For Freescale's eSPI controller, the max transaction length one time
is limitted by the SPCOM[TRANSLEN] field which is 0xFFFF. When used
mkfs.ext2 command to create ext2 filesystem on the flash, the read
length will exceed the max value of the SPCOM[TRANSLEN] field, so
change the read function to read page by page.
For other SPI flash driver, also needed to supply the read function
if used the eSPI controller.
Signed-off-by: Mingkai Hu <mingkai...@freescale.com>
---
v3:
- Add a quirks member for the SPI master to handle the contrains of the
SPI controller. I can't think of other method. :-(
drivers/mtd/devices/m25p80.c | 78 ++++++++++++++++++++++++++++++++++++++++++
drivers/spi/spi_fsl_lib.c | 4 ++
include/linux/spi/spi.h | 5 +++
3 files changed, 87 insertions(+), 0 deletions(-)
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 47d53c7..f65cca8 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -377,6 +377,81 @@ static int m25p80_read(struct mtd_info *mtd, loff_t from,
size_t len,
}
/*
+ * Read an address range from the flash chip page by page.
+ * Some controller has transaction length limitation such as the
+ * Freescale's eSPI controller can only trasmit 0xFFFF bytes one
+ * time, so we have to read page by page if the len is more than
+ * the limitation.
+ */
+static int m25p80_page_read(struct mtd_info *mtd, loff_t from, size_t len,
+ size_t *retlen, u_char *buf)
+{
+ struct m25p *flash = mtd_to_m25p(mtd);
+ struct spi_transfer t[2];
+ struct spi_message m;
+ u32 i, page_size = 0;
+
+ DEBUG(MTD_DEBUG_LEVEL2, "%s: %s %s 0x%08x, len %zd\n",
+ dev_name(&flash->spi->dev), __func__, "from",
+ (u32)from, len);
+
+ /* sanity checks */
+ if (!len)
+ return 0;
+
+ if (from + len > flash->mtd.size)
+ return -EINVAL;
+
+ spi_message_init(&m);
+ memset(t, 0, (sizeof t));
+
+ /* NOTE:
+ * OPCODE_FAST_READ (if available) is faster.
+ * Should add 1 byte DUMMY_BYTE.
+ */
+ t[0].tx_buf = flash->command;
+ t[0].len = m25p_cmdsz(flash) + FAST_READ_DUMMY_BYTE;
+ spi_message_add_tail(&t[0], &m);
+
+ t[1].rx_buf = buf;
+ spi_message_add_tail(&t[1], &m);
+
+ /* Byte count starts at zero. */
+ if (retlen)
+ *retlen = 0;
+
+ mutex_lock(&flash->lock);
+
+ /* Wait till previous write/erase is done. */
+ if (wait_till_ready(flash)) {
+ /* REVISIT status return?? */
+ mutex_unlock(&flash->lock);
+ return 1;
+ }
+
+ /* Set up the write data buffer. */
+ flash->command[0] = OPCODE_READ;
+
+ for (i = page_size; i < len; i += page_size) {
+ page_size = len - i;
+ if (page_size > flash->page_size)
+ page_size = flash->page_size;
+ m25p_addr2cmd(flash, from + i, flash->command);
+ t[1].len = page_size;
+ t[1].rx_buf = buf + i;
+
+ spi_sync(flash->spi, &m);
+
+ *retlen += m.actual_length - m25p_cmdsz(flash)
+ - FAST_READ_DUMMY_BYTE;
+ }
+
+ mutex_unlock(&flash->lock);
+
+ return 0;
+}
+
+/*
* Write an address range to the flash chip. Data must be written in
* FLASH_PAGESIZE chunks. The address range may be any size provided
* it is within the physical boundaries.
@@ -874,6 +949,9 @@ static int __devinit m25p_probe(struct spi_device *spi)
flash->mtd.erase = m25p80_erase;
flash->mtd.read = m25p80_read;
+ if (spi->master->quirks & SPI_QUIRK_TRANS_LEN_LIMIT)
+ flash->mtd.read = m25p80_page_read;
+
/* sst flash chips use AAI word program */
if (info->jedec_id >> 16 == 0xbf)
flash->mtd.write = sst_write;
diff --git a/drivers/spi/spi_fsl_lib.c b/drivers/spi/spi_fsl_lib.c
index 5cd741f..c8d8c2d 100644
--- a/drivers/spi/spi_fsl_lib.c
+++ b/drivers/spi/spi_fsl_lib.c
@@ -135,6 +135,10 @@ int mpc8xxx_spi_probe(struct device *dev, struct resource
*mem,
master->cleanup = mpc8xxx_spi_cleanup;
master->dev.of_node = dev->of_node;
+ if (of_get_property(dev->of_node,
+ "fsl,spi-quirk-trans-len-limit", NULL))
+ master->quirks |= SPI_QUIRK_TRANS_LEN_LIMIT;
+
mpc8xxx_spi = spi_master_get_devdata(master);
mpc8xxx_spi->dev = dev;
mpc8xxx_spi->get_rx = mpc8xxx_spi_rx_buf_u8;
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 92e52a1..4234dfd 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -304,6 +304,11 @@ struct spi_master {
/* called on release() to free memory provided by spi_master */
void (*cleanup)(struct spi_device *spi);
+
+ /* some constraints of the controller */
+ u16 quirks;
+#define SPI_QUIRK_TRANS_LEN_LIMIT BIT(0) /* have trans length limit */
+
};
static inline void *spi_master_get_devdata(struct spi_master *master)
--
1.6.4
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