[PATCH] mtd: spi-nor: read 6 bytes for the ID

[Huang Shijie <b32955@freescale.com>]

Currently, we read 5 bytes for ID, but s25fl128s has the same ext_id(0x4d01)
with s25fl129p1. The s25fl128s can support the DDR Quad read, while s25fl129p1
does not. So we have to distinguish the two NOR flashs.

This patch reads out 6 bytes for the ID, and use the 6 bytes ID to search the
right flash_info.

The detail of the patch is:
  [1] change the "ext_id" from u16 to u32.
      We can store two bytes or three bytes with the @ext_id now.

  [2] search the right flash_info with the 6byte ID and the new @ext_id.
      We use "matched" variable to track the legacy two bytes @ext_id.
      If the flash_info's @ext_id is three bytes, we will use the
      sixth byte of the ID to check it.

  [3] add the new item to spi_nor_ids for s25fl128s.

Signed-off-by: Huang Shijie <b32955@freescale.com>
---
based on Brian's patch set.
---
 drivers/mtd/spi-nor/spi-nor.c |   27 ++++++++++++++++++++++-----
 1 files changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d6f44d5..cd4b277 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -383,7 +383,7 @@ struct flash_info {
 	 * then a two byte device id.
 	 */
 	u32		jedec_id;
-	u16             ext_id;
+	u32		ext_id;
 
 	/* The size listed here is what works with SPINOR_OP_SE, which isn't
 	 * necessarily called a "sector" by the vendor.
@@ -505,6 +505,7 @@ const struct spi_device_id spi_nor_ids[] = {
 	{ "s70fl01gs",  INFO(0x010221, 0x4d00, 256 * 1024, 256, 0) },
 	{ "s25sl12800", INFO(0x012018, 0x0300, 256 * 1024,  64, 0) },
 	{ "s25sl12801", INFO(0x012018, 0x0301,  64 * 1024, 256, 0) },
+	{ "s25fl128s",	INFO(0x012018, 0x4d0180, 64 * 1024, 256, SPI_NOR_QUAD_READ) },
 	{ "s25fl129p0", INFO(0x012018, 0x4d00, 256 * 1024,  64, 0) },
 	{ "s25fl129p1", INFO(0x012018, 0x4d01,  64 * 1024, 256, 0) },
 	{ "s25sl004a",  INFO(0x010212,      0,  64 * 1024,   8, 0) },
@@ -593,12 +594,13 @@ EXPORT_SYMBOL_GPL(spi_nor_ids);
 static const struct spi_device_id *spi_nor_read_id(struct spi_nor *nor)
 {
 	int			tmp;
-	u8			id[5];
+	u8			id[6];
 	u32			jedec;
-	u16                     ext_jedec;
+	u32                     ext_jedec;
 	struct flash_info	*info;
+	int			matched = -1;
 
-	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, 5);
+	tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, 6);
 	if (tmp < 0) {
 		dev_dbg(nor->dev, " error %d reading JEDEC ID\n", tmp);
 		return ERR_PTR(tmp);
@@ -614,8 +616,23 @@ static const struct spi_device_id *spi_nor_read_id(struct spi_nor *nor)
 	for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
 		info = (void *)spi_nor_ids[tmp].driver_data;
 		if (info->jedec_id == jedec) {
-			if (info->ext_id == 0 || info->ext_id == ext_jedec)
+			if (info->ext_id == 0)
 				return &spi_nor_ids[tmp];
+
+			/* the legacy two bytes ext_id */
+			if ((info->ext_id >> 16) == 0) {
+				if (info->ext_id == ext_jedec)
+					matched = tmp;
+			} else {
+				/* check the sixth byte now */
+				ext_jedec = ext_jedec << 8 | id[5];
+				if (info->ext_id == ext_jedec)
+					return &spi_nor_ids[tmp];
+			}
+		} else {
+			/* shortcut */
+			if (matched != -1)
+				return &spi_nor_ids[matched];
 		}
 	}
 	dev_err(nor->dev, "unrecognized JEDEC id %06x\n", jedec);
-- 
1.7.2.rc3