drivers: intc: plic: use per-instance spinlock

Instead of doing an `irq_lock()`, use per-instance spinlock instead.

Refactored out an unlocked version of `local_irq_is_enabled`
from `riscv_plic_irq_is_enabled()` to achieve that.

Signed-off-by: Yong Cong Sin <[email protected]>

Author: ycsin

drivers/interrupt_controller/intc_plic.c

@@ -103,6 +103,7 @@ struct plic_stats {
 };
 
 struct plic_data {
+	struct k_spinlock lock;
 
 #ifdef CONFIG_PLIC_SHELL_IRQ_COUNT
 	struct plic_stats stats;
@@ -279,11 +280,13 @@ static void plic_irq_enable_set_state(uint32_t irq, bool enable)
  */
 void riscv_plic_irq_enable(uint32_t irq)
 {
-	uint32_t key = irq_lock();
+	const struct device *dev = get_plic_dev_from_irq(irq);
+	struct plic_data *data = dev->data;
+	k_spinlock_key_t key = k_spin_lock(&data->lock);
 
 	plic_irq_enable_set_state(irq, true);
 
-	irq_unlock(key);
+	k_spin_unlock(&data->lock, key);
 }
 
 /**
@@ -298,47 +301,58 @@ void riscv_plic_irq_enable(uint32_t irq)
  */
 void riscv_plic_irq_disable(uint32_t irq)
 {
-	uint32_t key = irq_lock();
+	const struct device *dev = get_plic_dev_from_irq(irq);
+	struct plic_data *data = dev->data;
+	k_spinlock_key_t key = k_spin_lock(&data->lock);
 
 	plic_irq_enable_set_state(irq, false);
 
-	irq_unlock(key);
+	k_spin_unlock(&data->lock, key);
 }
 
-/**
- * @brief Check if a riscv PLIC-specific interrupt line is enabled
- *
- * This routine checks if a RISCV PLIC-specific interrupt line is enabled.
- * @param irq IRQ number to check
- *
- * @return 1 or 0
- */
-int riscv_plic_irq_is_enabled(uint32_t irq)
+/* Check if the local IRQ of a PLIC instance is enabled */
+static int local_irq_is_enabled(const struct device *dev, uint32_t local_irq)
 {
-	const struct device *dev = get_plic_dev_from_irq(irq);
-	const uint32_t local_irq = irq_from_level_2(irq);
 	uint32_t bit_position = local_irq & PLIC_REG_MASK;
-	uint32_t en_value;
 	int is_enabled = IS_ENABLED(CONFIG_PLIC_IRQ_AFFINITY) ? 0 : 1;
-	uint32_t key = irq_lock();
 
 	for (uint32_t cpu_num = 0; cpu_num < arch_num_cpus(); cpu_num++) {
 		mem_addr_t en_addr =
 			get_context_en_addr(dev, cpu_num) + local_irq_to_reg_offset(local_irq);
+		uint32_t en_value = sys_read32(en_addr);
 
-		en_value = sys_read32(en_addr);
 		if (IS_ENABLED(CONFIG_PLIC_IRQ_AFFINITY)) {
 			is_enabled |= !!(en_value & BIT(bit_position));
 		} else {
 			is_enabled &= !!(en_value & BIT(bit_position));
 		}
 	}
 
-	irq_unlock(key);
-
 	return is_enabled;
 }
 
+/**
+ * @brief Check if a riscv PLIC-specific interrupt line is enabled
+ *
+ * This routine checks if a RISCV PLIC-specific interrupt line is enabled.
+ * @param irq IRQ number to check
+ *
+ * @return 1 or 0
+ */
+int riscv_plic_irq_is_enabled(uint32_t irq)
+{
+	const struct device *dev = get_plic_dev_from_irq(irq);
+	struct plic_data *data = dev->data;
+	const uint32_t local_irq = irq_from_level_2(irq);
+	int ret = 0;
+
+	K_SPINLOCK(&data->lock) {
+		ret = local_irq_is_enabled(dev, local_irq);
+	}
+
+	return ret;
+}
+
 /**
  * @brief Set priority of a riscv PLIC-specific interrupt line
  *
@@ -413,9 +427,10 @@ const struct device *riscv_plic_get_dev(void)
 int riscv_plic_irq_set_affinity(uint32_t irq, uint32_t cpumask)
 {
 	const struct device *dev = get_plic_dev_from_irq(irq);
-	const struct plic_data *data = dev->data;
+	struct plic_data *data = dev->data;
 	__maybe_unused const struct plic_config *config = dev->config;
 	const uint32_t local_irq = irq_from_level_2(irq);
+	k_spinlock_key_t key;
 
 	if (local_irq >= config->nr_irqs) {
 		__ASSERT(false, "overflow: irq %d, local_irq %d", irq, local_irq);
@@ -427,17 +442,15 @@ int riscv_plic_irq_set_affinity(uint32_t irq, uint32_t cpumask)
 		return -EINVAL;
 	}
 
-	uint32_t key = irq_lock();
-
+	key = k_spin_lock(&data->lock);
 	/* Updated irq_cpumask for next time setting plic enable register */
 	data->irq_cpumask[local_irq] = (plic_cpumask_t)cpumask;
 
 	/* If irq is enabled, apply the new irq affinity */
-	if (riscv_plic_irq_is_enabled(irq)) {
-		riscv_plic_irq_enable(irq);
+	if (local_irq_is_enabled(dev, local_irq)) {
+		plic_irq_enable_set_state(irq, true);
 	}
-
-	irq_unlock(key);
+	k_spin_unlock(&data->lock, key);
 
 	return 0;
 }