mtd: lpddr: add driver for LPDDR2-NVM PCM memories

Signed-off-by: Vincenzo Aliberti <vincenzo.aliberti@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/lpddr/Kconfig

-menu "LPDDR flash memory drivers"
-	depends on MTD!=n
+menu "LPDDR & LPDDR2 PCM memory drivers"
+	depends on MTD
 
 config MTD_LPDDR
 	tristate "Support for LPDDR flash chips"
@@ -17,4 +17,12 @@ config MTD_QINFO_PROBE
 	    Window QINFO interface, permits software to be used for entire
 	    families of devices. This serves similar purpose of CFI on legacy
 	    Flash products
+
+config MTD_LPDDR2_NVM
+	depends on MTD
+	tristate "Support for LPDDR2-NVM flash chips"
+	help
+	  This option enables support of PCM memories with a LPDDR2-NVM
+	  (Low power double data rate 2) interface.
+
 endmenu

drivers/mtd/lpddr/Makefile

@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_MTD_QINFO_PROBE)	+= qinfo_probe.o
 obj-$(CONFIG_MTD_LPDDR)	+= lpddr_cmds.o
+obj-$(CONFIG_MTD_LPDDR2_NVM) += lpddr2_nvm.o

drivers/mtd/lpddr/lpddr2_nvm.c

+/*
+ * LPDDR2-NVM MTD driver. This module provides read, write, erase, lock/unlock
+ * support for LPDDR2-NVM PCM memories
+ *
+ * Copyright © 2012 Micron Technology, Inc.
+ *
+ * Vincenzo Aliberti <vincenzo.aliberti@gmail.com>
+ * Domenico Manna <domenico.manna@gmail.com>
+ * Many thanks to Andrea Vigilante for initial enabling
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/ioport.h>
+#include <linux/err.h>
+
+/* Parameters */
+#define ERASE_BLOCKSIZE			(0x00020000/2)	/* in Word */
+#define WRITE_BUFFSIZE			(0x00000400/2)	/* in Word */
+#define OW_BASE_ADDRESS			0x00000000	/* OW offset */
+#define BUS_WIDTH			0x00000020	/* x32 devices */
+
+/* PFOW symbols address offset */
+#define PFOW_QUERY_STRING_P		(0x0000/2)	/* in Word */
+#define PFOW_QUERY_STRING_F		(0x0002/2)	/* in Word */
+#define PFOW_QUERY_STRING_O		(0x0004/2)	/* in Word */
+#define PFOW_QUERY_STRING_W		(0x0006/2)	/* in Word */
+
+/* OW registers address */
+#define CMD_CODE_OFS			(0x0080/2)	/* in Word */
+#define CMD_DATA_OFS			(0x0084/2)	/* in Word */
+#define CMD_ADD_L_OFS			(0x0088/2)	/* in Word */
+#define CMD_ADD_H_OFS			(0x008A/2)	/* in Word */
+#define MPR_L_OFS			(0x0090/2)	/* in Word */
+#define MPR_H_OFS			(0x0092/2)	/* in Word */
+#define CMD_EXEC_OFS			(0x00C0/2)	/* in Word */
+#define STATUS_REG_OFS			(0x00CC/2)	/* in Word */
+#define PRG_BUFFER_OFS			(0x0010/2)	/* in Word */
+
+/* Datamask */
+#define MR_CFGMASK			0x8000
+#define SR_OK_DATAMASK			0x0080
+
+/* LPDDR2-NVM Commands */
+#define LPDDR2_NVM_LOCK			0x0061
+#define LPDDR2_NVM_UNLOCK		0x0062
+#define LPDDR2_NVM_SW_PROGRAM		0x0041
+#define LPDDR2_NVM_SW_OVERWRITE		0x0042
+#define LPDDR2_NVM_BUF_PROGRAM		0x00E9
+#define LPDDR2_NVM_BUF_OVERWRITE	0x00EA
+#define LPDDR2_NVM_ERASE		0x0020
+
+/* LPDDR2-NVM Registers offset */
+#define LPDDR2_MODE_REG_DATA		0x0040
+#define LPDDR2_MODE_REG_CFG		0x0050
+
+/*
+ * Internal Type Definitions
+ * pcm_int_data contains memory controller details:
+ * @reg_data : LPDDR2_MODE_REG_DATA register address after remapping
+ * @reg_cfg  : LPDDR2_MODE_REG_CFG register address after remapping
+ * &bus_width: memory bus-width (eg: x16 2 Bytes, x32 4 Bytes)
+ */
+struct pcm_int_data {
+	void __iomem *ctl_regs;
+	int bus_width;
+};
+
+static DEFINE_MUTEX(lpdd2_nvm_mutex);
+
+/*
+ * Build a map_word starting from an u_long
+ */
+static inline map_word build_map_word(u_long myword)
+{
+	map_word val = { {0} };
+	val.x[0] = myword;
+	return val;
+}
+
+/*
+ * Build Mode Register Configuration DataMask based on device bus-width
+ */
+static inline u_int build_mr_cfgmask(u_int bus_width)
+{
+	u_int val = MR_CFGMASK;
+
+	if (bus_width == 0x0004)		/* x32 device */
+		val = val << 16;
+
+	return val;
+}
+
+/*
+ * Build Status Register OK DataMask based on device bus-width
+ */
+static inline u_int build_sr_ok_datamask(u_int bus_width)
+{
+	u_int val = SR_OK_DATAMASK;
+
+	if (bus_width == 0x0004)		/* x32 device */
+		val = (val << 16)+val;
+
+	return val;
+}
+
+/*
+ * Evaluates Overlay Window Control Registers address
+ */
+static inline u_long ow_reg_add(struct map_info *map, u_long offset)
+{
+	u_long val = 0;
+	struct pcm_int_data *pcm_data = map->fldrv_priv;
+
+	val = map->pfow_base + offset*pcm_data->bus_width;
+
+	return val;
+}
+
+/*
+ * Enable lpddr2-nvm Overlay Window
+ * Overlay Window is a memory mapped area containing all LPDDR2-NVM registers
+ * used by device commands as well as uservisible resources like Device Status
+ * Register, Device ID, etc
+ */
+static inline void ow_enable(struct map_info *map)
+{
+	struct pcm_int_data *pcm_data = map->fldrv_priv;
+
+	writel_relaxed(build_mr_cfgmask(pcm_data->bus_width) | 0x18,
+		pcm_data->ctl_regs + LPDDR2_MODE_REG_CFG);
+	writel_relaxed(0x01, pcm_data->ctl_regs + LPDDR2_MODE_REG_DATA);
+}
+
+/*
+ * Disable lpddr2-nvm Overlay Window
+ * Overlay Window is a memory mapped area containing all LPDDR2-NVM registers
+ * used by device commands as well as uservisible resources like Device Status
+ * Register, Device ID, etc
+ */
+static inline void ow_disable(struct map_info *map)
+{
+	struct pcm_int_data *pcm_data = map->fldrv_priv;
+
+	writel_relaxed(build_mr_cfgmask(pcm_data->bus_width) | 0x18,
+		pcm_data->ctl_regs + LPDDR2_MODE_REG_CFG);
+	writel_relaxed(0x02, pcm_data->ctl_regs + LPDDR2_MODE_REG_DATA);
+}
+
+/*
+ * Execute lpddr2-nvm operations
+ */
+static int lpddr2_nvm_do_op(struct map_info *map, u_long cmd_code,
+	u_long cmd_data, u_long cmd_add, u_long cmd_mpr, u_char *buf)
+{
+	map_word add_l = { {0} }, add_h = { {0} }, mpr_l = { {0} },
+		mpr_h = { {0} }, data_l = { {0} }, cmd = { {0} },
+		exec_cmd = { {0} }, sr;
+	map_word data_h = { {0} };	/* only for 2x x16 devices stacked */
+	u_long i, status_reg, prg_buff_ofs;
+	struct pcm_int_data *pcm_data = map->fldrv_priv;
+	u_int sr_ok_datamask = build_sr_ok_datamask(pcm_data->bus_width);
+
+	/* Builds low and high words for OW Control Registers */
+	add_l.x[0]	= cmd_add & 0x0000FFFF;
+	add_h.x[0]	= (cmd_add >> 16) & 0x0000FFFF;
+	mpr_l.x[0]	= cmd_mpr & 0x0000FFFF;
+	mpr_h.x[0]	= (cmd_mpr >> 16) & 0x0000FFFF;
+	cmd.x[0]	= cmd_code & 0x0000FFFF;
+	exec_cmd.x[0]	= 0x0001;
+	data_l.x[0]	= cmd_data & 0x0000FFFF;
+	data_h.x[0]	= (cmd_data >> 16) & 0x0000FFFF; /* only for 2x x16 */
+
+	/* Set Overlay Window Control Registers */
+	map_write(map, cmd, ow_reg_add(map, CMD_CODE_OFS));
+	map_write(map, data_l, ow_reg_add(map, CMD_DATA_OFS));
+	map_write(map, add_l, ow_reg_add(map, CMD_ADD_L_OFS));
+	map_write(map, add_h, ow_reg_add(map, CMD_ADD_H_OFS));
+	map_write(map, mpr_l, ow_reg_add(map, MPR_L_OFS));
+	map_write(map, mpr_h, ow_reg_add(map, MPR_H_OFS));
+	if (pcm_data->bus_width == 0x0004) {	/* 2x16 devices stacked */
+		map_write(map, cmd, ow_reg_add(map, CMD_CODE_OFS) + 2);
+		map_write(map, data_h, ow_reg_add(map, CMD_DATA_OFS) + 2);
+		map_write(map, add_l, ow_reg_add(map, CMD_ADD_L_OFS) + 2);
+		map_write(map, add_h, ow_reg_add(map, CMD_ADD_H_OFS) + 2);
+		map_write(map, mpr_l, ow_reg_add(map, MPR_L_OFS) + 2);
+		map_write(map, mpr_h, ow_reg_add(map, MPR_H_OFS) + 2);
+	}
+
+	/* Fill Program Buffer */
+	if ((cmd_code == LPDDR2_NVM_BUF_PROGRAM) ||
+		(cmd_code == LPDDR2_NVM_BUF_OVERWRITE)) {
+		prg_buff_ofs = (map_read(map,
+			ow_reg_add(map, PRG_BUFFER_OFS))).x[0];
+		for (i = 0; i < cmd_mpr; i++) {
+			map_write(map, build_map_word(buf[i]), map->pfow_base +
+			prg_buff_ofs + i);
+		}
+	}
+
+	/* Command Execute */
+	map_write(map, exec_cmd, ow_reg_add(map, CMD_EXEC_OFS));
+	if (pcm_data->bus_width == 0x0004)	/* 2x16 devices stacked */
+		map_write(map, exec_cmd, ow_reg_add(map, CMD_EXEC_OFS) + 2);
+
+	/* Status Register Check */
+	do {
+		sr = map_read(map, ow_reg_add(map, STATUS_REG_OFS));
+		status_reg = sr.x[0];
+		if (pcm_data->bus_width == 0x0004) {/* 2x16 devices stacked */
+			sr = map_read(map, ow_reg_add(map,
+				STATUS_REG_OFS) + 2);
+			status_reg += sr.x[0] << 16;
+		}
+	} while ((status_reg & sr_ok_datamask) != sr_ok_datamask);
+
+	return (((status_reg & sr_ok_datamask) == sr_ok_datamask) ? 0 : -EIO);
+}
+
+/*
+ * Execute lpddr2-nvm operations @ block level
+ */
+static int lpddr2_nvm_do_block_op(struct mtd_info *mtd, loff_t start_add,
+	uint64_t len, u_char block_op)
+{
+	struct map_info *map = mtd->priv;
+	u_long add, end_add;
+	int ret = 0;
+
+	mutex_lock(&lpdd2_nvm_mutex);
+
+	ow_enable(map);
+
+	add = start_add;
+	end_add = add + len;
+
+	do {
+		ret = lpddr2_nvm_do_op(map, block_op, 0x00, add, add, NULL);
+		if (ret)
+			goto out;
+		add += mtd->erasesize;
+	} while (add < end_add);
+
+out:
+	ow_disable(map);
+	mutex_unlock(&lpdd2_nvm_mutex);
+	return ret;
+}
+
+/*
+ * verify presence of PFOW string
+ */
+static int lpddr2_nvm_pfow_present(struct map_info *map)
+{
+	map_word pfow_val[4];
+	unsigned int found = 1;
+
+	mutex_lock(&lpdd2_nvm_mutex);
+
+	ow_enable(map);
+
+	/* Load string from array */
+	pfow_val[0] = map_read(map, ow_reg_add(map, PFOW_QUERY_STRING_P));
+	pfow_val[1] = map_read(map, ow_reg_add(map, PFOW_QUERY_STRING_F));
+	pfow_val[2] = map_read(map, ow_reg_add(map, PFOW_QUERY_STRING_O));
+	pfow_val[3] = map_read(map, ow_reg_add(map, PFOW_QUERY_STRING_W));
+
+	/* Verify the string loaded vs expected */
+	if (!map_word_equal(map, build_map_word('P'), pfow_val[0]))
+		found = 0;
+	if (!map_word_equal(map, build_map_word('F'), pfow_val[1]))
+		found = 0;
+	if (!map_word_equal(map, build_map_word('O'), pfow_val[2]))
+		found = 0;
+	if (!map_word_equal(map, build_map_word('W'), pfow_val[3]))
+		found = 0;
+
+	ow_disable(map);
+
+	mutex_unlock(&lpdd2_nvm_mutex);
+
+	return found;
+}
+
+/*
+ * lpddr2_nvm driver read method
+ */
+static int lpddr2_nvm_read(struct mtd_info *mtd, loff_t start_add,
+				size_t len, size_t *retlen, u_char *buf)
+{
+	struct map_info *map = mtd->priv;
+
+	mutex_lock(&lpdd2_nvm_mutex);
+
+	*retlen = len;
+
+	map_copy_from(map, buf, start_add, *retlen);
+
+	mutex_unlock(&lpdd2_nvm_mutex);
+	return 0;
+}
+
+/*
+ * lpddr2_nvm driver write method
+ */
+static int lpddr2_nvm_write(struct mtd_info *mtd, loff_t start_add,
+				size_t len, size_t *retlen, const u_char *buf)
+{
+	struct map_info *map = mtd->priv;
+	struct pcm_int_data *pcm_data = map->fldrv_priv;
+	u_long add, current_len, tot_len, target_len, my_data;
+	u_char *write_buf = (u_char *)buf;
+	int ret = 0;
+
+	mutex_lock(&lpdd2_nvm_mutex);
+
+	ow_enable(map);
+
+	/* Set start value for the variables */
+	add = start_add;
+	target_len = len;
+	tot_len = 0;
+
+	while (tot_len < target_len) {
+		if (!(IS_ALIGNED(add, mtd->writesize))) { /* do sw program */
+			my_data = write_buf[tot_len];
+			my_data += (write_buf[tot_len+1]) << 8;
+			if (pcm_data->bus_width == 0x0004) {/* 2x16 devices */
+				my_data += (write_buf[tot_len+2]) << 16;
+				my_data += (write_buf[tot_len+3]) << 24;
+			}
+			ret = lpddr2_nvm_do_op(map, LPDDR2_NVM_SW_OVERWRITE,
+				my_data, add, 0x00, NULL);
+			if (ret)
+				goto out;
+
+			add += pcm_data->bus_width;
+			tot_len += pcm_data->bus_width;
+		} else {		/* do buffer program */
+			current_len = min(target_len - tot_len,
+				(u_long) mtd->writesize);
+			ret = lpddr2_nvm_do_op(map, LPDDR2_NVM_BUF_OVERWRITE,
+				0x00, add, current_len, write_buf + tot_len);
+			if (ret)
+				goto out;
+
+			add += current_len;
+			tot_len += current_len;
+		}
+	}
+
+out:
+	*retlen = tot_len;
+	ow_disable(map);
+	mutex_unlock(&lpdd2_nvm_mutex);
+	return ret;
+}
+
+/*
+ * lpddr2_nvm driver erase method
+ */
+static int lpddr2_nvm_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+	int ret = lpddr2_nvm_do_block_op(mtd, instr->addr, instr->len,
+		LPDDR2_NVM_ERASE);
+	if (!ret) {
+		instr->state = MTD_ERASE_DONE;
+		mtd_erase_callback(instr);
+	}
+
+	return ret;
+}
+
+/*
+ * lpddr2_nvm driver unlock method
+ */
+static int lpddr2_nvm_unlock(struct mtd_info *mtd, loff_t start_add,
+	uint64_t len)
+{
+	return lpddr2_nvm_do_block_op(mtd, start_add, len, LPDDR2_NVM_UNLOCK);
+}
+
+/*
+ * lpddr2_nvm driver lock method
+ */
+static int lpddr2_nvm_lock(struct mtd_info *mtd, loff_t start_add,
+	uint64_t len)
+{
+	return lpddr2_nvm_do_block_op(mtd, start_add, len, LPDDR2_NVM_LOCK);
+}
+
+/*
+ * lpddr2_nvm driver probe method
+ */
+static int lpddr2_nvm_probe(struct platform_device *pdev)
+{
+	struct map_info *map;
+	struct mtd_info *mtd;
+	struct resource *add_range;
+	struct resource *control_regs;
+	struct pcm_int_data *pcm_data;
+
+	/* Allocate memory control_regs data structures */
+	pcm_data = devm_kzalloc(&pdev->dev, sizeof(*pcm_data), GFP_KERNEL);
+	if (!pcm_data)
+		return -ENOMEM;
+
+	pcm_data->bus_width = BUS_WIDTH;
+
+	/* Allocate memory for map_info & mtd_info data structures */
+	map = devm_kzalloc(&pdev->dev, sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+
+	mtd = devm_kzalloc(&pdev->dev, sizeof(*mtd), GFP_KERNEL);
+	if (!mtd)
+		return -ENOMEM;
+
+	/* lpddr2_nvm address range */
+	add_range = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+
+	/* Populate map_info data structure */
+	*map = (struct map_info) {
+		.virt		= devm_ioremap_resource(&pdev->dev, add_range),
+		.name		= pdev->dev.init_name,
+		.phys		= add_range->start,
+		.size		= resource_size(add_range),
+		.bankwidth	= pcm_data->bus_width / 2,
+		.pfow_base	= OW_BASE_ADDRESS,
+		.fldrv_priv	= pcm_data,
+	};
+	if (IS_ERR(map->virt))
+		return PTR_ERR(map->virt);
+
+	simple_map_init(map);	/* fill with default methods */
+
+	control_regs = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	pcm_data->ctl_regs = devm_ioremap_resource(&pdev->dev, control_regs);
+	if (IS_ERR(pcm_data->ctl_regs))
+		return PTR_ERR(pcm_data->ctl_regs);
+
+	/* Populate mtd_info data structure */
+	*mtd = (struct mtd_info) {
+		.name		= pdev->dev.init_name,
+		.type		= MTD_RAM,
+		.priv		= map,
+		.size		= resource_size(add_range),
+		.erasesize	= ERASE_BLOCKSIZE * pcm_data->bus_width,
+		.writesize	= 1,
+		.writebufsize	= WRITE_BUFFSIZE * pcm_data->bus_width,
+		.flags		= (MTD_CAP_NVRAM | MTD_POWERUP_LOCK),
+		._read		= lpddr2_nvm_read,
+		._write		= lpddr2_nvm_write,
+		._erase		= lpddr2_nvm_erase,
+		._unlock	= lpddr2_nvm_unlock,
+		._lock		= lpddr2_nvm_lock,
+	};
+
+	/* Verify the presence of the device looking for PFOW string */
+	if (!lpddr2_nvm_pfow_present(map)) {
+		pr_err("device not recognized\n");
+		return -EINVAL;
+	}
+	/* Parse partitions and register the MTD device */
+	return mtd_device_parse_register(mtd, NULL, NULL, NULL, 0);
+}
+
+/*
+ * lpddr2_nvm driver remove method
+ */
+static int lpddr2_nvm_remove(struct platform_device *pdev)
+{
+	return mtd_device_unregister(dev_get_drvdata(&pdev->dev));
+}
+
+/* Initialize platform_driver data structure for lpddr2_nvm */
+static struct platform_driver lpddr2_nvm_drv = {
+	.driver		= {
+		.name	= "lpddr2_nvm",
+	},
+	.probe		= lpddr2_nvm_probe,
+	.remove		= lpddr2_nvm_remove,
+};
+
+module_platform_driver(lpddr2_nvm_drv);
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Vincenzo Aliberti <vincenzo.aliberti@gmail.com>");
+MODULE_DESCRIPTION("MTD driver for LPDDR2-NVM PCM memories");

include/uapi/mtd/mtd-abi.h

@@ -109,6 +109,7 @@ struct mtd_write_req {
 #define MTD_CAP_RAM		(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE)
 #define MTD_CAP_NORFLASH	(MTD_WRITEABLE | MTD_BIT_WRITEABLE)
 #define MTD_CAP_NANDFLASH	(MTD_WRITEABLE)
+#define MTD_CAP_NVRAM		(MTD_WRITEABLE | MTD_BIT_WRITEABLE | MTD_NO_ERASE)
 
 /* Obsolete ECC byte placement modes (used with obsolete MEMGETOOBSEL) */
 #define MTD_NANDECC_OFF		0	// Switch off ECC (Not recommended)