[MTD] [NAND] CM-x270 MTD driver

This patch provides MTD support for NAND flash devices on CM-x270 modules.
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>

drivers/mtd/nand/Kconfig

@@ -258,6 +258,11 @@ config MTD_NAND_AT91
 	  Enables support for NAND Flash / Smart Media Card interface
 	  on Atmel AT91 processors.
 
+config MTD_NAND_CM_X270
+	tristate "Support for NAND Flash on CM-X270 modules"
+	depends on MTD_NAND && MACH_ARMCORE
+
+
 config MTD_NAND_NANDSIM
 	tristate "Support for NAND Flash Simulator"
 	depends on MTD_PARTITIONS

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_AT91)		+= at91_nand.o
+obj-$(CONFIG_MTD_NAND_CM_X270)		+= cmx270_nand.o
 obj-$(CONFIG_MTD_NAND_BASLER_EXCITE)	+= excite_nandflash.o
 
 nand-objs := nand_base.o nand_bbt.o

drivers/mtd/nand/cmx270_nand.c

+/*
+ *  linux/drivers/mtd/nand/cmx270-nand.c
+ *
+ *  Copyright (C) 2006 Compulab, Ltd.
+ *  Mike Rapoport <mike@compulab.co.il>
+ *
+ *  Derived from drivers/mtd/nand/h1910.c
+ *       Copyright (C) 2002 Marius Gröger (mag@sysgo.de)
+ *       Copyright (c) 2001 Thomas Gleixner (gleixner@autronix.de)
+ *
+ *
+ * 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.
+ *
+ *  Overview:
+ *   This is a device driver for the NAND flash device found on the
+ *   CM-X270 board.
+ */
+
+#include <linux/mtd/nand.h>
+#include <linux/mtd/partitions.h>
+
+#include <asm/io.h>
+#include <asm/irq.h>
+
+#include <asm/arch/hardware.h>
+#include <asm/arch/pxa-regs.h>
+
+#define GPIO_NAND_CS	(11)
+#define GPIO_NAND_RB	(89)
+
+/* This macro needed to ensure in-order operation of GPIO and local
+ * bus. Without both asm command and dummy uncached read there're
+ * states when NAND access is broken. I've looked for such macro(s) in
+ * include/asm-arm but found nothing approptiate.
+ * dmac_clean_range is close, but is makes cache invalidation
+ * unnecessary here and it cannot be used in module
+ */
+#define DRAIN_WB() \
+	do { \
+		unsigned char dummy; \
+		asm volatile ("mcr p15, 0, r0, c7, c10, 4":::"r0"); \
+		dummy=*((unsigned char*)UNCACHED_ADDR); \
+	} while(0)
+
+/* MTD structure for CM-X270 board */
+static struct mtd_info *cmx270_nand_mtd;
+
+/* remaped IO address of the device */
+static void __iomem *cmx270_nand_io;
+
+/*
+ * Define static partitions for flash device
+ */
+static struct mtd_partition partition_info[] = {
+	[0] = {
+		.name	= "cmx270-0",
+		.offset	= 0,
+		.size	= MTDPART_SIZ_FULL
+	}
+};
+#define NUM_PARTITIONS (ARRAY_SIZE(partition_info))
+
+const char *part_probes[] = { "cmdlinepart", NULL };
+
+static u_char cmx270_read_byte(struct mtd_info *mtd)
+{
+	struct nand_chip *this = mtd->priv;
+
+	return (readl(this->IO_ADDR_R) >> 16);
+}
+
+static void cmx270_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+	int i;
+	struct nand_chip *this = mtd->priv;
+
+	for (i=0; i<len; i++)
+		writel((*buf++ << 16), this->IO_ADDR_W);
+}
+
+static void cmx270_read_buf(struct mtd_info *mtd, u_char *buf, int len)
+{
+	int i;
+	struct nand_chip *this = mtd->priv;
+
+	for (i=0; i<len; i++)
+		*buf++ = readl(this->IO_ADDR_R) >> 16;
+}
+
+static int cmx270_verify_buf(struct mtd_info *mtd, const u_char *buf, int len)
+{
+	int i;
+	struct nand_chip *this = mtd->priv;
+
+	for (i=0; i<len; i++)
+		if (buf[i] != (u_char)(readl(this->IO_ADDR_R) >> 16))
+			return -EFAULT;
+
+	return 0;
+}
+
+static inline void nand_cs_on(void)
+{
+	GPCR(GPIO_NAND_CS) = GPIO_bit(GPIO_NAND_CS);
+}
+
+static void nand_cs_off(void)
+{
+	DRAIN_WB();
+
+	GPSR(GPIO_NAND_CS) = GPIO_bit(GPIO_NAND_CS);
+}
+
+/*
+ *	hardware specific access to control-lines
+ */
+static void cmx270_hwcontrol(struct mtd_info *mtd, int dat,
+			     unsigned int ctrl)
+{
+	struct nand_chip* this = mtd->priv;
+	unsigned int nandaddr = (unsigned int)this->IO_ADDR_W;
+
+	DRAIN_WB();
+
+	if (ctrl & NAND_CTRL_CHANGE) {
+		if ( ctrl & NAND_ALE )
+			nandaddr |=  (1 << 3);
+		else
+			nandaddr &= ~(1 << 3);
+		if ( ctrl & NAND_CLE )
+			nandaddr |=  (1 << 2);
+		else
+			nandaddr &= ~(1 << 2);
+		if ( ctrl & NAND_NCE )
+			nand_cs_on();
+		else
+			nand_cs_off();
+	}
+
+	DRAIN_WB();
+	this->IO_ADDR_W = (void __iomem*)nandaddr;
+	if (dat != NAND_CMD_NONE)
+		writel((dat << 16), this->IO_ADDR_W);
+
+	DRAIN_WB();
+}
+
+/*
+ *	read device ready pin
+ */
+static int cmx270_device_ready(struct mtd_info *mtd)
+{
+	DRAIN_WB();
+
+	return (GPLR(GPIO_NAND_RB) & GPIO_bit(GPIO_NAND_RB));
+}
+
+/*
+ * Main initialization routine
+ */
+static int cmx270_init(void)
+{
+	struct nand_chip *this;
+	const char *part_type;
+	struct mtd_partition *mtd_parts;
+	int mtd_parts_nb = 0;
+	int ret;
+
+	/* Allocate memory for MTD device structure and private data */
+	cmx270_nand_mtd = kzalloc(sizeof(struct mtd_info) +
+				  sizeof(struct nand_chip),
+				  GFP_KERNEL);
+	if (!cmx270_nand_mtd) {
+		printk("Unable to allocate CM-X270 NAND MTD device structure.\n");
+		return -ENOMEM;
+	}
+
+	cmx270_nand_io = ioremap(PXA_CS1_PHYS, 12);
+	if (!cmx270_nand_io) {
+		printk("Unable to ioremap NAND device\n");
+		ret = -EINVAL;
+		goto err1;
+	}
+
+	/* Get pointer to private data */
+	this = (struct nand_chip *)(&cmx270_nand_mtd[1]);
+
+	/* Link the private data with the MTD structure */
+	cmx270_nand_mtd->owner = THIS_MODULE;
+	cmx270_nand_mtd->priv = this;
+
+	/* insert callbacks */
+	this->IO_ADDR_R = cmx270_nand_io;
+	this->IO_ADDR_W = cmx270_nand_io;
+	this->cmd_ctrl = cmx270_hwcontrol;
+	this->dev_ready = cmx270_device_ready;
+
+	/* 15 us command delay time */
+	this->chip_delay = 20;
+	this->ecc.mode = NAND_ECC_SOFT;
+
+	/* read/write functions */
+	this->read_byte = cmx270_read_byte;
+	this->read_buf = cmx270_read_buf;
+	this->write_buf = cmx270_write_buf;
+	this->verify_buf = cmx270_verify_buf;
+
+	/* Scan to find existence of the device */
+	if (nand_scan (cmx270_nand_mtd, 1)) {
+		printk(KERN_NOTICE "No NAND device\n");
+		ret = -ENXIO;
+		goto err2;
+	}
+
+#ifdef CONFIG_MTD_CMDLINE_PARTS
+	mtd_parts_nb = parse_mtd_partitions(cmx270_nand_mtd, part_probes,
+					    &mtd_parts, 0);
+	if (mtd_parts_nb > 0)
+		part_type = "command line";
+	else
+		mtd_parts_nb = 0;
+#endif
+	if (!mtd_parts_nb) {
+		mtd_parts = partition_info;
+		mtd_parts_nb = NUM_PARTITIONS;
+		part_type = "static";
+	}
+
+	/* Register the partitions */
+	printk(KERN_NOTICE "Using %s partition definition\n", part_type);
+	ret = add_mtd_partitions(cmx270_nand_mtd, mtd_parts, mtd_parts_nb);
+	if (ret)
+		goto err2;
+
+	/* Return happy */
+	return 0;
+
+err2:
+	iounmap(cmx270_nand_io);
+err1:
+	kfree(cmx270_nand_mtd);
+
+	return ret;
+
+}
+module_init(cmx270_init);
+
+/*
+ * Clean up routine
+ */
+static void cmx270_cleanup(void)
+{
+	/* Release resources, unregister device */
+	nand_release(cmx270_nand_mtd);
+
+	iounmap(cmx270_nand_io);
+
+	/* Free the MTD device structure */
+	kfree (cmx270_nand_mtd);
+}
+module_exit(cmx270_cleanup);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
+MODULE_DESCRIPTION("NAND flash driver for Compulab CM-X270 Module");