diff options
Diffstat (limited to 'kernel/drivers/mtd/devices/phram.c')
| -rw-r--r-- | kernel/drivers/mtd/devices/phram.c | 328 |
1 files changed, 328 insertions, 0 deletions
diff --git a/kernel/drivers/mtd/devices/phram.c b/kernel/drivers/mtd/devices/phram.c new file mode 100644 index 000000000..8b66e52ca --- /dev/null +++ b/kernel/drivers/mtd/devices/phram.c @@ -0,0 +1,328 @@ +/** + * 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); + + /* + * This'll catch a few races. Free the thing before returning :) + * I don't feel at all ashamed. This kind of thing is possible anyway + * with flash, but unlikely. + */ + instr->state = MTD_ERASE_DONE; + mtd_erase_callback(instr); + 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; + case 'M': + shift += 10; + 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) { + kfree(name); + parse_err("illegal start address\n"); + } + + ret = parse_num64(&len, token[2]); + if (ret) { + kfree(name); + parse_err("illegal device length\n"); + } + + ret = register_device(name, start, len); + if (!ret) + pr_info("%s device: %#llx at %#llx\n", name, len, start); + else + kfree(name); + + return ret; +} + +static int phram_param_call(const char *val, 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, 000); +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"); |