arch: k210: Applied changes doned for fe310 recently.

NOTE: In the future, these code should be moved under common code
once they support both RV32 & RV64 architectures.

arch/risc-v/include/k210/irq.h

@@ -45,7 +45,9 @@
 
 /* Machine Interrupt Enable bit in mstatus register */
 
-#define MSTATUS_MIE  (0x1 << 3)
+#define MSTATUS_MIE   (0x1 << 3)  /* Machine Interrupt Enable */
+#define MSTATUS_MPIE  (0x1 << 7)  /* Machine Previous Interrupt Enable */
+#define MSTATUS_MPPM  (0x3 << 11) /* Machine Previous Privilege (m-mode) */
 
 /* In mie (machine interrupt enable) register */
 

arch/risc-v/src/k210/k210_clockconfig.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/arm/src/k210/k210_clockconfig.c
+ * arch/risc-v/src/k210/k210_clockconfig.c
  *
  *   Copyright (C) 2019 Masayuki Ishikawa. All rights reserved.
  *   Author: Masayuki Ishikawa <masayuki.ishikawa@gmail.com>

arch/risc-v/src/k210/k210_clockconfig.h

@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/arm/src/k210/k210_clockconfig.h
+ * arch/risc-v/src/k210/k210_clockconfig.h
  *
  *   Copyright (C) 2019 Masayuki Ishikawa. All rights reserved.
  *   Author: Masayuki Ishikawa <masayuki.ishikawa@gmail.com>

arch/risc-v/src/k210/k210_irq.c

@@ -103,7 +103,6 @@ void up_irqinitialize(void)
   /* Attach the ecall interrupt handler */
 
   irq_attach(K210_IRQ_ECALLM, up_swint, NULL);
-  up_enable_irq(K210_IRQ_ECALLM);
 
 #ifndef CONFIG_SUPPRESS_INTERRUPTS
 
@@ -191,13 +190,17 @@ void up_enable_irq(int irq)
  * Name: up_get_newintctx
  *
  * Description:
- *   Return a value for EPIC. But K210 doesn't use EPIC for event control.
+ *   Return initial mstatus when a task is created.
  *
  ****************************************************************************/
 
 uint32_t up_get_newintctx(void)
 {
-  return 0;
+  /* Set machine previous privilege mode to machine mode.
+   * Also set machine previous interrupt enable
+   */
+
+  return (MSTATUS_MPPM | MSTATUS_MPIE);
 }
 
 /****************************************************************************
@@ -240,7 +243,7 @@ irqstate_t up_irq_save(void)
 
 void up_irq_restore(irqstate_t flags)
 {
-  /* Machine mode - mstatus */
+  /* Write flags to mstatus */
 
   asm volatile("csrw mstatus, %0" : /* no output */ : "r" (flags));
 }

arch/risc-v/src/k210/k210_irq_dispatch.c

@@ -68,12 +68,13 @@ void *k210_dispatch_irq(uint64_t vector, uint64_t *regs)
   uint32_t  irq = (vector >> (27 + 32)) | (vector & 0xf);
   uint64_t *mepc = regs;
 
+  /* Firstly, check if the irq is machine external interrupt */
+
   if (K210_IRQ_MEXT == irq)
     {
-      /* Read & write K210_PLIC_CLAIM to clear pending */
-
       uint32_t val = getreg32(K210_PLIC_CLAIM);
-      putreg32(val, K210_PLIC_CLAIM);
+
+      /* Add the value to nuttx irq which is offset to the mext */
 
       irq += val;
     }
@@ -85,22 +86,32 @@ void *k210_dispatch_irq(uint64_t vector, uint64_t *regs)
       *mepc += 4;
     }
 
+  /* Acknowledge the interrupt */
+
+  up_ack_irq(irq);
+
 #ifdef CONFIG_SUPPRESS_INTERRUPTS
   PANIC();
 #else
-  /* Nested interrupts are not supported */
-
-  DEBUGASSERT(g_current_regs == NULL);
-
   /* Current regs non-zero indicates that we are processing an interrupt;
-   * CURRENT_REGS is also used to manage interrupt level context switches.
+   * g_current_regs is also used to manage interrupt level context switches.
+   *
+   * Nested interrupts are not supported
    */
 
+  DEBUGASSERT(g_current_regs == NULL);
   g_current_regs = regs;
 
   /* Deliver the IRQ */
 
   irq_dispatch(irq, regs);
+
+  if (K210_IRQ_MEXT <= irq)
+    {
+      /* Then write PLIC_CLAIM to clear pending in PLIC */
+
+      putreg32(irq - K210_IRQ_MEXT, K210_PLIC_CLAIM);
+    }
 #endif
 
   /* If a context switch occurred while processing the interrupt then
@@ -112,10 +123,6 @@ void *k210_dispatch_irq(uint64_t vector, uint64_t *regs)
   regs = (uint64_t *)g_current_regs;
   g_current_regs = NULL;
 
-  /* Set machine previous privilege mode to machine mode */
-
-  *(regs + REG_INT_CTX_NDX) |= 0x3 << 11;
-
   return regs;
 }
 

arch/risc-v/src/k210/k210_start.c

@@ -1,5 +1,5 @@
 /****************************************************************************
- * arch/risc-v/src/k210/k210_init.c
+ * arch/risc-v/src/k210/k210_start.c
  *
  *   Copyright (C) 2019 Masayuki Ishikawa. All rights reserved.
  *   Author: Masayuki Ishikawa <masayuki.ishikawa@gmail.com>