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@xxxxxxxxxx>
---
arch/mips/include/asm/pgtable.h | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h
index 539ddd148bbb..08f82e99ea8f 100644
--- a/arch/mips/include/asm/pgtable.h
+++ b/arch/mips/include/asm/pgtable.h
@@ -338,6 +338,16 @@ static inline pgprot_t pgprot_noncached(pgprot_t _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,
* and a page entry and page directory to the page they refer to.
--
2.0.0
