[LINUX RFC v2 3/4] spi-nor: add dual parallel mode support

From: Ranjit Waghmode
Date: Wed Aug 26 2015 - 02:27:56 EST


This patch adds support for dual parallel configuration by:

- Adding required parameters like isparallel and shift to spi_nor structure.
- Initializing all added parameters in spi_nor_scan()
- Updating read_sr() and read_fsr() for getting status of both flashes
- Increasing page_size, sector_size, erase_size and toatal flash size
as and when required.
- Dividing address by 2
- Updating spi->master->flags for qspi driver to change CS

Signed-off-by: Ranjit Waghmode <ranjit.waghmode@xxxxxxxxxx>
---
V2 Changes:
Splitted to separate MTD layer changes from SPI core changes
---
drivers/mtd/spi-nor/spi-nor.c | 91 ++++++++++++++++++++++++++++++++++---------
include/linux/mtd/spi-nor.h | 2 +
2 files changed, 74 insertions(+), 19 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index d78831b..6a2e80b 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -22,6 +22,7 @@
#include <linux/of_platform.h>
#include <linux/spi/flash.h>
#include <linux/mtd/spi-nor.h>
+#include <linux/spi/spi.h>

/* Define max times to check status register before we give up. */
#define MAX_READY_WAIT_JIFFIES (40 * HZ) /* M25P16 specs 40s max chip erase */
@@ -69,15 +70,24 @@ static const struct spi_device_id *spi_nor_match_id(const char *name);
static int read_sr(struct spi_nor *nor)
{
int ret;
- u8 val;
+ u8 val[2];

- ret = nor->read_reg(nor, SPINOR_OP_RDSR, &val, 1);
- if (ret < 0) {
- pr_err("error %d reading SR\n", (int) ret);
- return ret;
+ if (nor->isparallel) {
+ ret = nor->read_reg(nor, SPINOR_OP_RDSR, &val[0], 2);
+ if (ret < 0) {
+ pr_err("error %d reading SR\n", (int) ret);
+ return ret;
+ }
+ val[0] |= val[1];
+ } else {
+ ret = nor->read_reg(nor, SPINOR_OP_RDSR, &val[0], 1);
+ if (ret < 0) {
+ pr_err("error %d reading SR\n", (int) ret);
+ return ret;
+ }
}

- return val;
+ return val[0];
}

/*
@@ -87,16 +97,24 @@ static int read_sr(struct spi_nor *nor)
*/
static int read_fsr(struct spi_nor *nor)
{
- int ret;
- u8 val;
+ int ret, size;
+ u8 val[2];
+
+ size = 1;
+ val[1] = 0xff;
+
+ if (nor->isparallel)
+ size = 2;

- ret = nor->read_reg(nor, SPINOR_OP_RDFSR, &val, 1);
+ ret = nor->read_reg(nor, SPINOR_OP_RDFSR, &val[0], size);
if (ret < 0) {
pr_err("error %d reading FSR\n", ret);
return ret;
}

- return val;
+ val[0] &= val[1];
+
+ return val[0];
}

/*
@@ -317,6 +335,9 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
if (ret)
return ret;

+ if (nor->isparallel)
+ nor->spi->master->flags |= SPI_MASTER_DATA_STRIPE;
+
/* whole-chip erase? */
if (len == mtd->size) {
write_enable(nor);
@@ -340,6 +361,8 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)
while (len) {
write_enable(nor);

+ addr = addr >> nor->shift;
+
if (nor->erase(nor, addr)) {
ret = -EIO;
goto erase_err;
@@ -360,19 +383,22 @@ static int spi_nor_erase(struct mtd_info *mtd, struct erase_info *instr)

instr->state = MTD_ERASE_DONE;
mtd_erase_callback(instr);
-
+ if (nor->isparallel)
+ nor->spi->master->flags &= ~SPI_MASTER_DATA_STRIPE;
return ret;

erase_err:
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_ERASE);
instr->state = MTD_ERASE_FAILED;
+ if (nor->isparallel)
+ nor->spi->master->flags &= ~SPI_MASTER_DATA_STRIPE;
return ret;
}

static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
struct mtd_info *mtd = nor->mtd;
- uint32_t offset = ofs;
+ uint32_t offset = ofs >> nor->shift;
uint8_t status_old, status_new;
int ret = 0;

@@ -406,7 +432,7 @@ static int stm_lock(struct spi_nor *nor, loff_t ofs, uint64_t len)
static int stm_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
{
struct mtd_info *mtd = nor->mtd;
- uint32_t offset = ofs;
+ uint32_t offset = ofs >> nor->shift;
uint8_t status_old, status_new;
int ret = 0;

@@ -446,6 +472,8 @@ static int spi_nor_lock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
if (ret)
return ret;

+ ofs = ofs >> nor->shift;
+
ret = nor->flash_lock(nor, ofs, len);

spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_UNLOCK);
@@ -461,6 +489,8 @@ static int spi_nor_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
if (ret)
return ret;

+ ofs = ofs >> nor->shift;
+
ret = nor->flash_unlock(nor, ofs, len);

spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_LOCK);
@@ -738,7 +768,13 @@ static int spi_nor_read(struct mtd_info *mtd, loff_t from, size_t len,
if (ret)
return ret;

- ret = nor->read(nor, from, len, retlen, buf);
+ if (nor->isparallel)
+ nor->spi->master->flags |= SPI_MASTER_DATA_STRIPE;
+
+ ret = nor->read(nor, from >> nor->shift, len, retlen, buf);
+
+ if (nor->isparallel)
+ nor->spi->master->flags &= ~SPI_MASTER_DATA_STRIPE;

spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_READ);
return ret;
@@ -834,11 +870,11 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,

/* do all the bytes fit onto one page? */
if (page_offset + len <= nor->page_size) {
- nor->write(nor, to, len, retlen, buf);
+ nor->write(nor, to >> nor->shift, len, retlen, buf);
} else {
/* the size of data remaining on the first page */
page_size = nor->page_size - page_offset;
- nor->write(nor, to, page_size, retlen, buf);
+ nor->write(nor, to >> nor->shift, page_size, retlen, buf);

/* write everything in nor->page_size chunks */
for (i = page_size; i < len; i += page_size) {
@@ -852,12 +888,15 @@ static int spi_nor_write(struct mtd_info *mtd, loff_t to, size_t len,

write_enable(nor);

- nor->write(nor, to + i, page_size, retlen, buf + i);
+ nor->write(nor, (to + i) >> nor->shift, page_size,
+ retlen, buf + i);
}
}

ret = spi_nor_wait_till_ready(nor);
write_err:
+ if (nor->isparallel)
+ nor->spi->master->flags &= ~SPI_MASTER_DATA_STRIPE;
spi_nor_unlock_and_unprep(nor, SPI_NOR_OPS_WRITE);
return ret;
}
@@ -1073,6 +1112,20 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
mtd->_erase = spi_nor_erase;
mtd->_read = spi_nor_read;

+#ifdef CONFIG_OF
+ struct device_node *np_spi = of_get_next_parent(np);
+ u32 is_dual;
+
+ if (of_property_read_u32(np_spi, "is-dual", &is_dual) > 0) {
+ nor->shift = 1;
+ info->sector_size <<= nor->shift;
+ info->page_size <<= nor->shift;
+ mtd->size <<= nor->shift;
+ nor->isparallel = 1;
+ nor->spi->master->flags |= SPI_MASTER_BOTH_CS;
+ }
+#endif
+
/* nor protection support for STmicro chips */
if (JEDEC_MFR(info) == CFI_MFR_ST) {
nor->flash_lock = stm_lock;
@@ -1097,10 +1150,10 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, enum read_mode mode)
/* prefer "small sector" erase if possible */
if (info->flags & SECT_4K) {
nor->erase_opcode = SPINOR_OP_BE_4K;
- mtd->erasesize = 4096;
+ mtd->erasesize = 4096 << nor->shift;
} else if (info->flags & SECT_4K_PMC) {
nor->erase_opcode = SPINOR_OP_BE_4K_PMC;
- mtd->erasesize = 4096;
+ mtd->erasesize = 4096 << nor->shift;
} else
#endif
{
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index 1705dc3..6ef25a8 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -171,6 +171,8 @@ struct spi_nor {
u8 read_dummy;
u8 program_opcode;
enum read_mode flash_read;
+ bool shift;
+ bool isparallel;
bool sst_write_second;
u32 flags;
struct spi_nor_xfer_cfg cfg;
--
2.1.2

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