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mtd: spi-nor: Add quad I/O support for Micron SPI NOR 

This patch adds code which enables Quad I/O mode on Micron SPI NOR flashes.

For Micron SPI NOR flash, enabling or disabling quad I/O protocol can be
done By two methods, which are to use EVCR (Enhanced Volatile
Configuration Register) and the ENTER QUAD I/O MODE command. There is no
difference between these two methods. Unfortunately, for some Micron SPI
NOR flashes, there no ENTER Quad I/O command (35h), such as n25q064. But
for all current Micron SPI NOR, if it support quad I/O mode, using EVCR
definitely be supported. It is a recommended method to enable Quad I/O
mode by EVCR, Quad I/O protocol bit 7. When EVCR bit 7 is reset to 0,
the SPI NOR flash will operate in quad I/O mode.

This patch has been tested on N25Q512A and MT25TL256BAA1ESF. Micron SPI
NOR of spi_nor_ids[] table all support this method.

Signed-off-by: Bean Huo <beanhuo@micron.com>
Acked-by: Marek Vasut <marex@denx.de>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>
This commit is contained in:
Bean Huo 霍斌斌 (beanhuo) 2014-12-17 07:35:45 +00:00 committed by Brian Norris
parent ed0215cc3b
commit 548cd3ab54
2 changed files with 61 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

62
drivers/mtd/spi-nor/spi-nor.c
View File

@ -560,14 +560,14 @@ static const struct spi_device_id spi_nor_ids[] = {
{ "mx66l1g55g", INFO(0xc2261b, 0, 64 * 1024, 2048, SPI_NOR_QUAD_READ) },
/* Micron */
{ "n25q032", INFO(0x20ba16, 0, 64 * 1024, 64, 0) },
{ "n25q064", INFO(0x20ba17, 0, 64 * 1024, 128, 0) },
{ "n25q128a11", INFO(0x20bb18, 0, 64 * 1024, 256, 0) },
{ "n25q128a13", INFO(0x20ba18, 0, 64 * 1024, 256, 0) },
{ "n25q256a", INFO(0x20ba19, 0, 64 * 1024, 512, SECT_4K) },
{ "n25q512a", INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K) },
{ "n25q512ax3", INFO(0x20ba20, 0, 64 * 1024, 1024, USE_FSR) },
{ "n25q00", INFO(0x20ba21, 0, 64 * 1024, 2048, USE_FSR) },
{ "n25q032", INFO(0x20ba16, 0, 64 * 1024, 64, SPI_NOR_QUAD_READ) },
{ "n25q064", INFO(0x20ba17, 0, 64 * 1024, 128, SPI_NOR_QUAD_READ) },
{ "n25q128a11", INFO(0x20bb18, 0, 64 * 1024, 256, SPI_NOR_QUAD_READ) },
{ "n25q128a13", INFO(0x20ba18, 0, 64 * 1024, 256, SPI_NOR_QUAD_READ) },
{ "n25q256a", INFO(0x20ba19, 0, 64 * 1024, 512, SECT_4K | SPI_NOR_QUAD_READ) },
{ "n25q512a", INFO(0x20bb20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
{ "n25q512ax3", INFO(0x20ba20, 0, 64 * 1024, 1024, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
{ "n25q00", INFO(0x20ba21, 0, 64 * 1024, 2048, SECT_4K | USE_FSR | SPI_NOR_QUAD_READ) },
/* PMC */
{ "pm25lv512", INFO(0, 0, 32 * 1024, 2, SECT_4K_PMC) },
@ -891,6 +891,45 @@ static int spansion_quad_enable(struct spi_nor *nor)
return 0;
}
static int micron_quad_enable(struct spi_nor *nor)
{
int ret;
u8 val;
ret = nor->read_reg(nor, SPINOR_OP_RD_EVCR, &val, 1);
if (ret < 0) {
dev_err(nor->dev, "error %d reading EVCR\n", ret);
return ret;
}
write_enable(nor);
/* set EVCR, enable quad I/O */
nor->cmd_buf[0] = val & ~EVCR_QUAD_EN_MICRON;
ret = nor->write_reg(nor, SPINOR_OP_WD_EVCR, nor->cmd_buf, 1, 0);
if (ret < 0) {
dev_err(nor->dev, "error while writing EVCR register\n");
return ret;
}
ret = spi_nor_wait_till_ready(nor);
if (ret)
return ret;
/* read EVCR and check it */
ret = nor->read_reg(nor, SPINOR_OP_RD_EVCR, &val, 1);
if (ret < 0) {
dev_err(nor->dev, "error %d reading EVCR\n", ret);
return ret;
}
if (val & EVCR_QUAD_EN_MICRON) {
dev_err(nor->dev, "Micron EVCR Quad bit not clear\n");
return -EINVAL;
}
return 0;
}
static int set_quad_mode(struct spi_nor *nor, struct flash_info *info)
{
int status;
@ -903,6 +942,13 @@ static int set_quad_mode(struct spi_nor *nor, struct flash_info *info)
return -EINVAL;
}
return status;
case CFI_MFR_ST:
status = micron_quad_enable(nor);
if (status) {
dev_err(nor->dev, "Micron quad-read not enabled\n");
return -EINVAL;
}
return status;
default:
status = spansion_quad_enable(nor);
if (status) {

7
include/linux/mtd/spi-nor.h
View File

@ -56,6 +56,10 @@
/* Used for Spansion flashes only. */
#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 */
/* Status Register bits. */
#define SR_WIP 1 /* Write in progress */
#define SR_WEL 2 /* Write enable latch */
@ -67,6 +71,9 @@
#define SR_QUAD_EN_MX 0x40 /* Macronix Quad I/O */
/* Enhanced Volatile Configuration Register bits */
#define EVCR_QUAD_EN_MICRON 0x80 /* Micron Quad I/O */
/* Flag Status Register bits */
#define FSR_READY 0x80