[PATCH] mtd: spi-nor: Add 4-byte address support for is25lp256

[Liu Xiang]

The is25lp256 supports 4-byte opcodes and quad output.
In is25lp256, the DWORD1 of JEDEC Basic Flash Parameter Header
is 0xfff920e5. So the DWORD1[18:17] Address Bytes bits are 0b00,
means that 3-Byte only addressing. Now this limits nor->addr_width
to 3 and makes it inpossible to access the address above 16MB.
I think the size of flash is the most important judgement for
nor->addr_width. Once the size is larger than 16MB, nor->addr_width
must be 4. This can avoid the bad situation that manufacturer sets
incorrect value of register.

Signed-off-by: Liu Xiang <liu.xia...@zte.com.cn>
---
 drivers/mtd/spi-nor/spi-nor.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d9c368c..0203b09 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1065,7 +1065,7 @@ static int spi_nor_is_locked(struct mtd_info *mtd, loff_t 
ofs, uint64_t len)
        { "is25lp128",  INFO(0x9d6018, 0, 64 * 1024, 256,
                        SECT_4K | SPI_NOR_DUAL_READ) },
        { "is25lp256",  INFO(0x9d6019, 0, 64 * 1024, 512,
-                       SECT_4K | SPI_NOR_DUAL_READ) },
+                       SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ | 
SPI_NOR_4B_OPCODES) },
        { "is25wp032",  INFO(0x9d7016, 0, 64 * 1024,  64,
                        SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
        { "is25wp064",  INFO(0x9d7017, 0, 64 * 1024, 128,
@@ -2926,16 +2926,16 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
        if (ret)
                return ret;
 
-       if (nor->addr_width) {
-               /* already configured from SFDP */
-       } else if (info->addr_width) {
-               nor->addr_width = info->addr_width;
-       } else if (mtd->size > 0x1000000) {
+       if (mtd->size > 0x1000000) {
                /* enable 4-byte addressing if the device exceeds 16MiB */
                nor->addr_width = 4;
                if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
-                   info->flags & SPI_NOR_4B_OPCODES)
+                       info->flags & SPI_NOR_4B_OPCODES)
                        spi_nor_set_4byte_opcodes(nor, info);
+       } else if (nor->addr_width) {
+               /* already configured from SFDP */
+       } else if (info->addr_width) {
+               nor->addr_width = info->addr_width;
        } else {
                nor->addr_width = 3;
        }
-- 
1.9.1