drivers/mtd/devices/phram.c - third_party/linux - Git at Google

 // 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>[,<erasesize>]
  * <name> may be up to 63 characters.
  * <start>, <len>, and <erasesize> can be octal, decimal or hexadecimal.  If followed
  * by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
  * gigabytes. <erasesize> is optional and defaults to PAGE_SIZE.
  *
  * Example:
  *	phram=swap,64Mi,128Mi phram=test,900Mi,1Mi,64Ki
  */

 #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>
 #include <asm/div64.h>
 #include <linux/platform_device.h>
 #include <linux/of_address.h>
 #include <linux/of.h>

 struct phram_mtd_list {
 	struct mtd_info mtd;
 	struct list_head list;
 	bool cached;
 };

 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 int phram_map(struct phram_mtd_list *phram, phys_addr_t start, size_t len)
 {
 	void *addr = NULL;

 	if (phram->cached)
 		addr = memremap(start, len, MEMREMAP_WB);
 	else
 		addr = (void __force *)ioremap(start, len);
 	if (!addr)
 		return -EIO;

 	phram->mtd.priv = addr;

 	return 0;
 }

 static void phram_unmap(struct phram_mtd_list *phram)
 {
 	void *addr = phram->mtd.priv;

 	if (phram->cached) {
 		memunmap(addr);
 		return;
 	}

 	iounmap((void __iomem *)addr);
 }

 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);
 		phram_unmap(this);
 		kfree(this->mtd.name);
 		kfree(this);
 	}
 }

 static int register_device(struct platform_device *pdev, const char *name,
 			   phys_addr_t start, size_t len, uint32_t erasesize)
 {
 	struct device_node *np = pdev ? pdev->dev.of_node : NULL;
 	bool cached = np ? !of_property_read_bool(np, "no-map") : false;
 	struct phram_mtd_list *new;
 	int ret = -ENOMEM;

 	new = kzalloc(sizeof(*new), GFP_KERNEL);
 	if (!new)
 		goto out0;

 	new->cached = cached;

 	ret = phram_map(new, start, len);
 	if (ret) {
 		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 = erasesize;
 	new->mtd.writesize = 1;

 	mtd_set_of_node(&new->mtd, np);

 	ret = -EAGAIN;
 	if (mtd_device_register(&new->mtd, NULL, 0)) {
 		pr_err("Failed to register new device\n");
 		goto out2;
 	}

 	if (pdev)
 		platform_set_drvdata(pdev, new);
 	else
 		list_add_tail(&new->list, &phram_list);

 	return 0;

 out2:
 	phram_unmap(new);
 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>[,<erasesize>] for module case
  * - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
  * We leave 64 bytes for the device name, 20 for the address , 20 for the
  * size and 20 for the erasesize.
  * Example: phram.phram=rootfs,0xa0000000,512Mi,65536
  */
 static char phram_paramline[64 + 20 + 20 + 20];
 #endif

 static int phram_setup(const char *val)
 {
 	char buf[64 + 20 + 20 + 20], *str = buf;
 	char *token[4];
 	char *name;
 	uint64_t start;
 	uint64_t len;
 	uint64_t erasesize = PAGE_SIZE;
 	uint32_t rem;
 	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 < 4; 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;
 	}

 	if (token[3]) {
 		ret = parse_num64(&erasesize, token[3]);
 		if (ret) {
 			parse_err("illegal erasesize\n");
 			goto error;
 		}
 	}

 	if (len == 0 || erasesize == 0 || erasesize > len
 	    || erasesize > UINT_MAX) {
 		parse_err("illegal erasesize or len\n");
 		ret = -EINVAL;
 		goto error;
 	}

 	div_u64_rem(len, (uint32_t)erasesize, &rem);
 	if (rem) {
 		parse_err("len is not multiple of erasesize\n");
 		ret = -EINVAL;
 		goto error;
 	}

 	ret = register_device(NULL, name, start, len, (uint32_t)erasesize);
 	if (ret)
 		goto error;

 	pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
 	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>[,<erasesize>]\"");

 #ifdef CONFIG_OF
 static const struct of_device_id phram_of_match[] = {
 	{ .compatible = "phram" },
 	{}
 };
 MODULE_DEVICE_TABLE(of, phram_of_match);
 #endif

 static int phram_probe(struct platform_device *pdev)
 {
 	struct resource *res;

 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!res)
 		return -ENOMEM;

 	/* mtd_set_of_node() reads name from "label" */
 	return register_device(pdev, NULL, res->start, resource_size(res),
 			       PAGE_SIZE);
 }

 static int phram_remove(struct platform_device *pdev)
 {
 	struct phram_mtd_list *phram = platform_get_drvdata(pdev);

 	mtd_device_unregister(&phram->mtd);
 	phram_unmap(phram);
 	kfree(phram);

 	return 0;
 }

 static struct platform_driver phram_driver = {
 	.probe		= phram_probe,
 	.remove		= phram_remove,
 	.driver		= {
 		.name		= "phram",
 		.of_match_table	= of_match_ptr(phram_of_match),
 	},
 };

 static int __init init_phram(void)
 {
 	int ret;

 	ret = platform_driver_register(&phram_driver);
 	if (ret)
 		return ret;

 #ifndef MODULE
 	if (phram_paramline[0])
 		ret = phram_setup(phram_paramline);
 	phram_init_called = 1;
 #endif

 	if (ret)
 		platform_driver_unregister(&phram_driver);

 	return ret;
 }

 static void __exit cleanup_phram(void)
 {
 	unregister_devices();
 	platform_driver_unregister(&phram_driver);
 }

 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");
	// 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>[,<erasesize>]
	* <name> may be up to 63 characters.
	* <start>, <len>, and <erasesize> can be octal, decimal or hexadecimal. If followed
	* by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
	* gigabytes. <erasesize> is optional and defaults to PAGE_SIZE.
	*
	* Example:
	* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi,64Ki
	*/

	#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>
	#include <asm/div64.h>
	#include <linux/platform_device.h>
	#include <linux/of_address.h>
	#include <linux/of.h>

	struct phram_mtd_list {
	struct mtd_info mtd;
	struct list_head list;
	bool cached;
	};

	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 int phram_map(struct phram_mtd_list *phram, phys_addr_t start, size_t len)
	{
	void *addr = NULL;

	if (phram->cached)
	addr = memremap(start, len, MEMREMAP_WB);
	else
	addr = (void __force *)ioremap(start, len);
	if (!addr)
	return -EIO;

	phram->mtd.priv = addr;

	return 0;
	}

	static void phram_unmap(struct phram_mtd_list *phram)
	{
	void *addr = phram->mtd.priv;

	if (phram->cached) {
	memunmap(addr);
	return;
	}

	iounmap((void __iomem *)addr);
	}

	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);
	phram_unmap(this);
	kfree(this->mtd.name);
	kfree(this);
	}
	}

	static int register_device(struct platform_device pdev, const char name,
	phys_addr_t start, size_t len, uint32_t erasesize)
	{
	struct device_node *np = pdev ? pdev->dev.of_node : NULL;
	bool cached = np ? !of_property_read_bool(np, "no-map") : false;
	struct phram_mtd_list *new;
	int ret = -ENOMEM;

	new = kzalloc(sizeof(*new), GFP_KERNEL);
	if (!new)
	goto out0;

	new->cached = cached;

	ret = phram_map(new, start, len);
	if (ret) {
	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 = erasesize;
	new->mtd.writesize = 1;

	mtd_set_of_node(&new->mtd, np);

	ret = -EAGAIN;
	if (mtd_device_register(&new->mtd, NULL, 0)) {
	pr_err("Failed to register new device\n");
	goto out2;
	}

	if (pdev)
	platform_set_drvdata(pdev, new);
	else
	list_add_tail(&new->list, &phram_list);

	return 0;

	out2:
	phram_unmap(new);
	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>[,<erasesize>] for module case
	* - phram.phram=<device>,<address>,<size>[,<erasesize>] for built-in case
	* We leave 64 bytes for the device name, 20 for the address , 20 for the
	* size and 20 for the erasesize.
	* Example: phram.phram=rootfs,0xa0000000,512Mi,65536
	*/
	static char phram_paramline[64 + 20 + 20 + 20];
	#endif

	static int phram_setup(const char *val)
	{
	char buf[64 + 20 + 20 + 20], *str = buf;
	char *token[4];
	char *name;
	uint64_t start;
	uint64_t len;
	uint64_t erasesize = PAGE_SIZE;
	uint32_t rem;
	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 < 4; 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;
	}

	if (token[3]) {
	ret = parse_num64(&erasesize, token[3]);
	if (ret) {
	parse_err("illegal erasesize\n");
	goto error;
	}
	}

	if (len == 0 \|\| erasesize == 0 \|\| erasesize > len
	\|\| erasesize > UINT_MAX) {
	parse_err("illegal erasesize or len\n");
	ret = -EINVAL;
	goto error;
	}

	div_u64_rem(len, (uint32_t)erasesize, &rem);
	if (rem) {
	parse_err("len is not multiple of erasesize\n");
	ret = -EINVAL;
	goto error;
	}

	ret = register_device(NULL, name, start, len, (uint32_t)erasesize);
	if (ret)
	goto error;

	pr_info("%s device: %#llx at %#llx for erasesize %#llx\n", name, len, start, erasesize);
	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>[,<erasesize>]\"");

	#ifdef CONFIG_OF
	static const struct of_device_id phram_of_match[] = {
	{ .compatible = "phram" },
	{}
	};
	MODULE_DEVICE_TABLE(of, phram_of_match);
	#endif

	static int phram_probe(struct platform_device *pdev)
	{
	struct resource *res;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	if (!res)
	return -ENOMEM;

	/* mtd_set_of_node() reads name from "label" */
	return register_device(pdev, NULL, res->start, resource_size(res),
	PAGE_SIZE);
	}

	static int phram_remove(struct platform_device *pdev)
	{
	struct phram_mtd_list *phram = platform_get_drvdata(pdev);

	mtd_device_unregister(&phram->mtd);
	phram_unmap(phram);
	kfree(phram);

	return 0;
	}

	static struct platform_driver phram_driver = {
	.probe = phram_probe,
	.remove = phram_remove,
	.driver = {
	.name = "phram",
	.of_match_table = of_match_ptr(phram_of_match),
	},
	};

	static int __init init_phram(void)
	{
	int ret;

	ret = platform_driver_register(&phram_driver);
	if (ret)
	return ret;

	#ifndef MODULE
	if (phram_paramline[0])
	ret = phram_setup(phram_paramline);
	phram_init_called = 1;
	#endif

	if (ret)
	platform_driver_unregister(&phram_driver);

	return ret;
	}

	static void __exit cleanup_phram(void)
	{
	unregister_devices();
	platform_driver_unregister(&phram_driver);
	}

	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");