[RFC,4/8] mtd: rawnand: ams-delta: Optimize pointer resolution on read/write
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Message ID 20180718235710.18242-5-jmkrzyszt@gmail.com
State New
Headers show
Series
  • mtd: rawnand: ams-delta: Use gpio-omap accessors for data I/O
Related show

Commit Message

Janusz Krzysztofik July 18, 2018, 11:57 p.m. UTC
Further optimize processing speed of read/write callback functions by
resolving private structure pointer only once per callback and passing
it to all subfunctions instead of mtd_info.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
---
 drivers/mtd/nand/raw/ams-delta.c | 44 +++++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 19 deletions(-)

Comments

Boris Brezillon July 19, 2018, 6:25 a.m. UTC | #1
On Thu, 19 Jul 2018 01:57:06 +0200
Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:

> Further optimize processing speed of read/write callback functions by
> resolving private structure pointer only once per callback and passing
> it to all subfunctions instead of mtd_info.

Not sure this has a real impact on perfs, but I also prefer not using
mtd_info objects within NAND drivers, so I'm good with the change
itself (its probably worth changing the commit message though)

> 
> Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
> ---
>  drivers/mtd/nand/raw/ams-delta.c | 44 +++++++++++++++++++++++-----------------
>  1 file changed, 25 insertions(+), 19 deletions(-)
> 
> diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
> index dfefcd79b420..d7e4c9dbef67 100644
> --- a/drivers/mtd/nand/raw/ams-delta.c
> +++ b/drivers/mtd/nand/raw/ams-delta.c
> @@ -72,10 +72,9 @@ static const struct mtd_partition partition_info[] = {
>  	  .size		=  3 * SZ_256K },
>  };
>  
> -static void ams_delta_write_next_byte(struct mtd_info *mtd, u_char byte)
> +static void ams_delta_write_next_byte(struct ams_delta_nand *priv, u_char byte)
>  {
> -	struct nand_chip *this = mtd_to_nand(mtd);
> -	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +	struct nand_chip *this = &priv->nand_chip;
>  
>  	writew(byte, this->IO_ADDR_W);
>  	gpiod_set_value(priv->gpiod_nwe, 0);
> @@ -83,21 +82,18 @@ static void ams_delta_write_next_byte(struct mtd_info *mtd, u_char byte)
>  	gpiod_set_value(priv->gpiod_nwe, 1);
>  }
>  
> -static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
> +static void ams_delta_write_first_byte(struct ams_delta_nand *priv, u_char byte)
>  {
> -	struct nand_chip *this = mtd_to_nand(mtd);
> -	struct ams_delta_nand *priv = nand_get_controller_data(this);
>  	void __iomem *io_base = priv->io_base;
>  
>  	writew(0, io_base + OMAP_MPUIO_IO_CNTL);
>  
> -	ams_delta_write_next_byte(mtd, byte);
> +	ams_delta_write_next_byte(priv, byte);
>  }
>  
> -static u_char ams_delta_read_next_byte(struct mtd_info *mtd)
> +static u_char ams_delta_read_next_byte(struct ams_delta_nand *priv)
>  {
> -	struct nand_chip *this = mtd_to_nand(mtd);
> -	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +	struct nand_chip *this = &priv->nand_chip;
>  	u_char res;
>  
>  	gpiod_set_value(priv->gpiod_nre, 0);
> @@ -108,36 +104,46 @@ static u_char ams_delta_read_next_byte(struct mtd_info *mtd)
>  	return res;
>  }
>  
> -static u_char ams_delta_read_byte(struct mtd_info *mtd)
> +static u_char ams_delta_read_first_byte(struct ams_delta_nand *priv)
>  {
> -	struct nand_chip *this = mtd_to_nand(mtd);
> -	struct ams_delta_nand *priv = nand_get_controller_data(this);
>  	void __iomem *io_base = priv->io_base;
>  
>  	writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
>  
> -	return ams_delta_read_next_byte(mtd);
> +	return ams_delta_read_next_byte(priv);
> +}
> +
> +static u_char ams_delta_read_byte(struct mtd_info *mtd)
> +{
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
> +
> +	return ams_delta_read_first_byte(priv);
>  }
>  
>  static void ams_delta_write_buf(struct mtd_info *mtd, const u_char *buf,
>  				int len)
>  {
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
>  	int i;
>  
>  	if (len > 0)
> -		ams_delta_write_byte(mtd, buf[0]);
> +		ams_delta_write_first_byte(priv, buf[0]);
>  	for (i = 1; i < len; i++)
> -		ams_delta_write_next_byte(mtd, buf[i]);
> +		ams_delta_write_next_byte(priv, buf[i]);
>  }
>  
>  static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
>  {
> +	struct nand_chip *this = mtd_to_nand(mtd);
> +	struct ams_delta_nand *priv = nand_get_controller_data(this);
>  	int i;
>  
>  	if (len > 0)
> -		buf[0] = ams_delta_read_byte(mtd);
> +		buf[0] = ams_delta_read_first_byte(priv);
>  	for (i = 1; i < len; i++)
> -		buf[i] = ams_delta_read_next_byte(mtd);
> +		buf[i] = ams_delta_read_next_byte(priv);
>  }
>  
>  /*
> @@ -161,7 +167,7 @@ static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
>  	}
>  
>  	if (cmd != NAND_CMD_NONE)
> -		ams_delta_write_byte(mtd, cmd);
> +		ams_delta_write_first_byte(priv, cmd);
>  }
>  
>  static int ams_delta_nand_ready(struct mtd_info *mtd)

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Janusz Krzysztofik July 20, 2018, 6:14 p.m. UTC | #2
On Thursday, July 19, 2018 8:25:38 AM CEST Boris Brezillon wrote:
> On Thu, 19 Jul 2018 01:57:06 +0200
> Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:
> 
> > Further optimize processing speed of read/write callback functions by
> > resolving private structure pointer only once per callback and passing
> > it to all subfunctions instead of mtd_info.

OK, I'll call it simplification (the code looks more simple after that, doesn't 
it), not optimization if you agree.

Thanks,
Janusz



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Boris Brezillon July 20, 2018, 7:29 p.m. UTC | #3
On Fri, 20 Jul 2018 20:14:55 +0200
Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:

> On Thursday, July 19, 2018 8:25:38 AM CEST Boris Brezillon wrote:
> > On Thu, 19 Jul 2018 01:57:06 +0200
> > Janusz Krzysztofik <jmkrzyszt@gmail.com> wrote:
> >   
> > > Further optimize processing speed of read/write callback functions by
> > > resolving private structure pointer only once per callback and passing
> > > it to all subfunctions instead of mtd_info.  
> 
> OK, I'll call it simplification (the code looks more simple after that, doesn't 
> it),

Yep.

> not optimization if you agree.
> 
> Thanks,
> Janusz
> 
> 
> 

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Patch
diff mbox series

diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
index dfefcd79b420..d7e4c9dbef67 100644
--- a/drivers/mtd/nand/raw/ams-delta.c
+++ b/drivers/mtd/nand/raw/ams-delta.c
@@ -72,10 +72,9 @@  static const struct mtd_partition partition_info[] = {
 	  .size		=  3 * SZ_256K },
 };
 
-static void ams_delta_write_next_byte(struct mtd_info *mtd, u_char byte)
+static void ams_delta_write_next_byte(struct ams_delta_nand *priv, u_char byte)
 {
-	struct nand_chip *this = mtd_to_nand(mtd);
-	struct ams_delta_nand *priv = nand_get_controller_data(this);
+	struct nand_chip *this = &priv->nand_chip;
 
 	writew(byte, this->IO_ADDR_W);
 	gpiod_set_value(priv->gpiod_nwe, 0);
@@ -83,21 +82,18 @@  static void ams_delta_write_next_byte(struct mtd_info *mtd, u_char byte)
 	gpiod_set_value(priv->gpiod_nwe, 1);
 }
 
-static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
+static void ams_delta_write_first_byte(struct ams_delta_nand *priv, u_char byte)
 {
-	struct nand_chip *this = mtd_to_nand(mtd);
-	struct ams_delta_nand *priv = nand_get_controller_data(this);
 	void __iomem *io_base = priv->io_base;
 
 	writew(0, io_base + OMAP_MPUIO_IO_CNTL);
 
-	ams_delta_write_next_byte(mtd, byte);
+	ams_delta_write_next_byte(priv, byte);
 }
 
-static u_char ams_delta_read_next_byte(struct mtd_info *mtd)
+static u_char ams_delta_read_next_byte(struct ams_delta_nand *priv)
 {
-	struct nand_chip *this = mtd_to_nand(mtd);
-	struct ams_delta_nand *priv = nand_get_controller_data(this);
+	struct nand_chip *this = &priv->nand_chip;
 	u_char res;
 
 	gpiod_set_value(priv->gpiod_nre, 0);
@@ -108,36 +104,46 @@  static u_char ams_delta_read_next_byte(struct mtd_info *mtd)
 	return res;
 }
 
-static u_char ams_delta_read_byte(struct mtd_info *mtd)
+static u_char ams_delta_read_first_byte(struct ams_delta_nand *priv)
 {
-	struct nand_chip *this = mtd_to_nand(mtd);
-	struct ams_delta_nand *priv = nand_get_controller_data(this);
 	void __iomem *io_base = priv->io_base;
 
 	writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
 
-	return ams_delta_read_next_byte(mtd);
+	return ams_delta_read_next_byte(priv);
+}
+
+static u_char ams_delta_read_byte(struct mtd_info *mtd)
+{
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct ams_delta_nand *priv = nand_get_controller_data(this);
+
+	return ams_delta_read_first_byte(priv);
 }
 
 static void ams_delta_write_buf(struct mtd_info *mtd, const u_char *buf,
 				int len)
 {
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct ams_delta_nand *priv = nand_get_controller_data(this);
 	int i;
 
 	if (len > 0)
-		ams_delta_write_byte(mtd, buf[0]);
+		ams_delta_write_first_byte(priv, buf[0]);
 	for (i = 1; i < len; i++)
-		ams_delta_write_next_byte(mtd, buf[i]);
+		ams_delta_write_next_byte(priv, buf[i]);
 }
 
 static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 {
+	struct nand_chip *this = mtd_to_nand(mtd);
+	struct ams_delta_nand *priv = nand_get_controller_data(this);
 	int i;
 
 	if (len > 0)
-		buf[0] = ams_delta_read_byte(mtd);
+		buf[0] = ams_delta_read_first_byte(priv);
 	for (i = 1; i < len; i++)
-		buf[i] = ams_delta_read_next_byte(mtd);
+		buf[i] = ams_delta_read_next_byte(priv);
 }
 
 /*
@@ -161,7 +167,7 @@  static void ams_delta_hwcontrol(struct mtd_info *mtd, int cmd,
 	}
 
 	if (cmd != NAND_CMD_NONE)
-		ams_delta_write_byte(mtd, cmd);
+		ams_delta_write_first_byte(priv, cmd);
 }
 
 static int ams_delta_nand_ready(struct mtd_info *mtd)