mtd: spi-nor: add driver for NXP SPI Flash Interface (SPIFI)

Add SPI-NOR driver for the SPI Flash Interface (SPIFI)
controller that is found on newer NXP MCU devices.

The controller supports serial SPI Flash devices with 1-, 2-
and 4-bit width in either SPI mode 0 or 3. The controller
can operate in either command or memory mode. In memory mode
the Flash is exposed as normal memory and can be directly
accessed by the CPU.

Signed-off-by: Joachim Eastwood <manabian@gmail.com>
Reviewed-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/spi-nor/Kconfig

@@ -28,4 +28,15 @@ config SPI_FSL_QUADSPI
 	  This enables support for the Quad SPI controller in master mode.
 	  We only connect the NOR to this controller now.
 
+config SPI_NXP_SPIFI
+	tristate "NXP SPI Flash Interface (SPIFI)"
+	depends on OF && (ARCH_LPC18XX || COMPILE_TEST)
+	depends on HAS_IOMEM
+	help
+	  Enable support for the NXP LPC SPI Flash Interface controller.
+
+	  SPIFI is a specialized controller for connecting serial SPI
+	  Flash. Enable this option if you have a device with a SPIFI
+	  controller and want to access the Flash as a mtd device.
+
 endif # MTD_SPI_NOR

drivers/mtd/spi-nor/Makefile

@@ -1,2 +1,3 @@
 obj-$(CONFIG_MTD_SPI_NOR)	+= spi-nor.o
 obj-$(CONFIG_SPI_FSL_QUADSPI)	+= fsl-quadspi.o
+obj-$(CONFIG_SPI_NXP_SPIFI)	+= nxp-spifi.o

drivers/mtd/spi-nor/nxp-spifi.c

@@ -0,0 +1,482 @@
+/*
+ * SPI-NOR driver for NXP SPI Flash Interface (SPIFI)
+ *
+ * Copyright (C) 2015 Joachim Eastwood <manabian@gmail.com>
+ *
+ * Based on Freescale QuadSPI driver:
+ * Copyright (C) 2013 Freescale Semiconductor, Inc.
+ *
+ * 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/clk.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/iopoll.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/spi-nor.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/spi/spi.h>
+
+/* NXP SPIFI registers, bits and macros */
+#define SPIFI_CTRL				0x000
+#define  SPIFI_CTRL_TIMEOUT(timeout)		(timeout)
+#define  SPIFI_CTRL_CSHIGH(cshigh)		((cshigh) << 16)
+#define  SPIFI_CTRL_MODE3			BIT(23)
+#define  SPIFI_CTRL_DUAL			BIT(28)
+#define  SPIFI_CTRL_FBCLK			BIT(30)
+#define SPIFI_CMD				0x004
+#define  SPIFI_CMD_DATALEN(dlen)		((dlen) & 0x3fff)
+#define  SPIFI_CMD_DOUT				BIT(15)
+#define  SPIFI_CMD_INTLEN(ilen)			((ilen) << 16)
+#define  SPIFI_CMD_FIELDFORM(field)		((field) << 19)
+#define  SPIFI_CMD_FIELDFORM_ALL_SERIAL		SPIFI_CMD_FIELDFORM(0x0)
+#define  SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA	SPIFI_CMD_FIELDFORM(0x1)
+#define  SPIFI_CMD_FRAMEFORM(frame)		((frame) << 21)
+#define  SPIFI_CMD_FRAMEFORM_OPCODE_ONLY	SPIFI_CMD_FRAMEFORM(0x1)
+#define  SPIFI_CMD_OPCODE(op)			((op) << 24)
+#define SPIFI_ADDR				0x008
+#define SPIFI_IDATA				0x00c
+#define SPIFI_CLIMIT				0x010
+#define SPIFI_DATA				0x014
+#define SPIFI_MCMD				0x018
+#define SPIFI_STAT				0x01c
+#define  SPIFI_STAT_MCINIT			BIT(0)
+#define  SPIFI_STAT_CMD				BIT(1)
+#define  SPIFI_STAT_RESET			BIT(4)
+
+#define SPI_NOR_MAX_ID_LEN	6
+
+struct nxp_spifi {
+	struct device *dev;
+	struct clk *clk_spifi;
+	struct clk *clk_reg;
+	void __iomem *io_base;
+	void __iomem *flash_base;
+	struct mtd_info mtd;
+	struct spi_nor nor;
+	bool memory_mode;
+	u32 mcmd;
+};
+
+static int nxp_spifi_wait_for_cmd(struct nxp_spifi *spifi)
+{
+	u8 stat;
+	int ret;
+
+	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
+				 !(stat & SPIFI_STAT_CMD), 10, 30);
+	if (ret)
+		dev_warn(spifi->dev, "command timed out\n");
+
+	return ret;
+}
+
+static int nxp_spifi_reset(struct nxp_spifi *spifi)
+{
+	u8 stat;
+	int ret;
+
+	writel(SPIFI_STAT_RESET, spifi->io_base + SPIFI_STAT);
+	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
+				 !(stat & SPIFI_STAT_RESET), 10, 30);
+	if (ret)
+		dev_warn(spifi->dev, "state reset timed out\n");
+
+	return ret;
+}
+
+static int nxp_spifi_set_memory_mode_off(struct nxp_spifi *spifi)
+{
+	int ret;
+
+	if (!spifi->memory_mode)
+		return 0;
+
+	ret = nxp_spifi_reset(spifi);
+	if (ret)
+		dev_err(spifi->dev, "unable to enter command mode\n");
+	else
+		spifi->memory_mode = false;
+
+	return ret;
+}
+
+static int nxp_spifi_set_memory_mode_on(struct nxp_spifi *spifi)
+{
+	u8 stat;
+	int ret;
+
+	if (spifi->memory_mode)
+		return 0;
+
+	writel(spifi->mcmd, spifi->io_base + SPIFI_MCMD);
+	ret = readb_poll_timeout(spifi->io_base + SPIFI_STAT, stat,
+				 stat & SPIFI_STAT_MCINIT, 10, 30);
+	if (ret)
+		dev_err(spifi->dev, "unable to enter memory mode\n");
+	else
+		spifi->memory_mode = true;
+
+	return ret;
+}
+
+static int nxp_spifi_read_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
+{
+	struct nxp_spifi *spifi = nor->priv;
+	u32 cmd;
+	int ret;
+
+	ret = nxp_spifi_set_memory_mode_off(spifi);
+	if (ret)
+		return ret;
+
+	cmd = SPIFI_CMD_DATALEN(len) |
+	      SPIFI_CMD_OPCODE(opcode) |
+	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
+	      SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
+	writel(cmd, spifi->io_base + SPIFI_CMD);
+
+	while (len--)
+		*buf++ = readb(spifi->io_base + SPIFI_DATA);
+
+	return nxp_spifi_wait_for_cmd(spifi);
+}
+
+static int nxp_spifi_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf,
+			       int len, int write_enable)
+{
+	struct nxp_spifi *spifi = nor->priv;
+	u32 cmd;
+	int ret;
+
+	ret = nxp_spifi_set_memory_mode_off(spifi);
+	if (ret)
+		return ret;
+
+	cmd = SPIFI_CMD_DOUT |
+	      SPIFI_CMD_DATALEN(len) |
+	      SPIFI_CMD_OPCODE(opcode) |
+	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
+	      SPIFI_CMD_FRAMEFORM_OPCODE_ONLY;
+	writel(cmd, spifi->io_base + SPIFI_CMD);
+
+	while (len--)
+		writeb(*buf++, spifi->io_base + SPIFI_DATA);
+
+	return nxp_spifi_wait_for_cmd(spifi);
+}
+
+static int nxp_spifi_read(struct spi_nor *nor, loff_t from, size_t len,
+			  size_t *retlen, u_char *buf)
+{
+	struct nxp_spifi *spifi = nor->priv;
+	int ret;
+
+	ret = nxp_spifi_set_memory_mode_on(spifi);
+	if (ret)
+		return ret;
+
+	memcpy_fromio(buf, spifi->flash_base + from, len);
+	*retlen += len;
+
+	return 0;
+}
+
+static void nxp_spifi_write(struct spi_nor *nor, loff_t to, size_t len,
+			    size_t *retlen, const u_char *buf)
+{
+	struct nxp_spifi *spifi = nor->priv;
+	u32 cmd;
+	int ret;
+
+	ret = nxp_spifi_set_memory_mode_off(spifi);
+	if (ret)
+		return;
+
+	writel(to, spifi->io_base + SPIFI_ADDR);
+	*retlen += len;
+
+	cmd = SPIFI_CMD_DOUT |
+	      SPIFI_CMD_DATALEN(len) |
+	      SPIFI_CMD_FIELDFORM_ALL_SERIAL |
+	      SPIFI_CMD_OPCODE(nor->program_opcode) |
+	      SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
+	writel(cmd, spifi->io_base + SPIFI_CMD);
+
+	while (len--)
+		writeb(*buf++, spifi->io_base + SPIFI_DATA);
+
+	nxp_spifi_wait_for_cmd(spifi);
+}
+
+static int nxp_spifi_erase(struct spi_nor *nor, loff_t offs)
+{
+	struct nxp_spifi *spifi = nor->priv;
+	u32 cmd;
+	int ret;
+
+	ret = nxp_spifi_set_memory_mode_off(spifi);
+	if (ret)
+		return ret;
+
+	writel(offs, spifi->io_base + SPIFI_ADDR);
+
+	cmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL |
+	      SPIFI_CMD_OPCODE(nor->erase_opcode) |
+	      SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
+	writel(cmd, spifi->io_base + SPIFI_CMD);
+
+	return nxp_spifi_wait_for_cmd(spifi);
+}
+
+static int nxp_spifi_setup_memory_cmd(struct nxp_spifi *spifi)
+{
+	switch (spifi->nor.flash_read) {
+	case SPI_NOR_NORMAL:
+	case SPI_NOR_FAST:
+		spifi->mcmd = SPIFI_CMD_FIELDFORM_ALL_SERIAL;
+		break;
+	case SPI_NOR_DUAL:
+	case SPI_NOR_QUAD:
+		spifi->mcmd = SPIFI_CMD_FIELDFORM_QUAD_DUAL_DATA;
+		break;
+	default:
+		dev_err(spifi->dev, "unsupported SPI read mode\n");
+		return -EINVAL;
+	}
+
+	/* Memory mode supports address length between 1 and 4 */
+	if (spifi->nor.addr_width < 1 || spifi->nor.addr_width > 4)
+		return -EINVAL;
+
+	spifi->mcmd |= SPIFI_CMD_OPCODE(spifi->nor.read_opcode) |
+		       SPIFI_CMD_INTLEN(spifi->nor.read_dummy / 8) |
+		       SPIFI_CMD_FRAMEFORM(spifi->nor.addr_width + 1);
+
+	return 0;
+}
+
+static void nxp_spifi_dummy_id_read(struct spi_nor *nor)
+{
+	u8 id[SPI_NOR_MAX_ID_LEN];
+	nor->read_reg(nor, SPINOR_OP_RDID, id, SPI_NOR_MAX_ID_LEN);
+}
+
+static int nxp_spifi_setup_flash(struct nxp_spifi *spifi,
+				 struct device_node *np)
+{
+	struct mtd_part_parser_data ppdata;
+	enum read_mode flash_read;
+	u32 ctrl, property;
+	u16 mode = 0;
+	int ret;
+
+	if (!of_property_read_u32(np, "spi-rx-bus-width", &property)) {
+		switch (property) {
+		case 1:
+			break;
+		case 2:
+			mode |= SPI_RX_DUAL;
+			break;
+		case 4:
+			mode |= SPI_RX_QUAD;
+			break;
+		default:
+			dev_err(spifi->dev, "unsupported rx-bus-width\n");
+			return -EINVAL;
+		}
+	}
+
+	if (of_find_property(np, "spi-cpha", NULL))
+		mode |= SPI_CPHA;
+
+	if (of_find_property(np, "spi-cpol", NULL))
+		mode |= SPI_CPOL;
+
+	/* Setup control register defaults */
+	ctrl = SPIFI_CTRL_TIMEOUT(1000) |
+	       SPIFI_CTRL_CSHIGH(15) |
+	       SPIFI_CTRL_FBCLK;
+
+	if (mode & SPI_RX_DUAL) {
+		ctrl |= SPIFI_CTRL_DUAL;
+		flash_read = SPI_NOR_DUAL;
+	} else if (mode & SPI_RX_QUAD) {
+		ctrl &= ~SPIFI_CTRL_DUAL;
+		flash_read = SPI_NOR_QUAD;
+	} else {
+		ctrl |= SPIFI_CTRL_DUAL;
+		flash_read = SPI_NOR_NORMAL;
+	}
+
+	switch (mode & (SPI_CPHA | SPI_CPOL)) {
+	case SPI_MODE_0:
+		ctrl &= ~SPIFI_CTRL_MODE3;
+		break;
+	case SPI_MODE_3:
+		ctrl |= SPIFI_CTRL_MODE3;
+		break;
+	default:
+		dev_err(spifi->dev, "only mode 0 and 3 supported\n");
+		return -EINVAL;
+	}
+
+	writel(ctrl, spifi->io_base + SPIFI_CTRL);
+
+	spifi->mtd.priv  = &spifi->nor;
+	spifi->nor.mtd   = &spifi->mtd;
+	spifi->nor.dev   = spifi->dev;
+	spifi->nor.priv  = spifi;
+	spifi->nor.read  = nxp_spifi_read;
+	spifi->nor.write = nxp_spifi_write;
+	spifi->nor.erase = nxp_spifi_erase;
+	spifi->nor.read_reg  = nxp_spifi_read_reg;
+	spifi->nor.write_reg = nxp_spifi_write_reg;
+
+	/*
+	 * The first read on a hard reset isn't reliable so do a
+	 * dummy read of the id before calling spi_nor_scan().
+	 * The reason for this problem is unknown.
+	 *
+	 * The official NXP spifilib uses more or less the same
+	 * workaround that is applied here by reading the device
+	 * id multiple times.
+	 */
+	nxp_spifi_dummy_id_read(&spifi->nor);
+
+	ret = spi_nor_scan(&spifi->nor, NULL, flash_read);
+	if (ret) {
+		dev_err(spifi->dev, "device scan failed\n");
+		return ret;
+	}
+
+	ret = nxp_spifi_setup_memory_cmd(spifi);
+	if (ret) {
+		dev_err(spifi->dev, "memory command setup failed\n");
+		return ret;
+	}
+
+	ppdata.of_node = np;
+	ret = mtd_device_parse_register(&spifi->mtd, NULL, &ppdata, NULL, 0);
+	if (ret) {
+		dev_err(spifi->dev, "mtd device parse failed\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int nxp_spifi_probe(struct platform_device *pdev)
+{
+	struct device_node *flash_np;
+	struct nxp_spifi *spifi;
+	struct resource *res;
+	int ret;
+
+	spifi = devm_kzalloc(&pdev->dev, sizeof(*spifi), GFP_KERNEL);
+	if (!spifi)
+		return -ENOMEM;
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "spifi");
+	spifi->io_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spifi->io_base))
+		return PTR_ERR(spifi->io_base);
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "flash");
+	spifi->flash_base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(spifi->flash_base))
+		return PTR_ERR(spifi->flash_base);
+
+	spifi->clk_spifi = devm_clk_get(&pdev->dev, "spifi");
+	if (IS_ERR(spifi->clk_spifi)) {
+		dev_err(&pdev->dev, "spifi clock not found\n");
+		return PTR_ERR(spifi->clk_spifi);
+	}
+
+	spifi->clk_reg = devm_clk_get(&pdev->dev, "reg");
+	if (IS_ERR(spifi->clk_reg)) {
+		dev_err(&pdev->dev, "reg clock not found\n");
+		return PTR_ERR(spifi->clk_reg);
+	}
+
+	ret = clk_prepare_enable(spifi->clk_reg);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable reg clock\n");
+		return ret;
+	}
+
+	ret = clk_prepare_enable(spifi->clk_spifi);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to enable spifi clock\n");
+		goto dis_clk_reg;
+	}
+
+	spifi->dev = &pdev->dev;
+	platform_set_drvdata(pdev, spifi);
+
+	/* Initialize and reset device */
+	nxp_spifi_reset(spifi);
+	writel(0, spifi->io_base + SPIFI_IDATA);
+	writel(0, spifi->io_base + SPIFI_MCMD);
+	nxp_spifi_reset(spifi);
+
+	flash_np = of_get_next_available_child(pdev->dev.of_node, NULL);
+	if (!flash_np) {
+		dev_err(&pdev->dev, "no SPI flash device to configure\n");
+		ret = -ENODEV;
+		goto dis_clks;
+	}
+
+	ret = nxp_spifi_setup_flash(spifi, flash_np);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to setup flash chip\n");
+		goto dis_clks;
+	}
+
+	return 0;
+
+dis_clks:
+	clk_disable_unprepare(spifi->clk_spifi);
+dis_clk_reg:
+	clk_disable_unprepare(spifi->clk_reg);
+	return ret;
+}
+
+static int nxp_spifi_remove(struct platform_device *pdev)
+{
+	struct nxp_spifi *spifi = platform_get_drvdata(pdev);
+
+	mtd_device_unregister(&spifi->mtd);
+	clk_disable_unprepare(spifi->clk_spifi);
+	clk_disable_unprepare(spifi->clk_reg);
+
+	return 0;
+}
+
+static const struct of_device_id nxp_spifi_match[] = {
+	{.compatible = "nxp,lpc1773-spifi"},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, nxp_spifi_match);
+
+static struct platform_driver nxp_spifi_driver = {
+	.probe	= nxp_spifi_probe,
+	.remove	= nxp_spifi_remove,
+	.driver	= {
+		.name = "nxp-spifi",
+		.of_match_table = nxp_spifi_match,
+	},
+};
+module_platform_driver(nxp_spifi_driver);
+
+MODULE_DESCRIPTION("NXP SPI Flash Interface driver");
+MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
+MODULE_LICENSE("GPL v2");