Rather than probing the cache line sizes on every call of any cache maintenance function, probe them once during boot & store the values in the global data structure for later use. This will reduce the overhead of the cache maintenance functions, which isn't a big deal yet but becomes more important once L2 caches which may expose their properties via coprocessor 2 or the CM are supported.
Signed-off-by: Paul Burton paul.burton@imgtec.com ---
Changes in v3: None Changes in v2: None
arch/mips/cpu/cpu.c | 7 ++++++ arch/mips/include/asm/cache.h | 9 ++++++++ arch/mips/include/asm/global_data.h | 4 ++++ arch/mips/lib/cache.c | 43 +++++++++++++++++++++---------------- 4 files changed, 45 insertions(+), 18 deletions(-)
diff --git a/arch/mips/cpu/cpu.c b/arch/mips/cpu/cpu.c index 391feb3..1b919ed 100644 --- a/arch/mips/cpu/cpu.c +++ b/arch/mips/cpu/cpu.c @@ -8,6 +8,7 @@ #include <common.h> #include <command.h> #include <linux/compiler.h> +#include <asm/cache.h> #include <asm/mipsregs.h> #include <asm/reboot.h>
@@ -35,3 +36,9 @@ void write_one_tlb(int index, u32 pagemask, u32 hi, u32 low0, u32 low1) write_c0_index(index); tlb_write_indexed(); } + +int arch_cpu_init(void) +{ + mips_cache_probe(); + return 0; +} diff --git a/arch/mips/include/asm/cache.h b/arch/mips/include/asm/cache.h index 0cea581..669c362 100644 --- a/arch/mips/include/asm/cache.h +++ b/arch/mips/include/asm/cache.h @@ -19,4 +19,13 @@ */ #define CONFIG_SYS_CACHELINE_SIZE ARCH_DMA_MINALIGN
+/** + * mips_cache_probe() - Probe the properties of the caches + * + * Call this to probe the properties such as line sizes of the caches + * present in the system, if any. This must be done before cache maintenance + * functions such as flush_cache may be called. + */ +void mips_cache_probe(void); + #endif /* __MIPS_CACHE_H__ */ diff --git a/arch/mips/include/asm/global_data.h b/arch/mips/include/asm/global_data.h index 37f8ed5..8533b69 100644 --- a/arch/mips/include/asm/global_data.h +++ b/arch/mips/include/asm/global_data.h @@ -21,6 +21,10 @@ struct arch_global_data { unsigned long rev; unsigned long ver; #endif +#ifdef CONFIG_SYS_CACHE_SIZE_AUTO + unsigned short l1i_line_size; + unsigned short l1d_line_size; +#endif };
#include <asm-generic/global_data.h> diff --git a/arch/mips/lib/cache.c b/arch/mips/lib/cache.c index db81953..d8baf08 100644 --- a/arch/mips/lib/cache.c +++ b/arch/mips/lib/cache.c @@ -9,32 +9,39 @@ #include <asm/cacheops.h> #include <asm/mipsregs.h>
-static inline unsigned long icache_line_size(void) -{ - unsigned long conf1, il; +DECLARE_GLOBAL_DATA_PTR;
- if (!config_enabled(CONFIG_SYS_CACHE_SIZE_AUTO)) - return CONFIG_SYS_ICACHE_LINE_SIZE; +void mips_cache_probe(void) +{ +#ifdef CONFIG_SYS_CACHE_SIZE_AUTO + unsigned long conf1, il, dl;
conf1 = read_c0_config1(); + il = (conf1 & MIPS_CONF1_IL) >> MIPS_CONF1_IL_SHF; - if (!il) - return 0; - return 2 << il; + dl = (conf1 & MIPS_CONF1_DL) >> MIPS_CONF1_DL_SHF; + + gd->arch.l1i_line_size = il ? (2 << il) : 0; + gd->arch.l1d_line_size = dl ? (2 << dl) : 0; +#endif }
-static inline unsigned long dcache_line_size(void) +static inline unsigned long icache_line_size(void) { - unsigned long conf1, dl; - - if (!config_enabled(CONFIG_SYS_CACHE_SIZE_AUTO)) - return CONFIG_SYS_DCACHE_LINE_SIZE; +#ifdef CONFIG_SYS_CACHE_SIZE_AUTO + return gd->arch.l1i_line_size; +#else + return CONFIG_SYS_ICACHE_LINE_SIZE; +#endif +}
- conf1 = read_c0_config1(); - dl = (conf1 & MIPS_CONF1_DL) >> MIPS_CONF1_DL_SHF; - if (!dl) - return 0; - return 2 << dl; +static inline unsigned long dcache_line_size(void) +{ +#ifdef CONFIG_SYS_CACHE_SIZE_AUTO + return gd->arch.l1d_line_size; +#else + return CONFIG_SYS_DCACHE_LINE_SIZE; +#endif }
#define cache_loop(start, end, lsize, ops...) do { \