c - MicroZed 无法使用 xilffs 库写入 SD 卡

Question

我正在使用带有 Xilinx Zynq 7010 的 MicroZed 开发板，我试图在没有任何操作系统的情况下写入 SD 卡，仅使用 xilffs (LibXil 胖文件系统)库。

为了测试它，我正在使用这个 xilffs_polled_example.c Xilinx提供的测试文件，此时测试失败:

// Write data to file.
Res = f_write(&fil, (const void*)SourceAddress, FileSize, &NumBytesWritten);
if (Res) {
    xil_printf("6: Failed to write data to file\n");
    return XST_FAILURE;
}

但是，如果我注释掉那个测试数据验证测试，那么其他一切都成功了:

2: Successful mount
3: Successfully created FAT volume
4: Successfully opened file with permissions
5: Successfully put pointer at beginning of file
skip write test
7:Successfully put pointer back to beginning of file
8: Successfully read data from file
skip data verification
10: Successfully closed file

我认为这可能是 SD 卡处于错误模式/格式的问题。我已经使用 Windows 10 将 SD 卡格式化为 FAT32，如果 SD 卡处于只读模式，我认为此测试也会失败:

SD_File = (char *)FileName;
Res = f_open(&fil, (char *)FileName, FA_CREATE_ALWAYS | FA_WRITE | FA_READ);
if (Res) {
    xil_printf("4: Failed to open file with permissions\n");
    return XST_FAILURE;
}

下面是我的代码，除了要调试的打印语句外，它与链接文件基本相同。有没有人对问题可能有任何理论？

int FfsSdPolledExample(void)
{
    FRESULT Res;
    UINT NumBytesRead;
    UINT NumBytesWritten;
    u32 BuffCnt;
    u32 FileSize = (8*1024*1024);
    //TCHAR *Path = "0:/";
    const char *Path = "0:/";

    Platform = XGetPlatform_Info();
    if (Platform == XPLAT_ZYNQ_ULTRA_MP) {
         // Since 8MB in Emulation Platform taking long time, reduced
         // file size to 8KB.
        FileSize = 8*1024;
    }

    for(BuffCnt = 0; BuffCnt < FileSize; BuffCnt++){
        SourceAddress[BuffCnt] = TEST + BuffCnt;
    }

    // Register volume work area, initialize device
    Res = f_mount(&fatfs, Path, 0);
    if (Res != FR_OK) {
        xil_printf("2: Failed to mount\n");
        return XST_FAILURE;
    }
    xil_printf("2: Successful mount\n");

    // Path - Path to logical driver, 0 - FDISK format.
    // 0 - Cluster size is automatically determined based on Vol size.
    Res = f_mkfs(Path, 0, 0);
    if (Res != FR_OK) {
        xil_printf("3: Failed to create FAT volume\n");
        return XST_FAILURE;
    }
    xil_printf("3: Successfully created FAT volume\n");

    // Open file with required permissions.
    // Here - Creating new file with read/write permissions. .
    // To open file with write permissions, file system should not
    // be in Read Only mode.
    SD_File = (char *)FileName;

    Res = f_open(&fil, (char *)FileName, FA_CREATE_ALWAYS | FA_WRITE | FA_READ);
    if (Res) {
        xil_printf("4: Failed to open file with permissions\n");
        return XST_FAILURE;
    }
    xil_printf("4: Successfully opened file with permissions\n");

    // Pointer to beginning of file
    Res = f_lseek(&fil, 0);
    if (Res) {
        xil_printf("5: Failed to put pointer at beginning of file\n");
        return XST_FAILURE;
    }
    xil_printf("5: Successfully put pointer at beginning of file\n");

    // Write data to file.
    /*
    Res = f_write(&fil, (const void*)SourceAddress, FileSize,
            &NumBytesWritten);
    if (Res) {
        xil_printf("6: Failed to write data to file\n");
        return XST_FAILURE;
    }
    xil_printf("6: Successfully written data to file\n");
    */

    //Pointer to beginning of file .
    Res = f_lseek(&fil, 0);
    if (Res) {
        xil_printf("7: Failed to put pointer back to beginning of file\n");
        return XST_FAILURE;
    }
    xil_printf("7: Successfully put pointer back to beginning of file\n");

    //Read data from file.
    Res = f_read(&fil, (void*)DestinationAddress, FileSize,
            &NumBytesRead);
    if (Res) {
        xil_printf("8: Failed to read data from file\n");
        return XST_FAILURE;
    }
    xil_printf("8: Successfully read data from file\n");

    // Data verification
    /*
    for(BuffCnt = 0; BuffCnt < FileSize; BuffCnt++){
        if(SourceAddress[BuffCnt] != DestinationAddress[BuffCnt]){
            xil_printf("9: Data verification failed\n");
            return XST_FAILURE;
        }
    }
    xil_printf("9: Data verification passed\n");
    */

    //Close file.
    Res = f_close(&fil);
    if (Res) {
        xil_printf("10: Failed to close file\n");
        return XST_FAILURE;
    }
    xil_printf("10: Successfully closed file\n");

    return XST_SUCCESS;
}

Answer 1

我在设计中偶然发现了同样的问题。 xilffs 中的写入功能似乎已损坏。

长话短说，问题出在 diskio.c 中，它在连续写入期间行为异常。卡或 DMA 可能仍然很忙，并且硬件包装器功能从不检查它们是否空闲。

到目前为止还没有好的和稳定的解决方案，但是在 disk_write() 中的 XSdPs_WritePolled() 之前添加 usleep(200) 会有所帮助。

这是一个 BSP 源代码，要对其进行编辑，您需要使用您的 xilffs 副本创建一个本地存储库，并将其添加到本地存储库列表(xilinx 工具 -> 存储库)，然后在本地存储库中编辑 diskio.c 并重新生成 bsp (s).