DSTT: Add DMA support and reduce code size (#162) Fixes #111

arm9/source/patches/platform/dstt/DsttReadSdPatchCode.s

@@ -11,27 +11,11 @@
 dstt_readSd:
     push {r4-r7,lr}
 
-.global dstt_readSd_sdsc_shift
-dstt_readSd_sdsc_shift:
-    lsls r7, r0, #9
+    ldr r3, =0xA7180000
+    ldr r4, =0x040001A0
 
-    adr r0, dstt_stopTransmission_address
-    ldmia r0, {r0, r3, r4}
-
-    // request sd read for sector 0xaabbccdd
-    // 54 aa bb cc dd 00 00 00
-    movs r5, #0x54
-    strb r5, [r4,#0x8]
-    lsrs r5, r7, #24
-    strb r5, [r4,#0x9]
-    lsrs r5, r7, #16
-    strb r5, [r4,#0xA]
-    lsrs r5, r7, #8
-    strb r5, [r4,#0xB]
-    // make sure the last 3 bytes are zero
-    movs r5, #0xFF
-    ands r7, r5
-    str r7, [r4,#0xC] // storing as little-endian puts the bottom 8 bits as first byte
+    ldr r7, dstt_readSd_applySectorCommand_address
+    bl blx_r7
 
     movs r7, #0x80
     strb r7, [r4,#1]
@@ -48,42 +32,11 @@ cmd54_wait_loop:
     bcc cmd54_wait_loop
 
     ldr r5, [r6, #0x10]
-    // sd fifo full poll
-    // 80 xx xx xx xx xx xx xx
-    // xx bytes are leftover from previous command
-    strb r7, [r4,#0x8]
+    ldr r7, dstt_waitDataReady_address
+    bl blx_r7
 
-cmd80_poll_loop:
-    str r3, [r4,#4]
-
-cmd80_wait_loop:
-    ldrb r5, [r4,#6]
-    lsrs r5, r5, #8
-    bcc cmd80_wait_loop
-    ldr r5, [r6, #0x10]
-    cmp r5, #0
-    bne cmd80_poll_loop
-
-    // read sd fifo
-    // 81 xx xx xx xx xx xx xx
-    // xx bytes are leftover from previous command
-    movs r5, #0x81
-    strb r5, [r4,#0x8]
-    movs r5, #0xA1
-    strb r5, [r4,#7]
-
-cmd81_data_loop:
-    ldrb r5, [r4,#6]
-    lsrs r5, r5, #8 // check if data is ready
-    bcc cmd81_data_loop_check_transfer_end // if not skip reading
-
-    ldr r5, [r6, #0x10]
-    stmia r1!, {r5}
-
-cmd81_data_loop_check_transfer_end:
-    ldrb r5, [r4,#7]
-    lsrs r5, r5, #8 // check if transfer is done
-    bcs cmd81_data_loop
+    ldr r7, dstt_transferData_address
+    bl blx_r7
 
     subs r2, #1
     beq stop_transmission
@@ -99,77 +52,31 @@ cmd81_data_loop_check_transfer_end:
     b sector_loop
 
 stop_transmission:
-    bx r0
+    ldr r7, dstt_stopTransmission_address
+    bl blx_r7
+    pop {r4-r7,pc}
+
+blx_r7:
+    bx r7
 
 .balign 4
 
+.global dstt_readSd_applySectorCommand_address
+dstt_readSd_applySectorCommand_address:
+    .word 0
+
+.global dstt_waitDataReady_address
+dstt_waitDataReady_address:
+    .word 0
+
+.global dstt_transferData_address
+dstt_transferData_address:
+    .word 0
+
 .global dstt_stopTransmission_address
 dstt_stopTransmission_address:
     .word 0
 
-settings:
-    .word 0xA7180000
-
-regbase:
-    .word 0x040001A0
-
 .pool
 
-.section "dstt_readsd_stopTransmission", "ax"
-.thumb
-.global dstt_stopTransmission
-.type dstt_stopTransmission, %function
-dstt_stopTransmission:
-    // send SD_CMD12_STOP_TRANSMISSION
-
-    // set sd host mode DSTT_MODE_SDCMD_RESPONSE_32BIT, SD_CMD12_STOP_TRANSMISSION
-    // 51 00 00 00 00 0C 01 00
-    movs r5, #0x51
-    str r5, [r4,#0x8]
-    ldr r5,= 0x00010C00
-    str r5, [r4,#0xC]
-    str r3, [r4,#4]
-
-cmd51_1_wait_loop:
-    ldrb r5, [r4,#6]
-    lsrs r5, r5, #8
-    bcc cmd51_1_wait_loop
-    ldr r5, [r6, #0x10]
-
-    // sd busy poll
-    // 50 xx xx xx xx xx xx xx
-    // xx bytes are leftover from previous command
-    movs r5, #0x50
-    strb r5, [r4,#0x8]
-
-cmd50_poll_loop:
-    str r3, [r4,#4]
-
-cmd50_wait_loop:
-    ldrb r5, [r4,#6]
-    lsrs r5, r5, #8
-    bcc cmd50_wait_loop
-    ldr r5, [r6, #0x10]
-    cmp r5, #0
-    bne cmd50_poll_loop
-
-    // read sd response
-    // 52 xx xx xx xx xx xx xx
-    // xx bytes are leftover from previous command
-    movs r5, #0x52
-    strb r5, [r4,#0x8]
-    str r3, [r4,#4]
-
-cmd52_wait_loop:
-    ldrb r5, [r4,#6]
-    lsrs r5, r5, #8
-    bcc cmd52_wait_loop
-    ldr r5, [r6, #0x10]
-
-    pop {r4-r7,pc}
-
-.balign 4
-
-.pool
-
-.end
+.end