Rewrite MMIO handler

To adapt more MMIO in the future (e.g., VirtIO), the IIF(io) cannot be used since it supports only binary. Thus, rewrite using switch case can solve this.
ChinYikMing · Nov 5, 2024 · b2dfe75 · b2dfe75
1 parent e2bb7f0
commit b2dfe75
Showing 1 changed file with 34 additions and 25 deletions.
diff --git a/src/system.c b/src/system.c
@@ -22,39 +22,48 @@ void emu_update_uart_interrupts(riscv_t *rv)
     plic_update_interrupts(attr->plic);
 }
 
-#define MMIO_PLIC 1
-#define MMIO_UART 0
 #define MMIO_R 1
 #define MMIO_W 0
 
-uint8_t ret_char;
+enum SUPPORTED_MMIO {
+    MMIO_PLIC,
+    MMIO_UART,
+};
+
 /* clang-format off */
-#define MMIO_OP(io, rw)                                           \
-    IIF(io)( /* PLIC */                                           \
-        IIF(rw)( /* read */                                       \
-            read_val = plic_read(PRIV(rv)->plic, (addr & 0x3FFFFFF) >> 2);           \
-	    plic_update_interrupts(PRIV(rv)->plic); return read_val;          \
-	    ,     /* write */                                     \
-            plic_write(PRIV(rv)->plic, (addr & 0x3FFFFFF) >> 2, val);   \
-            plic_update_interrupts(PRIV(rv)->plic); return;                   \
-        )                                                         \
-        ,    /* UART */                                           \
-        IIF(rw)( /* read */                                       \
-            /*return 0x60 | 0x1; */                                   \
-	    ret_char = u8250_read(PRIV(rv)->uart, addr & 0xFFFFF);\
-	    emu_update_uart_interrupts(rv);\
-	    return ret_char;\
-	    ,   /* write */                                       \
-	    u8250_write(PRIV(rv)->uart, addr & 0xFFFFF, val);\
-	    emu_update_uart_interrupts(rv);\
-	    return;\
-	)                                                         \
-    )
+#define MMIO_OP(io, rw)                                                             \
+    switch(io){                                                                     \
+        case MMIO_PLIC:                                                             \
+            IIF(rw)( /* read */                                                     \
+                mmio_read_val = plic_read(PRIV(rv)->plic, (addr & 0x3FFFFFF) >> 2); \
+                plic_update_interrupts(PRIV(rv)->plic);                             \
+                return mmio_read_val;                                               \
+                ,    /* write */                                                    \
+                plic_write(PRIV(rv)->plic, (addr & 0x3FFFFFF) >> 2, val);           \
+                plic_update_interrupts(PRIV(rv)->plic);                             \
+                return;                                                             \
+            )                                                                       \
+            break;                                                                  \
+        case MMIO_UART:                                                             \
+            IIF(rw)( /* read */                                                     \
+                mmio_read_val = u8250_read(PRIV(rv)->uart, addr & 0xFFFFF);         \
+                emu_update_uart_interrupts(rv);                                     \
+                return mmio_read_val;                                               \
+                ,    /* write */                                                    \
+                u8250_write(PRIV(rv)->uart, addr & 0xFFFFF, val);                   \
+                emu_update_uart_interrupts(rv);                                     \
+                return;                                                             \
+	    )                                                                       \
+            break;                                                                  \
+        default:                                                                    \
+            fprintf(stderr, "unknown MMIO type %d\n", io);                          \
+            break;                                                                  \
+    }
 /* clang-format on */
 
 #define MMIO_READ()                                         \
     do {                                                    \
-        uint32_t read_val;                                  \
+        uint32_t mmio_read_val;                             \
         if ((addr >> 28) == 0xF) { /* MMIO at 0xF_______ */ \
             /* 256 regions of 1MiB */                       \
             switch ((addr >> 20) & MASK(8)) {               \