简介

作者：彭东林

邮箱：[email protected]

u-boot版本：u-boot-2015.04

Linux版本：Linux-3.14

硬件平台：tq2440，内存：64M NandFlash: 256MB

下面我们分两部分，u-boot和kernel，首先介绍u-boot中是如何支持mtdparts的，然后简单分析Linux内核设置分区的两种方式：

方式一

在平台代码中写死，然后在初始化NandFlash的时候设置。

方式二

在u-boot中设置，这个比较灵活，u-boot将分区信息（形如：mtdparts=xxx）添加到bootargs中，kernel在启动的时候会解析mtdparts。

u-boot中支持mtdparts命令

转载自：http://w3sun.blog.163.com/blog/static/1859535342012058369333/

分区方法

1)MTD层的分区

2)通过U-boot传递给内核的命令行中的mtdparts=...

3)其他可以让内核知道分区信息的任何办法，（内核默认的命令参数）

下面说到mtdparts，及它的用法：

mtdparts

mtdparts=fc000000.nor_flash:1920k(linux),128k(fdt),20M(ramdisk),4M(jffs2),382

72k(user),256k(env),384k(uboot)要想这个参数起作用，

内核中的mtd驱动必须要支持，即内核配置时需要选上

Device Drivers --->

Memory Technology Device (MTD) support --->

Command line partition table parsing

mtdparts的格式如下：

mtdparts=<mtddef>[;<mtddef]

<mtddef> := <mtd-id>:<partdef>[,<partdef>]

<partdef> := <size>[@offset][<name>][ro]

<mtd-id> := unique id used in mapping driver/device

<size> := standard linux memsize OR "-" to denote all remaining space

<name> := (NAME)

因此你在使用的时候需要按照下面的格式来设置：

mtdparts=mtd-id:<size1>@<offset1>(<name1>),<size2>@<offset2>(<name2>)

这有几个需要注意的地方：

a.mtd-id 必须要跟你当前平台的flash的mtd-id一致，不然整个mtdparts会失效怎样获取到

当前平台的flash的mtd-id？在bootargs参数列表中，可以指定当前flash的mtd-id，指定 mtdid

s:nand0=gen_nand.1，前面的nand0则表示第一个flash

b.size在设置的时候可以为实际的size(xxM,xxk,xx)，也可以为‘-‘这表示剩余的所有空间。相

关信息可以查看drivers/mtd/cmdlinepart.c中的注释找到相关描述。

U-boot环境变量有两个，他们分别是： bootcmd 和bootargs。

至于在我们自己的at91sam9263ek板子上为了实现mtdparts分区命令的支持需要在U-boot

-2010.06/include/configs/at91sam9263ek.h中添加相关的宏定义：

#define CONFIG_CMD_MTDPARTS

#define CONFIG_MTD_DEVICE

#define CONFIG_MTD_PARTITIONS

加入MTD分区信息：

#define MTDIDS_DEFAULT "nand0=atmel_nand"

#define MTDPARTS_DEFAULT "mtdparts=atmel_nand:[email protected](cramfs)," \

"15M(jffs2)," \

"30M(yaffs2)," \

"-(user)"

保存后退出，回到根目录，重新make

[[email protected] u-boot-2010.06]#make at91sam9263ek_dataflash_cs0_config

[root[email protected] u-boot-2010.06]#make all

将重新编译的u-boot.bin烧到dataflash中，使用mtdparts查看分区：

U-Boot> mtdparts

device nand0 <atmel_nand>, # parts = 4

#: name size offset mask_flags

0: cramfs 0x00f00000 0x00000000 0

1: jffs2 0x00f00000 0x00f00000 0

2: yaffs2 0x01e00000 0x01e00000 0

3: user 0x04400000 0x03c00000 0

active partition: nand0,0 - (cramfs) 0x00f00000 @ 0x00000000

defaults:

mtdids : nand0=atmel_nand

mtdparts: mtdparts=atmel_nand:[email protected](cramfs),15M(jffs2),30M(yaffs2),-(user)

重新设置分区：

U-Boot> setenv mtdparts mtdparts=atmel_nand:[email protected](a),30M(b),-(c)

U-Boot> save

Saving Environment to dataflash...

U-Boot> mtdparts

device nand0 <atmel_nand>, # parts = 3

#: name size offset mask_flags

0: a 0x01e00000 0x00000000 0

1: b 0x01e00000 0x01e00000 0

2: c 0x04400000 0x03c00000 0

active partition: nand0,0 - (a) 0x01e00000 @ 0x00000000

defaults:

mtdids : nand0=atmel_nand

mtdparts: mtdparts=atmel_nand:[email protected](cramfs),15M(jffs2),30M(yaffs2),-(user)

可以看到，我们可以手动设置分区了。最后还要恢复默认。

U-Boot>mtdparts default

Kernel中设置分区

相关的内核代码我已经上传到csdn上了，使用git管理，分支是transplant_to_tq2440

git clone [email protected]:pengdonglin137/linux-3-14-y.git

方法一、在平台代码中写死

在此之前我们先看看NandFlash是如何初始化的。

这里采用platform_device和platform_driver架构。

1. platform_device的注册

在arch/arm/mach-s3c24xx/mach-tq2440.c中:

   1:  static struct platform_device *tq2440_devices[] __initdata = {

   2:                  ......

   3:      &s3c_device_nand,

   4:  };

5:

   6:  static void __init tq2440_machine_init(void)

   7:  {

   8:                 ......

   9:      s3c_nand_set_platdata(&tq2440_nand_info);

  10:      platform_add_devices(tq2440_devices, ARRAY_SIZE(tq2440_devices));

  11:                  ......

  12:  }

13:

  14:  MACHINE_START(TQ2440, "TQ2440")

  15:                  ........

  16:      .init_machine    = tq2440_machine_init,

  17:                  ......

  18:  MACHINE_END

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第5行是nand控制器的platform_device;

第10行platform_add_device会将s3c_device_nand注册到系统中;

第9行设置的就是分区相关的信息

   1:  /* NAND parititon */

2:

   3:  static struct mtd_partition tq2440_nand_part[] = {

   4:      [0] = {

   5:          .name    = "Boot",

   6:          .offset = 0,

   7:          .size    = SZ_2M,

   8:      },

   9:      [1] = {

  10:          .name    = "Kernel",

  11:          .offset    = SZ_2M,

  12:          .size    = SZ_1M * 3,

  13:      },

  14:      [2] = {

  15:          .name    = "Rootfs",

  16:          .offset = SZ_1M * 5,

  17:          .size    = MTDPART_SIZ_FULL,

  18:      }

  19:  };

20:

  21:  static struct s3c2410_nand_set tq2440_nand_sets[] = {

  22:      [0] = {

  23:          .name        = "NAND",

  24:          .nr_chips    = 1,

  25:          .nr_partitions    = ARRAY_SIZE(tq2440_nand_part),

  26:          .partitions    = tq2440_nand_part,

  27:      },

  28:  };

29:

  30:  /* choose a set of timings which should suit most 512Mbit

  31:   * chips and beyond.

  32:  */

33:

  34:  static struct s3c2410_platform_nand tq2440_nand_info = {

  35:      .tacls        = 10,

  36:      .twrph0        = 25,

  37:      .twrph1        = 10,

  38:      .nr_sets    = ARRAY_SIZE(tq2440_nand_sets),

  39:      .sets        = tq2440_nand_sets,

  40:  };

第3行的结构体tq2440_nand_part就是分区信息，容易看出，这里一共分了3个区，分别是Boot、Kernel和Rootfs:

Boot

(2MB)

Kernel
(3MB)

Rootfs

(剩余)

然后将这个分区表存放到了第21行的tq2440_nand_set的元素[0]中，分区表的名字”NAND”，注意这里的名字很重要，将来u-boot中传入的mtdparts中的mtd-id一致。tq2440_nand_sets的每一个元素存放一张分区表；

第34行的结构体tq2440_nand_info中的tacls/twrph0/twrph1用于控制Nand控制器读写NandFlash时的时序参数。

s3c_device_nand是在文件arch/arm/plat-samsung/devs.c

   1:  /* NAND */

2:

   3:  #ifdef CONFIG_S3C_DEV_NAND

   4:  static struct resource s3c_nand_resource[] = {

   5:      [0] = DEFINE_RES_MEM(S3C_PA_NAND, SZ_1M),

   6:  };

7:

   8:  struct platform_device s3c_device_nand = {

   9:      .name        = "s3c2410-nand",

  10:      .id        = -1,

  11:      .num_resources    = ARRAY_SIZE(s3c_nand_resource),

  12:      .resource    = s3c_nand_resource,

  13:  };

14:

  15:  /*

  16:   * s3c_nand_copy_set() - copy nand set data

  17:   * @set: The new structure, directly copied from the old.

  18:   *

  19:   * Copy all the fields from the NAND set field from what is probably __initdata

  20:   * to new kernel memory. The code returns 0 if the copy happened correctly or

  21:   * an error code for the calling function to display.

  22:   *

  23:   * Note, we currently do not try and look to see if we‘ve already copied the

  24:   * data in a previous set.

  25:   */

  26:  static int __init s3c_nand_copy_set(struct s3c2410_nand_set *set)

  27:  {

  28:      void *ptr;

  29:      int size;

30:

  31:      size = sizeof(struct mtd_partition) * set->nr_partitions;

  32:      if (size) {

  33:          ptr = kmemdup(set->partitions, size, GFP_KERNEL);

  34:          set->partitions = ptr;

35:

  36:          if (!ptr)

  37:              return -ENOMEM;

  38:      }

39:

  40:      if (set->nr_map && set->nr_chips) {

  41:          size = sizeof(int) * set->nr_chips;

  42:          ptr = kmemdup(set->nr_map, size, GFP_KERNEL);

  43:          set->nr_map = ptr;

44:

  45:          if (!ptr)

  46:              return -ENOMEM;

  47:      }

48:

  49:      if (set->ecc_layout) {

  50:          ptr = kmemdup(set->ecc_layout,

  51:                    sizeof(struct nand_ecclayout), GFP_KERNEL);

  52:          set->ecc_layout = ptr;

53:

  54:          if (!ptr)

  55:              return -ENOMEM;

  56:      }

57:

  58:      return 0;

  59:  }

60:

  61:  void __init s3c_nand_set_platdata(struct s3c2410_platform_nand *nand)

  62:  {

  63:      struct s3c2410_platform_nand *npd;

  64:      int size;

  65:      int ret;

66:

  67:      /* note, if we get a failure in allocation, we simply drop out of the

  68:       * function. If there is so little memory available at initialisation

  69:       * time then there is little chance the system is going to run.

  70:       */

71:

  72:      npd = s3c_set_platdata(nand, sizeof(struct s3c2410_platform_nand),

  73:                  &s3c_device_nand);

  74:      if (!npd)

  75:          return;

76:

  77:      /* now see if we need to copy any of the nand set data */

78:

  79:      size = sizeof(struct s3c2410_nand_set) * npd->nr_sets;

  80:      if (size) {

  81:          struct s3c2410_nand_set *from = npd->sets;

  82:          struct s3c2410_nand_set *to;

  83:          int i;

84:

  85:          to = kmemdup(from, size, GFP_KERNEL);

  86:          npd->sets = to;    /* set, even if we failed */

87:

  88:          if (!to) {

  89:              printk(KERN_ERR "%s: no memory for sets\n", __func__);

  90:              return;

  91:          }

92:

  93:          for (i = 0; i < npd->nr_sets; i++) {

  94:              ret = s3c_nand_copy_set(to);

  95:              if (ret) {

  96:                  printk(KERN_ERR "%s: failed to copy set %d\n",

  97:                  __func__, i);

  98:                  return;

  99:              }

 100:              to++;

 101:          }

 102:      }

 103:  }

 104:  #endif /* CONFIG_S3C_DEV_NAND */

第72行将nand(也就是tq2440_nand_info)的副本存放到s3c_device_nand的dev.platform_data中，然后将nand的副本首地址npd返回；

第79行到第100行将tq2440_nand_info的分区信息拷贝一份，赋值给npd的sets成员；

2. platform_driver的注册

文件：drivers/mtd/nand/s3c2410.c

   1:  /* driver device registration */

2:

   3:  static struct platform_device_id s3c24xx_driver_ids[] = {

   4:      {

   5:          .name        = "s3c2410-nand",

   6:          .driver_data    = TYPE_S3C2410,

   7:      }, {

   8:          .name        = "s3c2440-nand",

   9:          .driver_data    = TYPE_S3C2440,

  10:      }, {

  11:          .name        = "s3c2412-nand",

  12:          .driver_data    = TYPE_S3C2412,

  13:      }, {

  14:          .name        = "s3c6400-nand",

  15:          .driver_data    = TYPE_S3C2412, /* compatible with 2412 */

  16:      },

  17:      { }

  18:  };

19:

  20:  MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);

21:

  22:  static struct platform_driver s3c24xx_nand_driver = {

  23:      .probe        = s3c24xx_nand_probe,

  24:      .remove        = s3c24xx_nand_remove,

  25:      .suspend    = s3c24xx_nand_suspend,

  26:      .resume        = s3c24xx_nand_resume,

  27:      .id_table    = s3c24xx_driver_ids,

  28:      .driver        = {

  29:          .name    = "s3c24xx-nand",

  30:          .owner    = THIS_MODULE,

  31:      },

  32:  };

33:

  34:  module_platform_driver(s3c24xx_nand_driver);

当注册s3c24xx_nand_driver的时候，由于s3c24xx_driver_ids中的”s3c2410-nand”与s3c_device_nand的name一致，因此函数s3c24xx_nand_probe被执行。

下面我们简要分析函数s3c24xx_nand_probe的实现：

   1:  /* s3c24xx_nand_probe

   2:   *

   3:   * called by device layer when it finds a device matching

   4:   * one our driver can handled. This code checks to see if

   5:   * it can allocate all necessary resources then calls the

   6:   * nand layer to look for devices

   7:  */

   8:  static int s3c24xx_nand_probe(struct platform_device *pdev)

   9:  {

  10:      struct s3c2410_platform_nand *plat = to_nand_plat(pdev);

  11:      enum s3c_cpu_type cpu_type;

  12:      struct s3c2410_nand_info *info;

  13:      struct s3c2410_nand_mtd *nmtd;

  14:      struct s3c2410_nand_set *sets;

  15:      struct resource *res;

  16:      int err = 0;

  17:      int size;

  18:      int nr_sets;

  19:      int setno;

20:

  21:      cpu_type = platform_get_device_id(pdev)->driver_data;

22:

  23:      pr_debug("s3c2410_nand_probe(%p)\n", pdev);

24:

  25:      info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL);

  26:      if (info == NULL) {

  27:          err = -ENOMEM;

  28:          goto exit_error;

  29:      }

30:

  31:      platform_set_drvdata(pdev, info);

32:

  33:      spin_lock_init(&info->controller.lock);

  34:      init_waitqueue_head(&info->controller.wq);

35:

  36:      /* get the clock source and enable it */

37:

  38:      info->clk = devm_clk_get(&pdev->dev, "nand");

  39:      if (IS_ERR(info->clk)) {

  40:          dev_err(&pdev->dev, "failed to get clock\n");

  41:          err = -ENOENT;

  42:          goto exit_error;

  43:      }

44:

  45:      s3c2410_nand_clk_set_state(info, CLOCK_ENABLE);

46:

  47:      /* allocate and map the resource */

48:

  49:      /* currently we assume we have the one resource */

  50:      res = pdev->resource;

  51:      size = resource_size(res);

52:

  53:      info->device    = &pdev->dev;

  54:      info->platform    = plat;

  55:      info->cpu_type    = cpu_type;

56:

  57:      info->regs = devm_ioremap_resource(&pdev->dev, res);

  58:      if (IS_ERR(info->regs)) {

  59:          err = PTR_ERR(info->regs);

  60:          goto exit_error;

  61:      }

62:

  63:      dev_dbg(&pdev->dev, "mapped registers at %p\n", info->regs);

64:

  65:      /* initialise the hardware */

66:

  67:      err = s3c2410_nand_inithw(info);

  68:      if (err != 0)

  69:          goto exit_error;

70:

  71:      sets = (plat != NULL) ? plat->sets : NULL;

  72:      nr_sets = (plat != NULL) ? plat->nr_sets : 1;

73:

  74:      info->mtd_count = nr_sets;

75:

  76:      /* allocate our information */

77:

  78:      size = nr_sets * sizeof(*info->mtds);

  79:      info->mtds = devm_kzalloc(&pdev->dev, size, GFP_KERNEL);

  80:      if (info->mtds == NULL) {

  81:          err = -ENOMEM;

  82:          goto exit_error;

  83:      }

84:

  85:      /* initialise all possible chips */

86:

  87:      nmtd = info->mtds;

88:

  89:      for (setno = 0; setno < nr_sets; setno++, nmtd++) {

  90:          pr_debug("initialising set %d (%p, info %p)\n",

  91:               setno, nmtd, info);

92:

  93:          s3c2410_nand_init_chip(info, nmtd, sets);

94:

  95:          nmtd->scan_res = nand_scan_ident(&nmtd->mtd,

  96:                           (sets) ? sets->nr_chips : 1,

  97:                           NULL);

98:

  99:          if (nmtd->scan_res == 0) {

 100:              s3c2410_nand_update_chip(info, nmtd);

 101:              nand_scan_tail(&nmtd->mtd);

 102:              s3c2410_nand_add_partition(info, nmtd, sets);

 103:          }

 104:

 105:          if (sets != NULL)

 106:              sets++;

 107:      }

 108:

 109:      err = s3c2410_nand_cpufreq_register(info);

 110:      if (err < 0) {

 111:          dev_err(&pdev->dev, "failed to init cpufreq support\n");

 112:          goto exit_error;

 113:      }

 114:

 115:      if (allow_clk_suspend(info)) {

 116:          dev_info(&pdev->dev, "clock idle support enabled\n");

 117:          s3c2410_nand_clk_set_state(info, CLOCK_SUSPEND);

 118:      }

 119:

 120:      pr_debug("initialised ok\n");

 121:      return 0;

 122:

 123:   exit_error:

 124:      s3c24xx_nand_remove(pdev);

 125:

 126:      if (err == 0)

 127:          err = -EINVAL;

 128:      return err;

 129:  }

第10行，获得tq2440_nand_info,其实是它的副本；

第21行，cpu_type是TYPE_S3C2410；

第38行，获得nand控制器的时钟；

第45行，使能nand控制器的时钟；

第67行，初始化nand控制器；

第72行，nr_sets的值是1；

第93行，根据cpu_type的设置初始化一些函数指针，如读函数、写函数以及片选函数；

第95行，读取NandFlash的ID，以及容量、规格（如pagesize），成功返回0；

第100行，设置一些关于ecc的信息；

第101行，设置一些关于oob读写的信息；

下面重点分析第102行的函数：s3c2410_nand_add_partition

   1:  static int s3c2410_nand_add_partition(struct s3c2410_nand_info *info,

   2:                        struct s3c2410_nand_mtd *mtd,

   3:                        struct s3c2410_nand_set *set)

   4:  {

   5:      if (set) {

   6:          mtd->mtd.name = set->name;

7:

   8:          return mtd_device_parse_register(&mtd->mtd, NULL, NULL,

   9:                       set->partitions, set->nr_partitions);

  10:      }

11:

  12:      return -ENODEV;

  13:  }

第6行的set->name就是”Nand”

第9行的set->partitions中存放的是分区表，set->nr_partitions存放的是这个分区表的包含的分区个数

   1:  int mtd_device_parse_register(struct mtd_info *mtd, const char * const *types,

   2:                    struct mtd_part_parser_data *parser_data,

   3:                    const struct mtd_partition *parts,

   4:                    int nr_parts)

   5:  {

   6:      int err;

   7:      struct mtd_partition *real_parts;

8:

   9:      err = parse_mtd_partitions(mtd, types, &real_parts, parser_data);

  10:      if (err <= 0 && nr_parts && parts) {

  11:          real_parts = kmemdup(parts, sizeof(*parts) * nr_parts,

  12:                       GFP_KERNEL);

  13:          if (!real_parts)

  14:              err = -ENOMEM;

  15:          else

  16:              err = nr_parts;

  17:      }

18:

  19:      if (err > 0) {

  20:          err = add_mtd_partitions(mtd, real_parts, err);

  21:          kfree(real_parts);

  22:      } else if (err == 0) {

  23:          err = add_mtd_device(mtd);

  24:          if (err == 1)

  25:              err = -ENODEV;

  26:      }

27:

  28:      return err;

  29:  }

第9行，parse_mtd_partitions用于解析命令行中设置的分区，如果命令行中没有设置mtdparts，那么返回0，如果设置了，并且解析没问题，那么返回大于零的数，否则返回小于零的数。

时间： 2024-10-12 16:23:35

u-boot中添加mtdparts支持以及Linux的分区设置

简介

u-boot中支持mtdparts命令

Kernel中设置分区

方法一、在平台代码中写死

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