[U-Boot-Users] [PATCH] SPARC: CFI flash_read64 defined weak function.

[Daniel Hellstrom]

Hello Wolfgang and Stefan,

This is a patch which defines flash_read64 weak in cfi_flash.c, 
cpu/leon3/cpu_init.c
defines this function for SPARC.

SPARC has implemented __raw_readq, it reads 64-bit from any 32-bit address.

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 specific and can be found in <asm-sparc/asi.h>.

This patch is also available at 
ftp://ftp.gaisler.com/gaisler.com/uboot/patches.

Best Regards,
Daniel Hellstrom


 drivers/mtd/cfi_flash.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)


diff --cc drivers/mtd/cfi_flash.c
index f04c72d,f04c72d..a55afc9
--- a/drivers/mtd/cfi_flash.c
+++ b/drivers/mtd/cfi_flash.c
@@@ -239,12 -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)