Messages in this thread | | | Subject | Re: [PATCH] ARM: mmp: map sram as MT_MEMORY rather than MT_DEVICE | From | Haojian Zhuang <> | Date | Tue, 23 Aug 2011 16:22:17 +0800 |
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On Tue, 2011-08-23 at 00:48 -0700, Leo Yan wrote: > > On 08/23/2011 10:08 AM, Andres Salomon wrote: > > On Tue, 23 Aug 2011 08:07:41 +0800 > > Eric Miao<eric.y.miao@gmail.com> wrote: > > > >> On Tue, Aug 23, 2011 at 7:47 AM, Andres Salomon<dilinger@queued.net> > >> wrote: > >>> The sram code allocates memory with ioremap, which assumes MT_DEVICE > >>> for memory protections. This explodes when we map sram for power > >>> management purposes and then attempt to execute it (jump_to_lp_sram) > >>> on the OLPC XO-1.75. Instead, we want to specify MT_MEMORY, which > >>> doesn't set the L_PTE_XN bit. > >>> > >>> Signed-off-by: Andres Salomon<dilinger@queued.net> > >>> --- > >>> arch/arm/mach-mmp/sram.c | 4 +++- > >>> 1 files changed, 3 insertions(+), 1 deletions(-) > >>> > >>> Eric, this patch is against the devel branch of your pxa tree. > >>> > >>> diff --git a/arch/arm/mach-mmp/sram.c b/arch/arm/mach-mmp/sram.c > >>> index 4304f95..ca4d3c1 100644 > >>> --- a/arch/arm/mach-mmp/sram.c > >>> +++ b/arch/arm/mach-mmp/sram.c > >>> @@ -21,6 +21,7 @@ > >>> #include<linux/err.h> > >>> #include<linux/slab.h> > >>> #include<linux/genalloc.h> > >>> +#include<asm/mach/map.h> > >>> > >>> #include<mach/sram.h> > >>> > >>> @@ -87,7 +88,8 @@ static int __devinit sram_probe(struct > >>> platform_device *pdev) > >>> > >>> info->sram_phys = (phys_addr_t)res->start; > >>> info->sram_size = resource_size(res); > >>> - info->sram_virt = ioremap(info->sram_phys, > >>> info->sram_size); > >>> + info->sram_virt = __arm_ioremap(info->sram_phys, > >>> info->sram_size, > >>> + MT_MEMORY); > >> > >> I doubt MT_MEMORY is intended for use with __arm_ioremap(). There > >> could be other way around to the L_PTE_XN bit. > >> > >> One other way I'm actually thinking of is to add the SRAM mapping to > >> mmp_map_io(). The difference of SRAM offset/size may result the > >> separation of mmp_map_io() into {pxa168,pxa910,mmp2}_map_io() > >> if necessary. > >> > > > > I guess I don't follow. I think you're talking about adding it to the > > standard_io_desc array, but that would require having it pre-mapped and > > knowing the virtual address. Or were you planning to ioremap it? > > I missed the L_PTE_XN bit. > The patch is originally for audio sram, so use the ioremap is ok for > that. But for the internal sram we should need the different mapping > property. > > so far, the standard_io_desc is shared by pxa168/pxa910/mmp2; > we can not add the sram's entry into it for now sram is only dedicated > to mmp2; just like Eric's suggestion, we need mmp2_map_io() only for > mmp2, and add the sram's entries into the structure. > if so, we need transfer the mapped info into the sram module, > and sram module just keep the info and do not need remap it again. > > so what's your opinion?
Could we use resource or platform data to specify sram is used for device or memory? If so, it may be helpful to customize.
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