[PATCH] [MTD] [NAND] GPIO NAND flash driver
Mike Rapoport
mike at compulab.co.il
Fri Oct 10 06:46:41 EDT 2008
Mike Frysinger wrote:
> On Wed, Oct 8, 2008 at 04:28, Mike Rapoport wrote:
>> Mike Frysinger wrote:
>>> On Wed, Oct 8, 2008 at 03:28, Russell King - ARM Linux wrote:
>>>> On Wed, Oct 08, 2008 at 02:20:13AM -0400, Mike Frysinger wrote:
>>>>> On Wed, Oct 8, 2008 at 02:01, Mike Rapoport wrote:
>>>>>> +/* gpio_nand_dosync()
>>>>>> + *
>>>>>> + * needed due to bus-reordering within the PXA 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) {
>>>>>> + /*
>>>>>> + * this should generate the read, followed by
>>>>>> + * something that depends on the read
>>>>>> + */
>>>>>> + tmp = readl(gpiomtd->io_sync);
>>>>>> + asm volatile("mov %1, %0\n" : "=r" (tmp) : "r" (tmp));
>>>>>> + }
>>>>>> +}
>>>>> there isnt much point in attempting to write a generic solution if
>>>>> you're just going to turn around and stick straight assembly in the
>>>>> middle of it. why not use a real arch-generic method like a memory
>>>>> barrier.
>>>> Linux memory barriers don't cater for what's required here. What's
>>>> required is what's there - a read from a separate region with a
>>>> dependency on that read. Linux has no such barrier.
>>> thanks, this kind of comment in the source would be useful ... but
>>> what is also needed is '#ifdef __arm__'
>> If '#ifdef' is preferable than 'depend on ARM' I can send an updated patch.
>
> i'd remove the "depend on ARM" and add "#ifdef __arm__" into the .c
> file. unless i missed something, there's nothing else arm specific in
> there.
> -mike
Would that be any better:
drivers/mtd/nand/Kconfig | 6 +
drivers/mtd/nand/Makefile | 1 +
drivers/mtd/nand/gpio.c | 373 +++++++++++++++++++++++++++++++++++++++++
include/linux/mtd/nand-gpio.h | 19 ++
4 files changed, 399 insertions(+), 0 deletions(-)
diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 41f361c..e98991b 100644
--- a/drivers/mtd/nand/Kconfig
+++ b/drivers/mtd/nand/Kconfig
@@ -56,6 +56,12 @@ config MTD_NAND_H1900
help
This enables the driver for the iPAQ h1900 flash.
+config MTD_NAND_GPIO
+ tristate "GPIO NAND Flash driver"
+ depends on GENERIC_GPIO
+ help
+ This enables a GPIO based NAND flash driver.
+
config MTD_NAND_SPIA
tristate "NAND Flash device on SPIA board"
depends on ARCH_P720T
diff --git a/drivers/mtd/nand/Makefile b/drivers/mtd/nand/Makefile
index b786c5d..39eefc2 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -24,6 +24,7 @@ obj-$(CONFIG_MTD_NAND_NANDSIM) += nandsim.o
obj-$(CONFIG_MTD_NAND_CS553X) += cs553x_nand.o
obj-$(CONFIG_MTD_NAND_NDFC) += ndfc.o
obj-$(CONFIG_MTD_NAND_ATMEL) += atmel_nand.o
+obj-$(CONFIG_MTD_NAND_GPIO) += gpio.o
obj-$(CONFIG_MTD_NAND_CM_X270) += cmx270_nand.o
obj-$(CONFIG_MTD_NAND_BASLER_EXCITE) += excite_nandflash.o
obj-$(CONFIG_MTD_NAND_PXA3xx) += pxa3xx_nand.o
diff --git a/drivers/mtd/nand/gpio.c b/drivers/mtd/nand/gpio.c
new file mode 100644
index 0000000..0c90779
--- /dev/null
+++ b/drivers/mtd/nand/gpio.c
@@ -0,0 +1,373 @@
+/*
+ * drivers/mtd/nand/gpio.c
+ *
+ * Updated, and converted to generic GPIO based driver by Russell King.
+ *
+ * Written by Ben Dooks <ben at simtec.co.uk>
+ * Based on 2.4 version by Mark Whittaker
+ *
+ * (c) 2004 Simtec Electronics
+ *
+ * Device driver for NAND connected via GPIO
+ *
+ * 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/init.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/gpio.h>
+#include <linux/io.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/nand-gpio.h>
+
+struct gpiomtd {
+ void __iomem *io_sync;
+ struct mtd_info mtd_info;
+ struct nand_chip nand_chip;
+ struct gpio_nand_platdata plat;
+};
+
+#define gpio_nand_getpriv(x) container_of(x, struct gpiomtd, mtd_info)
+
+
+#ifdef CONFIG_ARM
+/* gpio_nand_dosync()
+ *
+ * needed due to bus-reordering within the PXA 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 mtd_info *mtd, int cmd, unsigned int ctrl)
+{
+ struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
+
+ gpio_nand_dosync(gpiomtd);
+
+ if (ctrl & NAND_CTRL_CHANGE) {
+ gpio_set_value(gpiomtd->plat.gpio_nce, !(ctrl & NAND_NCE));
+ gpio_set_value(gpiomtd->plat.gpio_cle, !!(ctrl & NAND_CLE));
+ gpio_set_value(gpiomtd->plat.gpio_ale, !!(ctrl & NAND_ALE));
+ gpio_nand_dosync(gpiomtd);
+ }
+ if (cmd == NAND_CMD_NONE)
+ return;
+
+ writeb(cmd, gpiomtd->nand_chip.IO_ADDR_W);
+ gpio_nand_dosync(gpiomtd);
+}
+
+static void gpio_nand_writebuf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+
+ writesb(this->IO_ADDR_W, buf, len);
+}
+
+static void gpio_nand_readbuf(struct mtd_info *mtd, u_char *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+
+ readsb(this->IO_ADDR_R, buf, len);
+}
+
+static int gpio_nand_verifybuf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+ u8 read, *p = (u8 *) buf;
+ int i, err = 0;
+
+ for (i = 0; i < len; i++) {
+ read = readb(this->IO_ADDR_R);
+ if (read != p[i]) {
+ pr_debug("%s: err at %d (read %04x vs %04x)\n",
+ __func__, i, read, p[i]);
+ err = -EFAULT;
+ }
+ }
+ return err;
+}
+
+static void gpio_nand_writebuf16(struct mtd_info *mtd, const u_char *buf,
+ int len)
+{
+ struct nand_chip *this = mtd->priv;
+
+ if (IS_ALIGNED((unsigned long)buf, 2)) {
+ writesw(this->IO_ADDR_W, buf, len>>1);
+ } else {
+ int i;
+ u16 *ptr = (u16 *)buf;
+
+ for (i = 0; i < len; i += 2, ptr++)
+ writew(*ptr, this->IO_ADDR_W);
+ }
+}
+
+static void gpio_nand_readbuf16(struct mtd_info *mtd, u_char *buf, int len)
+{
+ struct nand_chip *this = mtd->priv;
+
+ if (IS_ALIGNED((unsigned long)buf, 2)) {
+ readsw(this->IO_ADDR_R, buf, len>>1);
+ } else {
+ int i;
+ u16 *ptr = (u16 *)buf;
+
+ for (i = 0; i < len; i += 2, ptr++)
+ *ptr = readw(this->IO_ADDR_R);
+ }
+}
+
+static int gpio_nand_verifybuf16(struct mtd_info *mtd, const u_char *buf,
+ int len)
+{
+ struct nand_chip *this = mtd->priv;
+ u16 read, *p = (u16 *) buf;
+ int i, err = 0;
+ len >>= 1;
+
+ for (i = 0; i < len; i++) {
+ read = readw(this->IO_ADDR_R);
+ if (read != p[i]) {
+ pr_debug("%s: err at %d (read %04x vs %04x)\n",
+ __func__, i, read, p[i]);
+ err = -EFAULT;
+ }
+ }
+ return err;
+}
+
+
+static int gpio_nand_devready(struct mtd_info *mtd)
+{
+ struct gpiomtd *gpiomtd = gpio_nand_getpriv(mtd);
+ return gpio_get_value(gpiomtd->plat.gpio_rdy);
+}
+
+static int gpio_nand_remove(struct platform_device *dev)
+{
+ struct gpiomtd *gpiomtd = platform_get_drvdata(dev);
+ struct resource *res;
+
+ nand_release(&gpiomtd->mtd_info);
+
+ res = platform_get_resource(dev, IORESOURCE_MEM, 1);
+ iounmap(gpiomtd->io_sync);
+ if (res)
+ release_mem_region(res->start, res->end - res->start + 1);
+
+ res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ iounmap(gpiomtd->nand_chip.IO_ADDR_R);
+ release_mem_region(res->start, res->end - res->start + 1);
+
+ if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
+ gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
+ gpio_set_value(gpiomtd->plat.gpio_nce, 1);
+
+ gpio_free(gpiomtd->plat.gpio_cle);
+ gpio_free(gpiomtd->plat.gpio_ale);
+ gpio_free(gpiomtd->plat.gpio_nce);
+ if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
+ gpio_free(gpiomtd->plat.gpio_nwp);
+ gpio_free(gpiomtd->plat.gpio_rdy);
+
+ kfree(gpiomtd);
+
+ return 0;
+}
+
+static void __iomem *request_and_remap(struct resource *res, size_t size,
+ const char *name, int *err)
+{
+ void __iomem *ptr;
+
+ if (!request_mem_region(res->start, res->end - res->start + 1, name)) {
+ *err = -EBUSY;
+ return NULL;
+ }
+
+ ptr = ioremap(res->start, size);
+ if (!ptr) {
+ release_mem_region(res->start, res->end - res->start + 1);
+ *err = -ENOMEM;
+ }
+ return ptr;
+}
+
+static int gpio_nand_probe(struct platform_device *dev)
+{
+ struct gpiomtd *gpiomtd;
+ struct nand_chip *this;
+ struct resource *res0, *res1;
+ int ret;
+
+ if (!dev->dev.platform_data)
+ return -EINVAL;
+
+ res0 = platform_get_resource(dev, IORESOURCE_MEM, 0);
+ if (!res0)
+ return -EINVAL;
+
+ gpiomtd = kzalloc(sizeof(*gpiomtd), GFP_KERNEL);
+ if (gpiomtd == NULL) {
+ dev_err(&dev->dev, "failed to create NAND MTD\n");
+ return -ENOMEM;
+ }
+
+ this = &gpiomtd->nand_chip;
+ this->IO_ADDR_R = request_and_remap(res0, 2, "NAND", &ret);
+ if (!this->IO_ADDR_R) {
+ dev_err(&dev->dev, "unable to map NAND\n");
+ goto err_map;
+ }
+
+ res1 = platform_get_resource(dev, IORESOURCE_MEM, 1);
+ if (res1) {
+ gpiomtd->io_sync = request_and_remap(res1, 4, "NAND sync", &ret);
+ if (!gpiomtd->io_sync) {
+ dev_err(&dev->dev, "unable to map sync NAND\n");
+ goto err_sync;
+ }
+ }
+
+ memcpy(&gpiomtd->plat, dev->dev.platform_data, sizeof(gpiomtd->plat));
+
+ ret = gpio_request(gpiomtd->plat.gpio_nce, "NAND NCE");
+ if (ret)
+ goto err_nce;
+ gpio_direction_output(gpiomtd->plat.gpio_nce, 1);
+ if (gpio_is_valid(gpiomtd->plat.gpio_nwp)) {
+ ret = gpio_request(gpiomtd->plat.gpio_nwp, "NAND NWP");
+ if (ret)
+ goto err_nwp;
+ gpio_direction_output(gpiomtd->plat.gpio_nwp, 1);
+ }
+ ret = gpio_request(gpiomtd->plat.gpio_ale, "NAND ALE");
+ if (ret)
+ goto err_ale;
+ gpio_direction_output(gpiomtd->plat.gpio_ale, 0);
+ ret = gpio_request(gpiomtd->plat.gpio_cle, "NAND CLE");
+ if (ret)
+ goto err_cle;
+ gpio_direction_output(gpiomtd->plat.gpio_cle, 0);
+ ret = gpio_request(gpiomtd->plat.gpio_rdy, "NAND RDY");
+ if (ret)
+ goto err_rdy;
+ gpio_direction_input(gpiomtd->plat.gpio_rdy);
+
+
+ this->IO_ADDR_W = this->IO_ADDR_R;
+ this->ecc.mode = NAND_ECC_SOFT;
+ this->options = gpiomtd->plat.options;
+ this->chip_delay = gpiomtd->plat.chip_delay;
+
+ /* install our routines */
+ this->cmd_ctrl = gpio_nand_cmd_ctrl;
+ this->dev_ready = gpio_nand_devready;
+
+ if (this->options & NAND_BUSWIDTH_16) {
+ this->read_buf = gpio_nand_readbuf16;
+ this->write_buf = gpio_nand_writebuf16;
+ this->verify_buf = gpio_nand_verifybuf16;
+ } else {
+ this->read_buf = gpio_nand_readbuf;
+ this->write_buf = gpio_nand_writebuf;
+ this->verify_buf = gpio_nand_verifybuf;
+ }
+
+ /* set the mtd private data for the nand driver */
+ gpiomtd->mtd_info.priv = this;
+ gpiomtd->mtd_info.owner = THIS_MODULE;
+
+ if (nand_scan(&gpiomtd->mtd_info, 1)) {
+ dev_err(&dev->dev, "no nand chips found?\n");
+ ret = -ENXIO;
+ goto err_wp;
+ }
+
+ if (gpiomtd->plat.adjust_parts)
+ gpiomtd->plat.adjust_parts(&gpiomtd->plat,
+ gpiomtd->mtd_info.size);
+
+ add_mtd_partitions(&gpiomtd->mtd_info, gpiomtd->plat.parts,
+ gpiomtd->plat.num_parts);
+ platform_set_drvdata(dev, gpiomtd);
+
+ return 0;
+
+err_wp:
+ if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
+ gpio_set_value(gpiomtd->plat.gpio_nwp, 0);
+ gpio_free(gpiomtd->plat.gpio_rdy);
+err_rdy:
+ gpio_free(gpiomtd->plat.gpio_cle);
+err_cle:
+ gpio_free(gpiomtd->plat.gpio_ale);
+err_ale:
+ if (gpio_is_valid(gpiomtd->plat.gpio_nwp))
+ gpio_free(gpiomtd->plat.gpio_nwp);
+err_nwp:
+ gpio_free(gpiomtd->plat.gpio_nce);
+err_nce:
+ iounmap(gpiomtd->io_sync);
+ if (res1)
+ release_mem_region(res1->start, res1->end - res1->start + 1);
+err_sync:
+ iounmap(gpiomtd->nand_chip.IO_ADDR_R);
+ release_mem_region(res0->start, res0->end - res0->start + 1);
+err_map:
+ kfree(gpiomtd);
+ return -ENOMEM;
+}
+
+static struct platform_driver gpio_nand_driver = {
+ .probe = gpio_nand_probe,
+ .remove = gpio_nand_remove,
+ .driver = {
+ .name = "gpio-nand",
+ },
+};
+
+static int __init gpio_nand_init(void)
+{
+ printk(KERN_INFO "GPIO NAND driver, (c) 2004 Simtec Electronics\n");
+
+ return platform_driver_register(&gpio_nand_driver);
+}
+
+static void __exit gpio_nand_exit(void)
+{
+ platform_driver_unregister(&gpio_nand_driver);
+}
+
+module_init(gpio_nand_init);
+module_exit(gpio_nand_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ben Dooks <ben at simtec.co.uk>");
+MODULE_DESCRIPTION("GPIO NAND Driver");
diff --git a/include/linux/mtd/nand-gpio.h b/include/linux/mtd/nand-gpio.h
new file mode 100644
index 0000000..51534e5
--- /dev/null
+++ b/include/linux/mtd/nand-gpio.h
@@ -0,0 +1,19 @@
+#ifndef __LINUX_MTD_NAND_GPIO_H
+#define __LINUX_MTD_NAND_GPIO_H
+
+#include <linux/mtd/nand.h>
+
+struct gpio_nand_platdata {
+ int gpio_nce;
+ int gpio_nwp;
+ int gpio_cle;
+ int gpio_ale;
+ int gpio_rdy;
+ void (*adjust_parts)(struct gpio_nand_platdata *, size_t);
+ struct mtd_partition *parts;
+ unsigned int num_parts;
+ unsigned int options;
+ int chip_delay;
+};
+
+#endif
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
>
--
Sincerely yours,
Mike.
More information about the linux-mtd
mailing list