Current MIPS systems do not require that loads be performed to force the parity of cache lines, a simple invalidate by clearing the tag for each line will suffice. Thus this patch makes the loads & subsequent second invalidation conditional upon the CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD option, and defines that for existing mips32 targets. Exceptions are malta where this is known to be unnecessary, and qemu-mips where caches are not implemented.
Signed-off-by: Paul Burton paul.burton@imgtec.com Cc: Daniel Schwierzeck daniel.schwierzeck@gmail.com --- Changes in v2: - None (rebase atop change to patch 1). --- arch/mips/Kconfig | 6 ++++++ arch/mips/lib/cache_init.S | 19 +++++++++++++------ 2 files changed, 19 insertions(+), 6 deletions(-)
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index ef78929..bc4283d 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -36,6 +36,7 @@ config TARGET_VCT select SUPPORTS_BIG_ENDIAN select SUPPORTS_CPU_MIPS32_R1 select SUPPORTS_CPU_MIPS32_R2 + select SYS_MIPS_CACHE_INIT_RAM_LOAD
config TARGET_DBAU1X00 bool "Support dbau1x00" @@ -43,12 +44,14 @@ config TARGET_DBAU1X00 select SUPPORTS_LITTLE_ENDIAN select SUPPORTS_CPU_MIPS32_R1 select SUPPORTS_CPU_MIPS32_R2 + select SYS_MIPS_CACHE_INIT_RAM_LOAD
config TARGET_PB1X00 bool "Support pb1x00" select SUPPORTS_LITTLE_ENDIAN select SUPPORTS_CPU_MIPS32_R1 select SUPPORTS_CPU_MIPS32_R2 + select SYS_MIPS_CACHE_INIT_RAM_LOAD
endchoice @@ -185,6 +188,9 @@ config 64BIT config SWAP_IO_SPACE bool
+config SYS_MIPS_CACHE_INIT_RAM_LOAD + bool + endif
endmenu diff --git a/arch/mips/lib/cache_init.S b/arch/mips/lib/cache_init.S index cbd04bd..04a36b2 100644 --- a/arch/mips/lib/cache_init.S +++ b/arch/mips/lib/cache_init.S @@ -113,6 +113,8 @@ LEAF(mips_cache_reset) l1_info t3, t9, MIPS_CONF1_DA_SHIFT #endif
+#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD + /* Determine the largest L1 cache size */ #if defined(CONFIG_SYS_ICACHE_SIZE) && defined(CONFIG_SYS_DCACHE_SIZE) #if CONFIG_SYS_ICACHE_SIZE > CONFIG_SYS_DCACHE_SIZE @@ -134,14 +136,15 @@ LEAF(mips_cache_reset) f_fill64 a0, -64, zero bne a0, a1, 2b
- /* - * The caches are probably in an indeterminate state, - * so we force good parity into them by doing an - * invalidate, load/fill, invalidate for each line. - */ +#endif /* CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD */
/* - * Assume bottom of RAM will generate good parity for the cache. + * The caches are probably in an indeterminate state, so we force good + * parity into them by doing an invalidate for each line. If + * CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD is set then we'll proceed to + * perform a load/fill & a further invalidate for each line, assuming + * that the bottom of RAM (having just been cleared) will generate good + * parity for the cache. */
/* @@ -153,12 +156,14 @@ LEAF(mips_cache_reset) PTR_ADDU t1, t0, t2 /* clear tag to invalidate */ cache_loop t0, t1, t8, INDEX_STORE_TAG_I +#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD /* fill once, so data field parity is correct */ PTR_LI t0, INDEX_BASE cache_loop t0, t1, t8, FILL /* invalidate again - prudent but not strictly neccessary */ PTR_LI t0, INDEX_BASE cache_loop t0, t1, t8, INDEX_STORE_TAG_I +#endif
/* * then initialize D-cache. @@ -169,6 +174,7 @@ LEAF(mips_cache_reset) PTR_ADDU t1, t0, t3 /* clear all tags */ cache_loop t0, t1, t9, INDEX_STORE_TAG_D +#ifdef CONFIG_SYS_MIPS_CACHE_INIT_RAM_LOAD /* load from each line (in cached space) */ PTR_LI t0, INDEX_BASE 2: LONG_L zero, 0(t0) @@ -177,6 +183,7 @@ LEAF(mips_cache_reset) /* clear all tags */ PTR_LI t0, INDEX_BASE cache_loop t0, t1, t9, INDEX_STORE_TAG_D +#endif
3: jr ra END(mips_cache_reset)