SD - Secure Digital is memory card that is used in many devices like mobile phones or cameras.
Detecting SD card
SD card can be founded on PCI device with class 0x08 and subclass 0x05. ProgIF 0x00 means DMA isn't supported, 0x01 means DMA is supported and 0x02 means vendor unique SD device. SD card using memory mapped ports that base address is in BAR0.