Add ACPI support in PLIC driver. Use the mapping created early during
boot to get details about the PLIC.

Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
Co-developed-by: Haibo Xu <redacted>
Signed-off-by: Haibo Xu <redacted>
---
 drivers/irqchip/irq-sifive-plic.c | 94 ++++++++++++++++++++++++-------
 1 file changed, 73 insertions(+), 21 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 9e22f7e378f5..12d60728329c 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 {

@@ -324,6 +327,10 @@ 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);

@@ -424,18 +431,37 @@ static const struct of_device_id plic_match[] = {
        {}
 };

+#ifdef CONFIG_ACPI
+
+static const struct acpi_device_id plic_acpi_match[] = {
+       { "RSCV0001", 0 },
+       {}
+};
+MODULE_DEVICE_TABLE(acpi, plic_acpi_match);
+
+#endif
 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;
        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 = riscv_acpi_get_gsi_info(dev->fwnode, gsi_base, id, nr_irqs, NULL);
+               if (rc) {
+                       dev_err(dev, "failed to find GSI mapping\n");
+                       return rc;
+               }
+
+               *nr_contexts = acpi_get_plic_nr_contexts(*id);
+               if (WARN_ON(!*nr_contexts)) {
+                       dev_err(dev, "no PLIC context available\n");
+                       return -EINVAL;
+               }
+
+               return 0;
+       }

        rc = of_property_read_u32(to_of_node(dev->fwnode), "riscv,ndev", nr_irqs);
        if (rc) {

@@ -449,23 +475,29 @@ 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(struct platform_device *pdev, u32 context,
-                                    u32 *parent_hwirq, int *parent_cpu)
+                                    u32 *parent_hwirq, int *parent_cpu, u32 id)
 {
        struct device *dev = &pdev->dev;
        struct of_phandle_args parent;
        unsigned long hartid;
        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)) {
+               hartid = acpi_get_ext_intc_parent_hartid(id, context);
+               if (hartid == INVALID_HARTID)
+                       return -EINVAL;
+
+               *parent_cpu = riscv_hartid_to_cpuid(hartid);
+               *parent_hwirq = RV_IRQ_EXT;
+               return 0;
+       }

        rc = of_irq_parse_one(to_of_node(dev->fwnode), context, &parent);
        if (rc)

@@ -489,6 +521,8 @@ static int plic_probe(struct platform_device *pdev)
        u32 nr_irqs, parent_hwirq;
        struct plic_priv *priv;
        irq_hw_number_t hwirq;
+       int id, context_id;
+       u32 gsi_base;

        if (is_of_node(dev->fwnode)) {
                const struct of_device_id *id;

@@ -498,7 +532,7 @@ 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);
+       error = plic_parse_nr_irqs_and_contexts(pdev, &nr_irqs, &nr_contexts, &gsi_base, &id);
        if (error)
                return error;

@@ -509,6 +543,8 @@ static int plic_probe(struct platform_device *pdev)
        priv->dev = dev;
        priv->plic_quirks = plic_quirks;
        priv->nr_irqs = nr_irqs;
+       priv->gsi_base = gsi_base;
+       priv->id = id;

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

@@ -519,12 +555,22 @@ static int plic_probe(struct platform_device *pdev)
                return -ENOMEM;

        for (i = 0; i < nr_contexts; i++) {
-               error = plic_parse_context_parent(pdev, i, &parent_hwirq, &cpu);
+               error = plic_parse_context_parent(pdev, i, &parent_hwirq, &cpu, priv->id);
                if (error) {
                        dev_warn(dev, "hwirq for context%d not found\n", i);
                        continue;
                }

+               if (is_of_node(dev->fwnode)) {
+                       context_id = i;
+               } else {
+                       context_id = acpi_get_plic_context(priv->id, i);
+                       if (context_id == INVALID_CONTEXT) {
+                               dev_warn(dev, "invalid context id for context%d\n", i);
+                               continue;
+                       }
+               }
+
                /*
                 * Skip contexts other than external interrupts for our
                 * privilege level.

@@ -562,10 +608,10 @@ static int plic_probe(struct platform_device *pdev)
                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, DIV_ROUND_UP(nr_irqs, 32),

@@ -581,8 +627,8 @@ static int plic_probe(struct platform_device *pdev)
                nr_handlers++;
        }

-       priv->irqdomain = irq_domain_add_linear(to_of_node(dev->fwnode), nr_irqs + 1,
-                                               &plic_irqdomain_ops, priv);
+       priv->irqdomain = irq_domain_create_linear(dev->fwnode, nr_irqs + 1,
+                                                  &plic_irqdomain_ops, priv);
        if (WARN_ON(!priv->irqdomain))
                goto fail_cleanup_contexts;

@@ -619,13 +665,18 @@ static int plic_probe(struct platform_device *pdev)
                }
        }

+#ifdef CONFIG_ACPI
+       if (!acpi_disabled)
+               acpi_dev_clear_dependencies(ACPI_COMPANION(dev));
+#endif
+
        dev_info(dev, "mapped %d interrupts with %d handlers for %d contexts.\n",
                 nr_irqs, nr_handlers, nr_contexts);
        return 0;

 fail_cleanup_contexts:
        for (i = 0; i < nr_contexts; i++) {
-               if (plic_parse_context_parent(pdev, i, &parent_hwirq, &cpu))
+               if (plic_parse_context_parent(pdev, i, &parent_hwirq, &cpu, priv->id))
                        continue;
                if (parent_hwirq != RV_IRQ_EXT || cpu < 0)
                        continue;

@@ -644,6 +695,7 @@ static struct platform_driver plic_driver = {
        .driver = {
                .name           = "riscv-plic",
                .of_match_table = plic_match,
+               .acpi_match_table = ACPI_PTR(plic_acpi_match),
        },
        .probe = plic_probe,
 };
--

2.43.0