linux/drivers/mtd/devices/slram.c
Linus Torvalds 623ff7739e MTD merge for 3.4
Artem's cleanup of the MTD API continues apace.
 Fixes and improvements for ST FSMC and SuperH FLCTL NAND, amongst others.
 More work on DiskOnChip G3, new driver for DiskOnChip G4.
 Clean up debug/warning printks in JFFS2 to use pr_<level>.
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Merge tag 'for-linus-3.4' of git://git.infradead.org/mtd-2.6

Pull MTD changes from David Woodhouse:
 - Artem's cleanup of the MTD API continues apace.
 - Fixes and improvements for ST FSMC and SuperH FLCTL NAND, amongst
   others.
 - More work on DiskOnChip G3, new driver for DiskOnChip G4.
 - Clean up debug/warning printks in JFFS2 to use pr_<level>.

Fix up various trivial conflicts, largely due to changes in calling
conventions for things like dmaengine_prep_slave_sg() (new inline
wrapper to hide new parameter, clashing with rewrite of previously last
parameter that used to be an 'append' flag, and is now a bitmap of
'unsigned long flags').

(Also some header file fallout - like so many merges this merge window -
and silly conflicts with sparse fixes)

* tag 'for-linus-3.4' of git://git.infradead.org/mtd-2.6: (120 commits)
  mtd: docg3 add protection against concurrency
  mtd: docg3 refactor cascade floors structure
  mtd: docg3 increase write/erase timeout
  mtd: docg3 fix inbound calculations
  mtd: nand: gpmi: fix function annotations
  mtd: phram: fix section mismatch for phram_setup
  mtd: unify initialization of erase_info->fail_addr
  mtd: support ONFI multi lun NAND
  mtd: sm_ftl: fix typo in major number.
  mtd: add device-tree support to spear_smi
  mtd: spear_smi: Remove default partition information from driver
  mtd: Add device-tree support to fsmc_nand
  mtd: fix section mismatch for doc_probe_device
  mtd: nand/fsmc: Remove sparse warnings and errors
  mtd: nand/fsmc: Add DMA support
  mtd: nand/fsmc: Access the NAND device word by word whenever possible
  mtd: nand/fsmc: Use dev_err to report error scenario
  mtd: nand/fsmc: Use devm routines
  mtd: nand/fsmc: Modify fsmc driver to accept nand timing parameters via platform
  mtd: fsmc_nand: add pm callbacks to support hibernation
  ...
2012-03-30 17:31:56 -07:00

350 lines
8.7 KiB
C

/*======================================================================
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 contiguous memory region. Therefore
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 <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 *, void **,
resource_size_t *);
static int slram_unpoint(struct mtd_info *, 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;
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, void **virt, resource_size_t *phys)
{
slram_priv_t *priv = mtd->priv;
*virt = priv->start + from;
*retlen = len;
return(0);
}
static int slram_unpoint(struct mtd_info *mtd, loff_t from, size_t len)
{
return 0;
}
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;
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;
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 (mtd_device_register((*curmtd)->mtdinfo, NULL, 0)) {
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;
mtd_device_unregister(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;
if (devlength < devstart)
goto err_out;
devlength -= 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 (devlength % SLRAM_BLK_SZ != 0)
goto err_out;
if ((devstart = register_device(devname, devstart, devlength))){
unregister_devices();
return((int)devstart);
}
return(0);
err_out:
E("slram: Illegal length parameter.\n");
return(-EINVAL);
}
#ifndef MODULE
static int __init mtd_slram_setup(char *str)
{
map = str;
return(1);
}
__setup("slram=", mtd_slram_setup);
#endif
static int __init 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; count < SLRAM_MAX_DEVICES_PARAMS && map[count];
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");