NOR驱动程序分析
协议层知道写数据、识别、擦除、烧写，所以我们只需要做最底层的硬件东西，告诉协议层nor flash的最小差异，注册硬件的地址、位宽等等硬件信息
框架分析：
do_map_probe("cfi_probe", s3c_nor_map);
struct mtd_info *do_map_probe(const char *name, struct map_info *map)
{
struct mtd_chip_driver *drv;
struct mtd_info *ret;
drv = get_mtd_chip_driver(name);
if (!drv && !request_module("%s", name))
drv = get_mtd_chip_driver(name);
if (!drv)
return NULL;
ret = drv->probe(map);
/* We decrease the use count here. It may have been a
probe-only module, which is no longer required from this
point, having given us a handle on (and increased the use
count of) the actual driver code.
*/
module_put(drv->module);
if (ret)
return ret;
return NULL;
} drv = get_mtd_chip_driver(name)
ret = drv->probe(map); // cfi_probe.c
static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
{
struct list_head *pos;
struct mtd_chip_driver *ret = NULL, *this;
spin_lock(&chip_drvs_lock);
list_for_each(pos, &chip_drvs_list) {
this = list_entry(pos, typeof(*this), list);
if (!strcmp(this->name, name)) {
ret = this;
break;
}
}
if (ret && !try_module_get(ret->module))
ret = NULL;
spin_unlock(&chip_drvs_lock);
return ret;
}从这个chip_drvs_list链表找，那这个链表谁设置的呢
void register_mtd_chip_driver(struct mtd_chip_driver *drv)
{
spin_lock(&chip_drvs_lock);
list_add(&drv->list, &chip_drvs_list);
spin_unlock(&chip_drvs_lock);
}谁来注册register_mtd_chip_driver
static int __init cfi_probe_init(void)
{
register_mtd_chip_driver(&cfi_chipdrv);
return 0;
}最终会调用cfi_probe函数
static struct mtd_chip_driver cfi_chipdrv = {
.probe = cfi_probe,
.name = "cfi_probe",
.module = THIS_MODULE
};struct mtd_info *cfi_probe(struct map_info *map)
{
/*
* Just use the generic probe stuff to call our CFI-specific
* chip_probe routine in all the possible permutations, etc.
*/
return mtd_do_chip_probe(map, &cfi_chip_probe);
}
mtd_do_chip_probe(map, &cfi_chip_probe);
struct mtd_info *mtd_do_chip_probe(struct map_info *map, struct chip_probe *cp)
{
struct mtd_info *mtd = NULL;
struct cfi_private *cfi;
/* First probe the map to see if we have CFI stuff there. */
cfi = genprobe_ident_chips(map, cp);
if (!cfi)
return NULL;
map->fldrv_priv = cfi;
/* OK we liked it. Now find a driver for the command set it talks */
mtd = check_cmd_set(map, 1); /* First the primary cmdset */
if (!mtd)
mtd = check_cmd_set(map, 0); /* Then the secondary */
if (mtd) {
if (mtd->size > map->size) {
printk(KERN_WARNING "Reducing visibility of %ldKiB chip to %ldKiB\n",
(unsigned long)mtd->size >> 10,
(unsigned long)map->size >> 10);
mtd->size = map->size;
}
return mtd;
}
printk(KERN_WARNING"gen_probe: No supported Vendor Command Set found\n");
kfree(cfi->cfiq);
kfree(cfi);
map->fldrv_priv = NULL;
return NULL;
｝cfi = genprobe_ident_chips(map, cp);
static int genprobe_new_chip(struct map_info *map, struct chip_probe *cp,
struct cfi_private *cfi)
{
int min_chips = (map_bankwidth(map)/4?:1); /* At most 4-bytes wide. */
int max_chips = map_bankwidth(map); /* And minimum 1 */
int nr_chips, type;
for (nr_chips = max_chips; nr_chips >= min_chips; nr_chips >>= 1) {
if (!cfi_interleave_supported(nr_chips))
continue;
cfi->interleave = nr_chips;
/* Minimum device size. Don't look for one 8-bit device
in a 16-bit bus, etc. */
type = map_bankwidth(map) / nr_chips;
for (; type <= CFI_DEVICETYPE_X32; type<<=1) {
cfi->device_type = type;
if (cp->probe_chip(map, 0, NULL, cfi))
return 1;
}
}
return 0;
}cp->probe_chip(map, 0, NULL, cfi)
cp是什么？
cp就是cfi_chip_probe
static struct chip_probe cfi_chip_probe = {
.name = "CFI",
.probe_chip = cfi_probe_chip
};进入cfi_probe_chip
static int __xipram cfi_probe_chip(struct map_info *map, __u32 base,
unsigned long *chip_map, struct cfi_private *cfi)
{
int i;
if ((base + 0) >= map->size) {
printk(KERN_NOTICE
"Probe at base[0x00](0x%08lx) past the end of the map(0x%08lx)\n",
(unsigned long)base, map->size -1);
return 0;
}
if ((base + 0xff) >= map->size) {
printk(KERN_NOTICE
"Probe at base[0x55](0x%08lx) past the end of the map(0x%08lx)\n",
(unsigned long)base + 0x55, map->size -1);
return 0;
}
xip_disable();
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
if (!qry_present(map,base,cfi)) {
xip_enable(base, map, cfi);
return 0;
}
if (!cfi->numchips) {
/* This is the first time we're called. Set up the CFI
stuff accordingly and return */
return cfi_chip_setup(map, cfi);
}
/* Check each previous chip to see if it's an alias */
for (i=0; i < (base >> cfi->chipshift); i++) {
unsigned long start;
if(!test_bit(i, chip_map)) {
/* Skip location; no valid chip at this address */
continue;
}
start = i << cfi->chipshift;
/* This chip should be in read mode if it's one
we've already touched. */
if (qry_present(map, start, cfi)) {
/* Eep. This chip also had the QRY marker.
* Is it an alias for the new one? */
cfi_send_gen_cmd(0xF0, 0, start, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, start, map, cfi, cfi->device_type, NULL);
/* If the QRY marker goes away, it's an alias */
if (!qry_present(map, start, cfi)) {
xip_allowed(base, map);
printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
map->name, base, start);
return 0;
}
/* Yes, it's actually got QRY for data. Most
* unfortunate. Stick the new chip in read mode
* too and if it's the same, assume it's an alias. */
/* FIXME: Use other modes to do a proper check */
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, start, map, cfi, cfi->device_type, NULL);
if (qry_present(map, base, cfi)) {
xip_allowed(base, map);
printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
map->name, base, start);
return 0;
}
}
}
/* OK, if we got to here, then none of the previous chips appear to
be aliases for the current one. */
set_bit((base >> cfi->chipshift), chip_map); /* Update chip map */
cfi->numchips++;
/* Put it back into Read Mode */
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
xip_allowed(base, map);
printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
map->name, cfi->interleave, cfi->device_type*8, base,
map->bankwidth*8);
return 1;
}
// 进入CFI模式
cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
// 看是否能读出"QRY"
qry_present(map,base,cfi)
static int __xipram qry_present(struct map_info *map, __u32 base,
struct cfi_private *cfi)
{
int osf = cfi->interleave * cfi->device_type; // scale factor
map_word val[3];
map_word qry[3];
qry[0] = cfi_build_cmd('Q', map, cfi);
qry[1] = cfi_build_cmd('R', map, cfi);
qry[2] = cfi_build_cmd('Y', map, cfi);
val[0] = map_read(map, base + osf*0x10);
val[1] = map_read(map, base + osf*0x11);
val[2] = map_read(map, base + osf*0x12);
if (!map_word_equal(map, qry[0], val[0]))
return 0;
if (!map_word_equal(map, qry[1], val[1]))
return 0;
if (!map_word_equal(map, qry[2], val[2]))
return 0;
return 1; // "QRY" found
}
do_map_probe("jedec_probe", s3c_nor_map);
struct mtd_info *do_map_probe(const char *name, struct map_info *map)
{
struct mtd_chip_driver *drv;
struct mtd_info *ret;
drv = get_mtd_chip_driver(name);
if (!drv && !request_module("%s", name))
drv = get_mtd_chip_driver(name);
if (!drv)
return NULL;
ret = drv->probe(map);
/* We decrease the use count here. It may have been a
probe-only module, which is no longer required from this
point, having given us a handle on (and increased the use
count of) the actual driver code.
*/
module_put(drv->module);
if (ret)
return ret;
return NULL;
}
drv = get_mtd_chip_driver(name)
static struct mtd_chip_driver *get_mtd_chip_driver (const char *name)
{
struct list_head *pos;
struct mtd_chip_driver *ret = NULL, *this;
spin_lock(&chip_drvs_lock);
list_for_each(pos, &chip_drvs_list) {
this = list_entry(pos, typeof(*this), list);
if (!strcmp(this->name, name)) {
ret = this;
break;
}
}
if (ret && !try_module_get(ret->module))
ret = NULL;
spin_unlock(&chip_drvs_lock);
return ret;
}
谁来调用chip_drvs_list
void register_mtd_chip_driver(struct mtd_chip_driver *drv)
{
spin_lock(&chip_drvs_lock);
list_add(&drv->list, &chip_drvs_list);
spin_unlock(&chip_drvs_lock);
}谁来注册这个register_mtd_chip_driver
static int __init cfi_probe_init(void)
{
register_mtd_chip_driver(&cfi_chipdrv);
return 0;
}
static struct mtd_chip_driver cfi_chipdrv = {
.probe = cfi_probe,
.name = "cfi_probe",
.module = THIS_MODULE
};
struct mtd_info *cfi_probe(struct map_info *map)
{
/*
* Just use the generic probe stuff to call our CFI-specific
* chip_probe routine in all the possible permutations, etc.
*/
return mtd_do_chip_probe(map, &cfi_chip_probe);
}
static struct chip_probe cfi_chip_probe = {
.name = "CFI",
.probe_chip = cfi_probe_chip
};
static int __xipram cfi_probe_chip(struct map_info *map, __u32 base,
unsigned long *chip_map, struct cfi_private *cfi)
{
int i;
if ((base + 0) >= map->size) {
printk(KERN_NOTICE
"Probe at base[0x00](0x%08lx) past the end of the map(0x%08lx)\n",
(unsigned long)base, map->size -1);
return 0;
}
if ((base + 0xff) >= map->size) {
printk(KERN_NOTICE
"Probe at base[0x55](0x%08lx) past the end of the map(0x%08lx)\n",
(unsigned long)base + 0x55, map->size -1);
return 0;
}
xip_disable();
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
if (!qry_present(map,base,cfi)) {
xip_enable(base, map, cfi);
return 0;
}
if (!cfi->numchips) {
/* This is the first time we're called. Set up the CFI
stuff accordingly and return */
return cfi_chip_setup(map, cfi);
}
/* Check each previous chip to see if it's an alias */
for (i=0; i < (base >> cfi->chipshift); i++) {
unsigned long start;
if(!test_bit(i, chip_map)) {
/* Skip location; no valid chip at this address */
continue;
}
start = i << cfi->chipshift;
/* This chip should be in read mode if it's one
we've already touched. */
if (qry_present(map, start, cfi)) {
/* Eep. This chip also had the QRY marker.
* Is it an alias for the new one? */
cfi_send_gen_cmd(0xF0, 0, start, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, start, map, cfi, cfi->device_type, NULL);
/* If the QRY marker goes away, it's an alias */
if (!qry_present(map, start, cfi)) {
xip_allowed(base, map);
printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
map->name, base, start);
return 0;
}
/* Yes, it's actually got QRY for data. Most
* unfortunate. Stick the new chip in read mode
* too and if it's the same, assume it's an alias. */
/* FIXME: Use other modes to do a proper check */
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, start, map, cfi, cfi->device_type, NULL);
if (qry_present(map, base, cfi)) {
xip_allowed(base, map);
printk(KERN_DEBUG "%s: Found an alias at 0x%x for the chip at 0x%lx\n",
map->name, base, start);
return 0;
}
}
}
/* OK, if we got to here, then none of the previous chips appear to
be aliases for the current one. */
set_bit((base >> cfi->chipshift), chip_map); /* Update chip map */
cfi->numchips++;
/* Put it back into Read Mode */
cfi_send_gen_cmd(0xF0, 0, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0xFF, 0, base, map, cfi, cfi->device_type, NULL);
xip_allowed(base, map);
printk(KERN_INFO "%s: Found %d x%d devices at 0x%x in %d-bit bank\n",
map->name, cfi->interleave, cfi->device_type*8, base,
map->bankwidth*8);
return 1;
}程序
/*
* 参考 drivers\mtd\maps\physmap.c
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#include <asm/io.h>
static struct map_info *s3c_nor_map;
static struct mtd_info *s3c_nor_mtd;
static struct mtd_partition s3c_nor_parts[] = {
[0] = {
.name = "bootloader_nor",
.size = 0x00040000,
.offset = 0,
},
[1] = {
.name = "root_nor",
.offset = MTDPART_OFS_APPEND,
.size = MTDPART_SIZ_FULL,
}
};
static int s3c_nor_init(void)
{
/* 1. 分配map_info结构体 */
s3c_nor_map = kzalloc(sizeof(struct map_info), GFP_KERNEL);;
/* 2. 设置: 物理基地址(phys), 大小(size), 位宽(bankwidth), 虚拟基地址(virt) */
s3c_nor_map->name = "s3c_nor";
s3c_nor_map->phys = 0;
s3c_nor_map->size = 0x1000000; /* >= NOR的真正大小 */
s3c_nor_map->bankwidth = 2;
s3c_nor_map->virt = ioremap(s3c_nor_map->phys, s3c_nor_map->size);
simple_map_init(s3c_nor_map);
/* 3. 使用: 调用NOR FLASH协议层提供的函数来识别 */
printk("use cfi_probe\n");
s3c_nor_mtd = do_map_probe("cfi_probe", s3c_nor_map);
if (!s3c_nor_mtd)//如果没有识别出来就用jedec_probe
{
printk("use jedec_probe\n");
s3c_nor_mtd = do_map_probe("jedec_probe", s3c_nor_map);
}
if (!s3c_nor_mtd)//如果两个都没识别出来没有识别出来就释放
{
iounmap(s3c_nor_map->virt);
kfree(s3c_nor_map);
return -EIO;
}
/* 4. add_mtd_partitions */
add_mtd_partitions(s3c_nor_mtd, s3c_nor_parts, 2);
return 0;
}
static void s3c_nor_exit(void)
{
del_mtd_partitions(s3c_nor_mtd);
iounmap(s3c_nor_map->virt);
kfree(s3c_nor_map);
}
module_init(s3c_nor_init);
module_exit(s3c_nor_exit);
MODULE_LICENSE("GPL");
如何测试：
测试1:通过配置内核支持NOR FLASH
1. make menuconfig
-> Device Drivers
-> Memory Technology Device (MTD) support
-> Mapping drivers for chip access
<M> CFI Flash device in physical memory map
(0x0) Physical start address of flash mapping // 物理基地址
(0x1000000) Physical length of flash mapping // 一定要大于真实长度，因为要ioemap
(2) Bank width in octets (NEW) // 位宽
2. make modules
cp drivers/mtd/maps/physmap.ko /work/nfs_root/first_fs
3. 启动开发板
ls /dev/mtd*
insmod physmap.ko
ls /dev/mtd*
cat /proc/mtd
测试2: 使用自己写的驱动程序:
1. ls /dev/mtd*
2. insmod s3c_nor.ko
3. ls /dev/mtd*
4. 格式化: flash_eraseall -j /dev/mtd1
5. mount -t jffs2 /dev/mtdblock1 /mnt
在/mnt目录下操作文件备注：
NOR FLASH识别过程:
do_map_probe("cfi_probe", s3c_nor_map);
drv = get_mtd_chip_driver(name)
ret = drv->probe(map); // cfi_probe.c
cfi_probe
mtd_do_chip_probe(map, &cfi_chip_probe);
cfi = genprobe_ident_chips(map, cp);
genprobe_new_chip(map, cp, &cfi)
cp->probe_chip(map, 0, NULL, cfi)
cfi_probe_chip
// 进入CFI模式
cfi_send_gen_cmd(0x98, 0x55, base, map, cfi, cfi->device_type, NULL);
// 看是否能读出"QRY"
qry_present(map,base,cfi)
.....
do_map_probe("jedec_probe", s3c_nor_map);
drv = get_mtd_chip_driver(name)
ret = drv->probe(map); // jedec_probe
jedec_probe
mtd_do_chip_probe(map, &jedec_chip_probe);
genprobe_ident_chips(map, cp);
genprobe_new_chip(map, cp, &cfi)
cp->probe_chip(map, 0, NULL, cfi)
jedec_probe_chip
// 解锁
cfi_send_gen_cmd(0xaa, cfi->addr_unlock1, base, map, cfi, cfi->device_type, NULL);
cfi_send_gen_cmd(0x55, cfi->addr_unlock2, base, map, cfi, cfi->device_type, NULL);
// 读ID命令
cfi_send_gen_cmd(0x90, cfi->addr_unlock1, base, map, cfi, cfi->device_type, NULL);
// 得到厂家ID，设备ID
cfi->mfr = jedec_read_mfr(map, base, cfi);
cfi->id = jedec_read_id(map, base, cfi);
// 和数组比较
jedec_table