File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
new file mode 100644
index 0000000..fe9ceb7
--- /dev/null
+++ b/drivers/mtd/devices/m25p80.c
@@ -0,0 +1,320 @@
+/*
+ * MTD SPI driver for ST M25Pxx (and similar) serial flash chips
+ *
+ * Author: Mike Lavender, mike@steroidmicros.com
+ *
+ * Copyright (c) 2005, Intec Automation Inc.
+ *
+ * Some parts are based on lart.c by Abraham Van Der Merwe
+ *
+ * Cleaned up and generalized based on mtd_dataflash.c
+ *
+ * This code 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/err.h>
+#include <linux/errno.h>
+#include <linux/module.h>
+#include <linux/device.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#include <linux/spi/spi.h>
+#include <linux/spi/flash.h>
+#include <linux/mtd/spi-nor.h>
+
+#define	MAX_CMD_SIZE		6
+struct m25p {
+	struct spi_device	*spi;
+	struct spi_nor		spi_nor;
+	u8			command[MAX_CMD_SIZE];
+};
+
+static int m25p80_read_reg(struct spi_nor *nor, u8 code, u8 *val, int len)
+{
+	struct m25p *flash = nor->priv;
+	struct spi_device *spi = flash->spi;
+	int ret;
+
+	ret = spi_write_then_read(spi, &code, 1, val, len);
+	if (ret < 0)
+		dev_err(&spi->dev, "error %d reading %x\n", ret, code);
+
+	return ret;
+}
+
+static void m25p_addr2cmd(struct spi_nor *nor, unsigned int addr, u8 *cmd)
+{
+	/* opcode is in cmd[0] */
+	cmd[1] = addr >> (nor->addr_width * 8 -  8);
+	cmd[2] = addr >> (nor->addr_width * 8 - 16);
+	cmd[3] = addr >> (nor->addr_width * 8 - 24);
+	cmd[4] = addr >> (nor->addr_width * 8 - 32);
+}
+
+static int m25p_cmdsz(struct spi_nor *nor)
+{
+	return 1 + nor->addr_width;
+}
+
+static int m25p80_write_reg(struct spi_nor *nor, u8 opcode, u8 *buf, int len)
+{
+	struct m25p *flash = nor->priv;
+	struct spi_device *spi = flash->spi;
+
+	flash->command[0] = opcode;
+	if (buf)
+		memcpy(&flash->command[1], buf, len);
+
+	return spi_write(spi, flash->command, len + 1);
+}
+
+static void m25p80_write(struct spi_nor *nor, loff_t to, size_t len,
+			size_t *retlen, const u_char *buf)
+{
+	struct m25p *flash = nor->priv;
+	struct spi_device *spi = flash->spi;
+	struct spi_transfer t[2] = {};
+	struct spi_message m;
+	int cmd_sz = m25p_cmdsz(nor);
+
+	spi_message_init(&m);
+
+	if (nor->program_opcode == SPINOR_OP_AAI_WP && nor->sst_write_second)
+		cmd_sz = 1;
+
+	flash->command[0] = nor->program_opcode;
+	m25p_addr2cmd(nor, to, flash->command);
+
+	t[0].tx_buf = flash->command;
+	t[0].len = cmd_sz;
+	spi_message_add_tail(&t[0], &m);
+
+	t[1].tx_buf = buf;
+	t[1].len = len;
+	spi_message_add_tail(&t[1], &m);
+
+	spi_sync(spi, &m);
+
+	*retlen += m.actual_length - cmd_sz;
+}
+
+static inline unsigned int m25p80_rx_nbits(struct spi_nor *nor)
+{
+	switch (nor->flash_read) {
+	case SPI_NOR_DUAL:
+		return 2;
+	case SPI_NOR_QUAD:
+		return 4;
+	default:
+		return 0;
+	}
+}
+
+/*
+ * Read an address range from the nor chip.  The address range
+ * may be any size provided it is within the physical boundaries.
+ */
+static int m25p80_read(struct spi_nor *nor, loff_t from, size_t len,
+			size_t *retlen, u_char *buf)
+{
+	struct m25p *flash = nor->priv;
+	struct spi_device *spi = flash->spi;
+	struct spi_transfer t[2];
+	struct spi_message m;
+	unsigned int dummy = nor->read_dummy;
+
+	/* convert the dummy cycles to the number of bytes */
+	dummy /= 8;
+
+	spi_message_init(&m);
+	memset(t, 0, (sizeof t));
+
+	flash->command[0] = nor->read_opcode;
+	m25p_addr2cmd(nor, from, flash->command);
+
+	t[0].tx_buf = flash->command;
+	t[0].len = m25p_cmdsz(nor) + dummy;
+	spi_message_add_tail(&t[0], &m);
+
+	t[1].rx_buf = buf;
+	t[1].rx_nbits = m25p80_rx_nbits(nor);
+	t[1].len = len;
+	spi_message_add_tail(&t[1], &m);
+
+	spi_sync(spi, &m);
+
+	*retlen = m.actual_length - m25p_cmdsz(nor) - dummy;
+	return 0;
+}
+
+static int m25p80_erase(struct spi_nor *nor, loff_t offset)
+{
+	struct m25p *flash = nor->priv;
+
+	dev_dbg(nor->dev, "%dKiB at 0x%08x\n",
+		flash->spi_nor.mtd.erasesize / 1024, (u32)offset);
+
+	/* Set up command buffer. */
+	flash->command[0] = nor->erase_opcode;
+	m25p_addr2cmd(nor, offset, flash->command);
+
+	spi_write(flash->spi, flash->command, m25p_cmdsz(nor));
+
+	return 0;
+}
+
+/*
+ * board specific setup should have ensured the SPI clock used here
+ * matches what the READ command supports, at least until this driver
+ * understands FAST_READ (for clocks over 25 MHz).
+ */
+static int m25p_probe(struct spi_device *spi)
+{
+	struct mtd_part_parser_data	ppdata;
+	struct flash_platform_data	*data;
+	struct m25p *flash;
+	struct spi_nor *nor;
+	enum read_mode mode = SPI_NOR_NORMAL;
+	char *flash_name = NULL;
+	int ret;
+
+	data = dev_get_platdata(&spi->dev);
+
+	flash = devm_kzalloc(&spi->dev, sizeof(*flash), GFP_KERNEL);
+	if (!flash)
+		return -ENOMEM;
+
+	nor = &flash->spi_nor;
+
+	/* install the hooks */
+	nor->read = m25p80_read;
+	nor->write = m25p80_write;
+	nor->erase = m25p80_erase;
+	nor->write_reg = m25p80_write_reg;
+	nor->read_reg = m25p80_read_reg;
+
+	nor->dev = &spi->dev;
+	nor->flash_node = spi->dev.of_node;
+	nor->priv = flash;
+
+	spi_set_drvdata(spi, flash);
+	flash->spi = spi;
+
+	if (spi->mode & SPI_RX_QUAD)
+		mode = SPI_NOR_QUAD;
+	else if (spi->mode & SPI_RX_DUAL)
+		mode = SPI_NOR_DUAL;
+
+	if (data && data->name)
+		nor->mtd.name = data->name;
+
+	/* For some (historical?) reason many platforms provide two different
+	 * names in flash_platform_data: "name" and "type". Quite often name is
+	 * set to "m25p80" and then "type" provides a real chip name.
+	 * If that's the case, respect "type" and ignore a "name".
+	 */
+	if (data && data->type)
+		flash_name = data->type;
+	else
+		flash_name = spi->modalias;
+
+	ret = spi_nor_scan(nor, flash_name, mode);
+	if (ret)
+		return ret;
+
+	ppdata.of_node = spi->dev.of_node;
+
+	return mtd_device_parse_register(&nor->mtd, NULL, &ppdata,
+			data ? data->parts : NULL,
+			data ? data->nr_parts : 0);
+}
+
+
+static int m25p_remove(struct spi_device *spi)
+{
+	struct m25p	*flash = spi_get_drvdata(spi);
+
+	/* Clean up MTD stuff. */
+	return mtd_device_unregister(&flash->spi_nor.mtd);
+}
+
+/*
+ * Do NOT add to this array without reading the following:
+ *
+ * Historically, many flash devices are bound to this driver by their name. But
+ * since most of these flash are compatible to some extent, and their
+ * differences can often be differentiated by the JEDEC read-ID command, we
+ * encourage new users to add support to the spi-nor library, and simply bind
+ * against a generic string here (e.g., "jedec,spi-nor").
+ *
+ * Many flash names are kept here in this list (as well as in spi-nor.c) to
+ * keep them available as module aliases for existing platforms.
+ */
+static const struct spi_device_id m25p_ids[] = {
+	/*
+	 * Entries not used in DTs that should be safe to drop after replacing
+	 * them with "nor-jedec" in platform data.
+	 */
+	{"s25sl064a"},	{"w25x16"},	{"m25p10"},	{"m25px64"},
+
+	/*
+	 * Entries that were used in DTs without "nor-jedec" fallback and should
+	 * be kept for backward compatibility.
+	 */
+	{"at25df321a"},	{"at25df641"},	{"at26df081a"},
+	{"mr25h256"},
+	{"mx25l4005a"},	{"mx25l1606e"},	{"mx25l6405d"},	{"mx25l12805d"},
+	{"mx25l25635e"},{"mx66l51235l"},
+	{"n25q064"},	{"n25q128a11"},	{"n25q128a13"},	{"n25q512a"},
+	{"s25fl256s1"},	{"s25fl512s"},	{"s25sl12801"},	{"s25fl008k"},
+	{"s25fl064k"},
+	{"sst25vf040b"},{"sst25vf016b"},{"sst25vf032b"},{"sst25wf040"},
+	{"m25p40"},	{"m25p80"},	{"m25p16"},	{"m25p32"},
+	{"m25p64"},	{"m25p128"},
+	{"w25x80"},	{"w25x32"},	{"w25q32"},	{"w25q32dw"},
+	{"w25q80bl"},	{"w25q128"},	{"w25q256"},
+
+	/* Flashes that can't be detected using JEDEC */
+	{"m25p05-nonjedec"},	{"m25p10-nonjedec"},	{"m25p20-nonjedec"},
+	{"m25p40-nonjedec"},	{"m25p80-nonjedec"},	{"m25p16-nonjedec"},
+	{"m25p32-nonjedec"},	{"m25p64-nonjedec"},	{"m25p128-nonjedec"},
+
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, m25p_ids);
+
+static const struct of_device_id m25p_of_table[] = {
+	/*
+	 * Generic compatibility for SPI NOR that can be identified by the
+	 * JEDEC READ ID opcode (0x9F). Use this, if possible.
+	 */
+	{ .compatible = "jedec,spi-nor" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, m25p_of_table);
+
+static struct spi_driver m25p80_driver = {
+	.driver = {
+		.name	= "m25p80",
+		.of_match_table = m25p_of_table,
+	},
+	.id_table	= m25p_ids,
+	.probe	= m25p_probe,
+	.remove	= m25p_remove,
+
+	/* REVISIT: many of these chips have deep power-down modes, which
+	 * should clearly be entered on suspend() to minimize power use.
+	 * And also when they're otherwise idle...
+	 */
+};
+
+module_spi_driver(m25p80_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mike Lavender");
+MODULE_DESCRIPTION("MTD SPI driver for ST M25Pxx flash chips");