From: Sascha Hauer <s.hauer@pengutronix.de>
To: Steve Schefter <steve@scheftech.com>
Cc: barebox@lists.infradead.org
Subject: Re: [PATCH] Avoid SDRAM access crash
Date: Wed, 4 Jul 2012 08:51:01 +0200 [thread overview]
Message-ID: <20120704065101.GD2698@pengutronix.de> (raw)
In-Reply-To: <4FF2D611.2040207@scheftech.com>
On Tue, Jul 03, 2012 at 07:22:57AM -0400, Steve Schefter wrote:
> Hi Sascha.
>
> >I wonder why this has never hit me. On what hardware did you see this?
>
> Me too. All I can say is that the timing is tight. I see crashes
> at various DRAM addresses, all depending on how much was left in
> cache when the tlb invalidate was done.
>
> I'm using the Phytec phyCORE-OMAP44xx card.
>
> >Does the following patch solve your problem aswell?
>
> It does. I see that routine contains a cache flush as well.
Ok, thanks for testing. I applied my version because it flushes only
the relevant parts of the cache and looks more like C ;)
Sascha
>
> Regards,
> Steve
>
> >
> >8<----------------------------------------------------
> >
> >ARM mmu: flush page tables in arm_mmu_remap_sdram()
> >
> >Signed-off-by: Sascha Hauer<s.hauer@pengutronix.de>
> >---
> > arch/arm/cpu/mmu.c | 5 ++++-
> > 1 file changed, 4 insertions(+), 1 deletion(-)
> >
> >diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
> >index 55b07a4..607f357 100644
> >--- a/arch/arm/cpu/mmu.c
> >+++ b/arch/arm/cpu/mmu.c
> >@@ -147,7 +147,7 @@ static int arm_mmu_remap_sdram(struct memory_bank *bank)
> > if ((phys& (SZ_1M - 1)) || (bank->size& (SZ_1M - 1)))
> > return -EINVAL;
> >
> >- ptes = memalign(0x400, num_ptes * sizeof(u32));
> >+ ptes = memalign(PAGE_SIZE, num_ptes * sizeof(u32));
> >
> > debug("ptes: 0x%p ttb_start: 0x%08lx ttb_end: 0x%08lx\n",
> > ptes, ttb_start, ttb_end);
> >@@ -165,6 +165,9 @@ static int arm_mmu_remap_sdram(struct memory_bank *bank)
> > pte += 256;
> > }
> >
> >+ dma_flush_range((unsigned long)ttb, (unsigned long)ttb + 0x4000);
> >+ dma_flush_range((unsigned long)ptes, num_ptes * sizeof(u32));
> >+
> > tlb_invalidate();
> >
> > return 0;
>
--
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next prev parent reply other threads:[~2012-07-04 6:51 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-02 17:22 steve
2012-07-03 7:36 ` Sascha Hauer
2012-07-03 11:22 ` Steve Schefter
2012-07-04 6:51 ` Sascha Hauer [this message]
2012-07-04 11:18 ` Steve Schefter
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