[PATCH v14 06/18] irqchip/sifive-plic: Parse number of irqs and contexts early in plic_probe

Anup Patel
2024-02-22T09:41:06Z

The SiFive PLIC driver needs to know the number of irqs and contexts
to complete initialization. Parse these details early in plic_probe()
to avoid unnecessary memory allocations and register mappings if these
details are not available.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
drivers/irqchip/irq-sifive-plic.c | 43 ++++++++++++++++++++++++-------
1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index f0df5d0cb76e..e6d23fde51ed 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -416,6 +416,34 @@ static const struct of_device_id plic_match[] = {
{}
};

+static int plic_parse_nr_irqs_and_contexts(struct platform_device *pdev,
+ u32 *nr_irqs, u32 *nr_contexts)
+{
+ struct device *dev = &pdev->dev;
+ int rc;
+
+ /*
+ * Currently, only OF fwnode is supported so extend this
+ * function for ACPI support.
+ */
+ if (!is_of_node(dev->fwnode))
+ return -EINVAL;
+
+ rc = of_property_read_u32(to_of_node(dev->fwnode), "riscv,ndev", nr_irqs);
+ if (rc) {
+ dev_err(dev, "riscv,ndev property not available\n");
+ return rc;
+ }
+
+ *nr_contexts = of_irq_count(to_of_node(dev->fwnode));
+ if (WARN_ON(!(*nr_contexts))) {
+ dev_err(dev, "no PLIC context available\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
static int plic_parse_context_parent(struct platform_device *pdev, u32 context,
u32 *parent_hwirq, int *parent_cpu)
{
@@ -464,31 +492,26 @@ static int plic_probe(struct platform_device *pdev)
plic_quirks = (unsigned long)id->data;
}

+ error = plic_parse_nr_irqs_and_contexts(pdev, &nr_irqs, &nr_contexts);
+ if (error)
+ return error;
+
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;

priv->dev = dev;
priv->plic_quirks = plic_quirks;
+ priv->nr_irqs = nr_irqs;

priv->regs = devm_platform_ioremap_resource(pdev, 0);
if (WARN_ON(!priv->regs))
return -EIO;

- of_property_read_u32(to_of_node(dev->fwnode), "riscv,ndev", &nr_irqs);
- if (WARN_ON(!nr_irqs))
- return -EINVAL;
-
- priv->nr_irqs = nr_irqs;
-
priv->prio_save = devm_bitmap_zalloc(dev, nr_irqs, GFP_KERNEL);
if (!priv->prio_save)
return -ENOMEM;

- nr_contexts = of_irq_count(to_of_node(dev->fwnode));
- if (WARN_ON(!nr_contexts))
- return -EINVAL;
-
for (i = 0; i < nr_contexts; i++) {
error = plic_parse_context_parent(pdev, i, &parent_hwirq, &cpu);
if (error) {
--
2.34.1