[PATCH 1/3] mtd: devices: m25p80: Simplify m25p80_read()

[PATCH 1/3] mtd: devices: m25p80: Simplify m25p80_read()

[Andrey Smirnov]

Spi_nor_read() already has an appropriate loop around .read() callback
to handle the case when not all of the data requested was written in a
signle ->read() call. Drop extra code doing the same thing in
m25p80_read().

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/mtd/devices/m25p80.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 651bab6d4e31..114f8ccea85b 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -125,7 +125,6 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 				   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
 				   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
 				   SPI_MEM_OP_DATA_IN(len, buf, 1));
-	size_t remaining = len;
 	int ret;
 
 	/* get transfer protocols. */
@@ -137,22 +136,15 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 	/* convert the dummy cycles to the number of bytes */
 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
 
-	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.addr.val += op.data.nbytes;
-		remaining -= op.data.nbytes;
-		op.data.buf.in += op.data.nbytes;
-	}
+	ret = spi_mem_exec_op(flash->spimem, &op);
+	if (ret)
+		return ret;
 
-	return len;
+	return op.data.nbytes;
 }
 
 /*
-- 
2.20.1

[PATCH 2/3] mtd: devices: m25p80: Drop extra length clamping in m25p80_write()

[Andrey Smirnov]

All of the needed length clamping should already be taken care of by
spi_mem_adjust_op_size(). No check like this is done in read path, so
this extra check in write doesn't appear to be necessary. Drop it.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/mtd/devices/m25p80.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index 114f8ccea85b..a54cad9bb6e3 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -103,7 +103,6 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 	ret = spi_mem_adjust_op_size(flash->spimem, &op);
 	if (ret)
 		return ret;
-	op.data.nbytes = len < op.data.nbytes ? len : op.data.nbytes;
 
 	ret = spi_mem_exec_op(flash->spimem, &op);
 	if (ret)
-- 
2.20.1

[PATCH 3/3] mtd: devices: m25p80: Share code between m25p80_read() and m25p80_write()

[Andrey Smirnov]

Move shared parts of m25p80_read() and m25p80_write() into a separate
subroutine and convert the rest of the code to use it. No functional
change intended.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Cc: Brian Norris <computersforpeace@gmail.com>
Cc: Boris Brezillon <boris.brezillon@bootlin.com>
Cc: Marek Vasut <marek.vasut@gmail.com>
Cc: Chris Healy <cphealy@gmail.com>
Cc: linux-mtd@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/mtd/devices/m25p80.c | 58 ++++++++++++++++--------------------
 1 file changed, 25 insertions(+), 33 deletions(-)

diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index a54cad9bb6e3..199f7c210799 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -81,34 +81,41 @@ static int m25p80_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
 	return ret;
 }
 
-static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
-			    const u_char *buf)
+static ssize_t m25p80_read_write(struct spi_nor *nor, struct spi_mem_op *op,
+				 enum spi_nor_protocol proto)
 {
 	struct m25p *flash = nor->priv;
-	struct spi_mem_op op =
-			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
-				   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
-				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
 	int ret;
 
 	/* get transfer protocols. */
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->write_proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->write_proto);
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->write_proto);
-
-	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
-		op.addr.nbytes = 0;
+	op->cmd.buswidth = spi_nor_get_protocol_inst_nbits(proto);
+	op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
+	op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);
 
-	ret = spi_mem_adjust_op_size(flash->spimem, &op);
+	ret = spi_mem_adjust_op_size(flash->spimem, op);
 	if (ret)
 		return ret;
 
-	ret = spi_mem_exec_op(flash->spimem, &op);
+	ret = spi_mem_exec_op(flash->spimem, op);
 	if (ret)
 		return ret;
 
-	return op.data.nbytes;
+	return op->data.nbytes;
+}
+
+static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
+			    const u_char *buf)
+{
+	struct spi_mem_op op =
+			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->program_opcode, 1),
+				   SPI_MEM_OP_ADDR(nor->addr_width, to, 1),
+				   SPI_MEM_OP_NO_DUMMY,
+				   SPI_MEM_OP_DATA_OUT(len, buf, 1));
+
+	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
+		op.addr.nbytes = 0;
+
+	return m25p80_read_write(nor, &op, nor->write_proto);
 }
 
 /*
@@ -118,32 +125,17 @@ static ssize_t m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
 static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
 			   u_char *buf)
 {
-	struct m25p *flash = nor->priv;
 	struct spi_mem_op op =
 			SPI_MEM_OP(SPI_MEM_OP_CMD(nor->read_opcode, 1),
 				   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
 				   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
 				   SPI_MEM_OP_DATA_IN(len, buf, 1));
-	int ret;
-
-	/* get transfer protocols. */
-	op.cmd.buswidth = spi_nor_get_protocol_inst_nbits(nor->read_proto);
-	op.addr.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
-	op.dummy.buswidth = op.addr.buswidth;
-	op.data.buswidth = spi_nor_get_protocol_data_nbits(nor->read_proto);
 
+	op.dummy.buswidth = spi_nor_get_protocol_addr_nbits(nor->read_proto);
 	/* convert the dummy cycles to the number of bytes */
 	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
 
-	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;
-
-	return op.data.nbytes;
+	return m25p80_read_write(nor, &op, nor->read_proto);
 }
 
 /*
-- 
2.20.1

Re: [PATCH 1/3] mtd: devices: m25p80: Simplify m25p80_read()

[Vignesh Raghavendra]

Hi,

On 01/04/19 10:19 AM, Andrey Smirnov wrote:
> Spi_nor_read() already has an appropriate loop around .read() callback
> to handle the case when not all of the data requested was written in a
> signle ->read() call. Drop extra code doing the same thing in
> m25p80_read().
> 

Thanks for the patch series! But we are in the process of completely
moving m25p80.c into spi-nor.c which should take care of this series.
See[1][2], I plan to post the next version shortly. Let me know if
something is missing.

[1] https://patchwork.ozlabs.org/patch/982925/
[2] https://patchwork.ozlabs.org/patch/982922/

Regards
Vignesh

> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Brian Norris <computersforpeace@gmail.com>
> Cc: Boris Brezillon <boris.brezillon@bootlin.com>
> Cc: Marek Vasut <marek.vasut@gmail.com>
> Cc: Chris Healy <cphealy@gmail.com>
> Cc: linux-mtd@lists.infradead.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/mtd/devices/m25p80.c | 22 +++++++---------------
>  1 file changed, 7 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
> index 651bab6d4e31..114f8ccea85b 100644
> --- a/drivers/mtd/devices/m25p80.c
> +++ b/drivers/mtd/devices/m25p80.c
> @@ -125,7 +125,6 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
>  				   SPI_MEM_OP_ADDR(nor->addr_width, from, 1),
>  				   SPI_MEM_OP_DUMMY(nor->read_dummy, 1),
>  				   SPI_MEM_OP_DATA_IN(len, buf, 1));
> -	size_t remaining = len;
>  	int ret;
>  
>  	/* get transfer protocols. */
> @@ -137,22 +136,15 @@ static ssize_t m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
>  	/* convert the dummy cycles to the number of bytes */
>  	op.dummy.nbytes = (nor->read_dummy * op.dummy.buswidth) / 8;
>  
> -	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.addr.val += op.data.nbytes;
> -		remaining -= op.data.nbytes;
> -		op.data.buf.in += op.data.nbytes;
> -	}
> +	ret = spi_mem_exec_op(flash->spimem, &op);
> +	if (ret)
> +		return ret;
>  
> -	return len;
> +	return op.data.nbytes;
>  }
>  
>  /*
> 

-- 
Regards
Vignesh