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Subject[PATCH v7 1/2] mtd: spi-nor: add spi_nor_init() function
Date
This patch extracts some chunks from spi_nor_init_params and spi_nor_scan()
and moves them into a new spi_nor_init() function.

Indeed, spi_nor_init() regroups all the required SPI flash commands to be
sent to the SPI flash memory before performing any runtime operations
(Fast Read, Page Program, Sector Erase, ...). Hence spi_nor_init():
1) removes the flash protection if applicable for certain vendors.
2) sets the Quad Enable bit, if needed, before using Quad SPI protocols.
3) makes the memory enter its (stateful) 4-byte address mode, if needed,
for SPI flash memory > 128Mbits not supporting the 4-byte address
instruction set.

spi_nor_scan() now ends by calling spi_nor_init() once the probe phase has
completed. Further patches could also use spi_nor_init() to implement the
mtd->_resume() handler for the spi-nor framework.

Signed-off-by: Kamal Dasu <kdasu.kdev@gmail.com>
---
drivers/mtd/spi-nor/spi-nor.c | 62 ++++++++++++++++++++++++++++++-------------
include/linux/mtd/spi-nor.h | 9 +++++++
2 files changed, 52 insertions(+), 19 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index 1413828..10033ed 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -1784,7 +1784,6 @@ static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
const struct spi_nor_hwcaps *hwcaps)
{
u32 ignored_mask, shared_mask;
- bool enable_quad_io;
int err;

/*
@@ -1829,20 +1828,42 @@ static int spi_nor_setup(struct spi_nor *nor, const struct flash_info *info,
return err;
}

- /* Enable Quad I/O if needed. */
- enable_quad_io = (spi_nor_get_protocol_width(nor->read_proto) == 4 ||
- spi_nor_get_protocol_width(nor->write_proto) == 4);
- if (enable_quad_io && params->quad_enable) {
- err = params->quad_enable(nor);
+ return 0;
+}
+
+static int spi_nor_init(struct spi_nor *nor)
+{
+ int err;
+
+ /*
+ * Atmel, SST, Intel/Numonyx, and others serial NOR tend to power up
+ * with the software protection bits set
+ */
+ if (JEDEC_MFR(nor->info) == SNOR_MFR_ATMEL ||
+ JEDEC_MFR(nor->info) == SNOR_MFR_INTEL ||
+ JEDEC_MFR(nor->info) == SNOR_MFR_SST ||
+ nor->info->flags & SPI_NOR_HAS_LOCK) {
+ write_enable(nor);
+ write_sr(nor, 0);
+ spi_nor_wait_till_ready(nor);
+ }
+
+ if (nor->quad_enable) {
+ err = nor->quad_enable(nor);
if (err) {
dev_err(nor->dev, "quad mode not supported\n");
return err;
}
}

+ if ((JEDEC_MFR(nor->info) != SNOR_MFR_SPANSION) &&
+ !(nor->info->flags & SPI_NOR_4B_OPCODES))
+ set_4byte(nor, nor->info, 1);
+
return 0;
}

+
int spi_nor_scan(struct spi_nor *nor, const char *name,
const struct spi_nor_hwcaps *hwcaps)
{
@@ -1853,6 +1874,7 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
struct device_node *np = spi_nor_get_flash_node(nor);
int ret;
int i;
+ bool enable_quad_io;

ret = spi_nor_check(nor);
if (ret)
@@ -1915,15 +1937,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
* with the software protection bits set
*/

- if (JEDEC_MFR(info) == SNOR_MFR_ATMEL ||
- JEDEC_MFR(info) == SNOR_MFR_INTEL ||
- JEDEC_MFR(info) == SNOR_MFR_SST ||
- info->flags & SPI_NOR_HAS_LOCK) {
- write_enable(nor);
- write_sr(nor, 0);
- spi_nor_wait_till_ready(nor);
- }
-
if (!mtd->name)
mtd->name = dev_name(dev);
mtd->priv = nor;
@@ -2002,8 +2015,6 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
if (JEDEC_MFR(info) == SNOR_MFR_SPANSION ||
info->flags & SPI_NOR_4B_OPCODES)
spi_nor_set_4byte_opcodes(nor, info);
- else
- set_4byte(nor, info, 1);
} else {
nor->addr_width = 3;
}
@@ -2020,8 +2031,21 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
return ret;
}

- dev_info(dev, "%s (%lld Kbytes)\n", info->name,
- (long long)mtd->size >> 10);
+ /* Send all the required SPI flash commands to initialize device */
+ nor->info = info;
+ /* Enable Quad I/O if needed. */
+ enable_quad_io = (spi_nor_get_protocol_width(nor->read_proto) == 4 ||
+ spi_nor_get_protocol_width(nor->write_proto) == 4);
+ if (enable_quad_io && params.quad_enable)
+ nor->quad_enable = params.quad_enable;
+
+ ret = spi_nor_init(nor);
+ if (ret)
+ return ret;
+
+ dev_info(dev, "%s (%lld Kbytes), %dByte addr, %s\n", info->name,
+ (long long)mtd->size >> 10, nor->addr_width,
+ (nor->quad_enable ? "quad io enabled" : "quad io disabled"));

dev_dbg(dev,
"mtd .name = %s, .size = 0x%llx (%lldMiB), "
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 55faa2f..db127b8 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -220,11 +220,17 @@ enum spi_nor_option_flags {
SNOR_F_READY_XSR_RDY = BIT(4),
};

+/* struct flash_info - Forward declaration of a structure used internally by
+ * spi_nor_scan()
+ */
+struct flash_info;
+
/**
* struct spi_nor - Structure for defining a the SPI NOR layer
* @mtd: point to a mtd_info structure
* @lock: the lock for the read/write/erase/lock/unlock operations
* @dev: point to a spi device, or a spi nor controller device.
+ * @info: spi-nor part JDEC MFR id and other info
* @page_size: the page size of the SPI NOR
* @addr_width: number of address bytes
* @erase_opcode: the opcode for erasing a sector
@@ -251,6 +257,7 @@ enum spi_nor_option_flags {
* @flash_lock: [FLASH-SPECIFIC] lock a region of the SPI NOR
* @flash_unlock: [FLASH-SPECIFIC] unlock a region of the SPI NOR
* @flash_is_locked: [FLASH-SPECIFIC] check if a region of the SPI NOR is
+ * @quad_enable: [FLASH-SPECIFIC] enables SPI NOR quad mode
* completely locked
* @priv: the private data
*/
@@ -258,6 +265,7 @@ struct spi_nor {
struct mtd_info mtd;
struct mutex lock;
struct device *dev;
+ const struct flash_info *info;
u32 page_size;
u8 addr_width;
u8 erase_opcode;
@@ -285,6 +293,7 @@ struct spi_nor {
int (*flash_lock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
int (*flash_unlock)(struct spi_nor *nor, loff_t ofs, uint64_t len);
int (*flash_is_locked)(struct spi_nor *nor, loff_t ofs, uint64_t len);
+ int (*quad_enable)(struct spi_nor *nor);

void *priv;
};
--
1.9.1
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