/dev/sdio/slot0

This allows access to the front SD slot.

GetDeviceStatus

 SD_GetDeviceStatus
 u32 buffer
 ios_ioctl( sd_fd, 0x0B, 0, 0, &buffer, 4);

buffer contains the status of the SD slot:

• 1: SD card is inserted.
• 2: No SD card is inserted.

ResetDevice

 SD_ResetDevice
 ios_ioctl( sd_fd, 4, 0, 0, buffer, 4);

GetOCRegister

 SD_GetOCRegister
 ios_ioctl( sd_fd, 0xC, 0, 0, buffer, 4);

GetHCRegister

 SD_GetHCRegister (untested iirc)
 ((u32*)inbuf)[0] = 0x28;
 ((u32*)inbuf)[3] = 1;
 ((u32*)inbuf)[4] = 0;
 
 ios_ioctl( sd_fd, 2, inbuf, 0x18, outbuf, 4);

SetHCRegister

 SD_SetHCRegister
 ((u32*)inbuf)[0] = 0x28;
 ((u32*)inbuf)[3] = 1;
 ((u32*)inbuf)[4] = value;
 
 ios_ioctl( sd_fd, 1, inbuf, 0x18, 0, 0);

SendCMD

 SD_SendCMD(cmd, cmd_type, resp_type, arg, buffer, block_count, sector_size)
 
 ((u32*)inbuf)[0]=cmd;
 ((u32*)inbuf)[1]=cmd_type;
 ((u32*)inbuf)[2]=resp_type;
 ((u32*)inbuf)[3]=arg;
 ((u32*)inbuf)[4]=block_count;
 ((u32*)inbuf)[5]=sector_size;
 ((u32*)inbuf)[6]=buffer;
 ((u32*)inbuf)[7]=0; // ?
 ((u32*)inbuf)[8]=0; // ?
 
 ios_ioctl( sd_fd, 7, inbuf, 0x24, outbuf, 0x10);

SD Commands

 SD_SendCmd(0x10, 3, 1, 0x200, 0, 0, 0) card_set_blocklen(0x200)
 SD_SendCmd(0x37, 3, 1, ?, 0, 0, 0) set data bus width

 SD_SendCmd(7, 3, 2, sd_status&0xFFFF0000, 0, 0, 0) // select
 SD_SendCmd(7, 3, 2, 0, 0, 0, 0) // deselect 
 IOS_Ioctl(fd, 11, 0, 0, (u32 *)&status, 4); // get status
 IOS_Ioctl(fd, 4, 0, 0, (u32 *)&status, 4) // reset and get status
 IOS_Ioctl(fd, 6, (u32 *)&clock, 4, 0, 0) // using 1 as clock seems to work

Set bus width to 4

 SD_SendCmd(0x37, 3, 1, sd_status&0xFFFF0000, 0, 0, 0)
 SD_SendCmd(6, 3, 1, 2, 0, 0, 0)

 //Read the HCR register and AND it with ~0x2. If width is 4 bit OR it with 0x2 and write it back.

Block Read

 IOS_ioctlv(fd, 7, 2 /* input n */, 1 /* output n */, vectors)

 // First vector is {0x12, 3, 1, blockno * 0x200, 1, 0x200, &buffer /* 0x200 bytes */, 1, 0}, the second one is the buffer again (WTF?) and the third one a 0x10 byte reply buffer.
 // Do a reset and a select before the first read and set block length to 0x200, bus width to 4 and clock to 1 to make this command work.
 // 0x12 is CMD18 READ_MULTIPLE_BLOCK
 // 3 seems to be CMDTYPE AC (Addressed Command) although it should be ADTC (Address Data Tranfer Command)
 // blockno * 0x200 (512) is the offset in bytes of the block as expected by CMD18
 // 0x200 (512) is the default block size

Block Write

Works the same way as reading does. Just use 0x19 instead of 0x12 in the first vector.
0x19 is CMD25 WRITE_MULTIPLE_BLOCK