diff options
| author | Ingo Molnar <mingo@kernel.org> | 2013-10-03 07:52:21 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-10-03 07:52:21 +0200 |
| commit | 6c09f6d830d03b78717403e7b42838a2ee2987ae (patch) | |
| tree | 6436ab6a237578406e004c891e134afd266fb95d /arch/mips/include/asm/timex.h | |
| parent | 389e067032fbb96e439abafae848dd447e4cafb4 (diff) | |
| parent | 15c03dd4859ab16f9212238f29dd315654aa94f6 (diff) | |
Merge tag 'v3.12-rc3' into timers/core
Merge Linux 3.12-rc3 - refresh the tree with the latest fixes before merging new bits.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/mips/include/asm/timex.h')
| -rw-r--r-- | arch/mips/include/asm/timex.h | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/arch/mips/include/asm/timex.h b/arch/mips/include/asm/timex.h index 6529704aa73a..c5424757da65 100644 --- a/arch/mips/include/asm/timex.h +++ b/arch/mips/include/asm/timex.h @@ -10,7 +10,9 @@ #ifdef __KERNEL__ +#include <asm/cpu-features.h> #include <asm/mipsregs.h> +#include <asm/cpu-type.h> /* * This is the clock rate of the i8253 PIT. A MIPS system may not have @@ -33,9 +35,38 @@ typedef unsigned int cycles_t; +/* + * On R4000/R4400 before version 5.0 an erratum exists such that if the + * cycle counter is read in the exact moment that it is matching the + * compare register, no interrupt will be generated. + * + * There is a suggested workaround and also the erratum can't strike if + * the compare interrupt isn't being used as the clock source device. + * However for now the implementaton of this function doesn't get these + * fine details right. + */ static inline cycles_t get_cycles(void) { - return 0; + switch (boot_cpu_type()) { + case CPU_R4400PC: + case CPU_R4400SC: + case CPU_R4400MC: + if ((read_c0_prid() & 0xff) >= 0x0050) + return read_c0_count(); + break; + + case CPU_R4000PC: + case CPU_R4000SC: + case CPU_R4000MC: + break; + + default: + if (cpu_has_counter) + return read_c0_count(); + break; + } + + return 0; /* no usable counter */ } #endif /* __KERNEL__ */ |