/*
* Physical mapping layer for MTD using the Axis partitiontable format
*
* Copyright (c) 2001, 2002 Axis Communications AB
*
* This file is under the GPL.
*
* First partition is always sector 0 regardless of if we find a partitiontable
* or not. In the start of the next sector, there can be a partitiontable that
* tells us what other partitions to define. If there isn't, we use a default
* partition split defined below.
*
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mtd/concat.h>
#include <linux/mtd/map.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/mtdram.h>
#include <linux/mtd/partitions.h>
#include <asm/axisflashmap.h>
#include <asm/mmu.h>
#include <arch/sv_addr_ag.h>
#ifdef CONFIG_CRIS_LOW_MAP
#define FLASH_UNCACHED_ADDR KSEG_8
#define FLASH_CACHED_ADDR KSEG_5
#else
#define FLASH_UNCACHED_ADDR KSEG_E
#define FLASH_CACHED_ADDR KSEG_F
#endif
#if CONFIG_ETRAX_FLASH_BUSWIDTH==1
#define flash_data __u8
#elif CONFIG_ETRAX_FLASH_BUSWIDTH==2
#define flash_data __u16
#elif CONFIG_ETRAX_FLASH_BUSWIDTH==4
#define flash_data __u32
#endif
/* From head.S */
extern unsigned long romfs_start, romfs_length, romfs_in_flash;
/* The master mtd for the entire flash. */
struct mtd_info* axisflash_mtd = NULL;
/* Map driver functions. */
static map_word flash_read(struct map_info *map, unsigned long ofs)
{
map_word tmp;
tmp.x[0] = *(flash_data *)(map->map_priv_1 + ofs);
return tmp;
}
static void flash_copy_from(struct map_info *map, void *to,
unsigned long from, ssize_t len)
{
memcpy(to, (void *)(map->map_priv_1 + from), len);
}
static void flash_write(struct map_info *map, map_word d, unsigned long adr)
{
*(flash_data *)(map->map_priv_1 + adr) = (flash_data)d.x[0];
}
/*
* The map for chip select e0.
*
* We run into tricky coherence situations if we mix cached with uncached
* accesses to we only use the uncached version here.
*
* The size field is the total size where the flash chips may be mapped on the
* chip select. MTD probes should find all devices there and it does not matter
* if there are unmapped gaps or aliases (mirrors of flash devices). The MTD
* probes will ignore them.
*
* The start address in map_priv_1 is in virtual memory so we cannot use
* MEM_CSE0_START but must rely on that FLASH_UNCACHED_ADDR is the start
* address of cse0.
*/
static struct map_info map_cse0 = {
.name = "cse0",
.size = MEM_CSE0_SIZE,
.bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
.read = flash_read,
.copy_from = flash_copy_from,
.write = flash_write,
.map_priv_1 = FLASH_UNCACHED_ADDR
};
/*
* The map for chip select e1.
*
* If there was a gap between cse0 and cse1, map_priv_1 would get the wrong
* address, but there isn't.
*/
static struct map_info map_cse1 = {
.name = "cse1",
.size = MEM_CSE1_SIZE,
.bankwidth = CONFIG_ETRAX_FLASH_BUSWIDTH,
.read = flash_read,
.copy_from = flash_copy_from,
.write = flash_write,
.map_priv_1 = FLASH_UNCACHED_ADDR + MEM_CSE0_SIZE
};
/* If no partition-table was found, we use this default-set. */
#define MAX_PARTITIONS 7
#define NUM_DEFAULT_PARTITIONS 3
/*
* Default flash size is 2MB. CONFIG_ETRAX_PTABLE_SECTOR is most likely the
* size of one flash block and "filesystem"-partition needs 5 blocks to be able
* to use JFFS.
*/
static struct mtd_partition axis_default_partitions[NUM_DEFAULT_PARTITIONS] = {
{
.name = "boot firmware",
.size = CONFIG_ETRAX_PTABLE_SECTOR,
.offset = 0
},
{
.name = "kernel",
.size = 0x200000 - (6 * CONFIG_ETRAX_PTABLE_SECTOR),
.offset = CONFIG_ETRAX_PTABLE_SECTOR
},
{
.name = "filesystem",
.size = 5 * CONFIG_ETRAX_PTABLE_SECTOR,
.offset = 0x200000 - (5 * CONFIG_ETRAX_PTABLE_SECTOR)
}
};
/* Initialize the ones normally used. */
static struct mtd_partition axis_partitions[MAX_PARTITIONS] = {
{
.name = "part0",
.size = CONFIG_ETRAX_PTABLE_SECTOR,
.offset = 0
},
{
.name = "part1",
.size = 0,
.offset = 0
},
{
.name = "part2",
.size = 0,
.offset = 0
},
{
.name = "part3",
.size = 0,
.offset = 0
},
{
.name = "part4",
.size = 0,
.offset = 0
},
{
.name = "part5",
.size = 0,
.offset = 0
},
{
.name = "part6",
.size = 0,
.offset = 0
},
};
#ifdef CONFIG_ETRAX_AXISFLASHMAP_MTD0WHOLE
/* Main flash device */
static struct mtd_partition main_partition = {
.name = "main",
.size = 0,
.offset = 0
};
#endif
/*
* Probe a chip select for AMD-compatible (JEDEC) or CFI-compatible flash
* chips in that order (because the amd_flash-driver is faster).
*/
static struct mtd_info *probe_cs(struct map_info *map_cs)
{
struct mtd_info *mtd_cs = NULL;
printk(KERN_INFO
"%s: Probing a 0x%08lx bytes large window at 0x%08lx.\n",
map_cs->name, map_cs->size, map_cs->map_priv_1);
#ifdef CONFIG_MTD_CFI
mtd_cs = do_map_probe("cfi_probe", map_cs);
#endif
#ifdef CONFIG_MTD_JEDECPROBE
if (!mtd_cs)
mtd_cs = do_map_probe("jedec_probe", map_cs);
#endif
return mtd_cs;
}
/*
* Probe each chip select individually for flash chips. If there are chips on
* both cse0 and cse1, the mtd_info structs will be concatenated to one struct
* so that MTD partitions can cross chip boundries.
*
* The only known restriction to how you can mount your chips is that each
* chip select must hold similar flash chips. But you need external hardware
* to do that anyway and you can put totally different chips on cse0 and cse1
* so it isn't really much of a restriction.
*/
static struct mtd_info *flash_probe(void)
{
struct mtd_info *mtd_cse0;
struct mtd_info *mtd_cse1;
struct mtd_info *mtd_cse;
mtd_cse0 = probe_cs(&map_cse0);
mtd_cse1 = probe_cs(&map_cse1);
if (!mtd_cse0 && !mtd_cse1) {
/* No chip found. */
return NULL;
}
if (mtd_cse0 && mtd_cse1) {
struct mtd_info *mtds[] = { mtd_cse0, mtd_cse1 };
/* Since the concatenation layer adds a small overhead we
* could try to figure out if the chips in cse0 and cse1 are
* identical and reprobe the whole cse0+cse1 window. But since
* flash chips are slow, the overhead is relatively small.
* So we use the MTD concatenation layer instead of further
* complicating the probing procedure.
*/
mtd_cse = mtd_concat_create(mtds, ARRAY_SIZE(mtds),
"cse0+cse1");
if (!mtd_cse) {
printk(KERN_ERR "%s and %s: Concatenation failed!\n",
map_cse0.name, map_cse1.name);
/* The best we can do now is to only use what we found
* at cse0.
*/
mtd_cse = mtd_cse0;
map_destroy(mtd_cse1);
}
} else {
mtd_cse = mtd_cse0? mtd_cse0 : mtd_cse1;
}
return mtd_cse;
}
/*
* Probe the flash chip(s) and, if it succeeds, read the partition-table
* and register the partitions with MTD.
*/
static int __init init_axis_flash(void)
{
struct mtd_info *mymtd;
int err = 0;
int pidx = 0;
struct partitiontable_head *ptable_head = NULL;
struct partitiontable_entry *ptable;
int use_default_ptable = 1; /* Until proven otherwise. */
const char pmsg[] = " /dev/flash%d at 0x%08x, size 0x%08x\n";
if (!(mymtd = flash_probe())) {
/* There's no reason to use this module if no flash chip can
* be identified. Make sure that's understood.
*/
printk(KERN_INFO "axisflashmap: Found no flash chip.\n");
} else {
printk(KERN_INFO "%s: 0x%08x bytes of flash memory.\n",
mymtd->name, mymtd->size);
axisflash_mtd = mymtd;
}
if (mymtd) {
mymtd->owner = THIS_MODULE;
ptable_head = (struct partitiontable_head *)(FLASH_CACHED_ADDR +
CONFIG_ETRAX_PTABLE_SECTOR +
PARTITION_TABLE_OFFSET);
}
pidx++; /* First partition is always set to the default. */
if (ptable_head && (ptable_head->magic == PARTITION_TABLE_MAGIC)
&& (ptable_head->size <
(MAX_PARTITIONS * sizeof(struct partitiontable_entry) +
PARTITIONTABLE_END_MARKER_SIZE))
&& (*(unsigned long*)((void*)ptable_head + sizeof(*ptable_head) +
ptable_head->size -
PARTITIONTABLE_END_MARKER_SIZE)
== PARTITIONTABLE_END_MARKER)) {
/* Looks like a start, sane length and end of a
* partition table, lets check csum etc.
*/
int ptable_ok = 0;
struct partitiontable_entry *max_addr =
(struct partitiontable_entry *)
((unsigned long)ptable_head + sizeof(*ptable_head) +
ptable_head->size);
unsigned long offset = CONFIG_ETRAX_PTABLE_SECTOR;
unsigned char *p;
unsigned long csum = 0;
ptable = (struct partitiontable_entry *)
((unsigned long)ptable_head + sizeof(*ptable_head));
/* Lets be PARANOID, and check the checksum. */
p = (unsigned char*) ptable;
while (p <= (unsigned char*)max_addr) {
csum += *p++;
csum += *p++;
csum += *p++;
csum += *p++;
}
ptable_ok = (csum == ptable_head->checksum);
/* Read the entries and use/show the info. */
printk(KERN_INFO " Found a%s partition table at 0x%p-0x%p.\n",
(ptable_ok ? " valid" : "n invalid"), ptable_head,
max_addr);
/* We have found a working bootblock. Now read the
* partition table. Scan the table. It ends when
* there is 0xffffffff, that is, empty flash.
*/
while (ptable_ok
&& ptable->offset != 0xffffffff
&& ptable < max_addr
&& pidx < MAX_PARTITIONS) {
axis_partitions[pidx].offset = offset + ptable->offset;
axis_partitions[pidx].size = ptable->size;
printk(pmsg, pidx, axis_partitions[pidx].offset,
axis_partitions[pidx].size);
pidx++;
ptable++;
}
use_default_ptable = !ptable_ok;
}
if (romfs_in_flash) {
/* Add an overlapping device for the root partition (romfs). */
axis_partitions[pidx].name = "romfs";
axis_partitions[pidx].size = romfs_length;
axis_partitions[pidx].offset = romfs_start - FLASH_CACHED_ADDR;
axis_partitions[pidx].mask_flags |= MTD_WRITEABLE;
printk(KERN_INFO
" Adding readonly flash partition for romfs image:\n");
printk(pmsg, pidx, axis_partitions[pidx].offset,
axis_partitions[pidx].size);
pidx++;
}
#ifdef CONFIG_ETRAX_AXISFLASHMAP_MTD0WHOLE
if (mymtd) {
main_partition.size = mymtd->size;
err = mtd_device_register(mymtd, &main_partition, 1);
if (err)
panic("axisflashmap: Could not initialize "
"partition for whole main mtd device!\n");
}
#endif
if (mymtd) {
if (use_default_ptable) {
printk(KERN_INFO " Using default partition table.\n");
err = mtd_device_register(mymtd,
axis_default_partitions,
NUM_DEFAULT_PARTITIONS);
} else {
err = mtd_device_register(mymtd, axis_partitions,
pidx);
}
if (err)
panic("axisflashmap could not add MTD partitions!\n");
}
if (!romfs_in_flash) {
/* Create an RAM device for the root partition (romfs). */
#if !defined(CONFIG_MTD_MTDRAM) || (CONFIG_MTDRAM_TOTAL_SIZE != 0) || (CONFIG_MTDRAM_ABS_POS != 0)
/* No use trying to boot this kernel from RAM. Panic! */
printk(KERN_EMERG "axisflashmap: Cannot create an MTD RAM "
"device due to kernel (mis)configuration!\n");
panic("This kernel cannot boot from RAM!\n");
#else
struct mtd_info *mtd_ram;
mtd_ram = kmalloc(sizeof(struct mtd_info), GFP_KERNEL);
if (!mtd_ram)
panic("axisflashmap couldn't allocate memory for "
"mtd_info!\n");
printk(KERN_INFO " Adding RAM partition for romfs image:\n");
printk(pmsg, pidx, (unsigned)romfs_start,
(unsigned)romfs_length);
err = mtdram_init_device(mtd_ram,
(void *)romfs_start,
romfs_length,
"romfs");
if (err)
panic("axisflashmap could not initialize MTD RAM "
"device!\n");
#endif
}
return err;
}
/* This adds the above to the kernels init-call chain. */
module_init(init_axis_flash);
EXPORT_SYMBOL(axisflash_mtd);