RT5350 nvram驅動分析
1、相關版本
sdk版本：MTK_Ralink_ApSoC_SDK_4200_20131106linux
kernel版本：linux-2.6.21.xide
2、分析
1.nvram初始化接口：void nvram_init(int index)
a. 編譯配置：cat sdk/RT288x_SDK/source/linux-2.6.21/.config | grep NVRAM函數
CONFIG_KERNEL_NVRAM=y
CONFIG_HOSTAP_FIRMWARE_NVRAM=y
spa
a. 位置：sdk/RT288x_SDK/source/lib/libnvram/nvram_env.c指針
b. nvram_init代碼片斷接口
from = fb[index].flash_offset + sizeof(fb[index].env.crc);
len = fb[index].flash_max_len - sizeof(fb[index].env.crc);
fb[index].env.data = (char *)malloc(len);
nvr.index = index;
nvr.value = fb[index].env.data;
fd = open(NV_DEV, O_RDONLY);
if (fd < 0) {
perror(NV_DEV);
goto out;
}
if (ioctl(fd, RALINK_NVRAM_IOCTL_GETALL, &nvr) < 0) {
perror("ioctl");
close(fd);
goto out;
}ip////////////////////////////////////////////////////////////////
內存p = fb[index].env.data;
for (i = 0; i < MAX_CACHE_ENTRY; i++) {
if (NULL == (q = strchr(p, '='))) {
LIBNV_PRINT("parsed failed - cannot find '='\n");
break;
}
*q = '\0'; //strip '='
fb[index].cache[i].name = strdup(p);
//printf(" %d '%s'->", i, p);
p = q + 1; //value
if (NULL == (q = strchr(p, '\0'))) {
LIBNV_PRINT("parsed failed - cannot find '\\0'\n");
break;
}
fb[index].cache[i].value = strdup(p);
//printf("'%s'\n", p);
p = q + 1; //next entry
if (p - fb[index].env.data + 1 >= len) //end of block
break;
if (*p == '\0') //end of env
break;
}
rem
這裏主要是跟進fb全局變量，獲取flash塊信息，打開NV_DEV （"/dev/nvram" ）設備，經過ioctl對其進行讀入操做，並複製到內存空間。因此nvram接口是對/dev/nvram設備進行操做的。那麼/dev/nvram設備是怎麼被加載的呢？get
2. nvram設備
a. 根據CONFIG_KERNEL_NVRAM=y ，在內核make menuconfig查找KERNEL_NVRAM
Symbol: KERNEL_NVRAM [=y] │
│ Prompt: Kernel NVRAM │
│ Defined at arch/mips/rt2880/Kconfig:182 │
│ Location: │
│ -> Machine selection
b. arch/mips/rt2880/Makefile:
obj-$(CONFIG_KERNEL_NVRAM) += nvram.o
發現nvram設備。
c. arch/mips/rt2880/nvram.c
late_initcall(ra_nvram_init);
module_exit(ra_nvram_exit);
EXPORT_SYMBOL(nvram_get);
EXPORT_SYMBOL(nvram_set);
EXPORT_SYMBOL(nvram_commit);
設備註冊接口。
d. 設備初始化接口ra_nvram_init
r = register_chrdev(ralink_nvram_major, RALINK_NVRAM_DEVNAME,
&ralink_nvram_fops);
if (r < 0) {
printk(KERN_ERR "ralink_nvram: unable to register character device\n");
return r;
}
if (ralink_nvram_major == 0) {
ralink_nvram_major = r;
printk(KERN_DEBUG "ralink_nvram: got dynamic major %d\n", r);
}init_MUTEX(&nvram_sem);
down(&nvram_sem);
for (i = 0; i < FLASH_BLOCK_NUM; i++)
init_nvram_block(i);
up(&nvram_sem);
先調用register_chrdev註冊設備RALINK_NVRAM_DEVNAME（"nvram")接口，而後調用init_nvram_block對複製flash到內存進行初始化。終於找到flash讀入的接口了。
3. init_nvram_block接口
//read data from flash
from = from + len;
len = fb[i].flash_max_len - len;
fb[i].env.data = (char *)kmalloc(len, GFP_KERNEL);
if (!fb[i].env.data)
return -ENOMEM;
ra_mtd_read_nm(RALINK_NVRAM_MTDNAME, from, len, (unsigned char *)fb[i].env.data);
調用MTD設備接口ra_mtd_read_nm對設備RALINK_NVRAM_MTDNAME（"Config"）進行讀入。
Symbol: MTD_SPI_RALINK [=y] │
│ Prompt: SPI │
│ Defined at arch/mips/rt2880/Kconfig:143 │
│ Depends on: <choice> && !RALINK_RT2880 │
│ Location: │
│ -> Machine selection │
│ -> Flash Type (<choice> [=y])
4. MTD設備接口ra_mtd_read_nm
位置：drivers/mtd/maps/ralink-flash.c
mtd = get_mtd_device_nm(name);
if (IS_ERR(mtd))
return (int)mtd;
ret = mtd->read(mtd, from, len, &rdlen, buf);
經過對mtd設備"Config"讀接口操做。
5. MTD設備初始化接口rt2880_mtd_init
for (i = 0; i < NUM_FLASH_BANKS; i++) {
printk(KERN_NOTICE "ralink flash device: 0x%x at 0x%x\n",
ralink_map[i].size, ralink_map[i].phys);
ralink_map[i].virt = ioremap_nocache(ralink_map[i].phys, ralink_map[i].size);
if (!ralink_map[i].virt) {
printk("Failed to ioremap\n");
return -EIO;
}
simple_map_init(&ralink_map[i]);
ralink_mtd[i] = do_map_probe("cfi_probe", &ralink_map[i]);
if (ralink_mtd[i]) {
ralink_mtd[i]->owner = THIS_MODULE;
ralink_mtd[i]->lock = ralink_lock;
ralink_mtd[i]->unlock = ralink_unlock;
++found;
}
else
iounmap(ralink_map[i].virt);
}
if (found == NUM_FLASH_BANKS) {
#ifdef CONFIG_RT2880_FLASH_32M
merged_mtd = mtd_concat_create(ralink_mtd, NUM_FLASH_BANKS,
"Ralink Merged Flash");
ret = add_mtd_partitions(merged_mtd, rt2880_partitions,
ARRAY_SIZE(rt2880_partitions));
#else
ret = add_mtd_partitions(ralink_mtd[0], rt2880_partitions,
ARRAY_SIZE(rt2880_partitions));
#endif
if (ret) {
for (i = 0; i < NUM_FLASH_BANKS; i++)
iounmap(ralink_map[i].virt);
return ret;
}
}
else {
printk("Error: %d flash device was found\n", found);
return -ENXIO;
}
#endif
構造map_info結構，調用do_map_probe，根據名字"cfi_probe"找到芯片驅動linux-2.6.21.x/drivers/mtd/chips/cfi_probe.c。
6. cfi_probe
return mtd_do_chip_probe(map, &cfi_chip_probe);
cfi_probe()直接調用mtd_do_chip_probe()，傳入cfi_probe_chip()函數指針和map_info。
7. mtd_do_chip_probe(linux-2.6.21.x/drivers/mtd/chips/gen_probe.c)
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 */
先調用genprobe_ident_chips()，cfi_probe_chip根據map_info探測芯片信息，後調用check_cmd_set()獲取和初始化芯片命令集。
8. ralink_spi.c(linux-2.6.21.x/drivers/mtd/ralink/ralink_spi.c)
static struct mtd_partition rt2880_partitions[] = {
{
name: "ALL",
size: MTDPART_SIZ_FULL,
offset: 0,
},
/* Put your own partition definitions here */
{
name: "Bootloader",
size: MTD_BOOT_PART_SIZE,
offset: 0,
}, {
name: "Config",
size: MTD_CONFIG_PART_SIZE,
offset: MTDPART_OFS_APPEND
}, {
name: "Factory",
size: MTD_FACTORY_PART_SIZE,
offset: MTDPART_OFS_APPEND
#ifdef CONFIG_RT2880_ROOTFS_IN_FLASH
}, {
name: "Kernel",
size: MTD_KERN_PART_SIZE,
offset: MTDPART_OFS_APPEND,
}, {
name: "RootFS",
size: MTD_ROOTFS_PART_SIZE,
offset: MTDPART_OFS_APPEND,
#ifdef CONFIG_ROOTFS_IN_FLASH_NO_PADDING
}, {
name: "Kernel_RootFS",
size: MTD_KERN_PART_SIZE + MTD_ROOTFS_PART_SIZE,
offset: MTD_BOOT_PART_SIZE + MTD_CONFIG_PART_SIZE + MTD_FACTORY_PART_SIZE,
#endif
#else //CONFIG_RT2880_ROOTFS_IN_RAM
}, {
name: "Kernel",
size: MTD_KERN_PART_SIZE,
offset: MTDPART_OFS_APPEND,
#endif
#ifdef CONFIG_DUAL_IMAGE
}, {
name: "Kernel2",
size: MTD_KERN2_PART_SIZE,
offset: MTD_KERN2_PART_OFFSET,
#ifdef CONFIG_RT2880_ROOTFS_IN_FLASH
}, {
name: "RootFS2",
size: MTD_ROOTFS2_PART_SIZE,
offset: MTD_ROOTFS2_PART_OFFSET,
#endif
#endif
}
};
mtd分區，cfi_probe_chip經過分區信息表關聯mtd接口到該設備的操做接口。
static int __init raspi_init(void)
{
register_mtd_chip_driver(&raspi_chipdrv);
raspi_chipdrv.probe(NULL);
return 0;
}
mtd設備初始化。
flash->chip = chip;
flash->mtd.name = "raspi";
flash->mtd.type = MTD_NORFLASH;
flash->mtd.writesize = 1;
flash->mtd.flags = MTD_CAP_NORFLASH;
flash->mtd.size = chip->sector_size * chip->n_sectors;
flash->mtd.erasesize = chip->sector_size;
flash->mtd.erase = ramtd_erase;
flash->mtd.read = ramtd_read;
flash->mtd.write = ramtd_write;
flash->mtd.lock = ramtd_lock;
flash->mtd.unlock = ramtd_unlock;
flash驅動具體操做接口。
- 1. [FAQ04184] [NVRAM] 如何添加驅動訪問NVRAM的進程
- 2. UBOOT_NAND驅動分析
- 3. emysql 驅動分析
- 4. eMMC驅動分析
- 5. MTD驅動分析
- 6. Linux驅動：LCD驅動框架分析
- 7. linux驅動之串口驅動分析
- 8. mtd驅動分析-硬件驅動層
- 9. 【驅動】DM9000網卡驅動分析
- 10. 【linux驅動分析】之dm9000驅動分析
- 更多相關文章...
- • IP地址分配（靜態分配+動態分配+零配置） - TCP/IP教程
- • 互聯網系統應用架構基礎分析 - 紅包項目實戰
- • Git五分鐘教程
- • 算法總結-滑動窗口
-
每一个你不满意的现在，都有一个你没有努力的曾经。
- 1. [FAQ04184] [NVRAM] 如何添加驅動訪問NVRAM的進程
- 2. UBOOT_NAND驅動分析
- 3. emysql 驅動分析
- 4. eMMC驅動分析
- 5. MTD驅動分析
- 6. Linux驅動：LCD驅動框架分析
- 7. linux驅動之串口驅動分析
- 8. mtd驅動分析-硬件驅動層
- 9. 【驅動】DM9000網卡驅動分析
- 10. 【linux驅動分析】之dm9000驅動分析