diff options
| author | Kevin Cernekee <cernekee@gmail.com> | 2014-10-21 08:28:00 +0400 |
|---|---|---|
| committer | Ralf Baechle <ralf@linux-mips.org> | 2014-11-24 09:45:12 +0300 |
| commit | d74b0172e4e2cea34104ba6bdacb3cffe33eaf0f (patch) | |
| tree | aca830adb2572cf37c1060c1b0ce4f9ac78700c0 /arch | |
| parent | d8010ceba66ac8d1953a1fb00ead89f4ee8a76f5 (diff) | |
| download | linux-d74b0172e4e2cea34104ba6bdacb3cffe33eaf0f.tar.xz | |
MIPS: BMIPS: Add special cache handling in c-r4k.c
BMIPS435x and BMIPS438x have a single shared L1 D$ and load/store unit,
so it isn't necessary to raise IPIs to keep both CPUs coherent.
BMIPS5000 has VIPT L1 caches that handle aliases in hardware, and its I$
fills from D$. But a special sequence with 2 SYNCs and 32 NOPs is needed
to ensure coherency.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: f.fainelli@gmail.com
Cc: mbizon@freebox.fr
Cc: jogo@openwrt.org
Cc: jfraser@broadcom.com
Cc: linux-mips@linux-mips.org
Cc: devicetree@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/8165/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/mips/mm/c-r4k.c | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index fbcd8674ff1d..dd261df005c2 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -917,6 +917,18 @@ static inline void alias_74k_erratum(struct cpuinfo_mips *c) } } +static void b5k_instruction_hazard(void) +{ + __sync(); + __sync(); + __asm__ __volatile__( + " nop; nop; nop; nop; nop; nop; nop; nop\n" + " nop; nop; nop; nop; nop; nop; nop; nop\n" + " nop; nop; nop; nop; nop; nop; nop; nop\n" + " nop; nop; nop; nop; nop; nop; nop; nop\n" + : : : "memory"); +} + static char *way_string[] = { NULL, "direct mapped", "2-way", "3-way", "4-way", "5-way", "6-way", "7-way", "8-way" }; @@ -1683,6 +1695,37 @@ void r4k_cache_init(void) coherency_setup(); board_cache_error_setup = r4k_cache_error_setup; + + /* + * Per-CPU overrides + */ + switch (current_cpu_type()) { + case CPU_BMIPS4350: + case CPU_BMIPS4380: + /* No IPI is needed because all CPUs share the same D$ */ + flush_data_cache_page = r4k_blast_dcache_page; + break; + case CPU_BMIPS5000: + /* We lose our superpowers if L2 is disabled */ + if (c->scache.flags & MIPS_CACHE_NOT_PRESENT) + break; + + /* I$ fills from D$ just by emptying the write buffers */ + flush_cache_page = (void *)b5k_instruction_hazard; + flush_cache_range = (void *)b5k_instruction_hazard; + flush_cache_sigtramp = (void *)b5k_instruction_hazard; + local_flush_data_cache_page = (void *)b5k_instruction_hazard; + flush_data_cache_page = (void *)b5k_instruction_hazard; + flush_icache_range = (void *)b5k_instruction_hazard; + local_flush_icache_range = (void *)b5k_instruction_hazard; + + /* Cache aliases are handled in hardware; allow HIGHMEM */ + current_cpu_data.dcache.flags &= ~MIPS_CACHE_ALIASES; + + /* Optimization: an L2 flush implicitly flushes the L1 */ + current_cpu_data.options |= MIPS_CPU_INCLUSIVE_CACHES; + break; + } } static int r4k_cache_pm_notifier(struct notifier_block *self, unsigned long cmd, |