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authorDaniel Hellstrom <daniel@gaisler.com>2008-03-28 20:40:19 +0100
committerStefan Roese <sr@denx.de>2008-03-29 06:51:04 +0100
commit97bf85d784fbed485e652eb907589ad0d5cb7262 (patch)
treebfff8d652628f9363f275702b85a37317973baa1 /drivers/mtd/cfi_flash.c
parent90447ecbbac8572457b6d8903073ac3f120995ba (diff)
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MTD/CFI: flash_read64 is defined a weak function (for SPARC)
SPARC has implemented __raw_readq, it reads 64-bit from any 32-bit address. SPARC CPUs implement flash_read64 which calls __raw_readq. For current SPARC architectures (LEON2 and LEON3) each read from the FLASH must lead to a cache miss. This is because FLASH can not be set non-cacheable since program code resides there, and alternatively disabling cache is poor from performance view, or doing a cache flush between each read is even poorer. Forcing a cache miss on a SPARC is done by a special instruction "lda" - load alternative space, the alternative space number (ASI) is processor implementation spcific and can be found by including <asm/processor.h>. Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Diffstat (limited to 'drivers/mtd/cfi_flash.c')
-rw-r--r--drivers/mtd/cfi_flash.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c
index 3f8911e..40fddcd 100644
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@ -239,12 +239,14 @@ static u32 flash_read32(void *addr)
return __raw_readl(addr);
}
-static u64 flash_read64(void *addr)
+static u64 __flash_read64(void *addr)
{
/* No architectures currently implement __raw_readq() */
return *(volatile u64 *)addr;
}
+u64 flash_read64(void *addr)__attribute__((weak, alias("__flash_read64")));
+
/*-----------------------------------------------------------------------
*/
#if defined(CFG_ENV_IS_IN_FLASH) || defined(CFG_ENV_ADDR_REDUND) || (CFG_MONITOR_BASE >= CFG_FLASH_BASE)