mini2440 linux移植 nandflash驱动的移植

hetin 2011-01-26

展开全文

根据《Mini2440_Linux移植开发实战指南》一文进行nandflash驱动的移植出现了不少问题

make zImage出错：
arch/arm/mach-s3c2440/mach-mini2440.c:189: error: array type has incomplete element type
arch/arm/mach-s3c2440/mach-mini2440.c:190: error: array index in non-array initializer
arch/arm/mach-s3c2440/mach-mini2440.c:190: error: (near initialization for 'smdk_default_nand_part')
arch/arm/mach-s3c2440/mach-mini2440.c:191: error: field name not in record or union initializer
arch/arm/mach-s3c2440/mach-mini2440.c:191: error: (near initialization for 'smdk_default_nand_part')

arch/arm/mach-s3c2440/mach-mini2440.c:193: error: unknown field 'tacls' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:193: warning: excess elements in struct initializer
arch/arm/mach-s3c2440/mach-mini2440.c:193: warning: (near initialization for 'mini2440_nand_info')
arch/arm/mach-s3c2440/mach-mini2440.c:194: error: unknown field 'twrph0' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:194: warning: excess elements in struct initializer
arch/arm/mach-s3c2440/mach-mini2440.c:194: warning: (near initialization for 'mini2440_nand_info')
arch/arm/mach-s3c2440/mach-mini2440.c:195: error: unknown field 'twrph1' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:195: warning: excess elements in struct initializer
arch/arm/mach-s3c2440/mach-mini2440.c:195: warning: (near initialization for 'mini2440_nand_info')
arch/arm/mach-s3c2440/mach-mini2440.c:196: error: unknown field 'nr_sets' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:196: warning: type defaults to 'int' in declaration of 'type name'
arch/arm/mach-s3c2440/mach-mini2440.c:196: warning: type defaults to 'int' in declaration of 'type name'
arch/arm/mach-s3c2440/mach-mini2440.c:196: error: negative width in bit-field '<anonymous>'
arch/arm/mach-s3c2440/mach-mini2440.c:196: warning: excess elements in struct initializer
arch/arm/mach-s3c2440/mach-mini2440.c:196: warning: (near initialization for 'mini2440_nand_info')
arch/arm/mach-s3c2440/mach-mini2440.c:197: error: unknown field 'sets' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:197: warning: excess elements in struct initializer
arch/arm/mach-s3c2440/mach-mini2440.c:197: warning: (near initialization for 'mini2440_nand_info')
arch/arm/mach-s3c2440/mach-mini2440.c:198: error: unknown field 'ingnore_unset_ecc' specified in initializer
arch/arm/mach-s3c2440/mach-mini2440.c:198: warning: excess elements in struct initializer

于是在自己的mach－mini2440.c中加入
#include <linux/mtd/mtd.h>
#include <linux/mtd/nand.h>
#include <linux/mtd/nand_ecc.h>
#include <linux/mtd/partitions.h>
#include <plat/nand.h>

S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=4, 39ns Twrph0=8 79ns, Twrph1=8 79ns
Unable to handle kernel NULL pointer dereference at virtual address 00000018
pgd = c0004000
[00000018] *pgd=00000000
Internal error: Oops: 5 [#1]
last sysfs file:
Modules linked in:

因为 mini2440的 flash的参数应该是：
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c2440-nand s3c2440-nand: Tacls=3, 29ns Twrph0=7 69ns, Twrph1=3 29ns
从以上差别可以看出我们按照友善提供的Linux移植开发实战所修改的下面一个结构体里设置的参数并没有生效：
static struct s3c2410_platform_nand mini2440_nand_info = {
        .tacls          = 20,
        .twrph0         = 60,
        .twrph1         = 20,
        .nr_sets        = ARRAY_SIZE(mini2440_nand_sets),
        .sets           = mini2440_nand_sets,
};
以上的结构体是mini2440开发板上使用的nand flash的一些配置信息，其中包括芯片操作时序信息。
查看nand flash相应的datasheet里面对nand flash控制器的NFCONF寄存器有如下描述
CLE/ALE是高电平使能而TACLS是CLE/ALE使能的持续时间，也就是CLE/ALE信号线高电平持续的时间；
nWE是低电平使能 TWRPH0对应于nWE的使能持续时间，也就是nWE信号线低电平的持续时间；
而TWRPH1对应于nWE信号线高电平的持续时间。
具体如下图：

而通过内核打印信息+Source Insight查找到输出
S3C24XX NAND Driver, (c) 2004 Simtec Electronics
s3c24xx-nand s3c2440-nand: Tacls=4, 39ns Twrph0=8 79ns, Twrph1=8 79ns
语句信息的函数在内核源码中nand flash驱动程序里的drivers/mtd/nand/s3c2410.c文件中。
分析Linux内核中的nand flash驱动drivers/mtd/nand/s3c2410.c文件中的相应函数，
其中的static int s3c2410_nand_setrate(struct s3c2410_nand_info *info)函数发现：
    struct s3c2410_platform_nand *plat = info->platform;
        int tacls_max = (info->cpu_type == TYPE_S3C2412) ? 8 : 4;
         …………
    info->clk_rate = clkrate;
        clkrate /= 1000;        /* turn clock into kHz for ease of use */
if (plat != NULL) {
                tacls = s3c_nand_calc_rate(plat->tacls, clkrate, tacls_max);
                twrph0 = s3c_nand_calc_rate(plat->twrph0, clkrate, 8);
                twrph1 = s3c_nand_calc_rate(plat->twrph1, clkrate, 8);
} else {
          /* default timings */
   tacls = tacls_max;
                twrph0 = 8;
                twrph1 = 8;
            }
        if (tacls < 0 || twrph0 < 0 || twrph1 < 0) {
                dev_err(info->device, "cannot get suitable timings\n");
                return -EINVAL;
        }
        dev_info(info->device, "Tacls=%d, %dns Twrph0=%d %dns, Twrph1=%d %dns\n",
               tacls, to_ns(tacls, clkrate), twrph0, to_ns(twrph0, clkrate), twrph1, to_ns(twrph1, clkrate));
由以上内容可以看出，内核并没有使用我们的mini2440_nand_info结构体中的配置，而是使用了它的默认配给，即
} else {
          /* default timings */
   tacls = tacls_max;
                twrph0 = 8;
                twrph1 = 8;
            }
中的配置信息。这点和我们改的内核输出s3c24xx-nand s3c2440-nand: Tacls=4, 39ns Twrph0=8 79ns, Twrph1=8 79ns完全符合。
因此可以判断我们需要在mach-mini2440.c的mini2440_machine_init（）函数中增加s3c_device_nand.dev.platform_data = &mini240_nand_info;

   http://xliuning.spaces./blog/cns!C9DB9E35C9DE3752!329.entry