From mboxrd@z Thu Jan 1 00:00:00 1970 From: jmkrzyszt@gmail.com (Janusz Krzysztofik) Date: Tue, 7 Aug 2018 00:29:13 +0200 Subject: [RFC PATCH v2 07/12] mtd: rawnand: ams-delta: Set port direction once per transfer In-Reply-To: <20180806222918.12644-1-jmkrzyszt@gmail.com> References: <20180718235710.18242-1-jmkrzyszt@gmail.com> <20180806222918.12644-1-jmkrzyszt@gmail.com> Message-ID: <20180806222918.12644-8-jmkrzyszt@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org In its current shape, the driver sets data port direction before each byte read/write operation, even during multi-byte transfers. Since performance of the driver is completely not acceptable on Amstrad Delta after it has been converted to GPIO bitbang, try to improve things a bit by setting the port direction only on first byte of each transfer. Resulting performance on Amstrad Delta is still far from acceptable. Signed-off-by: Janusz Krzysztofik --- drivers/mtd/nand/raw/ams-delta.c | 58 ++++++++++++++++++++++++++++++++-------- 1 file changed, 47 insertions(+), 11 deletions(-) diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c index 78996ddf82e0..d02c48c013e8 100644 --- a/drivers/mtd/nand/raw/ams-delta.c +++ b/drivers/mtd/nand/raw/ams-delta.c @@ -69,6 +69,30 @@ static const struct mtd_partition partition_info[] = { .size = 3 * SZ_256K }, }; +static void ams_delta_write_commit(struct ams_delta_nand *priv) +{ + gpiod_set_value(priv->gpiod_nwe, 0); + ndelay(40); + gpiod_set_value(priv->gpiod_nwe, 1); +} + +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); + struct gpio_descs *data_gpiods = priv->data_gpiods; + unsigned long bits = byte; + int i, value_array[data_gpiods->ndescs]; + + for (i = 0; i < data_gpiods->ndescs; i++) + value_array[i] = test_bit(i, &bits); + + gpiod_set_raw_array_value(data_gpiods->ndescs, data_gpiods->desc, + value_array); + + ams_delta_write_commit(priv); +} + static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte) { struct nand_chip *this = mtd_to_nand(mtd); @@ -81,12 +105,10 @@ static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte) gpiod_direction_output_raw(data_gpiods->desc[i], test_bit(i, &bits)); - gpiod_set_value(priv->gpiod_nwe, 0); - ndelay(40); - gpiod_set_value(priv->gpiod_nwe, 1); + ams_delta_write_commit(priv); } -static u_char ams_delta_read_byte(struct mtd_info *mtd) +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); @@ -94,9 +116,6 @@ static u_char ams_delta_read_byte(struct mtd_info *mtd) unsigned long bits = 0; int i, value_array[data_gpiods->ndescs]; - for (i = 0; i < data_gpiods->ndescs; i++) - gpiod_direction_input(data_gpiods->desc[i]); - gpiod_set_value(priv->gpiod_nre, 0); ndelay(40); @@ -112,21 +131,38 @@ static u_char ams_delta_read_byte(struct mtd_info *mtd) return bits; } +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); + struct gpio_descs *data_gpiods = priv->data_gpiods; + int i; + + for (i = 0; i < data_gpiods->ndescs; i++) + gpiod_direction_input(data_gpiods->desc[i]); + + 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 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 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