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authorArnd Bergmann <arnd@arndb.de>2017-07-21 22:38:06 +0200
committerBoris Brezillon <boris.brezillon@free-electrons.com>2017-08-23 16:49:18 +0200
commit55bafbc277dcce7aab0ba28563075f3b517e6134 (patch)
treeb6fd8aab3d6e6538e1597ddf99849845cefc4387
parentmtd: nand: pxa3xx_nand: enable building on mvebu 64-bit platforms (diff)
downloadlinux-55bafbc277dcce7aab0ba28563075f3b517e6134.tar.xz
linux-55bafbc277dcce7aab0ba28563075f3b517e6134.zip
mtd: orion-nand: fix build error with ARMv4
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. I first posted a version of this patch back in 2014, and there was some discussion about it then. This fixes the bugs identified back then and should be a reasonable alternative for the rare corner case. Link: https://patchwork.kernel.org/patch/4144791/ Cc: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
-rw-r--r--drivers/mtd/nand/orion_nand.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
index 209170ed2b76..41cb7acfc044 100644
--- a/drivers/mtd/nand/orion_nand.c
+++ b/drivers/mtd/nand/orion_nand.c
@@ -54,13 +54,16 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
{
struct nand_chip *chip = mtd_to_nand(mtd);
void __iomem *io_base = chip->IO_ADDR_R;
+#if __LINUX_ARM_ARCH__ >= 5
uint64_t *buf64;
+#endif
int i = 0;
while (len && (unsigned long)buf & 7) {
*buf++ = readb(io_base);
len--;
}
+#if __LINUX_ARM_ARCH__ >= 5
buf64 = (uint64_t *)buf;
while (i < len/8) {
/*
@@ -74,6 +77,10 @@ static void orion_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
buf64[i++] = x;
}
i *= 8;
+#else
+ readsl(io_base, buf, len/4);
+ i = len / 4 * 4;
+#endif
while (i < len)
buf[i++] = readb(io_base);
}