/*====================================================================== $Id: slram.c,v 1.36 2005/11/07 11:14:25 gleixner Exp $ This driver provides a method to access memory not used by the kernel itself (i.e. if the kernel commandline mem=xxx is used). To actually use slram at least mtdblock or mtdchar is required (for block or character device access). Usage: if compiled as loadable module: modprobe slram map=<name>,<start>,<end/offset> if statically linked into the kernel use the following kernel cmd.line slram=<name>,<start>,<end/offset> <name>: name of the device that will be listed in /proc/mtd <start>: start of the memory region, decimal or hex (0xabcdef) <end/offset>: end of the memory region. It's possible to use +0x1234 to specify the offset instead of the absolute address NOTE: With slram it's only possible to map a contigous memory region. Therfore if there's a device mapped somewhere in the region specified slram will fail to load (see kernel log if modprobe fails). - Jochen Schaeuble <psionic@psionic.de> ======================================================================*/ #include <linux/module.h> #include <asm/uaccess.h> #include <linux/types.h> #include <linux/kernel.h> #include <linux/ptrace.h> #include <linux/slab.h> #include <linux/string.h> #include <linux/timer.h> #include <linux/major.h> #include <linux/fs.h> #include <linux/ioctl.h> #include <linux/init.h> #include <asm/io.h> #include <asm/system.h> #include <linux/mtd/mtd.h> #define SLRAM_MAX_DEVICES_PARAMS 6 /* 3 parameters / device */ #define SLRAM_BLK_SZ 0x4000 #define T(fmt, args...) printk(KERN_DEBUG fmt, ## args) #define E(fmt, args...) printk(KERN_NOTICE fmt, ## args) typedef struct slram_priv { u_char *start; u_char *end; } slram_priv_t; typedef struct slram_mtd_list { struct mtd_info *mtdinfo; struct slram_mtd_list *next; } slram_mtd_list_t; #ifdef MODULE static char *map[SLRAM_MAX_DEVICES_PARAMS]; module_param_array(map, charp, NULL, 0); MODULE_PARM_DESC(map, "List of memory regions to map. \"map=<name>, <start>, <length / end>\""); #else static char *map; #endif static slram_mtd_list_t *slram_mtdlist = NULL; static int slram_erase(struct mtd_info *, struct erase_info *); static int slram_point(struct mtd_info *, loff_t, size_t, size_t *, u_char **); static void slram_unpoint(struct mtd_info *, u_char *, loff_t, size_t); static int slram_read(struct mtd_info *, loff_t, size_t, size_t *, u_char *); static int slram_write(struct mtd_info *, loff_t, size_t, size_t *, const u_char *); static int slram_erase(struct mtd_info *mtd, struct erase_info *instr) { slram_priv_t *priv = mtd->priv; if (instr->addr + instr->len > mtd->size) { return(-EINVAL); } memset(priv->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 slram_point(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char **mtdbuf) { slram_priv_t *priv = mtd->priv; if (from + len > mtd->size) return -EINVAL; *mtdbuf = priv->start + from; *retlen = len; return(0); } static void slram_unpoint(struct mtd_info *mtd, u_char *addr, loff_t from, size_t len) { } static int slram_read(struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf) { slram_priv_t *priv = mtd->priv; if (from > mtd->size) return -EINVAL; if (from + len > mtd->size) len = mtd->size - from; memcpy(buf, priv->start + from, len); *retlen = len; return(0); } static int slram_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen, const u_char *buf) { slram_priv_t *priv = mtd->priv; if (to + len > mtd->size) return -EINVAL; memcpy(priv->start + to, buf, len); *retlen = len; return(0); } /*====================================================================*/ static int register_device(char *name, unsigned long start, unsigned long length) { slram_mtd_list_t **curmtd; curmtd = &slram_mtdlist; while (*curmtd) { curmtd = &(*curmtd)->next; } *curmtd = kmalloc(sizeof(slram_mtd_list_t), GFP_KERNEL); if (!(*curmtd)) { E("slram: Cannot allocate new MTD device.\n"); return(-ENOMEM); } (*curmtd)->mtdinfo = kzalloc(sizeof(struct mtd_info), GFP_KERNEL); (*curmtd)->next = NULL; if ((*curmtd)->mtdinfo) { (*curmtd)->mtdinfo->priv = kzalloc(sizeof(slram_priv_t), GFP_KERNEL); if (!(*curmtd)->mtdinfo->priv) { kfree((*curmtd)->mtdinfo); (*curmtd)->mtdinfo = NULL; } } if (!(*curmtd)->mtdinfo) { E("slram: Cannot allocate new MTD device.\n"); return(-ENOMEM); } if (!(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start = ioremap(start, length))) { E("slram: ioremap failed\n"); return -EIO; } ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end = ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start + length; (*curmtd)->mtdinfo->name = name; (*curmtd)->mtdinfo->size = length; (*curmtd)->mtdinfo->flags = MTD_CAP_RAM; (*curmtd)->mtdinfo->erase = slram_erase; (*curmtd)->mtdinfo->point = slram_point; (*curmtd)->mtdinfo->unpoint = slram_unpoint; (*curmtd)->mtdinfo->read = slram_read; (*curmtd)->mtdinfo->write = slram_write; (*curmtd)->mtdinfo->owner = THIS_MODULE; (*curmtd)->mtdinfo->type = MTD_RAM; (*curmtd)->mtdinfo->erasesize = SLRAM_BLK_SZ; (*curmtd)->mtdinfo->writesize = 1; if (add_mtd_device((*curmtd)->mtdinfo)) { E("slram: Failed to register new device\n"); iounmap(((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start); kfree((*curmtd)->mtdinfo->priv); kfree((*curmtd)->mtdinfo); return(-EAGAIN); } T("slram: Registered device %s from %luKiB to %luKiB\n", name, (start / 1024), ((start + length) / 1024)); T("slram: Mapped from 0x%p to 0x%p\n", ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->start, ((slram_priv_t *)(*curmtd)->mtdinfo->priv)->end); return(0); } static void unregister_devices(void) { slram_mtd_list_t *nextitem; while (slram_mtdlist) { nextitem = slram_mtdlist->next; del_mtd_device(slram_mtdlist->mtdinfo); iounmap(((slram_priv_t *)slram_mtdlist->mtdinfo->priv)->start); kfree(slram_mtdlist->mtdinfo->priv); kfree(slram_mtdlist->mtdinfo); kfree(slram_mtdlist); slram_mtdlist = nextitem; } } static unsigned long handle_unit(unsigned long value, char *unit) { if ((*unit == 'M') || (*unit == 'm')) { return(value * 1024 * 1024); } else if ((*unit == 'K') || (*unit == 'k')) { return(value * 1024); } return(value); } static int parse_cmdline(char *devname, char *szstart, char *szlength) { char *buffer; unsigned long devstart; unsigned long devlength; if ((!devname) || (!szstart) || (!szlength)) { unregister_devices(); return(-EINVAL); } devstart = simple_strtoul(szstart, &buffer, 0); devstart = handle_unit(devstart, buffer); if (*(szlength) != '+') { devlength = simple_strtoul(szlength, &buffer, 0); devlength = handle_unit(devlength, buffer) - devstart; } else { devlength = simple_strtoul(szlength + 1, &buffer, 0); devlength = handle_unit(devlength, buffer); } T("slram: devname=%s, devstart=0x%lx, devlength=0x%lx\n", devname, devstart, devlength); if ((devstart < 0) || (devlength < 0) || (devlength % SLRAM_BLK_SZ != 0)) { E("slram: Illegal start / length parameter.\n"); return(-EINVAL); } if ((devstart = register_device(devname, devstart, devlength))){ unregister_devices(); return((int)devstart); } return(0); } #ifndef MODULE static int __init mtd_slram_setup(char *str) { map = str; return(1); } __setup("slram=", mtd_slram_setup); #endif static int init_slram(void) { char *devname; int i; #ifndef MODULE char *devstart; char *devlength; i = 0; if (!map) { E("slram: not enough parameters.\n"); return(-EINVAL); } while (map) { devname = devstart = devlength = NULL; if (!(devname = strsep(&map, ","))) { E("slram: No devicename specified.\n"); break; } T("slram: devname = %s\n", devname); if ((!map) || (!(devstart = strsep(&map, ",")))) { E("slram: No devicestart specified.\n"); } T("slram: devstart = %s\n", devstart); if ((!map) || (!(devlength = strsep(&map, ",")))) { E("slram: No devicelength / -end specified.\n"); } T("slram: devlength = %s\n", devlength); if (parse_cmdline(devname, devstart, devlength) != 0) { return(-EINVAL); } } #else int count; for (count = 0; (map[count]) && (count < SLRAM_MAX_DEVICES_PARAMS); count++) { } if ((count % 3 != 0) || (count == 0)) { E("slram: not enough parameters.\n"); return(-EINVAL); } for (i = 0; i < (count / 3); i++) { devname = map[i * 3]; if (parse_cmdline(devname, map[i * 3 + 1], map[i * 3 + 2])!=0) { return(-EINVAL); } } #endif /* !MODULE */ return(0); } static void __exit cleanup_slram(void) { unregister_devices(); } module_init(init_slram); module_exit(cleanup_slram); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Jochen Schaeuble <psionic@psionic.de>"); MODULE_DESCRIPTION("MTD driver for uncached system RAM");