static int init_file_system(void)
{
char super_block[BLOCK_SIZE];
int num_directory_blocks;
int block_num;
struct fs_header *header;
// SDMMC not supported on FPGA currently. Fall back to ramdisk if it fails.
if (init_sdmmc_device() < 0)
{
printf("init_file_system: SDMMC init failed, using ramdisk\n");
use_ramdisk = 1;
}
// Read directory
if (read_block(0, super_block) <= 0)
{
printf("init_file_system: error reading directory\n");
return -1;
}
header = (struct fs_header*) super_block;
if (memcmp(header->magic, FS_MAGIC, 4) != 0)
{
printf("init_file_system: invalid magic value\n");
return -1;
}
num_directory_blocks = ((header->num_directory_entries - 1)
* sizeof(struct directory_entry)
+ sizeof(struct fs_header) + BLOCK_SIZE - 1)
/ BLOCK_SIZE;
directory = (struct fs_header*) kmalloc((num_directory_blocks * BLOCK_SIZE + PAGE_SIZE - 1)
& ~(PAGE_SIZE - 1));
memcpy(directory, super_block, BLOCK_SIZE);
for (block_num = 1; block_num < num_directory_blocks; block_num++)
{
if (read_block(block_num, ((char*)directory) + BLOCK_SIZE * block_num) <= 0)
return -1;
}
return 0;
}
int main()
{
char *buf = (char*) 0x200000;
if (init_sdmmc_device() < 0)
{
printf("error initializing card\n");
return -1;
}
// Read blocks in reverse order to verify address is set correctly.
for (int i = TRANSFER_LENGTH - 1; i >= 0; i--)
{
if (read_sdmmc_device(i, buf + i * SDMMC_BLOCK_SIZE) < 0)
{
printf("read_sdmmc_device returned error\n");
return 1;
}
}
return 0;
}