// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) ???? Jochen Schäuble <[email protected]>
* Copyright (c) 2003-2004 Joern Engel <[email protected]>
*
* 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 void 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);
}
static struct platform_driver phram_driver = {
.probe = phram_probe,
.remove_new = 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 <[email protected]>");
MODULE_DESCRIPTION("MTD driver for physical RAM");
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