[PATCH v4] drivers: mtd: m25p80: add quad read support
Brian Norris
computersforpeace at gmail.com
Fri Nov 8 13:37:25 EST 2013
From: Sourav Poddar <sourav.poddar at ti.com>
Some flash also support quad read mode. Adding support for quad read
mode in m25p80 for Spansion and Macronix flash.
[Tweaked by Brian]
With this patch, quad-read support will override fast-read and
normal-read, if the SPI controller and flash chip both support it.
Signed-off-by: Sourav Poddar <sourav.poddar at ti.com>
Signed-off-by: Brian Norris <computersforpeace at gmail.com>
---
v3 -> v4
I made a few final tweaks to Sourav's patch. It got the precedence logic
wrong, where fast and normal read might override quad-read, and then
normal-read would in some cases override either of the others!
drivers/mtd/devices/m25p80.c | 141 ++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 139 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 04f8a24..f2f781d 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -41,6 +41,7 @@
#define OPCODE_WRSR 0x01 /* Write status register 1 byte */
#define OPCODE_NORM_READ 0x03 /* Read data bytes (low frequency) */
#define OPCODE_FAST_READ 0x0b /* Read data bytes (high frequency) */
+#define OPCODE_QUAD_READ 0x6b /* Read data bytes */
#define OPCODE_PP 0x02 /* Page program (up to 256 bytes) */
#define OPCODE_BE_4K 0x20 /* Erase 4KiB block */
#define OPCODE_BE_4K_PMC 0xd7 /* Erase 4KiB block on PMC chips */
@@ -48,10 +49,12 @@
#define OPCODE_CHIP_ERASE 0xc7 /* Erase whole flash chip */
#define OPCODE_SE 0xd8 /* Sector erase (usually 64KiB) */
#define OPCODE_RDID 0x9f /* Read JEDEC ID */
+#define OPCODE_RDCR 0x35 /* Read configuration register */
/* 4-byte address opcodes - used on Spansion and some Macronix flashes. */
#define OPCODE_NORM_READ_4B 0x13 /* Read data bytes (low frequency) */
#define OPCODE_FAST_READ_4B 0x0c /* Read data bytes (high frequency) */
+#define OPCODE_QUAD_READ_4B 0x6c /* Read data bytes */
#define OPCODE_PP_4B 0x12 /* Page program (up to 256 bytes) */
#define OPCODE_SE_4B 0xdc /* Sector erase (usually 64KiB) */
@@ -76,6 +79,11 @@
#define SR_BP2 0x10 /* Block protect 2 */
#define SR_SRWD 0x80 /* SR write protect */
+#define SR_QUAD_EN_MX 0x40 /* Macronix Quad I/O */
+
+/* Configuration Register bits. */
+#define CR_QUAD_EN_SPAN 0x2 /* Spansion Quad I/O */
+
/* Define max times to check status register before we give up. */
#define MAX_READY_WAIT_JIFFIES (40 * HZ) /* M25P16 specs 40s max chip erase */
#define MAX_CMD_SIZE 6
@@ -87,6 +95,7 @@
enum read_type {
M25P80_NORMAL = 0,
M25P80_FAST,
+ M25P80_QUAD,
};
struct m25p {
@@ -136,6 +145,26 @@ static int read_sr(struct m25p *flash)
}
/*
+ * Read configuration register, returning its value in the
+ * location. Return the configuration register value.
+ * Returns negative if error occured.
+ */
+static int read_cr(struct m25p *flash)
+{
+ u8 code = OPCODE_RDCR;
+ int ret;
+ u8 val;
+
+ ret = spi_write_then_read(flash->spi, &code, 1, &val, 1);
+ if (ret < 0) {
+ dev_err(&flash->spi->dev, "error %d reading CR\n", ret);
+ return ret;
+ }
+
+ return val;
+}
+
+/*
* Write status register 1 byte
* Returns negative if error occurred.
*/
@@ -225,6 +254,95 @@ static int wait_till_ready(struct m25p *flash)
}
/*
+ * Write status Register and configuration register with 2 bytes
+ * The first byte will be written to the status register, while the
+ * second byte will be written to the configuration register.
+ * Return negative if error occured.
+ */
+static int write_sr_cr(struct m25p *flash, u16 val)
+{
+ flash->command[0] = OPCODE_WRSR;
+ flash->command[1] = val & 0xff;
+ flash->command[2] = (val >> 8);
+
+ return spi_write(flash->spi, flash->command, 3);
+}
+
+static int macronix_quad_enable(struct m25p *flash)
+{
+ int ret, val;
+ u8 cmd[2];
+ cmd[0] = OPCODE_WRSR;
+
+ val = read_sr(flash);
+ cmd[1] = val | SR_QUAD_EN_MX;
+ write_enable(flash);
+
+ spi_write(flash->spi, &cmd, 2);
+
+ if (wait_till_ready(flash))
+ return 1;
+
+ ret = read_sr(flash);
+ if (!(ret > 0 && (ret & SR_QUAD_EN_MX))) {
+ dev_err(&flash->spi->dev,
+ "Macronix Quad bit not set");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int spansion_quad_enable(struct m25p *flash)
+{
+ int ret;
+ int quad_en = CR_QUAD_EN_SPAN << 8;
+
+ write_enable(flash);
+
+ ret = write_sr_cr(flash, quad_en);
+ if (ret < 0) {
+ dev_err(&flash->spi->dev,
+ "error while writing configuration register");
+ return -EINVAL;
+ }
+
+ /* read back and check it */
+ ret = read_cr(flash);
+ if (!(ret > 0 && (ret & CR_QUAD_EN_SPAN))) {
+ dev_err(&flash->spi->dev,
+ "Spansion Quad bit not set");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int set_quad_mode(struct m25p *flash, u32 jedec_id)
+{
+ int status;
+
+ switch (JEDEC_MFR(jedec_id)) {
+ case CFI_MFR_MACRONIX:
+ status = macronix_quad_enable(flash);
+ if (status) {
+ dev_err(&flash->spi->dev,
+ "Macronix quad-read not enabled");
+ return -EINVAL;
+ }
+ return status;
+ default:
+ status = spansion_quad_enable(flash);
+ if (status) {
+ dev_err(&flash->spi->dev,
+ "Spansion quad-read not enabled");
+ return -EINVAL;
+ }
+ return status;
+ }
+}
+
+/*
* Erase the whole flash memory
*
* Returns 0 if successful, non-zero otherwise.
@@ -363,6 +481,7 @@ static inline int m25p80_dummy_cycles_read(struct m25p *flash)
{
switch (flash->flash_read) {
case M25P80_FAST:
+ case M25P80_QUAD:
return 1;
case M25P80_NORMAL:
return 0;
@@ -727,6 +846,7 @@ struct flash_info {
#define SST_WRITE 0x04 /* use SST byte programming */
#define M25P_NO_FR 0x08 /* Can't do fastread */
#define SECT_4K_PMC 0x10 /* OPCODE_BE_4K_PMC works uniformly */
+#define M25P80_QUAD_READ 0x20 /* Flash supports Quad Read */
};
#define INFO(_jedec_id, _ext_id, _sector_size, _n_sectors, _flags) \
@@ -804,7 +924,7 @@ static const struct spi_device_id m25p_ids[] = {
{ "mx25l12855e", INFO(0xc22618, 0, 64 * 1024, 256, 0) },
{ "mx25l25635e", INFO(0xc22019, 0, 64 * 1024, 512, 0) },
{ "mx25l25655e", INFO(0xc22619, 0, 64 * 1024, 512, 0) },
- { "mx66l51235l", INFO(0xc2201a, 0, 64 * 1024, 1024, 0) },
+ { "mx66l51235l", INFO(0xc2201a, 0, 64 * 1024, 1024, M25P80_QUAD_READ) },
/* Micron */
{ "n25q064", INFO(0x20ba17, 0, 64 * 1024, 128, 0) },
@@ -824,7 +944,7 @@ static const struct spi_device_id m25p_ids[] = {
{ "s25sl032p", INFO(0x010215, 0x4d00, 64 * 1024, 64, 0) },
{ "s25sl064p", INFO(0x010216, 0x4d00, 64 * 1024, 128, 0) },
{ "s25fl256s0", INFO(0x010219, 0x4d00, 256 * 1024, 128, 0) },
- { "s25fl256s1", INFO(0x010219, 0x4d01, 64 * 1024, 512, 0) },
+ { "s25fl256s1", INFO(0x010219, 0x4d01, 64 * 1024, 512, M25P80_QUAD_READ) },
{ "s25fl512s", INFO(0x010220, 0x4d00, 256 * 1024, 256, 0) },
{ "s70fl01gs", INFO(0x010221, 0x4d00, 256 * 1024, 256, 0) },
{ "s25sl12800", INFO(0x012018, 0x0300, 256 * 1024, 64, 0) },
@@ -966,6 +1086,7 @@ static int m25p_probe(struct spi_device *spi)
unsigned i;
struct mtd_part_parser_data ppdata;
struct device_node *np = spi->dev.of_node;
+ int ret;
/* Platform data helps sort out which chip type we have, as
* well as how this board partitions it. If we don't have
@@ -1093,8 +1214,21 @@ static int m25p_probe(struct spi_device *spi)
if (info->flags & M25P_NO_FR)
flash->flash_read = M25P80_NORMAL;
+ /* Quad-read mode takes precedence over fast/normal */
+ if (spi->mode & SPI_RX_QUAD && info->flags & M25P80_QUAD_READ) {
+ ret = set_quad_mode(flash, info->jedec_id);
+ if (ret) {
+ dev_err(&flash->spi->dev, "quad mode not supported\n");
+ return ret;
+ }
+ flash->flash_read = M25P80_QUAD;
+ }
+
/* Default commands */
switch (flash->flash_read) {
+ case M25P80_QUAD:
+ flash->read_opcode = OPCODE_QUAD_READ;
+ break;
case M25P80_FAST:
flash->read_opcode = OPCODE_FAST_READ;
break;
@@ -1116,6 +1250,9 @@ static int m25p_probe(struct spi_device *spi)
if (JEDEC_MFR(info->jedec_id) == CFI_MFR_AMD) {
/* Dedicated 4-byte command set */
switch (flash->flash_read) {
+ case M25P80_QUAD:
+ flash->read_opcode = OPCODE_QUAD_READ;
+ break;
case M25P80_FAST:
flash->read_opcode = OPCODE_FAST_READ_4B;
break;
--
1.8.4.2
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