Added a workaround for bad GameStar compatible adaptors into ATAD.

iop/dev9/atad/Makefile

@@ -15,6 +15,9 @@ ATA_MWDMA_MODES ?= 0
 #Enable to enable support for PIO modes 0-4 (as in early ATAD modules), instead of just PIO mode 0.
 ATA_ALL_PIO_MODES ?= 0
 
+#Disable to disable the workaround for bad GameStar compatible adaptors.
+ATA_GAMESTAR_WORKAROUND ?= 1
+
 IOP_BIN ?= ps2atad.irx
 
 IOP_INCS += -I$(PS2SDKSRC)/iop/dev9/dev9/include
@@ -32,6 +35,10 @@ ifeq ($(ATA_ALL_PIO_MODES),1)
 IOP_CFLAGS += -DATA_ALL_PIO_MODES=1
 endif
 
+ifeq ($(ATA_GAMESTAR_WORKAROUND),1)
+IOP_CFLAGS += -DATA_GAMESTAR_WORKAROUND=1
+endif
+
 include $(PS2SDKSRC)/Defs.make
 include $(PS2SDKSRC)/iop/Rules.bin.make
 include $(PS2SDKSRC)/iop/Rules.make

iop/dev9/atad/src/ps2atad.c

@@ -54,6 +54,9 @@ static int ata_evflg = -1;
 
 //Workarounds
 static u8 ata_disable_lba48 = 0;	//Please read the comments in _start().
+#ifdef ATA_GAMESTAR_WORKAROUND
+static u8 ata_gamestar_workaround = 0;
+#endif
 
 /* Local device info kept for drives 0 and 1.  */
 static ata_devinfo_t atad_devinfo[2];
@@ -223,6 +226,12 @@ int _start(int argc, char *argv[])
 		The obvious workaround here would be to disable 48-bit LBA support when ATAD is loaded on a PSX. */
 	ata_disable_lba48 = (SPD_REG16(SPD_R_REV_3) & SPD_CAPS_DVR)?1:0;
 
+#ifdef ATA_GAMESTAR_WORKAROUND
+	/*	A GameStar masquerades as a SCPH-10281, but malfunctions if transfers are not done according to the old ps2atad design.
+		All official adaptors appear to have different values for these two registers, but not the GameStar. */
+	ata_gamestar_workaround = (SPD_REG16(SPD_R_REV) == SPD_REG16(SPD_R_REV_1));
+#endif
+
 	if ((ata_evflg = ata_create_event_flag()) < 0) {
 		M_PRINTF("Couldn't create event flag, exiting.\n");
 		res = 1;
@@ -798,6 +807,11 @@ int ata_device_sector_io(int device, void *buf, u32 lba, u32 nsectors, int dir)
 	u16 sector, lcyl, hcyl, select, command, len;
 
 	while (res == 0 && nsectors > 0) {
+#ifdef ATA_GAMESTAR_WORKAROUND
+		if (ata_gamestar_workaround)
+			ata_set_dir(dir);
+#endif
+
 		/* Variable lba is only 32 bits so no change for lcyl and hcyl.  */
 		lcyl = (lba >> 8) & 0xff;
 		hcyl = (lba >> 16) & 0xff;
@@ -826,8 +840,13 @@ int ata_device_sector_io(int device, void *buf, u32 lba, u32 nsectors, int dir)
 			if ((res = ata_io_start(buf, len, 0, len, sector, lcyl, hcyl, select, command)) != 0)
 				break;
 
+#ifdef ATA_GAMESTAR_WORKAROUND
+			if (!ata_gamestar_workaround)
+				ata_set_dir(dir);
+#else
 			/* Set up (part of) the transfer here. In v1.04, this was called at the top of the outer loop. */
 			ata_set_dir(dir);
+#endif
 
 			res = ata_io_finish();
 
@@ -1060,7 +1079,11 @@ static void ata_set_dir(int dir)
 	val = SPD_REG16(SPD_R_IF_CTRL) & 1;
 	val |= (dir == ATA_DIR_WRITE) ? 0x4c : 0x4e;
 	SPD_REG16(SPD_R_IF_CTRL) = val;
+#ifdef ATA_GAMESTAR_WORKAROUND
+	SPD_REG16(SPD_R_XFR_CTRL) = dir | (ata_gamestar_workaround ? 0x86 : 0x6);
+#else
 	SPD_REG16(SPD_R_XFR_CTRL) = dir | 0x6;	//In v1.04, DMA was enabled here (0x86 instead of 0x6)
+#endif
 }
 
 static void ata_pio_mode(int mode)