lib: utils/irqchip: plic: Allow enabling IRQs by default

Unlike other platforms, Ariane and OpenPiton enable all IRQs by default.
This was described in commit b44e844880d0 ("Add support for Ariane FPGA
SoC") as "due to some issue of the design." Add this workaround behind a
flag in plic_warm_irqchip_init(), so every platform can use the same
warm init function.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

4 files changed, 21 insertions, 53 deletions

diff --git a/include/sbi_utils/irqchip/plic.h b/include/sbi_utils/irqchip/plic.h
index 2eda631..5da0905 100644
--- a/include/sbi_utils/irqchip/plic.h
+++ b/include/sbi_utils/irqchip/plic.h
@@ -16,8 +16,12 @@ struct plic_data {
 	unsigned long addr;
 	unsigned long size;
 	unsigned long num_src;
+	unsigned long flags;
 };
 
+/** Work around a bug on Ariane that requires enabling interrupts at boot */
+#define PLIC_FLAG_ARIANE_BUG		BIT(0)
+
 /* 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);
 
@@ -30,9 +34,6 @@ void plic_context_save(const struct plic_data *plic, int context_id,
 void plic_context_restore(const struct plic_data *plic, int context_id,
 			  const u32 *enable, u32 threshold, u32 num);
 
-int plic_context_init(const struct plic_data *plic, int context_id,
-		      bool enable, u32 threshold);
-
 int plic_warm_irqchip_init(const struct plic_data *plic,
 			   int m_cntx_id, int s_cntx_id);
 
diff --git a/lib/utils/irqchip/plic.c b/lib/utils/irqchip/plic.c
index 193e320..c66a688 100644
--- a/lib/utils/irqchip/plic.c
+++ b/lib/utils/irqchip/plic.c
@@ -121,8 +121,8 @@ void plic_context_restore(const struct plic_data *plic, int context_id,
 	plic_set_thresh(plic, context_id, threshold);
 }
 
-int plic_context_init(const struct plic_data *plic, int context_id,
-		      bool enable, u32 threshold)
+static int plic_context_init(const struct plic_data *plic, int context_id,
+			     bool enable, u32 threshold)
 {
 	u32 ie_words, ie_value;
 
@@ -143,18 +143,23 @@ int plic_context_init(const struct plic_data *plic, int context_id,
 int plic_warm_irqchip_init(const struct plic_data *plic,
 			   int m_cntx_id, int s_cntx_id)
 {
+	bool enable;
 	int ret;
 
-	/* By default, disable all IRQs for M-mode of target HART */
+	/*
+	 * By default, disable all IRQs for the target HART. Ariane
+	 * has a bug which requires enabling all interrupts at boot.
+	 */
+	enable = plic->flags & PLIC_FLAG_ARIANE_BUG;
+
 	if (m_cntx_id > -1) {
-		ret = plic_context_init(plic, m_cntx_id, false, 0x7);
+		ret = plic_context_init(plic, m_cntx_id, enable, 0x7);
 		if (ret)
 			return ret;
 	}
 
-	/* By default, disable all IRQs for S-mode of target HART */
 	if (s_cntx_id > -1) {
-		ret = plic_context_init(plic, s_cntx_id, false, 0x7);
+		ret = plic_context_init(plic, s_cntx_id, enable, 0x7);
 		if (ret)
 			return ret;
 	}
diff --git a/platform/fpga/ariane/platform.c b/platform/fpga/ariane/platform.c
index d25506a..0d019df 100644
--- a/platform/fpga/ariane/platform.c
+++ b/platform/fpga/ariane/platform.c
@@ -39,6 +39,7 @@ static struct plic_data plic = {
 	.addr = ARIANE_PLIC_ADDR,
 	.size = ARIANE_PLIC_SIZE,
 	.num_src = ARIANE_PLIC_NUM_SOURCES,
+	.flags = PLIC_FLAG_ARIANE_BUG,
 };
 
 static struct aclint_mswi_data mswi = {
@@ -93,27 +94,6 @@ static int ariane_final_init(bool cold_boot)
 	return 0;
 }
 
-static int plic_ariane_warm_irqchip_init(int m_cntx_id, int s_cntx_id)
-{
-	int ret;
-
-	/* By default, enable all IRQs for M-mode of target HART */
-	if (m_cntx_id > -1) {
-		ret = plic_context_init(&plic, m_cntx_id, true, 0x1);
-		if (ret)
-			return ret;
-	}
-
-	/* Enable all IRQs for S-mode of target HART */
-	if (s_cntx_id > -1) {
-		ret = plic_context_init(&plic, s_cntx_id, true, 0x0);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
 /*
  * Initialize the ariane interrupt controller for current HART.
  */
@@ -127,7 +107,8 @@ static int ariane_irqchip_init(bool cold_boot)
 		if (ret)
 			return ret;
 	}
-	return plic_ariane_warm_irqchip_init(2 * hartid, 2 * hartid + 1);
+
+	return plic_warm_irqchip_init(&plic, 2 * hartid, 2 * hartid + 1);
 }
 
 /*
diff --git a/platform/fpga/openpiton/platform.c b/platform/fpga/openpiton/platform.c
index 1ed4283..9f59f5f 100644
--- a/platform/fpga/openpiton/platform.c
+++ b/platform/fpga/openpiton/platform.c
@@ -43,6 +43,7 @@ static struct plic_data plic = {
 	.addr = OPENPITON_DEFAULT_PLIC_ADDR,
 	.size = OPENPITON_DEFAULT_PLIC_SIZE,
 	.num_src = OPENPITON_DEFAULT_PLIC_NUM_SOURCES,
+	.flags = PLIC_FLAG_ARIANE_BUG,
 };
 
 static struct aclint_mswi_data mswi = {
@@ -124,27 +125,6 @@ static int openpiton_final_init(bool cold_boot)
 	return 0;
 }
 
-static int plic_openpiton_warm_irqchip_init(int m_cntx_id, int s_cntx_id)
-{
-	int ret;
-
-	/* By default, enable all IRQs for M-mode of target HART */
-	if (m_cntx_id > -1) {
-		ret = plic_context_init(&plic, m_cntx_id, true, 0x1);
-		if (ret)
-			return ret;
-	}
-
-	/* Enable all IRQs for S-mode of target HART */
-	if (s_cntx_id > -1) {
-		ret = plic_context_init(&plic, s_cntx_id, true, 0x0);
-		if (ret)
-			return ret;
-	}
-
-	return 0;
-}
-
 /*
  * Initialize the openpiton interrupt controller for current HART.
  */
@@ -158,7 +138,8 @@ static int openpiton_irqchip_init(bool cold_boot)
 		if (ret)
 			return ret;
 	}
-	return plic_openpiton_warm_irqchip_init(2 * hartid, 2 * hartid + 1);
+
+	return plic_warm_irqchip_init(&plic, 2 * hartid, 2 * hartid + 1);
 }
 
 /*