Subject: Please help with the OMAP static mapping mess

From: [email-masked] (Tony Lindgren)
Date: Mon, 3 Oct 2011 15:59:09 -0700

* Nicolas Pitre <[email-masked]> [111003 15:05]:
> On Mon, 3 Oct 2011, Nicolas Pitre wrote:
> 
> > On Mon, 3 Oct 2011, Tony Lindgren wrote:
> > 
> > > * Nicolas Pitre <[email-masked]> [111003 11:26]:
> > > > 
> > > > Furthermore... there is also a static mapping for physical address 
> > > > 0x4e000000 using virtual address 0xff100000 which is already reserved 
> > > > for other purposes i.e. the consistent DMA area.  It is not immediately 
> > > > obvious where this comes from without being intimate with the OMAP code. 
> > > > Can this be fixed as well i.e. moved elsewhere please?
> > > 
> > > This sounds like a bug somewhere. Which omap are you seeing this on?
> > 
> > OMAP4430 on a Panda board.
> > 
> > Here are the static mappings I'm seeing:
> > 
> > phys = 0x44000000 virt = 0xf8000000 size = 0x100000
> > phys = 0x4a000000 virt = 0xfc000000 size = 0x400000
> > phys = 0x50000000 virt = 0xf9000000 size = 0x100000
> > phys = 0x4c000000 virt = 0xfd100000 size = 0x100000
> > phys = 0x4d000000 virt = 0xfe100000 size = 0x100000
> > phys = 0x4e000000 virt = 0xff100000 size = 0x100000 <---
> > phys = 0x48000000 virt = 0xfa000000 size = 0x400000
> > phys = 0x54000000 virt = 0xfe800000 size = 0x800000
> 
> It looks like this comes from OMAP44XX_DMM_VIRT.
> 
> #define OMAP44XX_DMM_PHYS       OMAP44XX_DMM_BASE
>                                                 /* 0x4e000000 --> 0xfd300000 */
> #define OMAP44XX_DMM_VIRT       (OMAP44XX_DMM_PHYS + OMAP4_L3_PER_IO_OFFSET)
> #define OMAP44XX_DMM_SIZE       SZ_1M
> 
> The comment suggesting a mapping correspondance is obviously wrong. We have:
> 
> #define OMAP44XX_DMM_BASE       0x4e000000
> #define OMAP4_L3_PER_IO_OFFSET  0xb1100000
> 
> Hence 0x4e000000 + 0xb1100000 = 0xff100000.

Seem like it might cause some random patterns in tiler :)
Santosh, can youp please check it?

Regards,

Tony