329 lines
6.5 KiB
C
329 lines
6.5 KiB
C
/**
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* Copyright (c) ???? Jochen Schäuble <psionic@psionic.de>
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* Copyright (c) 2003-2004 Joern Engel <joern@wh.fh-wedel.de>
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*
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* Usage:
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*
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* one commend line parameter per device, each in the form:
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* phram=<name>,<start>,<len>
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* <name> may be up to 63 characters.
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* <start> and <len> can be octal, decimal or hexadecimal. If followed
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* by "ki", "Mi" or "Gi", the numbers will be interpreted as kilo, mega or
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* gigabytes.
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*
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* Example:
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* phram=swap,64Mi,128Mi phram=test,900Mi,1Mi
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/io.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/mtd/mtd.h>
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struct phram_mtd_list {
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struct mtd_info mtd;
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struct list_head list;
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};
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static LIST_HEAD(phram_list);
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static int phram_erase(struct mtd_info *mtd, struct erase_info *instr)
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{
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u_char *start = mtd->priv;
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memset(start + instr->addr, 0xff, instr->len);
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/*
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* This'll catch a few races. Free the thing before returning :)
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* I don't feel at all ashamed. This kind of thing is possible anyway
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* with flash, but unlikely.
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*/
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instr->state = MTD_ERASE_DONE;
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mtd_erase_callback(instr);
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return 0;
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}
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static int phram_point(struct mtd_info *mtd, loff_t from, size_t len,
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size_t *retlen, void **virt, resource_size_t *phys)
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{
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*virt = mtd->priv + from;
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*retlen = len;
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return 0;
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}
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static int phram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
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{
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return 0;
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}
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static int phram_read(struct mtd_info *mtd, loff_t from, size_t len,
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size_t *retlen, u_char *buf)
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{
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u_char *start = mtd->priv;
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memcpy(buf, start + from, len);
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*retlen = len;
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return 0;
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}
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static int phram_write(struct mtd_info *mtd, loff_t to, size_t len,
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size_t *retlen, const u_char *buf)
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{
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u_char *start = mtd->priv;
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memcpy(start + to, buf, len);
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*retlen = len;
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return 0;
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}
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static void unregister_devices(void)
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{
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struct phram_mtd_list *this, *safe;
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list_for_each_entry_safe(this, safe, &phram_list, list) {
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mtd_device_unregister(&this->mtd);
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iounmap(this->mtd.priv);
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kfree(this->mtd.name);
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kfree(this);
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}
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}
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static int register_device(char *name, phys_addr_t start, size_t len)
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{
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struct phram_mtd_list *new;
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int ret = -ENOMEM;
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new = kzalloc(sizeof(*new), GFP_KERNEL);
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if (!new)
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goto out0;
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ret = -EIO;
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new->mtd.priv = ioremap(start, len);
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if (!new->mtd.priv) {
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pr_err("ioremap failed\n");
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goto out1;
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}
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new->mtd.name = name;
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new->mtd.size = len;
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new->mtd.flags = MTD_CAP_RAM;
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new->mtd._erase = phram_erase;
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new->mtd._point = phram_point;
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new->mtd._unpoint = phram_unpoint;
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new->mtd._read = phram_read;
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new->mtd._write = phram_write;
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new->mtd.owner = THIS_MODULE;
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new->mtd.type = MTD_RAM;
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new->mtd.erasesize = PAGE_SIZE;
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new->mtd.writesize = 1;
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ret = -EAGAIN;
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if (mtd_device_register(&new->mtd, NULL, 0)) {
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pr_err("Failed to register new device\n");
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goto out2;
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}
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list_add_tail(&new->list, &phram_list);
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return 0;
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out2:
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iounmap(new->mtd.priv);
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out1:
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kfree(new);
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out0:
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return ret;
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}
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static int parse_num64(uint64_t *num64, char *token)
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{
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size_t len;
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int shift = 0;
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int ret;
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len = strlen(token);
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/* By dwmw2 editorial decree, "ki", "Mi" or "Gi" are to be used. */
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if (len > 2) {
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if (token[len - 1] == 'i') {
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switch (token[len - 2]) {
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case 'G':
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shift += 10;
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case 'M':
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shift += 10;
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case 'k':
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shift += 10;
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token[len - 2] = 0;
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break;
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default:
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return -EINVAL;
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}
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}
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}
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ret = kstrtou64(token, 0, num64);
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*num64 <<= shift;
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return ret;
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}
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static int parse_name(char **pname, const char *token)
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{
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size_t len;
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char *name;
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len = strlen(token) + 1;
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if (len > 64)
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return -ENOSPC;
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name = kstrdup(token, GFP_KERNEL);
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if (!name)
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return -ENOMEM;
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*pname = name;
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return 0;
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}
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static inline void kill_final_newline(char *str)
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{
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char *newline = strrchr(str, '\n');
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if (newline && !newline[1])
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*newline = 0;
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}
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#define parse_err(fmt, args...) do { \
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pr_err(fmt , ## args); \
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return 1; \
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} while (0)
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#ifndef MODULE
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static int phram_init_called;
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/*
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* This shall contain the module parameter if any. It is of the form:
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* - phram=<device>,<address>,<size> for module case
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* - phram.phram=<device>,<address>,<size> for built-in case
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* We leave 64 bytes for the device name, 20 for the address and 20 for the
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* size.
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* Example: phram.phram=rootfs,0xa0000000,512Mi
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*/
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static char phram_paramline[64 + 20 + 20];
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#endif
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static int phram_setup(const char *val)
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{
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char buf[64 + 20 + 20], *str = buf;
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char *token[3];
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char *name;
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uint64_t start;
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uint64_t len;
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int i, ret;
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if (strnlen(val, sizeof(buf)) >= sizeof(buf))
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parse_err("parameter too long\n");
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strcpy(str, val);
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kill_final_newline(str);
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for (i = 0; i < 3; i++)
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token[i] = strsep(&str, ",");
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if (str)
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parse_err("too many arguments\n");
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if (!token[2])
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parse_err("not enough arguments\n");
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ret = parse_name(&name, token[0]);
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if (ret)
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return ret;
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ret = parse_num64(&start, token[1]);
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if (ret) {
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kfree(name);
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parse_err("illegal start address\n");
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}
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ret = parse_num64(&len, token[2]);
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if (ret) {
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kfree(name);
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parse_err("illegal device length\n");
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}
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ret = register_device(name, start, len);
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if (!ret)
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pr_info("%s device: %#llx at %#llx\n", name, len, start);
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else
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kfree(name);
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return ret;
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}
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static int phram_param_call(const char *val, const struct kernel_param *kp)
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{
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#ifdef MODULE
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return phram_setup(val);
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#else
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/*
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* If more parameters are later passed in via
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* /sys/module/phram/parameters/phram
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* and init_phram() has already been called,
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* we can parse the argument now.
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*/
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if (phram_init_called)
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return phram_setup(val);
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/*
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* During early boot stage, we only save the parameters
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* here. We must parse them later: if the param passed
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* from kernel boot command line, phram_param_call() is
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* called so early that it is not possible to resolve
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* the device (even kmalloc() fails). Defer that work to
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* phram_setup().
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*/
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if (strlen(val) >= sizeof(phram_paramline))
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return -ENOSPC;
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strcpy(phram_paramline, val);
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return 0;
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#endif
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}
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module_param_call(phram, phram_param_call, NULL, NULL, 000);
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MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>\"");
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static int __init init_phram(void)
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{
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int ret = 0;
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#ifndef MODULE
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if (phram_paramline[0])
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ret = phram_setup(phram_paramline);
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phram_init_called = 1;
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#endif
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return ret;
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}
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static void __exit cleanup_phram(void)
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{
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unregister_devices();
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}
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module_init(init_phram);
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module_exit(cleanup_phram);
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("Joern Engel <joern@wh.fh-wedel.de>");
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MODULE_DESCRIPTION("MTD driver for physical RAM");
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