[RFC PATCH v2 05/12] mtd: rawnand: ams-delta: use GPIO API for data read/write

Janusz Krzysztofik
2018-08-06T22:29:11Z

Don't readw()/writew() data directly from/to GPIO port which is under
control of gpio-omap driver, use GPIO API instead.

Degrade of performance on Amstrad Delta is completely not acceptable.

The driver should work with any 8+-bit bidirectional GPIO port, not
only OMAP.

Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
---
drivers/mtd/nand/raw/ams-delta.c | 97 ++++++++++++++++------------------------
1 file changed, 38 insertions(+), 59 deletions(-)

diff --git a/drivers/mtd/nand/raw/ams-delta.c b/drivers/mtd/nand/raw/ams-delta.c
index 09d6901fc94d..78996ddf82e0 100644
--- a/drivers/mtd/nand/raw/ams-delta.c
+++ b/drivers/mtd/nand/raw/ams-delta.c
@@ -24,13 +24,10 @@
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
-#include <linux/platform_data/gpio-omap.h>
+#include <linux/platform_device.h>

-#include <asm/io.h>
#include <asm/sizes.h>

-#include <mach/hardware.h>
-
/*
* MTD structure for E3 (Delta)
*/
@@ -44,7 +41,7 @@ struct ams_delta_nand {
struct gpio_desc *gpiod_nwe;
struct gpio_desc *gpiod_ale;
struct gpio_desc *gpiod_cle;
- void __iomem *io_base;
+ struct gpio_descs *data_gpiods;
};

/*
@@ -76,10 +73,14 @@ static void ams_delta_write_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;
+ struct gpio_descs *data_gpiods = priv->data_gpiods;
+ unsigned long bits = byte;
+ int i;
+
+ for (i = 0; i < data_gpiods->ndescs; i++)
+ gpiod_direction_output_raw(data_gpiods->desc[i],
+ test_bit(i, &bits));

- 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);
@@ -87,18 +88,28 @@ static void ams_delta_write_byte(struct mtd_info *mtd, u_char byte)

static u_char ams_delta_read_byte(struct mtd_info *mtd)
{
- 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;
+ struct gpio_descs *data_gpiods = priv->data_gpiods;
+ 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);
- writew(~0, io_base + OMAP_MPUIO_IO_CNTL);
- res = readw(this->IO_ADDR_R);
+
+ gpiod_get_raw_array_value(data_gpiods->ndescs, data_gpiods->desc,
+ value_array);
+
gpiod_set_value(priv->gpiod_nre, 1);

- return res;
+ for (i = 0; i < data_gpiods->ndescs; i++)
+ if (value_array[i])
+ __set_bit(i, &bits);
+
+ return bits;
}

static void ams_delta_write_buf(struct mtd_info *mtd, const u_char *buf,
@@ -159,14 +170,8 @@ static int ams_delta_init(struct platform_device *pdev)
struct ams_delta_nand *priv;
struct nand_chip *this;
struct mtd_info *mtd;
- struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
- void __iomem *io_base;
- struct gpio_descs *data_gpiods;
int err = 0;

- if (!res)
- return -ENXIO;
-
/* Allocate memory for MTD device structure and private data */
priv = devm_kzalloc(&pdev->dev, sizeof(struct ams_delta_nand),
GFP_KERNEL);
@@ -179,25 +184,8 @@ static int ams_delta_init(struct platform_device *pdev)
mtd = nand_to_mtd(this);
mtd->dev.parent = &pdev->dev;

- /*
- * Don't try to request the memory region from here,
- * it should have been already requested from the
- * gpio-omap driver and requesting it again would fail.
- */
-
- io_base = ioremap(res->start, resource_size(res));
- if (io_base == NULL) {
- dev_err(&pdev->dev, "ioremap failed\n");
- err = -EIO;
- goto out_free;
- }
-
- priv->io_base = io_base;
nand_set_controller_data(this, priv);

- /* Set address of NAND IO lines */
- this->IO_ADDR_R = io_base + OMAP_MPUIO_INPUT_LATCH;
- this->IO_ADDR_W = io_base + OMAP_MPUIO_OUTPUT;
this->read_byte = ams_delta_read_byte;
this->write_buf = ams_delta_write_buf;
this->read_buf = ams_delta_read_buf;
@@ -207,7 +195,7 @@ static int ams_delta_init(struct platform_device *pdev)
if (IS_ERR(priv->gpiod_rdy)) {
err = PTR_ERR(priv->gpiod_rdy);
dev_warn(&pdev->dev, "RDY GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

if (priv->gpiod_rdy)
@@ -225,66 +213,60 @@ static int ams_delta_init(struct platform_device *pdev)
if (IS_ERR(priv->gpiod_nwp)) {
err = PTR_ERR(priv->gpiod_nwp);
dev_err(&pdev->dev, "NWP GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

priv->gpiod_nce = devm_gpiod_get(&pdev->dev, "nce", GPIOD_OUT_HIGH);
if (IS_ERR(priv->gpiod_nce)) {
err = PTR_ERR(priv->gpiod_nce);
dev_err(&pdev->dev, "NCE GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

priv->gpiod_nre = devm_gpiod_get(&pdev->dev, "nre", GPIOD_OUT_HIGH);
if (IS_ERR(priv->gpiod_nre)) {
err = PTR_ERR(priv->gpiod_nre);
dev_err(&pdev->dev, "NRE GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

priv->gpiod_nwe = devm_gpiod_get(&pdev->dev, "nwe", GPIOD_OUT_HIGH);
if (IS_ERR(priv->gpiod_nwe)) {
err = PTR_ERR(priv->gpiod_nwe);
dev_err(&pdev->dev, "NWE GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

priv->gpiod_ale = devm_gpiod_get(&pdev->dev, "ale", GPIOD_OUT_LOW);
if (IS_ERR(priv->gpiod_ale)) {
err = PTR_ERR(priv->gpiod_ale);
dev_err(&pdev->dev, "ALE GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}

priv->gpiod_cle = devm_gpiod_get(&pdev->dev, "cle", GPIOD_OUT_LOW);
if (IS_ERR(priv->gpiod_cle)) {
err = PTR_ERR(priv->gpiod_cle);
dev_err(&pdev->dev, "CLE GPIO request failed (%d)\n", err);
- goto out_mtd;
+ return err;
}
/* Request array of data pins, initialize them as input */
- data_gpiods = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_IN);
- if (IS_ERR(data_gpiods)) {
- err = PTR_ERR(data_gpiods);
+ priv->data_gpiods = devm_gpiod_get_array(&pdev->dev, "data", GPIOD_IN);
+ if (IS_ERR(priv->data_gpiods)) {
+ err = PTR_ERR(priv->data_gpiods);
dev_err(&pdev->dev, "data GPIO request failed: %d\n", err);
- goto out_mtd;
+ return err;
}

/* Scan to find existence of the device */
err = nand_scan(mtd, 1);
if (err)
- goto out_mtd;
+ return err;

/* Register the partitions */
mtd_device_register(mtd, partition_info, ARRAY_SIZE(partition_info));

- goto out;
-
- out_mtd:
- iounmap(io_base);
-out_free:
- out:
- return err;
+ return 0;
}

/*
@@ -294,13 +276,10 @@ static int ams_delta_cleanup(struct platform_device *pdev)
{
struct ams_delta_nand *priv = platform_get_drvdata(pdev);
struct mtd_info *mtd = nand_to_mtd(&priv->nand_chip);
- void __iomem *io_base = priv->io_base;

- /* Release resources, unregister device */
+ /* Unregister device */
nand_release(mtd);

- iounmap(io_base);
-
return 0;
}

--
2.16.4