orion_nand_read_buf uses an inline assembly with the "ldrd" instruction, which is only available from ARMv5 upwards. This used to be fine, since all users have an ARMv5 or ARMv7 CPU, but now we can also build a multiplatform kernel with ARMv4 support enabled in addition to the "kirkwood" (mvebu) platform.
This provides an alternative to call the readsl() function that is supposed to have the same effect and is also optimized for performance. This patch is untested, and it would be worthwhile to check if there is any performance impact, especially in case the readsl version is actually faster. Signed-off-by: Arnd Bergmann <[email protected]> Cc: David Woodhouse <[email protected]> Cc: Brian Norris <[email protected]> Cc: Jingoo Han <[email protected]> Cc: [email protected] --- drivers/mtd/nand/orion_nand.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c index dd7fe81..c7b5e8a 100644 --- a/drivers/mtd/nand/orion_nand.c +++ b/drivers/mtd/nand/orion_nand.c @@ -56,6 +56,7 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) *buf++ = readb(io_base); len--; } +#if __LINUX_ARM_ARCH__ >= 5 buf64 = (uint64_t *)buf; while (i < len/8) { /* @@ -68,6 +69,10 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len) asm volatile ("ldrd\t%0, [%1]" : "=&r" (x) : "r" (io_base)); buf64[i++] = x; } +#else + readsl(io_base, buf, len/8); + i = len / 8 * 8; +#endif i *= 8; while (i < len) buf[i++] = readb(io_base); -- 1.8.3.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
