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| author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2013-10-08 08:43:00 -0700 |
|---|---|---|
| committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2013-10-08 08:43:00 -0700 |
| commit | e3c55d406bd8df1a878546002c93db90c42be10c (patch) | |
| tree | efb0ba2707c95fd7166cf1b76887c43c977e37dd /arch/mips/include/asm/timex.h | |
| parent | 4d6e482675f13e33599fc3d18fc723959be0a9b6 (diff) | |
| parent | d0e639c9e06d44e713170031fe05fb60ebe680af (diff) | |
Merge tag 'v3.12-rc4' into next
Merge with mainline to bring in changes to input subsystem that were
committed through other trees.
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__ */ |