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authorMatthieu CASTET <matthieu.castet@parrot.com>2012-11-06 11:51:44 +0100
committerArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-12-03 16:36:52 +0200
commit64b37b2a63eb2f80b65c7185f0013f8ffc637ae3 (patch)
treeccc8cd81dbcbef0fb8d69856a00dfb795d78b80a /include/linux/mtd
parent2fd71a294a0aac407ec69e04916dc28eb39c8ac0 (diff)
mtd: nand: add NAND_BUSWIDTH_AUTO to autodetect bus width
The driver call nand_scan_ident in 8 bit mode, then readid or onfi detection are done (and detect bus width). The driver should update its bus width before calling nand_scan_tail. This work because readid and onfi are read work 8 byte mode. Note that nand_scan_ident send command (NAND_CMD_RESET, NAND_CMD_READID, NAND_CMD_PARAM), address and read data The ONFI specificication is not very clear for x16 device if high byte of address should be driven to 0, but according to [1] it should be ok to not drive it during autodetection. [1] 3.3.2. Target Initialization [...] The Read ID and Read Parameter Page commands only use the lower 8-bits of the data bus. The host shall not issue commands that use a word data width on x16 devices until the host determines the device supports a 16-bit data bus width in the parameter page. Signed-off-by: Matthieu CASTET <matthieu.castet@parrot.com> Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Diffstat (limited to 'include/linux/mtd')
-rw-r--r--include/linux/mtd/nand.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/mtd/nand.h b/include/linux/mtd/nand.h
index 9d8a6048aacd..7ccb3c59ed60 100644
--- a/include/linux/mtd/nand.h
+++ b/include/linux/mtd/nand.h
@@ -219,6 +219,13 @@ typedef enum {
#define NAND_OWN_BUFFERS 0x00020000
/* Chip may not exist, so silence any errors in scan */
#define NAND_SCAN_SILENT_NODEV 0x00040000
+/*
+ * Autodetect nand buswidth with readid/onfi.
+ * This suppose the driver will configure the hardware in 8 bits mode
+ * when calling nand_scan_ident, and update its configuration
+ * before calling nand_scan_tail.
+ */
+#define NAND_BUSWIDTH_AUTO 0x00080000
/* Options set by nand scan */
/* Nand scan has allocated controller struct */