[RFC PATCH v2 16/21] irqchip: irq-sifive-plic: Add ACPI support

Sunil V L
2023-10-25T20:25:50Z

Add ACPI support in PLIC driver. In ACPI, IO devices use Global System
Interrupts (GSI) which is a flat space split across multiple PLICs. So,
the driver also need to provide the mapping from GSI to correct PLIC.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Co-developed-by: Haibo Xu <haibo1.xu@intel.com>
Signed-off-by: Haibo Xu <haibo1.xu@intel.com>
---
arch/riscv/include/asm/irq.h | 6 ++
drivers/irqchip/irq-sifive-plic.c | 113 +++++++++++++++++++++++++-----
2 files changed, 101 insertions(+), 18 deletions(-)

diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index 00eb8b0333c2..eff442766c87 100644
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -28,6 +28,12 @@ struct fwnode_handle *aplic_get_gsi_domain_id(u32 gsi);
static inline struct fwnode_handle *aplic_get_gsi_domain_id(u32 gsi) { return NULL; }
#endif

+#ifdef CONFIG_SIFIVE_PLIC
+struct fwnode_handle *plic_get_gsi_domain_id(u32 gsi);
+#else
+static inline struct fwnode_handle *plic_get_gsi_domain_id(u32 gsi) { return NULL; }
+#endif
+
int __init acpi_get_intc_index_hartid(u32 index, unsigned long *hartid);
int acpi_get_ext_intc_parent_hartid(u8 id, u32 idx, unsigned long *hartid);
void acpi_get_plic_nr_contexts(u8 id, int *nr_contexts);
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index c8f8a8cdcce1..9c61084a74eb 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -3,6 +3,7 @@
* Copyright (C) 2017 SiFive
* Copyright (C) 2018 Christoph Hellwig
*/
+#include <linux/acpi.h>
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -70,6 +71,8 @@ struct plic_priv {
unsigned long plic_quirks;
unsigned int nr_irqs;
unsigned long *prio_save;
+ u32 gsi_base;
+ int id;
};

struct plic_handler {
@@ -316,6 +319,10 @@ static int plic_irq_domain_translate(struct irq_domain *d,
{
struct plic_priv *priv = d->host_data;

+ /* For DT, gsi_base is always zero. */
+ if (fwspec->param[0] >= priv->gsi_base)
+ fwspec->param[0] = fwspec->param[0] - priv->gsi_base;
+
if (test_bit(PLIC_QUIRK_EDGE_INTERRUPT, &priv->plic_quirks))
return irq_domain_translate_twocell(d, fwspec, hwirq, type);

@@ -417,17 +424,31 @@ 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)
+ u32 *nr_irqs, u32 *nr_contexts,
+ u32 *gsi_base, u32 *id)
{
struct device *dev = &pdev->dev;
+ struct acpi_madt_plic *plic;
int rc;

- /*
- * Currently, only OF fwnode is supported so extend this
- * function for ACPI support.
- */
- if (!is_of_node(dev->fwnode))
- return -EINVAL;
+ if (!is_of_node(dev->fwnode)) {
+ plic = *(struct acpi_madt_plic **)dev_get_platdata(dev);
+ if (!plic) {
+ dev_err(dev, "PLIC platform data is NULL!\n");
+ return -EINVAL;
+ }
+
+ *nr_irqs = plic->num_irqs;
+ acpi_get_plic_nr_contexts(plic->id, nr_contexts);
+ if (WARN_ON(!*nr_contexts)) {
+ dev_err(dev, "no PLIC context available\n");
+ return -EINVAL;
+ }
+
+ *gsi_base = plic->gsi_base;
+ *id = plic->id;
+ return 0;
+ }

rc = of_property_read_u32(to_of_node(dev->fwnode),
"riscv,ndev", nr_irqs);
@@ -442,23 +463,28 @@ static int plic_parse_nr_irqs_and_contexts(struct platform_device *pdev,
return -EINVAL;
}

+ *gsi_base = 0;
+ *id = 0;
+
return 0;
}

static int plic_parse_context_parent_hwirq(struct platform_device *pdev,
- u32 context, u32 *parent_hwirq,
+ u32 context, u32 id, u32 *parent_hwirq,
unsigned long *parent_hartid)
{
struct device *dev = &pdev->dev;
struct of_phandle_args parent;
int rc;

- /*
- * Currently, only OF fwnode is supported so extend this
- * function for ACPI support.
- */
- if (!is_of_node(dev->fwnode))
- return -EINVAL;
+ if (!is_of_node(dev->fwnode)) {
+ rc = acpi_get_ext_intc_parent_hartid(id, context, parent_hartid);
+ if (rc)
+ return rc;
+
+ *parent_hwirq = RV_IRQ_EXT;
+ return 0;
+ }

rc = of_irq_parse_one(to_of_node(dev->fwnode), context, &parent);
if (rc)
@@ -472,6 +498,32 @@ static int plic_parse_context_parent_hwirq(struct platform_device *pdev,
return 0;
}

+#ifdef CONFIG_ACPI
+
+LIST_HEAD(plic_list);
+struct plic_priv_list {
+ struct plic_priv *priv;
+ struct list_head list;
+};
+
+struct fwnode_handle *plic_get_gsi_domain_id(u32 gsi)
+{
+ struct plic_priv_list *plic_element;
+ struct list_head *i, *tmp;
+
+ /* Find the PLIC that manages this GSI. */
+ list_for_each_safe(i, tmp, &plic_list) {
+ plic_element = list_entry(i, struct plic_priv_list, list);
+ if (gsi >= plic_element->priv->gsi_base &&
+ gsi <= (plic_element->priv->gsi_base + plic_element->priv->nr_irqs))
+ return plic_element->priv->dev->fwnode;
+ }
+
+ return NULL;
+}
+
+#endif
+
static int plic_probe(struct platform_device *pdev)
{
int rc, nr_contexts, nr_handlers = 0, i, cpu;
@@ -483,7 +535,9 @@ static int plic_probe(struct platform_device *pdev)
struct plic_priv *priv;
irq_hw_number_t hwirq;
struct resource *res;
+ int id, context_id;
bool cpuhp_setup;
+ u32 gsi_base;

if (is_of_node(dev->fwnode)) {
const struct of_device_id *id;
@@ -510,19 +564,21 @@ static int plic_probe(struct platform_device *pdev)
return -EIO;
}

- rc = plic_parse_nr_irqs_and_contexts(pdev, &nr_irqs, &nr_contexts);
+ rc = plic_parse_nr_irqs_and_contexts(pdev, &nr_irqs, &nr_contexts, &gsi_base, &id);
if (rc) {
dev_err(dev, "failed to parse irqs and contexts\n");
return rc;
}
priv->nr_irqs = nr_irqs;
+ priv->gsi_base = gsi_base;
+ priv->id = id;

priv->prio_save = devm_bitmap_zalloc(dev, nr_irqs, GFP_KERNEL);
if (!priv->prio_save)
return -ENOMEM;

for (i = 0; i < nr_contexts; i++) {
- rc = plic_parse_context_parent_hwirq(pdev, i,
+ rc = plic_parse_context_parent_hwirq(pdev, i, priv->id,
&parent_hwirq, &hartid);
if (rc) {
dev_warn(dev, "hwirq for context%d not found\n", i);
@@ -574,13 +630,23 @@ static int plic_probe(struct platform_device *pdev)
goto done;
}

+ if (is_of_node(dev->fwnode)) {
+ context_id = i;
+ } else {
+ rc = acpi_get_plic_context(priv->id, i, &context_id);
+ if (rc) {
+ dev_warn(dev, "invalid context id for context%d\n", i);
+ continue;
+ }
+ }
+
cpumask_set_cpu(cpu, &priv->lmask);
handler->present = true;
handler->hart_base = priv->regs + CONTEXT_BASE +
- i * CONTEXT_SIZE;
+ context_id * CONTEXT_SIZE;
raw_spin_lock_init(&handler->enable_lock);
handler->enable_base = priv->regs + CONTEXT_ENABLE_BASE +
- i * CONTEXT_ENABLE_SIZE;
+ context_id * CONTEXT_ENABLE_SIZE;
handler->priv = priv;

handler->enable_save = devm_kcalloc(dev,
@@ -624,6 +690,17 @@ static int plic_probe(struct platform_device *pdev)
register_syscore_ops(&plic_irq_syscore_ops);
}

+#ifdef CONFIG_ACPI
+ struct plic_priv_list *plic_element;
+
+ plic_element = devm_kzalloc(dev, sizeof(*plic_element), GFP_KERNEL);
+ if (!plic_element)
+ return -ENOMEM;
+
+ plic_element->priv = priv;
+ list_add_tail(&plic_element->list, &plic_list);
+#endif
+
dev_info(dev, "mapped %d interrupts with %d handlers for"
" %d contexts.\n", nr_irqs, nr_handlers, nr_contexts);
return 0;
--
2.39.2