diff options
Diffstat (limited to 'drivers/mtd/devices/phram.c')
| -rw-r--r-- | drivers/mtd/devices/phram.c | 285 |
1 files changed, 285 insertions, 0 deletions
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c new file mode 100644 index 00000000000..5f8e164ddb7 --- /dev/null +++ b/drivers/mtd/devices/phram.c @@ -0,0 +1,285 @@ +/** + * $Id: phram.c,v 1.11 2005/01/05 18:05:13 dwmw2 Exp $ + * + * Copyright (c) ???? Jochen Schäuble <psionic@psionic.de> + * Copyright (c) 2003-2004 Jörn 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 + * + */ + +#include <asm/io.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> +#include <linux/moduleparam.h> +#include <linux/mtd/mtd.h> + +#define ERROR(fmt, args...) printk(KERN_ERR "phram: " fmt , ## args) + +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; + + if (instr->addr + instr->len > mtd->size) + return -EINVAL; + + 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, u_char **mtdbuf) +{ + u_char *start = mtd->priv; + + if (from + len > mtd->size) + return -EINVAL; + + *mtdbuf = start + from; + *retlen = len; + return 0; +} + +static void phram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len) +{ +} + +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; + + if (from + len > mtd->size) + return -EINVAL; + + 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; + + if (to + len > mtd->size) + return -EINVAL; + + memcpy(start + to, buf, len); + + *retlen = len; + return 0; +} + + + +static void unregister_devices(void) +{ + struct phram_mtd_list *this; + + list_for_each_entry(this, &phram_list, list) { + del_mtd_device(&this->mtd); + iounmap(this->mtd.priv); + kfree(this); + } +} + +static int register_device(char *name, unsigned long start, unsigned long len) +{ + struct phram_mtd_list *new; + int ret = -ENOMEM; + + new = kmalloc(sizeof(*new), GFP_KERNEL); + if (!new) + goto out0; + + memset(new, 0, sizeof(*new)); + + ret = -EIO; + new->mtd.priv = ioremap(start, len); + if (!new->mtd.priv) { + ERROR("ioremap failed\n"); + goto out1; + } + + + new->mtd.name = name; + new->mtd.size = len; + new->mtd.flags = MTD_CAP_RAM | MTD_ERASEABLE | MTD_VOLATILE; + 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 = 0; + + ret = -EAGAIN; + if (add_mtd_device(&new->mtd)) { + ERROR("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 ustrtoul(const char *cp, char **endp, unsigned int base) +{ + unsigned long result = simple_strtoul(cp, endp, base); + + switch (**endp) { + case 'G': + result *= 1024; + case 'M': + result *= 1024; + case 'k': + result *= 1024; + /* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */ + if ((*endp)[1] == 'i') + (*endp) += 2; + } + return result; +} + +static int parse_num32(uint32_t *num32, const char *token) +{ + char *endp; + unsigned long n; + + n = ustrtoul(token, &endp, 0); + if (*endp) + return -EINVAL; + + *num32 = n; + return 0; +} + +static int parse_name(char **pname, const char *token) +{ + size_t len; + char *name; + + len = strlen(token) + 1; + if (len > 64) + return -ENOSPC; + + name = kmalloc(len, GFP_KERNEL); + if (!name) + return -ENOMEM; + + strcpy(name, token); + + *pname = name; + return 0; +} + +#define parse_err(fmt, args...) do { \ + ERROR(fmt , ## args); \ + return 0; \ +} while (0) + +static int phram_setup(const char *val, struct kernel_param *kp) +{ + char buf[64+12+12], *str = buf; + char *token[3]; + char *name; + uint32_t start; + uint32_t len; + int i, ret; + + if (strnlen(val, sizeof(buf)) >= sizeof(buf)) + parse_err("parameter too long\n"); + + strcpy(str, val); + + 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 == -ENOMEM) + parse_err("out of memory\n"); + if (ret == -ENOSPC) + parse_err("name too long\n"); + if (ret) + return 0; + + ret = parse_num32(&start, token[1]); + if (ret) + parse_err("illegal start address\n"); + + ret = parse_num32(&len, token[2]); + if (ret) + parse_err("illegal device length\n"); + + register_device(name, start, len); + + return 0; +} + +module_param_call(phram, phram_setup, NULL, NULL, 000); +MODULE_PARM_DESC(phram,"Memory region to map. \"map=<name>,<start>,<length>\""); + + +static int __init init_phram(void) +{ + return 0; +} + +static void __exit cleanup_phram(void) +{ + unregister_devices(); +} + +module_init(init_phram); +module_exit(cleanup_phram); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Jörn Engel <joern@wh.fh-wedel.de>"); +MODULE_DESCRIPTION("MTD driver for physical RAM"); |