mtd: devices: m25p80: Make sure WRITE_EN is issued before each write

Message ID 1528870158-14781-1-git-send-email-yogeshnarayan.gaur@nxp.com
State Accepted
Delegated to: Boris Brezillon
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  • mtd: devices: m25p80: Make sure WRITE_EN is issued before each write
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Commit Message

Yogesh Narayan Gaur June 13, 2018, 6:09 a.m.
Some SPI controllers can't write nor->page_size bytes in a single step
because their TX FIFO is too small, but when that happens we should
make sure a WRITE_EN command before each write access and READ_SR command
after each write access is issued.

The core is already taking care of that, so all we have to do here is
return the actual number of bytes that were written during the
spi_mem_exec_op() operation.

Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@nxp.com>
---
 drivers/mtd/devices/m25p80.c | 23 ++++++++---------------
 1 file changed, 8 insertions(+), 15 deletions(-)

Comments

Boris Brezillon Oct. 3, 2018, 7:10 a.m. | #1
On Wed, 13 Jun 2018 11:39:18 +0530
Yogesh Gaur <yogeshnarayan.gaur@nxp.com> wrote:

> Some SPI controllers can't write nor->page_size bytes in a single step
> because their TX FIFO is too small, but when that happens we should
> make sure a WRITE_EN command before each write access and READ_SR command
> after each write access is issued.
> 
> The core is already taking care of that, so all we have to do here is
> return the actual number of bytes that were written during the
> spi_mem_exec_op() operation.
> 
> Signed-off-by: Yogesh Gaur <yogeshnarayan.gaur@nxp.com>

Queued to spi-nor/next.

Thanks,

Boris

> ---
>  drivers/mtd/devices/m25p80.c | 23 ++++++++---------------
>  1 file changed, 8 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index e84563d..60224fe 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -72,7 +72,6 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
>  				   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
>  				   SPI_MEM_OP_DUMMY(0, 1),
>  				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
> -	size_t remaining = len;
>  	int ret;
>  
>  	/* get transfer protocols. */
> @@ -84,22 +83,16 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
>  	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
>  		op.addr.nbytes = 0;
>  
> -	while (remaining) {
> -		op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
> -		ret = spi_mem_adjust_op_size(flash->spimem, &op);
> -		if (ret)
> -			return ret;
> -
> -		ret = spi_mem_exec_op(flash->spimem, &op);
> -		if (ret)
> -			return ret;
> +	ret = spi_mem_adjust_op_size(flash->spimem, &op);
> +	if (ret)
> +		return ret;
> +	op.data.nbytes = len < op.data.nbytes ? len : op.data.nbytes;
>  
> -		op.addr.val += op.data.nbytes;
> -		remaining -= op.data.nbytes;
> -		op.data.buf.out += op.data.nbytes;
> -	}
> +	ret = spi_mem_exec_op(flash->spimem, &op);
> +	if (ret)
> +		return ret;
>  
> -	return len;
> +	return op.data.nbytes;
>  }
>  
>  /*

Patch

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index e84563d..60224fe 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -72,7 +72,6 @@  static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 				   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
 				   SPI_MEM_OP_DUMMY(0, 1),
 				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
-	size_t remaining = len;
 	int ret;
 
 	/* get transfer protocols. */
@@ -84,22 +83,16 @@  static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
 		op.addr.nbytes = 0;
 
-	while (remaining) {
-		op.data.nbytes = remaining < UINT_MAX ? remaining : UINT_MAX;
-		ret = spi_mem_adjust_op_size(flash->spimem, &op);
-		if (ret)
-			return ret;
-
-		ret = spi_mem_exec_op(flash->spimem, &op);
-		if (ret)
-			return ret;
+	ret = spi_mem_adjust_op_size(flash->spimem, &op);
+	if (ret)
+		return ret;
+	op.data.nbytes = len < op.data.nbytes ? len : op.data.nbytes;
 
-		op.addr.val += op.data.nbytes;
-		remaining -= op.data.nbytes;
-		op.data.buf.out += op.data.nbytes;
-	}
+	ret = spi_mem_exec_op(flash->spimem, &op);
+	if (ret)
+		return ret;
 
-	return len;
+	return op.data.nbytes;
 }
 
 /*