1 files changed, 357 insertions, 0 deletions

diff --git a/drivers/mtd/devices/slram.c b/drivers/mtd/devices/slram.c
new file mode 100644
index 000000000000..5ab15e643be7
--- /dev/null
+++ b/drivers/mtd/devices/slram.c
@@ -0,0 +1,357 @@
+/*======================================================================
+
+  $Id: slram.c,v 1.33 2005/01/05 18:05:13 dwmw2 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/sched.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 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;
+
+        *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;
+        
+        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 = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
+        (*curmtd)->next = NULL;
+        
+        if ((*curmtd)->mtdinfo) {
+                memset((char *)(*curmtd)->mtdinfo, 0, sizeof(struct mtd_info));
+                (*curmtd)->mtdinfo->priv =
+                        kmalloc(sizeof(slram_priv_t), GFP_KERNEL);
+                
+                if (!(*curmtd)->mtdinfo->priv) {
+                        kfree((*curmtd)->mtdinfo);
+                        (*curmtd)->mtdinfo = NULL;
+                } else {
+                        memset((*curmtd)->mtdinfo->priv,0,sizeof(slram_priv_t));
+                }
+        }
+
+        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_CLEAR_BITS | MTD_SET_BITS |
+                                        MTD_WRITEB_WRITEABLE | MTD_VOLATILE;
+        (*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 = 0x0;
+
+        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)) {
+                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");