linux-kernel - Re: n900 in next-20170901

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Date:   Fri, 10 Nov 2017 15:37:28 +0900
From:   Joonsoo Kim <iamjoonsoo.kim@....com>
To:     Tony Lindgren <tony@...mide.com>
Cc:     Pavel Machek <pavel@....cz>, pali.rohar@...il.com, sre@...nel.org,
        kernel list <linux-kernel@...r.kernel.org>,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
        linux-omap@...r.kernel.org, khilman@...nel.org,
        aaro.koskinen@....fi, ivo.g.dimitrov.75@...il.com,
        patrikbachan@...il.com, serge@...lyn.com, abcloriens@...il.com,
        "Aneesh Kumar K.V" <aneesh.kumar@...ux.vnet.ibm.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>,
        Russell King <linux@...linux.org.uk>
Subject: Re: n900 in next-20170901

On Thu, Nov 09, 2017 at 07:26:10PM -0800, Tony Lindgren wrote:
> * Joonsoo Kim <iamjoonsoo.kim@....com> [171110 00:10]:
> > On Thu, Nov 09, 2017 at 07:08:54AM -0800, Tony Lindgren wrote:
> > > Hmm OK. Does your first patch above now have the initcall issue too?
> > > It boots if I make that also subsys_initcall and then I get:
> > 
> > > [    2.078094] vmalloc_pool_init: DMA: get vmalloc area: d0010000
> > 
> > Yes, first patch has the initcall issue and it's intentional in order
> > to check the theory. I checked following log for this.
> > 
> > - Boot failure
> > SRAM_ADDR: omap_map_sram: P: 0x40208000 - 0x4020f000
> > SRAM_ADDR: omap_map_sram: V: 0xd0050000 - 0xd0057000
> > 
> > - Boot success
> > SRAM_ADDR: omap_map_sram: P: 0x40208000 - 0x4020f000
> > SRAM_ADDR: omap_map_sram: V: 0xd0008000 - 0xd000f000
> > 
> > When failure, virtual address for sram is higher than normal one due
> > to vmalloc area allocation in __dma_alloc_remap(). If it is deferred,
> > virtual address is the same with success case and then the system work.
> > 
> > So, my next theory is that there is n900 specific assumption that sram
> > should have that address. Could you check if any working tree for n900
> > which doesn't have my CMA series work or not with adding
> > "arm/dma: vmalloc area allocation"?
> 
> Oh I see, sorry I was not following you earlier. So you mean that
> by adding the vmalloc_pool_init() initcall the va mapping for SRAM
> changes.

Exactly.

> 
> And yes, save_secure_ram_context seems to be doing some sketchy
> virt to phys calculation with sram_phy_addr_mask. Here's a small
> patch to fix that for your CMA series, maybe you can merge it
> with your series to avoid breaking booting for git bisect.
> 
> Then I'll follow up on cleaning up save_secure_ram_context later.

Thanks for the patch. However, the patch should be modified. See below.

> Regards,
> 
> Tony
> 
> 8< -------------------------
> >From tony Mon Sep 17 00:00:00 2001
> From: Tony Lindgren <tony@...mide.com>
> Date: Thu, 9 Nov 2017 17:05:34 -0800
> Subject: [PATCH] ARM: OMAP2+: Add static SRAM mapping for
>  save_secure_ram_context
> 
> With the CMA changes from Joonsoo Kim <iamjoonsoo.kim@....com>, it
> was noticed that n900 stopped booting. After investigating it turned
> out that n900 save_secure_ram_context does some whacky virtual to
> physical address translation for the SRAM data address.
> 
> Let's fix this for CMA changes by adding a static mapping for SRAM
> on omap3. Then we can follow up with a patch to clean up the address
> translation in save_secure_ram_context later on.
> 
> Debugged-by: Joonsoo Kim <iamjoonsoo.kim@....com>
> Signed-off-by: Tony Lindgren <tony@...mide.com>
> ---
>  arch/arm/mach-omap2/io.c    | 6 ++++++
>  arch/arm/mach-omap2/iomap.h | 4 ++++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
> --- a/arch/arm/mach-omap2/io.c
> +++ b/arch/arm/mach-omap2/io.c
> @@ -139,6 +139,12 @@ static struct map_desc omap243x_io_desc[] __initdata = {
>  
>  #ifdef	CONFIG_ARCH_OMAP3
>  static struct map_desc omap34xx_io_desc[] __initdata = {
> +	{
> +		.virtual	= OMAP34XX_SRAM_VIRT,
> +		.pfn		= __phys_to_pfn(OMAP34XX_SRAM_PHYS),
> +		.length		= OMAP34XX_SRAM_SIZE,
> +		.type		= MT_DEVICE
> +	},
>  	{
>  		.virtual	= L3_34XX_VIRT,
>  		.pfn		= __phys_to_pfn(L3_34XX_PHYS),
> diff --git a/arch/arm/mach-omap2/iomap.h b/arch/arm/mach-omap2/iomap.h
> --- a/arch/arm/mach-omap2/iomap.h
> +++ b/arch/arm/mach-omap2/iomap.h
> @@ -123,6 +123,10 @@
>   * VPOM3430 was not working for Int controller
>   */
>  
> +#define OMAP34XX_SRAM_PHYS	0x40200000
> +#define OMAP34XX_SRAM_VIRT	0xd0010000
> +#define OMAP34XX_SRAM_SIZE	0x10000

For my testing environment, vmalloc address space is started at
roughly 0xe0000000 so 0xd0010000 would not be valid. And, PHYS
can be different according to the system type. Maybe either
OMAP3_SRAM_PUB_PA or OMAP3_SRAM_PA. It seems that SIZE and TYPE should
be considered, too. My understanding is correct?

Thanks.