Send cmd to SD card but error 22 on Linux

Asked Aug 03 '16 at 06:07

Active Jan 22 '18 at 11:50

Viewed 733 times

I refer an article:

Any way to send commands to SD card from Linux userspace?

and use the source of mmc-util to send cmd to SD card, there is the code:

int cmd_test(int fd, __u8 *ext_csd)
{
    int ret = 0;
    struct mmc_ioc_cmd idata;
    memset(&idata, 0, sizeof(idata));
    memset(ext_csd, 0, sizeof(__u8) * 512);
    idata.write_flag = 0;
    idata.opcode = 17;
    idata.arg = 0;
    idata.flags = MMC_DATA_READ;
    idata.blksz = 512;
    idata.blocks = 1;
    mmc_ioc_cmd_set_data(idata, ext_csd);

    ret = ioctl(fd, MMC_IOC_CMD, &idata);
    if (ret)
        perror("ioctl");

    return ret;
}

finally receive error 22: invalid argument. I try another opcode like 10, 56..., it finally result same error. The SD card is connected by usb reader, does it cause the error? or there are parameter setting error?

Thanks.

edited May 23 '17 at 12:14

Community

asked Aug 03 '16 at 06:07

KKJoe

Where are you getting your file descriptor from? – LordWilmore Aug 03 '16 at 06:21
I refer the source from this http://git.kernel.org/cgit/linux/kernel/git/cjb/mmc-utils.git/tree/mmc_cmds.c – KKJoe Aug 03 '16 at 08:26
Yes but you're calling the function, passing a file descriptor in the parameter `fd`. Where are you getting that value from, i.e. how are you opening the file? – LordWilmore Aug 03 '16 at 08:30
I open the file by this way: fd = open(device, O_RDWR); – KKJoe Aug 03 '16 at 09:03
See this project: https://github.com/BertoldVdb/sdtool – i486 Jan 22 '18 at 12:17

Send cmd to SD card but error 22 on Linux

0 Answers0