1 files changed, 408 insertions, 0 deletions
diff --git a/drivers/mtd/nand/raw/gpio.c b/drivers/mtd/nand/raw/gpio.c
new file mode 100644
index 000000000..dcf28cff7
--- /dev/null
+++ b/drivers/mtd/nand/raw/gpio.c
@@ -0,0 +1,408 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * 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")
+ */
+
+#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>
+#include <linux/delay.h>
+
+struct gpiomtd {
+	struct nand_controller	base;
+	void __iomem		*io;
+	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 int gpio_nand_exec_instr(struct nand_chip *chip,
+				const struct nand_op_instr *instr)
+{
+	struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
+	unsigned int i;
+
+	switch (instr->type) {
+	case NAND_OP_CMD_INSTR:
+		gpio_nand_dosync(gpiomtd);
+		gpiod_set_value(gpiomtd->cle, 1);
+		gpio_nand_dosync(gpiomtd);
+		writeb(instr->ctx.cmd.opcode, gpiomtd->io);
+		gpio_nand_dosync(gpiomtd);
+		gpiod_set_value(gpiomtd->cle, 0);
+		return 0;
+
+	case NAND_OP_ADDR_INSTR:
+		gpio_nand_dosync(gpiomtd);
+		gpiod_set_value(gpiomtd->ale, 1);
+		gpio_nand_dosync(gpiomtd);
+		for (i = 0; i < instr->ctx.addr.naddrs; i++)
+			writeb(instr->ctx.addr.addrs[i], gpiomtd->io);
+		gpio_nand_dosync(gpiomtd);
+		gpiod_set_value(gpiomtd->ale, 0);
+		return 0;
+
+	case NAND_OP_DATA_IN_INSTR:
+		gpio_nand_dosync(gpiomtd);
+		if ((chip->options & NAND_BUSWIDTH_16) &&
+		    !instr->ctx.data.force_8bit)
+			ioread16_rep(gpiomtd->io, instr->ctx.data.buf.in,
+				     instr->ctx.data.len / 2);
+		else
+			ioread8_rep(gpiomtd->io, instr->ctx.data.buf.in,
+				    instr->ctx.data.len);
+		return 0;
+
+	case NAND_OP_DATA_OUT_INSTR:
+		gpio_nand_dosync(gpiomtd);
+		if ((chip->options & NAND_BUSWIDTH_16) &&
+		    !instr->ctx.data.force_8bit)
+			iowrite16_rep(gpiomtd->io, instr->ctx.data.buf.out,
+				      instr->ctx.data.len / 2);
+		else
+			iowrite8_rep(gpiomtd->io, instr->ctx.data.buf.out,
+				     instr->ctx.data.len);
+		return 0;
+
+	case NAND_OP_WAITRDY_INSTR:
+		if (!gpiomtd->rdy)
+			return nand_soft_waitrdy(chip, instr->ctx.waitrdy.timeout_ms);
+
+		return nand_gpio_waitrdy(chip, gpiomtd->rdy,
+					 instr->ctx.waitrdy.timeout_ms);
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int gpio_nand_exec_op(struct nand_chip *chip,
+			     const struct nand_operation *op,
+			     bool check_only)
+{
+	struct gpiomtd *gpiomtd = gpio_nand_getpriv(nand_to_mtd(chip));
+	unsigned int i;
+	int ret = 0;
+
+	if (check_only)
+		return 0;
+
+	gpio_nand_dosync(gpiomtd);
+	gpiod_set_value(gpiomtd->nce, 0);
+	for (i = 0; i < op->ninstrs; i++) {
+		ret = gpio_nand_exec_instr(chip, &op->instrs[i]);
+		if (ret)
+			break;
+
+		if (op->instrs[i].delay_ns)
+			ndelay(op->instrs[i].delay_ns);
+	}
+	gpio_nand_dosync(gpiomtd);
+	gpiod_set_value(gpiomtd->nce, 1);
+
+	return ret;
+}
+
+static int gpio_nand_attach_chip(struct nand_chip *chip)
+{
+	if (chip->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT &&
+	    chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
+		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
+
+	return 0;
+}
+
+static const struct nand_controller_ops gpio_nand_ops = {
+	.exec_op = gpio_nand_exec_op,
+	.attach_chip = gpio_nand_attach_chip,
+};
+
+#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);
+	struct nand_chip *chip = &gpiomtd->nand_chip;
+	int ret;
+
+	ret = mtd_device_unregister(nand_to_mtd(chip));
+	WARN_ON(ret);
+	nand_cleanup(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;
+
+	gpiomtd->io = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(gpiomtd->io))
+		return PTR_ERR(gpiomtd->io);
+
+	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;
+	}
+
+	nand_controller_init(&gpiomtd->base);
+	gpiomtd->base.ops = &gpio_nand_ops;
+
+	nand_set_flash_node(chip, pdev->dev.of_node);
+	chip->options		= gpiomtd->plat.options;
+	chip->controller	= &gpiomtd->base;
+
+	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);
+
+	/*
+	 * This driver assumes that the default ECC engine should be TYPE_SOFT.
+	 * Set ->engine_type before registering the NAND devices in order to
+	 * provide a driver specific default value.
+	 */
+	chip->ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+
+	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");