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mips: add c0 register access plumbing 

C0 is a coprocessor register set defined in certain MIPS
architectures. This patch adds macros necessary to access the
registers and a couple of helper macros to access two particular
registers needed in the next patch.

The definitions come straight from arch/mips/include/asm/mipsregs.h in
the 3.14 kernel tree.

BRANCH=none
BUG=chrome-os-partner:31438
TEST=the following patch demonstrates timer counter C0 register
     configuration and use.

Change-Id: Ia5d52ffa75f2dd66d4cee3a4ed0af5122ccb2113
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: eb3d69eaf1561ca0b995720c24dafe2e6e22707d
Original-Change-Id: Ia4b1da40ecc1a03cf1cba0c648d42cd189fbcf93
Original-Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/227887
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/9336
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
This commit is contained in:
Vadim Bendebury 2014-11-05 17:51:19 -08:00 committed by Patrick Georgi
parent 0812568b5a
commit fc934b2da2
1 changed files with 48 additions and 0 deletions
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48
src/arch/mips/include/arch/cpu.h
View File

@ -40,4 +40,52 @@ struct cpu_info {
#endif /* !__PRE_RAM__ */
/***************************************************************************
* The following section was copied from arch/mips/include/asm/mipsregs.h in
* the 3.14 kernel tree.
*/
/*
* Macros to access the system control coprocessor
*/
#define __read_32bit_c0_register(source, sel) \
({ int __res; \
if (sel == 0) \
__asm__ __volatile__( \
"mfc0\t%0, " #source "\n\t" \
: "=r" (__res)); \
else \
__asm__ __volatile__( \
".set\tmips32\n\t" \
"mfc0\t%0, " #source ", " #sel "\n\t" \
".set\tmips0\n\t" \
: "=r" (__res)); \
__res; \
})
#define __write_32bit_c0_register(register, sel, value) \
do { \
if (sel == 0) \
__asm__ __volatile__( \
"mtc0\t%z0, " #register "\n\t" \
: : "Jr" ((unsigned int)(value))); \
else \
__asm__ __volatile__( \
".set\tmips32\n\t" \
"mtc0\t%z0, " #register ", " #sel "\n\t" \
".set\tmips0" \
: : "Jr" ((unsigned int)(value))); \
} while (0)
/* Shortcuts to access various internal registers, keep adding as needed. */
#define read_c0_count() __read_32bit_c0_register($9, 0)
#define write_c0_count(val) __write_32bit_c0_register($9, 0, (val))
#define read_c0_cause() __read_32bit_c0_register($13, 0)
#define write_c0_cause(val) __write_32bit_c0_register($13, 0, (val))
#define C0_CAUSE_DC (1 << 27)
/**************************************************************************/
#endif /* __MIPS_ARCH_CPU_H */