FB_SYNC_COMP_HIGH_ACT | FB_SYNC_VERT_HIGH_ACT,
+		.vmode		= FB_VMODE_NONINTERLACED
+	},
 };
 
 static char *fb_mode = "1024x768-32@60";
@@ -329,8 +344,11 @@  static int fsl_diu_enable_panel(struct fb_info *info)
 	if (mfbi->type != MFB_TYPE_OFF) {
 		switch (mfbi->index) {
 		case 0:				/* plane 0 */
-			if (hw->desc[0] != ad->paddr)
+			if (in_be32(&hw->desc[0]) != ad->paddr) {
+				out_be32(&dr.diu_reg->diu_mode, 0);
 				out_be32(&hw->desc[0], ad->paddr);
+				out_be32(&dr.diu_reg->diu_mode, 1);
+			}
 			break;
 		case 1:				/* plane 1 AOI 0 */
 			cmfbi = machine_data->fsl_diu_info[2]->par;
@@ -389,7 +407,7 @@  static int fsl_diu_disable_panel(struct fb_info *info)
 
 	switch (mfbi->index) {
 	case 0:					/* plane 0 */
-		if (hw->desc[0] != machine_data->dummy_ad->paddr)
+		if (in_be32(&hw->desc[0]) != machine_data->dummy_ad->paddr)
 			out_be32(&hw->desc[0],
 				machine_data->dummy_ad->paddr);
 		break;
@@ -1100,6 +1118,10 @@  static int fsl_diu_open(struct fb_info *info, int user)
 	struct mfb_info *mfbi = info->par;
 	int res = 0;
 
+	/* free boot splash memory on first /dev/fb0 open */
+	if (!mfbi->index && diu_ops.release_bootmem)
+		diu_ops.release_bootmem();
+
 	spin_lock(&diu_lock);
 	mfbi->count++;
 	if (mfbi->count == 1) {
@@ -1427,6 +1449,7 @@  static int __devinit fsl_diu_probe(struct of_device *ofdev,
 	int ret, i, error = 0;
 	struct resource res;
 	struct fsl_diu_data *machine_data;
+	int diu_mode;
 
 	machine_data = kzalloc(sizeof(struct fsl_diu_data), GFP_KERNEL);
 	if (!machine_data)
@@ -1463,7 +1486,9 @@  static int __devinit fsl_diu_probe(struct of_device *ofdev,
 		goto error2;
 	}
 
-	out_be32(&dr.diu_reg->diu_mode, 0);		/* disable DIU anyway*/
+	diu_mode = in_be32(&dr.diu_reg->diu_mode);
+	if (diu_mode != MFB_MODE1)
+		out_be32(&dr.diu_reg->diu_mode, 0);	/* disable DIU */
 
 	/* Get the IRQ of the DIU */
 	machine_data->irq = irq_of_parse_and_map(np, 0);
@@ -1511,7 +1536,12 @@  static int __devinit fsl_diu_probe(struct of_device *ofdev,
 	machine_data->dummy_ad->offset_xyd = 0;
 	machine_data->dummy_ad->next_ad = 0;
 
-	out_be32(&dr.diu_reg->desc[0], machine_data->dummy_ad->paddr);
+	/* Let DIU display splash screen if it was pre-initialized
+	 * by the bootloader, set dummy area descriptor otherwise.
+	 */
+	if (diu_mode != MFB_MODE1)
+		out_be32(&dr.diu_reg->desc[0], machine_data->dummy_ad->paddr);
+
 	out_be32(&dr.diu_reg->desc[1], machine_data->dummy_ad->paddr);
 	out_be32(&dr.diu_reg->desc[2], machine_data->dummy_ad->paddr);