lib: sbi: Add sbi_trap_set_external_irqfn() API

This patch adds sbi_trap_set_external_irqfn() API which can be used by
OpenSBI platform code to set a callback function for external interrupts.
The RISC-V AIA IMSIC driver will use this API to implement inter-processor
interrupts on-top-of MSIs.

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>

diff --git a/include/sbi/sbi_trap.h b/include/sbi/sbi_trap.h
index d205056..4f611fa 100644 (file)
--- a/include/sbi/sbi_trap.h
+++ b/include/sbi/sbi_trap.h
@@ -205,6 +205,8 @@ struct sbi_trap_info {
 int sbi_trap_redirect(struct sbi_trap_regs *regs,
                      struct sbi_trap_info *trap);
 
+void sbi_trap_set_external_irqfn(int (*fn)(struct sbi_trap_regs *regs));
+
 struct sbi_trap_regs *sbi_trap_handler(struct sbi_trap_regs *regs);
 
 void __noreturn sbi_trap_exit(const struct sbi_trap_regs *regs);

diff --git a/lib/sbi/sbi_trap.c b/lib/sbi/sbi_trap.c
index bc8961f..faab90a 100644 (file)
--- a/lib/sbi/sbi_trap.c
+++ b/lib/sbi/sbi_trap.c
@@ -195,6 +195,27 @@ int sbi_trap_redirect(struct sbi_trap_regs *regs,
        return 0;
 }
 
+static int default_irqfn(struct sbi_trap_regs *regs)
+{
+       return SBI_ENODEV;
+}
+
+static int (*ext_irqfn)(struct sbi_trap_regs *regs) = default_irqfn;
+
+/**
+ * Set external irq handler function
+ *
+ * This function is called by OpenSBI platform code to set a handler for
+ * external interrupts
+ *
+ * @param fn function pointer for handling external irqs
+ */
+void sbi_trap_set_external_irqfn(int (*fn)(struct sbi_trap_regs *regs))
+{
+       if (fn)
+               ext_irqfn = fn;
+}
+
 static int sbi_trap_nonaia_irq(struct sbi_trap_regs *regs, ulong mcause)
 {
        mcause &= ~(1UL << (__riscv_xlen - 1));
@@ -205,6 +226,8 @@ static int sbi_trap_nonaia_irq(struct sbi_trap_regs *regs, ulong mcause)
        case IRQ_M_SOFT:
                sbi_ipi_process();
                break;
+       case IRQ_M_EXT:
+               return ext_irqfn(regs);
        default:
                return SBI_ENOENT;
        };
@@ -214,6 +237,7 @@ static int sbi_trap_nonaia_irq(struct sbi_trap_regs *regs, ulong mcause)
 
 static int sbi_trap_aia_irq(struct sbi_trap_regs *regs, ulong mcause)
 {
+       int rc;
        unsigned long mtopi;
 
        while ((mtopi = csr_read(CSR_MTOPI))) {
@@ -225,6 +249,11 @@ static int sbi_trap_aia_irq(struct sbi_trap_regs *regs, ulong mcause)
                case IRQ_M_SOFT:
                        sbi_ipi_process();
                        break;
+               case IRQ_M_EXT:
+                       rc = ext_irqfn(regs);
+                       if (rc)
+                               return rc;
+                       break;
                default:
                        return SBI_ENOENT;
                }