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Message-Id: <20180718235710.18242-4-jmkrzyszt@gmail.com>
Date: Thu, 19 Jul 2018 01:57:05 +0200
From: Janusz Krzysztofik <jmkrzyszt@...il.com>
To: Boris Brezillon <boris.brezillon@...tlin.com>,
Miquel Raynal <miquel.raynal@...tlin.com>
Cc: Tony Lindgren <tony@...mide.com>,
Aaro Koskinen <aaro.koskinen@....fi>,
Grygorii Strashko <grygorii.strashko@...com>,
Santosh Shilimkar <ssantosh@...nel.org>,
Kevin Hilman <khilman@...nel.org>,
Linus Walleij <linus.walleij@...aro.org>,
Richard Weinberger <richard@....at>,
David Woodhouse <dwmw2@...radead.org>,
Brian Norris <computersforpeace@...il.com>,
Marek Vasut <marek.vasut@...il.com>,
linux-mtd@...ts.infradead.org,
linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org,
linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org,
Artem Bityutskiy <artem.bityutskiy@...ux.intel.com>,
Janusz Krzysztofik <jmkrzyszt@...il.com>
Subject: [RFC PATCH 3/8] mtd: rawnand: ams-delta: Set port direction once per transfer
In its current shape, the driver sets data port direction before each
byte read/write operation, even during multi-byte transfers. Optimize
that by setting the port direction only on first byte of each transfer.
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@...il.com>
---
drivers/mtd/nand/raw/ams-delta.c | 42 ++++++++++++++++++++++++++++++----------
1 file changed, 32 insertions(+), 10 deletions(-)
diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
index 6ac38e9cfa1a..dfefcd79b420 100644
--- a/drivers/mtd/nand/raw/ams-delta.c
+++ b/drivers/mtd/nand/raw/ams-delta.c
@@ -72,50 +72,72 @@ static const struct mtd_partition partition_info[] = {
.size = 3 * SZ_256K },
};
-static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
+static void ams_delta_write_next_byte(struct mtd_info *mtd, 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);
writew(byte, this->IO_ADDR_W);
gpiod_set_value(priv->gpiod_nwe, 0);
ndelay(40);
gpiod_set_value(priv->gpiod_nwe, 1);
}
-static u_char ams_delta_read_byte(struct mtd_info *mtd)
+static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)
{
- u_char res;
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);
+}
+
+static u_char ams_delta_read_next_byte(struct mtd_info *mtd)
+{
+ struct nand_chip *this = mtd_to_nand(mtd);
+ struct ams_delta_nand *priv = nand_get_controller_data(this);
+ u_char res;
+
gpiod_set_value(priv->gpiod_nre, 0);
ndelay(40);
- writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
res = readw(this->IO_ADDR_R);
gpiod_set_value(priv->gpiod_nre, 1);
return res;
}
+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);
+ void __iomem *io_base = priv->io_base;
+
+ writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
+
+ return ams_delta_read_next_byte(mtd);
+}
+
static void ams_delta_write_buf(struct mtd_info *mtd, const u_char *buf,
int len)
{
int i;
- for (i=0; i<len; i++)
- ams_delta_write_byte(mtd, buf[i]);
+ if (len > 0)
+ ams_delta_write_byte(mtd, buf[0]);
+ for (i = 1; i < len; i++)
+ ams_delta_write_next_byte(mtd, buf[i]);
}
static void ams_delta_read_buf(struct mtd_info *mtd, u_char *buf, int len)
{
int i;
- for (i=0; i<len; i++)
- buf[i] = ams_delta_read_byte(mtd);
+ if (len > 0)
+ buf[0] = ams_delta_read_byte(mtd);
+ for (i = 1; i < len; i++)
+ buf[i] = ams_delta_read_next_byte(mtd);
}
/*
--
2.16.4
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