[RFC,v2] mtd: nand: add support for ts72xx

diff --git a/drivers/mtd/nand/raw/Kconfig b/drivers/mtd/nand/raw/Kconfig
index b523354dfb00..16219909d4c3 100644
--- a/drivers/mtd/nand/raw/Kconfig
+++ b/drivers/mtd/nand/raw/Kconfig
@@ -456,6 +456,13 @@  config MTD_NAND_RENESAS
 	  Enables support for the NAND controller found on Renesas R-Car
 	  Gen3 and RZ/N1 SoC families.
 
+config MTD_NAND_TS72XX
+	tristate "ts72xx NAND controller"
+	depends on ARCH_EP93XX && HAS_IOMEM
+	help
+	  Enables support for NAND controller on ts72xx SBCs.
+	  This is a legacy driver based on gen_nand.
+
 comment "Misc"
 
 config MTD_SM_COMMON
diff --git a/drivers/mtd/nand/raw/Makefile b/drivers/mtd/nand/raw/Makefile
index d93e861d8ba7..c0c42385d1ed 100644
--- a/drivers/mtd/nand/raw/Makefile
+++ b/drivers/mtd/nand/raw/Makefile
@@ -35,6 +35,7 @@  obj-$(CONFIG_MTD_NAND_MLC_LPC32XX)      += lpc32xx_mlc.o
 obj-$(CONFIG_MTD_NAND_SH_FLCTL)		+= sh_flctl.o
 obj-$(CONFIG_MTD_NAND_MXC)		+= mxc_nand.o
 obj-$(CONFIG_MTD_NAND_SOCRATES)		+= socrates_nand.o
+obj-$(CONFIG_MTD_NAND_TS72XX)           += technologic-nand-controller.o
 obj-$(CONFIG_MTD_NAND_TXX9NDFMC)	+= txx9ndfmc.o
 obj-$(CONFIG_MTD_NAND_MPC5121_NFC)	+= mpc5121_nfc.o
 obj-$(CONFIG_MTD_NAND_VF610_NFC)	+= vf610_nfc.o
diff --git a/drivers/mtd/nand/raw/technologic-nand-controller.c b/drivers/mtd/nand/raw/technologic-nand-controller.c
new file mode 100644
index 000000000000..2d163a523dcc
--- /dev/null
+++ b/drivers/mtd/nand/raw/technologic-nand-controller.c
@@ -0,0 +1,220 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Technologic Systems TS72xx NAND controller driver
+ *
+ * Copyright (C) 2023 Nikita Shubin <nikita.shubin@maquefel.me>
+ *
+ * Derived from: plat_nand.c
+ *  Author: Vitaly Wool <vitalywool@gmail.com>
+ */
+
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/platnand.h>
+
+#define TS72XX_NAND_CONTROL_ADDR_LINE	BIT(22)	/* 0xN0400000 */
+#define TS72XX_NAND_BUSY_ADDR_LINE	BIT(23)	/* 0xN0800000 */
+
+#define TS72XX_NAND_ALE			BIT(0)
+#define TS72XX_NAND_CLE			BIT(1)
+#define TS72XX_NAND_NCE			BIT(2)
+
+#define TS72XX_NAND_CTRL_CLE		(TS72XX_NAND_NCE | TS72XX_NAND_CLE)
+#define TS72XX_NAND_CTRL_ALE		(TS72XX_NAND_NCE | TS72XX_NAND_ALE)
+
+struct ts72xx_nand_data {
+	struct nand_controller	controller;
+	struct nand_chip	chip;
+	void __iomem		*base;
+	void __iomem		*ctrl;
+	void __iomem		*busy;
+};
+
+static inline struct ts72xx_nand_data *chip_to_ts72xx(struct nand_chip *chip)
+{
+	return container_of(chip, struct ts72xx_nand_data, chip);
+}
+
+static int ts72xx_nand_attach_chip(struct nand_chip *chip)
+{
+	switch (chip->ecc.engine_type) {
+	case NAND_ECC_ENGINE_TYPE_SOFT:
+		if (chip->ecc.algo == NAND_ECC_ALGO_UNKNOWN)
+			chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
+		chip->ecc.algo = NAND_ECC_ALGO_HAMMING;
+		break;
+	case NAND_ECC_ENGINE_TYPE_ON_HOST:
+		return -EINVAL;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static void ts72xx_nand_ctrl(struct nand_chip *chip, u8 value)
+{
+	struct ts72xx_nand_data *data = chip_to_ts72xx(chip);
+	unsigned char bits = ioread8(data->ctrl) & ~GENMASK(2, 0);
+
+	iowrite8(bits | value, data->ctrl);
+}
+
+static int ts72xx_nand_exec_instr(struct nand_chip *chip,
+				const struct nand_op_instr *instr)
+{
+	struct ts72xx_nand_data *data = chip_to_ts72xx(chip);
+	unsigned int i, timeout_us;
+	u32 status;
+	int ret;
+
+	switch (instr->type) {
+	case NAND_OP_CMD_INSTR:
+		ts72xx_nand_ctrl(chip, TS72XX_NAND_CTRL_CLE);
+		iowrite8(instr->ctx.cmd.opcode, data->base);
+		ts72xx_nand_ctrl(chip, TS72XX_NAND_NCE);
+		break;
+
+	case NAND_OP_ADDR_INSTR:
+		ts72xx_nand_ctrl(chip, TS72XX_NAND_CTRL_ALE);
+		for (i = 0; i < instr->ctx.addr.naddrs; i++)
+			iowrite8(instr->ctx.addr.addrs[i], data->base);
+		ts72xx_nand_ctrl(chip, TS72XX_NAND_NCE);
+		break;
+
+	case NAND_OP_DATA_IN_INSTR:
+		ioread8_rep(data->base, instr->ctx.data.buf.in, instr->ctx.data.len);
+		break;
+
+	case NAND_OP_DATA_OUT_INSTR:
+		iowrite8_rep(data->base, instr->ctx.data.buf.in, instr->ctx.data.len);
+		break;
+
+	case NAND_OP_WAITRDY_INSTR:
+		timeout_us = instr->ctx.waitrdy.timeout_ms * 1000;
+		ret = readb_poll_timeout(data->busy, status, status & BIT(5), 0, timeout_us);
+		if (ret)
+			return ret;
+
+		break;
+	}
+
+	if (instr->delay_ns)
+		ndelay(instr->delay_ns);
+
+	return 0;
+}
+
+static int ts72xx_nand_exec_op(struct nand_chip *chip,
+			       const struct nand_operation *op, bool check_only)
+{
+	unsigned int i;
+	int ret;
+
+	for (i = 0; i < op->ninstrs; i++) {
+		ret = ts72xx_nand_exec_instr(chip, &op->instrs[i]);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static const struct nand_controller_ops ts72xx_nand_ops = {
+	.attach_chip = ts72xx_nand_attach_chip,
+	.exec_op = ts72xx_nand_exec_op,
+};
+
+static int ts72xx_nand_probe(struct platform_device *pdev)
+{
+	struct ts72xx_nand_data *data;
+	struct fwnode_handle *child;
+	struct mtd_info *mtd;
+	int err;
+
+	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	nand_controller_init(&data->controller);
+	data->controller.ops = &ts72xx_nand_ops;
+	data->chip.controller = &data->controller;
+
+	data->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(data->base))
+		return PTR_ERR(data->base);
+	data->ctrl = data->base + TS72XX_NAND_CONTROL_ADDR_LINE;
+	data->busy = data->base + TS72XX_NAND_BUSY_ADDR_LINE;
+
+	child = fwnode_get_next_child_node(dev_fwnode(&pdev->dev), NULL);
+	if (!child)
+		return dev_err_probe(&pdev->dev, -ENXIO,
+				"ts72xx controller node should have exactly one child\n");
+
+	nand_set_flash_node(&data->chip, to_of_node(child));
+	mtd = nand_to_mtd(&data->chip);
+	mtd->dev.parent = &pdev->dev;
+	platform_set_drvdata(pdev, data);
+
+	/*
+	 * 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.
+	 */
+	data->chip.ecc.engine_type = NAND_ECC_ENGINE_TYPE_SOFT;
+
+	/* Scan to find existence of the device */
+	err = nand_scan(&data->chip, 1);
+	if (err)
+		goto err_handle_put;
+
+	err = mtd_device_parse_register(mtd, NULL, NULL, NULL, 0);
+	if (err)
+		goto err_clean_nand;
+
+	return 0;
+
+err_clean_nand:
+	nand_cleanup(&data->chip);
+err_handle_put:
+	fwnode_handle_put(child);
+	return err;
+}
+
+static void ts72xx_nand_remove(struct platform_device *pdev)
+{
+	struct ts72xx_nand_data *data = platform_get_drvdata(pdev);
+	struct nand_chip *chip = &data->chip;
+	int ret;
+
+	ret = mtd_device_unregister(nand_to_mtd(chip));
+	WARN_ON(ret);
+	nand_cleanup(chip);
+}
+
+static const struct of_device_id ts72xx_id_table[] = {
+	{ .compatible = "technologic,ts7200-nand" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ts72xx_id_table);
+
+static struct platform_driver ts72xx_nand_driver = {
+	.driver = {
+		.name = "ts72xx-nand",
+		.of_match_table = ts72xx_id_table,
+	},
+	.probe = ts72xx_nand_probe,
+	.remove_new = ts72xx_nand_remove,
+};
+module_platform_driver(ts72xx_nand_driver);
+
+MODULE_AUTHOR("Nikita Shubin <nikita.shubin@maquefel.me>");
+MODULE_DESCRIPTION("Technologic Systems TS72xx NAND controller driver");
+MODULE_LICENSE("GPL");