Add support for DATEL devices (GAMES n' MUSIC and Action Replay DS(i) Media Edition) (#64)

arm9/source/patches/platform/datel/DatelWriteSectorsAsm.s

@@ -0,0 +1,117 @@
+#include "asminc.h"
+
+.syntax unified
+.thumb
+
+.section "datel_write", "ax"
+
+.global datel_writeSectorSdhcLabel
+
+@ All the called functions leave every registers unchanged, except for r0 in case the function has a return value
+
+@datel_SDWriteMultipleSector(u32 sector, const u8 * buffer, u32 num_sectors)
+BEGIN_ASM_FUNC datel_SDWriteMultipleSector
+    @ Among those regs, there's r2 being pushed, accessed afterwards from the stack
+    push {r1-r7, lr}
+    movs r4, r1
+    @ We get the number of bytes total to write, which we'll compare to against in the main loop
+    lsls r3, r2, #9
+
+    @ Total written bytes
+    movs r5, #0
+
+datel_writeSectorSdhcLabel:
+    @ if not sdhc this needs to be shifted to the left by 9
+    lsls r0, #9
+    @mov r0, r0
+
+    @ this message needs 1 byte of extra clock before it starts waiting for the start token
+    movs r1, DATEL_SDIO_CMD25_WRITE_MULTIPLE_BLOCK
+    movs r2, #1
+    ldr r7, datel_SDWriteMultipleSector_SpiSendSDIOCommand
+    bl datel_SDWriteMultipleSector_Interwork
+    bne CMD25_not_ok
+
+    @ r6 contains datel_SDWriteMultipleSector_WaitSpiByteTimeout
+    @ r7 contains datel_SDWriteMultipleSector_ReadSpiByte
+    adr r1, datel_SDWriteMultipleSector_WaitSpiByteTimeout
+    ldm r1!, {r6,r7}
+    @ r1 contains datel_readWriteSpiByte
+    adds r1, r7, #2
+
+    @ We use the r2 set above to put 0x10000 to use later as write timeout
+    @ it's 1 bigger than the timeout len but we save an instruction
+    @ ldr r2, =DATEL_SD_WRITE_TIMEOUT_LEN
+    lsls r2, r2, #16
+
+write_next_sector:
+
+    @ Send start token
+    movs r0, DATEL_SPI_MULTI_BLOCK_WRITE_TOKEN
+
+    bl datel_SDWriteMultipleSector_InterworkR1 @ call datel_readWriteSpiByte
+
+write_next_byte:
+    ldrb r0, [r4, r5]
+    bl datel_SDWriteMultipleSector_InterworkR1 @ call datel_readWriteSpiByte
+
+    adds r5, #1
+    @ Shifting left by 0x17 will set the Zero flag if the number that was shifted is a multiple
+    @ of 0x200 (indicating a full sector has been written)
+    lsls r0, r5, #0x17
+    bne write_next_byte
+
+    @ write dummy crc
+    bl datel_SDWriteMultipleSector_Interwork @ call datel_readSpiByte
+    bl datel_SDWriteMultipleSector_Interwork @ call datel_readSpiByte
+
+    bl datel_SDWriteMultipleSector_Interwork @ call datel_readSpiByte
+
+    @ we check if the lower nibble is equal to DATEL_SD_WRITE_OK
+    subs r0, DATEL_SD_WRITE_OK
+    lsls r0,#28
+    bne write_command_failed
+
+    @ Wait for card to write data
+    bl datel_SDWriteMultipleSector_InterworkR6 @ call datel_waitSpiByteTimeout
+    beq sector_write_timeout_expired
+
+    @ r3 holds the total number of bytes to write
+    cmp r3, r5
+    bne write_next_sector
+
+    @ send stop token
+    movs r0, DATEL_SPI_END_MULTI_BLOCK_WRITE
+    bl datel_SDWriteMultipleSector_InterworkR1 @ call datel_readWriteSpiByte
+
+    @ send 1 byte clock
+    bl datel_SDWriteMultipleSector_Interwork @ call datel_readSpiByte
+
+    bl datel_SDWriteMultipleSector_InterworkR6 @ call datel_waitSpiByteTimeout
+
+    @ pop {r1-r7, pc}
+
+CMD25_not_ok:
+write_command_failed:
+sector_write_timeout_expired:
+    @ movs r0, #0
+    pop {r1-r7, pc}
+
+datel_SDWriteMultipleSector_Interwork:
+    bx r7
+datel_SDWriteMultipleSector_InterworkR6:
+    bx r6
+datel_SDWriteMultipleSector_InterworkR1:
+    bx r1
+.balign 4
+.pool
+
+.global datel_SDWriteMultipleSector_SpiSendSDIOCommand
+datel_SDWriteMultipleSector_SpiSendSDIOCommand:
+    .word 0
+.global datel_SDWriteMultipleSector_WaitSpiByteTimeout
+datel_SDWriteMultipleSector_WaitSpiByteTimeout:
+    .word 0
+.global datel_SDWriteMultipleSector_ReadSpiByte
+datel_SDWriteMultipleSector_ReadSpiByte:
+    .word 0