1 files changed, 327 insertions, 0 deletions
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
new file mode 100644
index 000000000..087b5e86d
--- /dev/null
+++ b/drivers/mtd/devices/phram.c
@@ -0,0 +1,327 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/**
+ * Copyright (c) ????		Jochen Schäuble <psionic@psionic.de>
+ * Copyright (c) 2003-2004	Joern Engel <joern@wh.fh-wedel.de>
+ *
+ * Usage:
+ *
+ * one commend line parameter per device, each in the form:
+ *   phram=<name>,<start>,<len>
+ * <name> may be up to 63 characters.
+ * <start> and <len> can be octal, decimal or hexadecimal.  If followed
+ * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
+ * gigabytes.
+ *
+ * Example:
+ *	phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+
+struct phram_mtd_list {
+	struct mtd_info mtd;
+	struct list_head list;
+};
+
+static LIST_HEAD(phram_list);
+
+static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
+{
+	u_char *start = mtd->priv;
+
+	memset(start + instr->addr, 0xff, instr->len);
+
+	return 0;
+}
+
+static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
+		size_t *retlen, void **virt, resource_size_t *phys)
+{
+	*virt = mtd->priv + from;
+	*retlen = len;
+	return 0;
+}
+
+static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
+{
+	return 0;
+}
+
+static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
+		size_t *retlen, u_char *buf)
+{
+	u_char *start = mtd->priv;
+
+	memcpy(buf, start + from, len);
+	*retlen = len;
+	return 0;
+}
+
+static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
+		size_t *retlen, const u_char *buf)
+{
+	u_char *start = mtd->priv;
+
+	memcpy(start + to, buf, len);
+	*retlen = len;
+	return 0;
+}
+
+static void unregister_devices(void)
+{
+	struct phram_mtd_list *this, *safe;
+
+	list_for_each_entry_safe(this, safe, &phram_list, list) {
+		mtd_device_unregister(&this->mtd);
+		iounmap(this->mtd.priv);
+		kfree(this->mtd.name);
+		kfree(this);
+	}
+}
+
+static int register_device(char *name, phys_addr_t start, size_t len)
+{
+	struct phram_mtd_list *new;
+	int ret = -ENOMEM;
+
+	new = kzalloc(sizeof(*new), GFP_KERNEL);
+	if (!new)
+		goto out0;
+
+	ret = -EIO;
+	new->mtd.priv = ioremap(start, len);
+	if (!new->mtd.priv) {
+		pr_err("ioremap failed\n");
+		goto out1;
+	}
+
+
+	new->mtd.name = name;
+	new->mtd.size = len;
+	new->mtd.flags = MTD_CAP_RAM;
+	new->mtd._erase = phram_erase;
+	new->mtd._point = phram_point;
+	new->mtd._unpoint = phram_unpoint;
+	new->mtd._read = phram_read;
+	new->mtd._write = phram_write;
+	new->mtd.owner = THIS_MODULE;
+	new->mtd.type = MTD_RAM;
+	new->mtd.erasesize = PAGE_SIZE;
+	new->mtd.writesize = 1;
+
+	ret = -EAGAIN;
+	if (mtd_device_register(&new->mtd, NULL, 0)) {
+		pr_err("Failed to register new device\n");
+		goto out2;
+	}
+
+	list_add_tail(&new->list, &phram_list);
+	return 0;
+
+out2:
+	iounmap(new->mtd.priv);
+out1:
+	kfree(new);
+out0:
+	return ret;
+}
+
+static int parse_num64(uint64_t *num64, char *token)
+{
+	size_t len;
+	int shift = 0;
+	int ret;
+
+	len = strlen(token);
+	/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
+	if (len > 2) {
+		if (token[len - 1] == 'i') {
+			switch (token[len - 2]) {
+			case 'G':
+				shift += 10;
+				fallthrough;
+			case 'M':
+				shift += 10;
+				fallthrough;
+			case 'k':
+				shift += 10;
+				token[len - 2] = 0;
+				break;
+			default:
+				return -EINVAL;
+			}
+		}
+	}
+
+	ret = kstrtou64(token, 0, num64);
+	*num64 <<= shift;
+
+	return ret;
+}
+
+static int parse_name(char **pname, const char *token)
+{
+	size_t len;
+	char *name;
+
+	len = strlen(token) + 1;
+	if (len > 64)
+		return -ENOSPC;
+
+	name = kstrdup(token, GFP_KERNEL);
+	if (!name)
+		return -ENOMEM;
+
+	*pname = name;
+	return 0;
+}
+
+
+static inline void kill_final_newline(char *str)
+{
+	char *newline = strrchr(str, '\n');
+
+	if (newline && !newline[1])
+		*newline = 0;
+}
+
+
+#define parse_err(fmt, args...) do {	\
+	pr_err(fmt , ## args);	\
+	return 1;		\
+} while (0)
+
+#ifndef MODULE
+static int phram_init_called;
+/*
+ * This shall contain the module parameter if any. It is of the form:
+ * - phram=<device>,<address>,<size> for module case
+ * - phram.phram=<device>,<address>,<size> for built-in case
+ * We leave 64 bytes for the device name, 20 for the address and 20 for the
+ * size.
+ * Example: phram.phram=rootfs,0xa0000000,512Mi
+ */
+static char phram_paramline[64 + 20 + 20];
+#endif
+
+static int phram_setup(const char *val)
+{
+	char buf[64 + 20 + 20], *str = buf;
+	char *token[3];
+	char *name;
+	uint64_t start;
+	uint64_t len;
+	int i, ret;
+
+	if (strnlen(val, sizeof(buf)) >= sizeof(buf))
+		parse_err("parameter too long\n");
+
+	strcpy(str, val);
+	kill_final_newline(str);
+
+	for (i = 0; i < 3; i++)
+		token[i] = strsep(&str, ",");
+
+	if (str)
+		parse_err("too many arguments\n");
+
+	if (!token[2])
+		parse_err("not enough arguments\n");
+
+	ret = parse_name(&name, token[0]);
+	if (ret)
+		return ret;
+
+	ret = parse_num64(&start, token[1]);
+	if (ret) {
+		parse_err("illegal start address\n");
+		goto error;
+	}
+
+	ret = parse_num64(&len, token[2]);
+	if (ret) {
+		parse_err("illegal device length\n");
+		goto error;
+	}
+
+	ret = register_device(name, start, len);
+	if (ret)
+		goto error;
+
+	pr_info("%s device: %#llx at %#llx\n", name, len, start);
+	return 0;
+
+error:
+	kfree(name);
+	return ret;
+}
+
+static int phram_param_call(const char *val, const struct kernel_param *kp)
+{
+#ifdef MODULE
+	return phram_setup(val);
+#else
+	/*
+	 * If more parameters are later passed in via
+	 * /sys/module/phram/parameters/phram
+	 * and init_phram() has already been called,
+	 * we can parse the argument now.
+	 */
+
+	if (phram_init_called)
+		return phram_setup(val);
+
+	/*
+	 * During early boot stage, we only save the parameters
+	 * here. We must parse them later: if the param passed
+	 * from kernel boot command line, phram_param_call() is
+	 * called so early that it is not possible to resolve
+	 * the device (even kmalloc() fails). Defer that work to
+	 * phram_setup().
+	 */
+
+	if (strlen(val) >= sizeof(phram_paramline))
+		return -ENOSPC;
+	strcpy(phram_paramline, val);
+
+	return 0;
+#endif
+}
+
+module_param_call(phram, phram_param_call, NULL, NULL, 0200);
+MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
+
+
+static int __init init_phram(void)
+{
+	int ret = 0;
+
+#ifndef MODULE
+	if (phram_paramline[0])
+		ret = phram_setup(phram_paramline);
+	phram_init_called = 1;
+#endif
+
+	return ret;
+}
+
+static void __exit cleanup_phram(void)
+{
+	unregister_devices();
+}
+
+module_init(init_phram);
+module_exit(cleanup_phram);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
+MODULE_DESCRIPTION("MTD driver for physical RAM");