DATEL: Make read sector function vram safe (#80)

* DATEL: Make read sector function vram safe

The platform code was performing reads in single byte units, breaking in case the destination buffer was in vram.
This caused issues with some games (e.g. Castelvania Order of Ecclesia), and also broke soft resetting.

* Halve wait timeout on sector read since we read 2 bytes at the time
This commit is contained in:
Edoardo Lolletti
2025-12-30 20:10:02 +01:00
committed by GitHub
parent 842dd8e63a
commit 992e2d1053
4 changed files with 30 additions and 11 deletions

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@@ -8,7 +8,7 @@ extern u16 datel_readSectorSdhcLabel;
extern u32 datel_SDReadMultipleSector_SpiSendSDIOCommandR0;
extern u32 datel_SDReadMultipleSector_ReadSpiByteTimeout;
extern u32 datel_SDReadMultipleSector_ReadSpiByte;
extern u32 datel_SDReadMultipleSector_ReadSpiShort;
extern "C" void datel_SDReadMultipleSector(u32 srcSector, void* dst, u32 sectorCount);
@@ -23,7 +23,7 @@ public:
datel_SDReadMultipleSector_SpiSendSDIOCommandR0 = (u32)datelSendSDIOCommandPatchCode->GetSpiSendSDIOCommandR0Function();
datel_SDReadMultipleSector_ReadSpiByteTimeout = (u32)datelReadSpiBytePatchCode->GetReadSpiByteTimeoutFunction();
datel_SDReadMultipleSector_ReadSpiByte = (u32)datelReadSpiBytePatchCode->GetReadSpiByteFunction();
datel_SDReadMultipleSector_ReadSpiShort = (u32)datelReadSpiBytePatchCode->GetReadSpiShortFunction();
}
const SdReadFunc GetSdReadFunction() const override

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@@ -37,13 +37,13 @@ read_next_sector:
cmp r0, DATEL_SPI_START_DATA_TOKEN
bne wrong_spi_start_token
@ preload datel_readSpiByte
ldr r7, datel_SDReadMultipleSector_ReadSpiByte
@ preload datel_readSpiShort
ldr r7, datel_SDReadMultipleSector_ReadSpiShort
read_next_byte:
bl datel_SDReadMultipleSector_Interwork
strb r0, [r4, r5]
strh r0, [r4, r5]
adds r5, #1
adds r5, #2
@ 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
@@ -51,7 +51,6 @@ read_next_byte:
@ drop crc
bl datel_SDReadMultipleSector_Interwork
bl datel_SDReadMultipleSector_Interwork
cmp r3, r5
bne read_next_sector
@@ -65,8 +64,12 @@ read_next_byte:
adds r7, #2
bl datel_SDReadMultipleSector_Interwork
ldr r4, =DATEL_SD_CMD_TIMEOUT_LEN
ldr r7, datel_SDReadMultipleSector_ReadSpiByte
@ use a timeout of 0x1000 instead of 0xFFF, easier to setup, then halve it
@ since we're reading 2 bytes at the time
@ ldr r4, =DATEL_SD_CMD_TIMEOUT_LEN
movs r4, #1
lsls r4, #11
ldr r7, datel_SDReadMultipleSector_ReadSpiShort
1:
bl datel_SDReadMultipleSector_Interwork
bne read_timeout_expired
@@ -97,6 +100,6 @@ datel_SDReadMultipleSector_SpiSendSDIOCommandR0:
.global datel_SDReadMultipleSector_ReadSpiByteTimeout
datel_SDReadMultipleSector_ReadSpiByteTimeout:
.word 0
.global datel_SDReadMultipleSector_ReadSpiByte
datel_SDReadMultipleSector_ReadSpiByte:
.global datel_SDReadMultipleSector_ReadSpiShort
datel_SDReadMultipleSector_ReadSpiShort:
.word 0

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@@ -7,6 +7,7 @@ DEFINE_SECTION_SYMBOLS(datel_spi_send);
extern "C" u8 datel_readSpiByte();
extern "C" u8 datel_readWriteSpiByte(u8 value);
extern "C" u16 datel_readSpiShort();
extern "C" u8 datel_readSpiByteTimeout();
extern "C" bool datel_waitSpiByteTimeout();
@@ -27,6 +28,11 @@ public:
return GetAddressAtTarget((void*)datel_readSpiByte);
}
const void* GetReadSpiShortFunction() const
{
return GetAddressAtTarget((void*)datel_readSpiShort);
}
const void* GetReadWriteSpiByteFunction() const
{
return GetAddressAtTarget((void*)datel_readWriteSpiByte);

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@@ -29,6 +29,16 @@ BEGIN_ASM_FUNC datel_readWriteSpiByte
cmp r0, #0
pop {r1-r3, pc}
@u16 datel_readWriteSpiShort();
BEGIN_ASM_FUNC datel_readSpiShort
push {r1-r7, lr}
bl datel_readSpiByte
movs r1, r0
bl datel_readSpiByte
lsls r0, #8
orrs r0, r1
pop {r1-r7, pc}
@u8 datel_readSpiByteTimeout(void);
BEGIN_ASM_FUNC datel_readSpiByteTimeout
push {r1-r4, lr}