/*
* Updated, and converted to generic GPIO based driver by Russell King.
*
* Written by Ben Dooks <ben@simtec.co.uk>
* Based on 2.4 version by Mark Whittaker
*
* © 2004 Simtec Electronics
*
* Device driver for NAND flash that uses a memory mapped interface to
* read/write the NAND commands and data, and GPIO pins for control signals
* (the DT binding refers to this as "GPIO assisted NAND flash")
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
*/
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/gpio/consumer.h>
#include <linux/io.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/rawnand.h>
#include <linux/mtd/partitions.h>
#include <linux/mtd/nand-gpio.h>
#include <linux/of.h>
#include <linux/of_address.h>
struct gpiomtd {
void __iomem *io_sync;
struct nand_chip nand_chip;
struct gpio_nand_platdata plat;
struct gpio_desc *nce; /* Optional chip enable */
struct gpio_desc *cle;
struct gpio_desc *ale;
struct gpio_desc *rdy;
struct gpio_desc *nwp; /* Optional write protection */
};
static inline struct gpiomtd *gpio_nand_getpriv(struct mtd_info *mtd)
{
return container_of(mtd_to_nand(mtd), struct gpiomtd, nand_chip);
}
#ifdef CONFIG_ARM
/* gpio_nand_dosync()
*
* Make sure the GPIO state changes occur in-order with writes to NAND
* memory region.
* Needed on PXA due to bus-reordering within the SoC itself (see section on
* I/O ordering in PXA manual (section 2.3, p35)
*/
static void gpio_nand_dosync(struct gpiomtd *gpiomtd)
{
unsigned long tmp;
if (gpiomtd->io_sync) {
/*
* Linux memory barriers don't cater for what's required here.
* What's required is what's here - a read from a separate
* region with a dependency on that read.
*/
tmp = readl(gpiomtd->io_sync);
asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
}
}
#else
static inline void gpio_nand_dosync(struct gpiomtd *gpiomtd) {}
#endif
static void gpio_nand_cmd_ctrl(struct nand_chip *chip, int cmd,
unsigned int ctrl)
{
struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
gpio_nand_dosync(gpiomtd);
if (ctrl & NAND_CTRL_CHANGE) {
if (gpiomtd->nce)
gpiod_set_value(gpiomtd->nce, !(ctrl & NAND_NCE));
gpiod_set_value(gpiomtd->cle, !!(ctrl & NAND_CLE));
gpiod_set_value(gpiomtd->ale, !!(ctrl & NAND_ALE));
gpio_nand_dosync(gpiomtd);
}
if (cmd == NAND_CMD_NONE)
return;
writeb(cmd, gpiomtd->nand_chip.legacy.IO_ADDR_W);
gpio_nand_dosync(gpiomtd);
}
static int gpio_nand_devready(struct nand_chip *chip)
{
struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
return gpiod_get_value(gpiomtd->rdy);
}
#ifdef CONFIG_OF
static const struct of_device_id gpio_nand_id_table[] = {
{ .compatible = "gpio-control-nand" },
{}
};
MODULE_DEVICE_TABLE(of, gpio_nand_id_table);
static int gpio_nand_get_config_of(const struct device *dev,
struct gpio_nand_platdata *plat)
{
u32 val;
if (!dev->of_node)
return -ENODEV;
if (!of_property_read_u32(dev->of_node, "bank-width", &val)) {
if (val == 2) {
plat->options |= NAND_BUSWIDTH_16;
} else if (val != 1) {
dev_err(dev, "invalid bank-width %u\n", val);
return -EINVAL;
}
}
if (!of_property_read_u32(dev->of_node, "chip-delay", &val))
plat->chip_delay = val;
return 0;
}
static struct resource *gpio_nand_get_io_sync_of(struct platform_device *pdev)
{
struct resource *r;
u64 addr;
if (of_property_read_u64(pdev->dev.of_node,
"gpio-control-nand,io-sync-reg", &addr))
return NULL;
r = devm_kzalloc(&pdev->dev, sizeof(*r), GFP_KERNEL);
if (!r)
return NULL;
r->start = addr;
r->end = r->start + 0x3;
r->flags = IORESOURCE_MEM;
return r;
}
#else /* CONFIG_OF */
static inline int gpio_nand_get_config_of(const struct device *dev,
struct gpio_nand_platdata *plat)
{
return -ENOSYS;
}
static inline struct resource *
gpio_nand_get_io_sync_of(struct platform_device *pdev)
{
return NULL;
}
#endif /* CONFIG_OF */
static inline int gpio_nand_get_config(const struct device *dev,
struct gpio_nand_platdata *plat)
{
int ret = gpio_nand_get_config_of(dev, plat);
if (!ret)
return ret;
if (dev_get_platdata(dev)) {
memcpy(plat, dev_get_platdata(dev), sizeof(*plat));
return 0;
}
return -EINVAL;
}
static inline struct resource *
gpio_nand_get_io_sync(struct platform_device *pdev)
{
struct resource *r = gpio_nand_get_io_sync_of(pdev);
if (r)
return r;
return platform_get_resource(pdev, IORESOURCE_MEM, 1);
}
static int gpio_nand_remove(struct platform_device *pdev)
{
struct gpiomtd *gpiomtd = platform_get_drvdata(pdev);
nand_release(&gpiomtd->nand_chip);
/* Enable write protection and disable the chip */
if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
gpiod_set_value(gpiomtd->nwp, 0);
if (gpiomtd->nce && !IS_ERR(gpiomtd->nce))
gpiod_set_value(gpiomtd->nce, 0);
return 0;
}
static int gpio_nand_probe(struct platform_device *pdev)
{
struct gpiomtd *gpiomtd;
struct nand_chip *chip;
struct mtd_info *mtd;
struct resource *res;
struct device *dev = &pdev->dev;
int ret = 0;
if (!dev->of_node && !dev_get_platdata(dev))
return -EINVAL;
gpiomtd = devm_kzalloc(dev, sizeof(*gpiomtd), GFP_KERNEL);
if (!gpiomtd)
return -ENOMEM;
chip = &gpiomtd->nand_chip;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
chip->legacy.IO_ADDR_R = devm_ioremap_resource(dev, res);
if (IS_ERR(chip->legacy.IO_ADDR_R))
return PTR_ERR(chip->legacy.IO_ADDR_R);
res = gpio_nand_get_io_sync(pdev);
if (res) {
gpiomtd->io_sync = devm_ioremap_resource(dev, res);
if (IS_ERR(gpiomtd->io_sync))
return PTR_ERR(gpiomtd->io_sync);
}
ret = gpio_nand_get_config(dev, &gpiomtd->plat);
if (ret)
return ret;
/* Just enable the chip */
gpiomtd->nce = devm_gpiod_get_optional(dev, "nce", GPIOD_OUT_HIGH);
if (IS_ERR(gpiomtd->nce))
return PTR_ERR(gpiomtd->nce);
/* We disable write protection once we know probe() will succeed */
gpiomtd->nwp = devm_gpiod_get_optional(dev, "nwp", GPIOD_OUT_LOW);
if (IS_ERR(gpiomtd->nwp)) {
ret = PTR_ERR(gpiomtd->nwp);
goto out_ce;
}
gpiomtd->ale = devm_gpiod_get(dev, "ale", GPIOD_OUT_LOW);
if (IS_ERR(gpiomtd->ale)) {
ret = PTR_ERR(gpiomtd->ale);
goto out_ce;
}
gpiomtd->cle = devm_gpiod_get(dev, "cle", GPIOD_OUT_LOW);
if (IS_ERR(gpiomtd->cle)) {
ret = PTR_ERR(gpiomtd->cle);
goto out_ce;
}
gpiomtd->rdy = devm_gpiod_get_optional(dev, "rdy", GPIOD_IN);
if (IS_ERR(gpiomtd->rdy)) {
ret = PTR_ERR(gpiomtd->rdy);
goto out_ce;
}
/* Using RDY pin */
if (gpiomtd->rdy)
chip->legacy.dev_ready = gpio_nand_devready;
nand_set_flash_node(chip, pdev->dev.of_node);
chip->legacy.IO_ADDR_W = chip->legacy.IO_ADDR_R;
chip->ecc.mode = NAND_ECC_SOFT;
chip->ecc.algo = NAND_ECC_HAMMING;
chip->options = gpiomtd->plat.options;
chip->legacy.chip_delay = gpiomtd->plat.chip_delay;
chip->legacy.cmd_ctrl = gpio_nand_cmd_ctrl;
mtd = nand_to_mtd(chip);
mtd->dev.parent = dev;
platform_set_drvdata(pdev, gpiomtd);
/* Disable write protection, if wired up */
if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
gpiod_direction_output(gpiomtd->nwp, 1);
ret = nand_scan(chip, 1);
if (ret)
goto err_wp;
if (gpiomtd->plat.adjust_parts)
gpiomtd->plat.adjust_parts(&gpiomtd->plat, mtd->size);
ret = mtd_device_register(mtd, gpiomtd->plat.parts,
gpiomtd->plat.num_parts);
if (!ret)
return 0;
err_wp:
if (gpiomtd->nwp && !IS_ERR(gpiomtd->nwp))
gpiod_set_value(gpiomtd->nwp, 0);
out_ce:
if (gpiomtd->nce && !IS_ERR(gpiomtd->nce))
gpiod_set_value(gpiomtd->nce, 0);
return ret;
}
static struct platform_driver gpio_nand_driver = {
.probe = gpio_nand_probe,
.remove = gpio_nand_remove,
.driver = {
.name = "gpio-nand",
.of_match_table = of_match_ptr(gpio_nand_id_table),
},
};
module_platform_driver(gpio_nand_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
MODULE_DESCRIPTION("GPIO NAND Driver");
