The quad (or dual) mode of a spi-nor memory may be enabled at boot time by
non-volatile bits in some setting register. Also such a mode may have
already been enabled at early stage by some boot loader.

Hence, we should not guess the spi-nor memory is always configured for the
regular SPI 1-1-1 protocol.

Micron and Macronix memories, once their Quad (or dual for Micron) mode
enabled, no longer process the regular JEDEC Read ID (0x9f) command but
instead reply to a new command: JEDEC Read ID Multiple I/O (0xaf).
Besides, in Quad mode both memory manufacturers expect ALL commands to
use the SPI 4-4-4 protocol. For Micron memories, enabling their Dual mode
implies to use the SPI 2-2-2 protocol for ALL commands.

Signed-off-by: Cyrille Pitchen <cyrille.pitc...@atmel.com>
---
 drivers/mtd/spi-nor/spi-nor.c | 52 +++++++++++++++++++++++++++++++++++++++----
 include/linux/mtd/spi-nor.h   | 23 +++++++++++++++++--
 2 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 3b2460efc019..bf17736750c1 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -73,6 +73,11 @@ struct flash_info {
 
 #define JEDEC_MFR(info)        ((info)->id[0])
 
+struct read_id_config {
+       enum read_mode          mode;
+       enum spi_protocol       proto;
+};
+
 static const struct flash_info *spi_nor_match_id(const char *name);
 
 /*
@@ -867,11 +872,16 @@ static const struct flash_info spi_nor_ids[] = {
        { },
 };
 
-static const struct flash_info *spi_nor_read_id(struct spi_nor *nor)
+static const struct flash_info *spi_nor_read_id(struct spi_nor *nor,
+                                               enum read_mode mode)
 {
-       int                     tmp;
+       int                     i, tmp;
        u8                      id[SPI_NOR_MAX_ID_LEN];
        const struct flash_info *info;
+       static const struct read_id_config configs[] = {
+               {SPI_NOR_QUAD, SPI_PROTO_4_4_4},
+               {SPI_NOR_DUAL, SPI_PROTO_2_2_2}
+       };
 
        tmp = nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
        if (tmp < 0) {
@@ -879,6 +889,34 @@ static const struct flash_info *spi_nor_read_id(struct 
spi_nor *nor)
                return ERR_PTR(tmp);
        }
 
+       /* Special case for Micron/Macronix qspi nor. */
+       if ((id[0] == 0xff && id[1] == 0xff && id[2] == 0xff) ||
+           (id[0] == 0x00 && id[1] == 0x00 && id[2] == 0x00))
+               for (i = 0; i < ARRAY_SIZE(configs); ++i) {
+                       if (configs[i].mode != mode)
+                               continue;
+
+                       /* Set this protocol for all commands. */
+                       nor->reg_proto = configs[i].proto;
+                       nor->read_proto = configs[i].proto;
+                       nor->write_proto = configs[i].proto;
+                       nor->erase_proto = configs[i].proto;
+
+                       /*
+                        * Multiple I/O Read ID only returns the Manufacturer ID
+                        * (1 byte) and the Device ID (2 bytes). So we reset the
+                        * remaining bytes.
+                        */
+                       memset(id, 0, sizeof(id));
+                       tmp = nor->read_reg(nor, SPINOR_OP_MIO_RDID, id, 3);
+                       if (tmp < 0) {
+                               dev_dbg(nor->dev,
+                                       "error %d reading JEDEC ID Multi I/O\n",
+                                       tmp);
+                               return ERR_PTR(tmp);
+                       }
+               }
+
        for (tmp = 0; tmp < ARRAY_SIZE(spi_nor_ids) - 1; tmp++) {
                info = &spi_nor_ids[tmp];
                if (info->id_len) {
@@ -1178,11 +1216,17 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, 
enum read_mode mode)
        if (ret)
                return ret;
 
+       /* Reset SPI protocol for all commands */
+       nor->erase_proto = SPI_PROTO_1_1_1;
+       nor->read_proto = SPI_PROTO_1_1_1;
+       nor->write_proto = SPI_PROTO_1_1_1;
+       nor->reg_proto = SPI_PROTO_1_1_1;
+
        if (name)
                info = spi_nor_match_id(name);
        /* Try to auto-detect if chip name wasn't specified or not found */
        if (!info)
-               info = spi_nor_read_id(nor);
+               info = spi_nor_read_id(nor, mode);
        if (IS_ERR_OR_NULL(info))
                return -ENOENT;
 
@@ -1193,7 +1237,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, 
enum read_mode mode)
        if (name && info->id_len) {
                const struct flash_info *jinfo;
 
-               jinfo = spi_nor_read_id(nor);
+               jinfo = spi_nor_read_id(nor, mode);
                if (IS_ERR(jinfo)) {
                        return PTR_ERR(jinfo);
                } else if (jinfo != info) {
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index fac3f6f53981..c91986a99caf 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -75,8 +75,9 @@
 #define SPINOR_OP_BRWR         0x17    /* Bank register write */
 
 /* Used for Micron flashes only. */
-#define SPINOR_OP_RD_EVCR      0x65    /* Read EVCR register */
-#define SPINOR_OP_WD_EVCR      0x61    /* Write EVCR register */
+#define SPINOR_OP_MIO_RDID     0xaf    /* Multiple I/O Read JEDEC ID */
+#define SPINOR_OP_RD_EVCR      0x65    /* Read EVCR register */
+#define SPINOR_OP_WD_EVCR      0x61    /* Write EVCR register */
 
 /* Status Register bits. */
 #define SR_WIP                 BIT(0)  /* Write in progress */
@@ -105,6 +106,16 @@ enum read_mode {
        SPI_NOR_QUAD,
 };
 
+enum spi_protocol {
+       SPI_PROTO_1_1_1,        /* SPI */
+       SPI_PROTO_1_1_2,        /* Dual Output */
+       SPI_PROTO_1_1_4,        /* Quad Output */
+       SPI_PROTO_1_2_2,        /* Dual IO */
+       SPI_PROTO_1_4_4,        /* Quad IO */
+       SPI_PROTO_2_2_2,        /* Dual Command */
+       SPI_PROTO_4_4_4,        /* Quad Command */
+};
+
 #define SPI_NOR_MAX_CMD_SIZE   8
 enum spi_nor_ops {
        SPI_NOR_OPS_READ = 0,
@@ -132,6 +143,10 @@ enum spi_nor_option_flags {
  * @flash_read:                the mode of the read
  * @sst_write_second:  used by the SST write operation
  * @flags:             flag options for the current SPI-NOR (SNOR_F_*)
+ * @erase_proto:       the SPI protocol used by erase operations
+ * @read_proto:                the SPI protocol used by read operations
+ * @write_proto:       the SPI protocol used by write operations
+ * @reg_proto          the SPI protocol used by read_reg/write_reg operations
  * @cmd_buf:           used by the write_reg
  * @prepare:           [OPTIONAL] do some preparations for the
  *                     read/write/erase/lock/unlock operations
@@ -160,6 +175,10 @@ struct spi_nor {
        u8                      read_opcode;
        u8                      read_dummy;
        u8                      program_opcode;
+       enum spi_protocol       erase_proto;
+       enum spi_protocol       read_proto;
+       enum spi_protocol       write_proto;
+       enum spi_protocol       reg_proto;
        enum read_mode          flash_read;
        bool                    sst_write_second;
        u32                     flags;
-- 
1.8.2.2

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