[RFC PATCH 4/8] mtd: rawnand: ams-delta: Optimize pointer resolution on read/write

Janusz Krzysztofik
2018-07-18T23:57:00Z

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(-)

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)
--
2.16.4