3 files changed, 18 insertions, 13 deletions

diff --git a/include/sbi_utils/irqchip/plic.h b/include/sbi_utils/irqchip/plic.h
index 5da09055..cbe66761 100644
--- a/include/sbi_utils/irqchip/plic.h
+++ b/include/sbi_utils/irqchip/plic.h
@@ -21,6 +21,8 @@ struct plic_data {
 
 /** Work around a bug on Ariane that requires enabling interrupts at boot */
 #define PLIC_FLAG_ARIANE_BUG		BIT(0)
+/** PLIC must be delegated to S-mode like T-HEAD C906 and C910 */
+#define PLIC_FLAG_THEAD_DELEGATION	BIT(1)
 
 /* So far, priorities on all consumers of these functions fit in 8 bits. */
 void plic_priority_save(const struct plic_data *plic, u8 *priority, u32 num);
@@ -28,6 +30,8 @@ void plic_priority_save(const struct plic_data *plic, u8 *priority, u32 num);
 void plic_priority_restore(const struct plic_data *plic, const u8 *priority,
 			   u32 num);
 
+void plic_delegate(const struct plic_data *plic);
+
 void plic_context_save(const struct plic_data *plic, int context_id,
 		       u32 *enable, u32 *threshold, u32 num);
 
diff --git a/lib/utils/irqchip/fdt_irqchip_plic.c b/lib/utils/irqchip/fdt_irqchip_plic.c
index a8aa4fcd..3c57a0f5 100644
--- a/lib/utils/irqchip/fdt_irqchip_plic.c
+++ b/lib/utils/irqchip/fdt_irqchip_plic.c
@@ -164,10 +164,7 @@ static int irqchip_plic_cold_init(const void *fdt, int nodeoff,
 	if (rc)
 		goto fail_free_data;
 
-	if (match->data) {
-		void (*plic_plat_init)(struct plic_data *) = match->data;
-		plic_plat_init(pd);
-	}
+	pd->flags = (unsigned long)match->data;
 
 	rc = plic_cold_irqchip_init(pd);
 	if (rc)
@@ -184,19 +181,12 @@ fail_free_data:
 	return rc;
 }
 
-#define THEAD_PLIC_CTRL_REG 0x1ffffc
-
-static void thead_plic_plat_init(struct plic_data *pd)
-{
-	writel_relaxed(BIT(0), (char *)pd->addr + THEAD_PLIC_CTRL_REG);
-}
-
 void thead_plic_restore(void)
 {
 	struct sbi_scratch *scratch = sbi_scratch_thishart_ptr();
 	struct plic_data *plic = plic_get_hart_data_ptr(scratch);
 
-	thead_plic_plat_init(plic);
+	plic_delegate(plic);
 }
 
 static const struct fdt_match irqchip_plic_match[] = {
@@ -204,7 +194,7 @@ static const struct fdt_match irqchip_plic_match[] = {
 	{ .compatible = "riscv,plic0" },
 	{ .compatible = "sifive,plic-1.0.0" },
 	{ .compatible = "thead,c900-plic",
-	  .data = thead_plic_plat_init },
+	  .data = (void *)PLIC_FLAG_THEAD_DELEGATION },
 	{ /* sentinel */ }
 };
 
diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
index c66a6886..a432a8c4 100644
--- a/lib/utils/irqchip/plic.c
+++ b/lib/utils/irqchip/plic.c
@@ -24,6 +24,8 @@
 #define PLIC_CONTEXT_BASE 0x200000
 #define PLIC_CONTEXT_STRIDE 0x1000
 
+#define THEAD_PLIC_CTRL_REG 0x1ffffc
+
 static u32 plic_get_priority(const struct plic_data *plic, u32 source)
 {
 	volatile void *plic_priority = (char *)plic->addr +
@@ -93,6 +95,13 @@ static void plic_set_ie(const struct plic_data *plic, u32 cntxid,
 	writel(val, plic_ie);
 }
 
+void plic_delegate(const struct plic_data *plic)
+{
+	/* If this is a T-HEAD PLIC, delegate access to S-mode */
+	if (plic->flags & PLIC_FLAG_THEAD_DELEGATION)
+		writel_relaxed(BIT(0), (char *)plic->addr + THEAD_PLIC_CTRL_REG);
+}
+
 void plic_context_save(const struct plic_data *plic, int context_id,
 		       u32 *enable, u32 *threshold, u32 num)
 {
@@ -178,6 +187,8 @@ int plic_cold_irqchip_init(const struct plic_data *plic)
 	for (i = 1; i <= plic->num_src; i++)
 		plic_set_priority(plic, i, 0);
 
+	plic_delegate(plic);
+
 	return sbi_domain_root_add_memrange(plic->addr, plic->size, BIT(20),
 					(SBI_DOMAIN_MEMREGION_MMIO |
 					 SBI_DOMAIN_MEMREGION_SHARED_SURW_MRW));