[MTD] [NAND] GPIO NAND flash driver

The patch adds support for NAND flashes connected to GPIOs.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

4 files changed, 401 insertions, 0 deletions

diff --git a/drivers/mtd/nand/Kconfig b/drivers/mtd/nand/Kconfig
index 89b4d39386ab..b9eed9925462 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 9bfeca324b32..b661586afbfc 100644
--- a/drivers/mtd/nand/Makefile
+++ b/drivers/mtd/nand/Makefile
@@ -23,6 +23,7 @@ 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 000000000000..8f902e75aa85
--- /dev/null
+++ b/drivers/mtd/nand/gpio.c
@@ -0,0 +1,375 @@
+/*
+ * drivers/mtd/nand/gpio.c
+ *
+ * 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 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()
+ *
+ * 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 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;
+        unsigned char read, *p = (unsigned char *) 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;
+                unsigned short *ptr = (unsigned short *)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;
+                unsigned short *ptr = (unsigned short *)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;
+        unsigned short read, *p = (unsigned short *) 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;