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MIPS: pgtable.h: Implement the pgprot_writecombine function for MIPS

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Previously, the pgprot_writecombine function was simply defined
as pgprot_uncached in include/asm-generic/pgtable.h. This is not
optimal for cores that can actually do write-combine memory writes
so define this function to take into account the core's cache coherency
attribute to achieve such behavior.

Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/7403/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
Markos Chandras 2014-07-18 10:51:33 +01:00 committed by Ralf Baechle
parent 4f12b91d2d
commit 4b050ba7a6
1 changed files with 10 additions and 0 deletions
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10
arch/mips/include/asm/pgtable.h
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@ -366,6 +366,16 @@ static inline pgprot_t pgprot_noncached(pgprot_t _prot)
return __pgprot(prot); return __pgprot(prot);
} }
static inline pgprot_t pgprot_writecombine(pgprot_t _prot)
{
unsigned long prot = pgprot_val(_prot);
/* cpu_data[0].writecombine is already shifted by _CACHE_SHIFT */
prot = (prot & ~_CACHE_MASK) | cpu_data[0].writecombine;
return __pgprot(prot);
}
/* /*
* Conversion functions: convert a page and protection to a page entry, * Conversion functions: convert a page and protection to a page entry,
* and a page entry and page directory to the page they refer to. * and a page entry and page directory to the page they refer to.