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[25/35] mtd: st_spi_fsm: Add the ability to read from a Serial Flash device

Message ID 1392735362-1245-26-git-send-email-lee.jones@linaro.org
State New
Headers show

Commit Message

Lee Jones Feb. 18, 2014, 2:55 p.m. UTC
When a read is issued by userspace the MTD framework calls back into
the driver to conduct the actual command issue and data extraction.
Here we provide the routines which do exactly that.

Acked-by Angus Clark <angus.clark@st.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
 drivers/mtd/devices/st_spi_fsm.c | 99 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 99 insertions(+)

Comments

Brian Norris March 20, 2014, 7:55 a.m. UTC | #1
On Tue, Feb 18, 2014 at 02:55:52PM +0000, Lee Jones wrote:
> diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
> index fe538bb..e4815fe 100644
> --- a/drivers/mtd/devices/st_spi_fsm.c
> +++ b/drivers/mtd/devices/st_spi_fsm.c
> @@ -942,6 +945,100 @@ static int stfsm_n25q_config(struct stfsm *fsm)
[...]
> +static int stfsm_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
> +			  size_t *retlen, u_char *buf)
> +{
> +	struct stfsm *fsm = dev_get_drvdata(mtd->dev.parent);
> +	uint32_t bytes;
> +
> +	dev_dbg(fsm->dev, "%s from 0x%08x, len %zd\n",
> +		__func__, (u32)from, len);
> +
> +	mutex_lock(&fsm->lock);
> +
> +	while (len > 0) {
> +		bytes = min_t(size_t, len, FLASH_PAGESIZE);
> +
> +		stfsm_read(fsm, buf, bytes, from);
> +
> +		buf += bytes;
> +		from += bytes;
> +		len -= bytes;
> +
> +		if (retlen)

Same as with your _write implementation; you can assume that retlen is
always non-NULL.

> +			*retlen += bytes;
> +	}
> +
> +	mutex_unlock(&fsm->lock);
> +
> +	return 0;
> +}
> +
>  static void stfsm_read_jedec(struct stfsm *fsm, uint8_t *const jedec)
>  {
>  	const struct stfsm_seq *seq = &stfsm_seq_read_jedec;

Brian
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diff mbox

Patch

diff --git a/drivers/mtd/devices/st_spi_fsm.c b/drivers/mtd/devices/st_spi_fsm.c
index fe538bb..e4815fe 100644
--- a/drivers/mtd/devices/st_spi_fsm.c
+++ b/drivers/mtd/devices/st_spi_fsm.c
@@ -238,6 +238,9 @@ 
 #define FLASH_CMD_READ4_1_1_4  0x6c
 #define FLASH_CMD_READ4_1_4_4  0xec
 
+#define FLASH_PAGESIZE         256			/* In Bytes    */
+#define FLASH_PAGESIZE_32      (FLASH_PAGESIZE / 4)	/* In uint32_t */
+
 /*
  * Flags to tweak operation of default read/write/erase routines
  */
@@ -942,6 +945,100 @@  static int stfsm_n25q_config(struct stfsm *fsm)
 	return 0;
 }
 
+static int stfsm_read(struct stfsm *fsm, uint8_t *buf, uint32_t size,
+		      uint32_t offset)
+{
+	struct stfsm_seq *seq = &stfsm_seq_read;
+	uint32_t data_pads;
+	uint32_t read_mask;
+	uint32_t size_ub;
+	uint32_t size_lb;
+	uint32_t size_mop;
+	uint32_t tmp[4];
+	uint32_t page_buf[FLASH_PAGESIZE_32];
+	uint8_t *p;
+
+	dev_dbg(fsm->dev, "reading %d bytes from 0x%08x\n", size, offset);
+
+	/* Enter 32-bit address mode, if required */
+	if (fsm->configuration & CFG_READ_TOGGLE_32BIT_ADDR)
+		stfsm_enter_32bit_addr(fsm, 1);
+
+	/* Must read in multiples of 32 cycles (or 32*pads/8 Bytes) */
+	data_pads = ((seq->seq_cfg >> 16) & 0x3) + 1;
+	read_mask = (data_pads << 2) - 1;
+
+	/* Handle non-aligned buf */
+	p = ((uint32_t)buf & 0x3) ? (uint8_t *)page_buf : buf;
+
+	/* Handle non-aligned size */
+	size_ub = (size + read_mask) & ~read_mask;
+	size_lb = size & ~read_mask;
+	size_mop = size & read_mask;
+
+	seq->data_size = TRANSFER_SIZE(size_ub);
+	seq->addr1 = (offset >> 16) & 0xffff;
+	seq->addr2 = offset & 0xffff;
+
+	stfsm_load_seq(fsm, seq);
+
+	if (size_lb)
+		stfsm_read_fifo(fsm, (uint32_t *)p, size_lb);
+
+	if (size_mop) {
+		stfsm_read_fifo(fsm, tmp, read_mask + 1);
+		memcpy(p + size_lb, &tmp, size_mop);
+	}
+
+	/* Handle non-aligned buf */
+	if ((uint32_t)buf & 0x3)
+		memcpy(buf, page_buf, size);
+
+	/* Wait for sequence to finish */
+	stfsm_wait_seq(fsm);
+
+	stfsm_clear_fifo(fsm);
+
+	/* Exit 32-bit address mode, if required */
+	if (fsm->configuration & CFG_READ_TOGGLE_32BIT_ADDR)
+		stfsm_enter_32bit_addr(fsm, 0);
+
+	return 0;
+}
+
+/*
+ * Read an address range from the flash chip. The address range
+ * may be any size provided it is within the physical boundaries.
+ */
+static int stfsm_mtd_read(struct mtd_info *mtd, loff_t from, size_t len,
+			  size_t *retlen, u_char *buf)
+{
+	struct stfsm *fsm = dev_get_drvdata(mtd->dev.parent);
+	uint32_t bytes;
+
+	dev_dbg(fsm->dev, "%s from 0x%08x, len %zd\n",
+		__func__, (u32)from, len);
+
+	mutex_lock(&fsm->lock);
+
+	while (len > 0) {
+		bytes = min_t(size_t, len, FLASH_PAGESIZE);
+
+		stfsm_read(fsm, buf, bytes, from);
+
+		buf += bytes;
+		from += bytes;
+		len -= bytes;
+
+		if (retlen)
+			*retlen += bytes;
+	}
+
+	mutex_unlock(&fsm->lock);
+
+	return 0;
+}
+
 static void stfsm_read_jedec(struct stfsm *fsm, uint8_t *const jedec)
 {
 	const struct stfsm_seq *seq = &stfsm_seq_read_jedec;
@@ -1198,6 +1295,8 @@  static int stfsm_probe(struct platform_device *pdev)
 	fsm->mtd.size		= info->sector_size * info->n_sectors;
 	fsm->mtd.erasesize	= info->sector_size;
 
+	fsm->mtd._read  = stfsm_mtd_read;
+
 	dev_err(&pdev->dev,
 		"Found serial flash device: %s\n"
 		" size = %llx (%lldMiB) erasesize = 0x%08x (%uKiB)\n",