diff options
| author | Daniel Hellstrom <daniel@gaisler.com> | 2008-03-28 20:40:19 +0100 |
|---|---|---|
| committer | Stefan Roese <sr@denx.de> | 2008-03-29 06:51:04 +0100 |
| commit | 97bf85d784fbed485e652eb907589ad0d5cb7262 (patch) | |
| tree | bfff8d652628f9363f275702b85a37317973baa1 /drivers/mtd | |
| parent | 90447ecbbac8572457b6d8903073ac3f120995ba (diff) | |
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')
| -rw-r--r-- | drivers/mtd/cfi_flash.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/mtd/cfi_flash.c b/drivers/mtd/cfi_flash.c index 3f8911eb87..40fddcddad 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) |