Commit 4b050ba7 authored Jul 18, 2014 by Markos Chandras Committed by Ralf Baechle Sep 22, 2014

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



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>

parent 4f12b91d

arch/mips/include/asm/pgtable.h

+10 −0

Original line number	Diff line number	Diff line
		@@ -366,6 +366,16 @@ 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.