Possible data sources for SD driver:
- mmc_sd_switch():
- length: 64 byte;
- buffer on stack
- mmc_test_bus_width():
- length: 4 or 8 byte
- buffer in program memory or on stack
- mmc_app_send_scr():
- length: 8 byte
- buffer from device ivar structure
- mmc_app_sd_status():
- length: 64 byte
- buffer from device ivar structure
- mmc_send_ext_csd():
- length: MMC_EXTCSD_SIZE = 512
- buffer from device ivar structure
- rtems_bsd_mmcsd_disk_read_write():
- length: depends on read
- buffer from rtems_blkdev buffer -> already aligned
- mmcsd_ioctl_cmd():
- length: depends on call
- buffer malloced, not aligned -> patched in RTEMS
So the problematic buffers are only the ones up to 512 bytes. Copy these data
into a buffer to avoid that problem.
