dmac: Drop old DMAC interface and header

And move the code initializing DMAC on Naomi to the DMAC driver.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>

Author: pcercuei

kernel/arch/dreamcast/hardware/dmac.c

@@ -33,6 +33,20 @@ typedef enum dma_register {
 #define REG_CHCR_TRANSFER_END   BIT(1)
 #define REG_CHCR_DMAC_EN        BIT(0)
 
+#define REG_DMAOR_DDT           BIT(15)
+#define REG_DMAOR_PR            GENMASK(9, 8)
+#define REG_DMAOR_COD           BIT(4)
+#define REG_DMAOR_AE            BIT(2)
+#define REG_DMAOR_NMIF          BIT(1)
+#define REG_DMAOR_DME           BIT(0)
+
+enum dmaor_pr_mode {
+    DMAOR_PR_CH0123,
+    DMAOR_PR_CH0231,
+    DMAOR_PR_CH2013,
+    DMAOR_PR_ROUND_ROBIN,
+};
+
 static const dma_config_t *channels_cfg[4];
 
 static const irq_t channel_to_irq[] = {
@@ -173,3 +187,22 @@ void dma_transfer_abort(dma_channel_t channel) {
     dmac_write(channel, DMA_REG_CHCR, 0);
     genwait_wake_all((void *)&channels_cfg[channel]);
 }
+
+void dma_init(void) {
+    /* Set default settings for DMA #2.
+     * These are set by the bios on Dreamcast, but should be set by the OS
+     * on Naomi. */
+    uint32_t chcr, dmaor;
+
+    dmac_write(2, DMA_REG_SAR, 0);
+
+    chcr = FIELD_PREP(REG_CHCR_SRC_ADDRMODE, DMA_ADDRMODE_INCREMENT)
+        | FIELD_PREP(REG_CHCR_REQUEST, DMA_REQUEST_EXTERNAL_MEM_TO_DEV)
+        | FIELD_PREP(REG_CHCR_DMAC_EN, 1);
+    dmac_write(2, DMA_REG_CHCR, chcr);
+
+    dmaor = REG_DMAOR_DDT
+        | FIELD_PREP(REG_DMAOR_PR, DMAOR_PR_CH2013)
+        | REG_DMAOR_DME;
+    dmac_write(0, DMA_REG_DMAOR, dmaor);
+}

kernel/arch/dreamcast/include/dc/dmac.h

@@ -25,7 +25,6 @@
 #include <dc/pvr.h>
 #include <dc/vmufs.h>
 #include <dc/syscalls.h>
-#include <dc/dmac.h>
 
 #include "initall_hdrs.h"
 
@@ -40,6 +39,7 @@ extern uintptr_t _bss_start, end;
 extern void _init(void);
 extern void _fini(void);
 extern void __verify_newlib_patch();
+extern void dma_init(void);
 
 void (*__kos_init_early_fn)(void) __attribute__((weak,section(".data"))) = NULL;
 
@@ -280,13 +280,7 @@ void arch_main(void) {
     uint8 *bss_start = (uint8 *)(&_bss_start);
     int rv;
 
-    if (KOS_PLATFORM_IS_NAOMI) {
-        /* Ugh. I'm really not sure why we have to set up these DMA registers this
-           way on boot, but failing to do so breaks maple... */
-        DMAC_SAR2 = 0;
-        DMAC_CHCR2 = 0x1201;
-        DMAC_DMAOR = 0x8201;
-    }
+    dma_init();
 
     /* Ensure the WDT is not enabled from a previous session */
     wdt_disable();