[PATCH v8 06/16] irqchip/sifive-plic: Convert PLIC driver into a platform driver

Anup Patel
2023-09-12T17:51:02Z

The PLIC driver does not require very early initialization so let us
convert it into a platform driver.

As part of the conversion, the PLIC probing undergoes the following
changes:
1. Use dev_info(), dev_err() and dev_warn() instead of pr_info(),
pr_err() and pr_warn()
2. Use devm_xyz() APIs wherever applicable
3. Use fwnode APIs to read PLIC properties so that PLIC driver
is suitable for ACPI as well.
4. PLIC is now probed after CPUs are brought-up so we have to
setup cpuhp state after context handler of all online CPUs
are initialized otherwise we see crash on multi-socket systems

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
---
drivers/irqchip/irq-sifive-plic.c | 198 +++++++++++++++++-------------
1 file changed, 112 insertions(+), 86 deletions(-)

diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c
index 62ba27553cc3..72d6e06ef52b 100644
--- a/drivers/irqchip/irq-sifive-plic.c
+++ b/drivers/irqchip/irq-sifive-plic.c
@@ -3,7 +3,6 @@
* Copyright (C) 2017 SiFive
* Copyright (C) 2018 Christoph Hellwig
*/
-#define pr_fmt(fmt) "plic: " fmt
#include <linux/cpu.h>
#include <linux/interrupt.h>
#include <linux/io.h>
@@ -13,8 +12,6 @@
#include <linux/irqdomain.h>
#include <linux/module.h>
#include <linux/of.h>
-#include <linux/of_address.h>
-#include <linux/of_irq.h>
#include <linux/platform_device.h>
#include <linux/spinlock.h>
#include <linux/syscore_ops.h>
@@ -64,6 +61,7 @@
#define PLIC_QUIRK_EDGE_INTERRUPT 0

struct plic_priv {
+ struct device *dev;
struct cpumask lmask;
struct irq_domain *irqdomain;
void __iomem *regs;
@@ -85,7 +83,6 @@ struct plic_handler {
struct plic_priv *priv;
};
static int plic_parent_irq __ro_after_init;
-static bool plic_cpuhp_setup_done __ro_after_init;
static DEFINE_PER_CPU(struct plic_handler, plic_handlers);

static int plic_irq_set_type(struct irq_data *d, unsigned int type);
@@ -371,7 +368,8 @@ static void plic_handle_irq(struct irq_desc *desc)
int err = generic_handle_domain_irq(handler->priv->irqdomain,
hwirq);
if (unlikely(err))
- pr_warn_ratelimited("can't find mapping for hwirq %lu\n",
+ dev_warn_ratelimited(handler->priv->dev,
+ "can't find mapping for hwirq %lu\n",
hwirq);
}

@@ -406,57 +404,83 @@ static int plic_starting_cpu(unsigned int cpu)
return 0;
}

-static int __init __plic_init(struct device_node *node,
- struct device_node *parent,
- unsigned long plic_quirks)
+static const struct of_device_id plic_match[] = {
+ { .compatible = "sifive,plic-1.0.0" },
+ { .compatible = "riscv,plic0" },
+ { .compatible = "andestech,nceplic100",
+ .data = (const void *)BIT(PLIC_QUIRK_EDGE_INTERRUPT) },
+ { .compatible = "thead,c900-plic",
+ .data = (const void *)BIT(PLIC_QUIRK_EDGE_INTERRUPT) },
+ {}
+};
+
+static int plic_probe(struct platform_device *pdev)
{
- int error = 0, nr_contexts, nr_handlers = 0, i;
- u32 nr_irqs;
- struct plic_priv *priv;
+ int rc, nr_contexts, nr_handlers = 0, i, cpu;
+ unsigned long plic_quirks = 0, hartid;
+ struct fwnode_reference_args parent;
+ struct device *dev = &pdev->dev;
struct plic_handler *handler;
- unsigned int cpu;
+ struct irq_domain *domain;
+ struct plic_priv *priv;
+ irq_hw_number_t hwirq;
+ struct resource *res;
+ bool cpuhp_setup;
+ u32 nr_irqs;
+
+ if (is_of_node(dev->fwnode)) {
+ const struct of_device_id *id;
+
+ id = of_match_node(plic_match, to_of_node(dev->fwnode));
+ if (id)
+ plic_quirks = (unsigned long)id->data;
+ }

- priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
-
+ priv->dev = dev;
priv->plic_quirks = plic_quirks;

- priv->regs = of_iomap(node, 0);
- if (WARN_ON(!priv->regs)) {
- error = -EIO;
- goto out_free_priv;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "failed to get MMIO resource\n");
+ return -EINVAL;
+ }
+ priv->regs = devm_ioremap(dev, res->start, resource_size(res));
+ if (!priv->regs) {
+ dev_err(dev, "failed map MMIO registers\n");
+ return -EIO;
}

- error = -EINVAL;
- of_property_read_u32(node, "riscv,ndev", &nr_irqs);
- if (WARN_ON(!nr_irqs))
- goto out_iounmap;
-
+ rc = fwnode_property_read_u32_array(dev->fwnode, "riscv,ndev",
+ &nr_irqs, 1);
+ if (rc) {
+ dev_err(dev, "riscv,ndev property not available\n");
+ return rc;
+ }
priv->nr_irqs = nr_irqs;

- priv->prio_save = bitmap_alloc(nr_irqs, GFP_KERNEL);
+ priv->prio_save = devm_bitmap_zalloc(dev, nr_irqs, GFP_KERNEL);
if (!priv->prio_save)
- goto out_free_priority_reg;
-
- nr_contexts = of_irq_count(node);
- if (WARN_ON(!nr_contexts))
- goto out_free_priority_reg;
+ return -ENOMEM;

- error = -ENOMEM;
- priv->irqdomain = irq_domain_add_linear(node, nr_irqs + 1,
- &plic_irqdomain_ops, priv);
- if (WARN_ON(!priv->irqdomain))
- goto out_free_priority_reg;
+ nr_contexts = 0;
+ while (!fwnode_property_get_reference_args(dev->fwnode,
+ "interrupts-extended", "#interrupt-cells",
+ 0, nr_contexts, &parent))
+ nr_contexts++;
+ if (WARN_ON(!nr_contexts)) {
+ dev_err(dev, "no PLIC context available\n");
+ return -EINVAL;
+ }

for (i = 0; i < nr_contexts; i++) {
- struct of_phandle_args parent;
- irq_hw_number_t hwirq;
- int cpu;
- unsigned long hartid;
-
- if (of_irq_parse_one(node, i, &parent)) {
- pr_err("failed to parse parent for context %d.\n", i);
+ rc = fwnode_property_get_reference_args(dev->fwnode,
+ "interrupts-extended", "#interrupt-cells",
+ 0, i, &parent);
+ if (rc) {
+ dev_warn(dev, "parent irq for context%d not found\n", i);
continue;
}

@@ -477,22 +501,23 @@ static int __init __plic_init(struct device_node *node,
continue;
}

- error = riscv_get_intc_hartid(of_fwnode_handle(parent.np),
- &hartid);
- if (error < 0) {
- pr_warn("failed to parse hart ID for context %d.\n", i);
+ rc = riscv_get_intc_hartid(parent.fwnode, &hartid);
+ if (rc < 0) {
+ dev_warn(dev, "failed to get hart ID for context%d.\n", i);
continue;
}

cpu = riscv_hartid_to_cpuid(hartid);
if (cpu < 0) {
- pr_warn("Invalid cpuid for context %d\n", i);
+ dev_warn(dev, "Invalid cpuid for context %d\n", i);
continue;
}

/* Find parent domain and register chained handler */
- if (!plic_parent_irq && irq_find_host(parent.np)) {
- plic_parent_irq = irq_of_parse_and_map(node, i);
+ domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(),
+ DOMAIN_BUS_ANY);
+ if (!plic_parent_irq && domain) {
+ plic_parent_irq = irq_create_mapping(domain, RV_IRQ_EXT);
if (plic_parent_irq)
irq_set_chained_handler(plic_parent_irq,
plic_handle_irq);
@@ -505,7 +530,7 @@ static int __init __plic_init(struct device_node *node,
*/
handler = per_cpu_ptr(&plic_handlers, cpu);
if (handler->present) {
- pr_warn("handler already present for context %d.\n", i);
+ dev_warn(dev, "handler already present for context%d.\n", i);
plic_set_threshold(handler, PLIC_DISABLE_THRESHOLD);
goto done;
}
@@ -519,10 +544,13 @@ static int __init __plic_init(struct device_node *node,
i * CONTEXT_ENABLE_SIZE;
handler->priv = priv;

- handler->enable_save = kcalloc(DIV_ROUND_UP(nr_irqs, 32),
- sizeof(*handler->enable_save), GFP_KERNEL);
+ handler->enable_save = devm_kcalloc(dev,
+ DIV_ROUND_UP(nr_irqs, 32),
+ sizeof(*handler->enable_save),
+ GFP_KERNEL);
if (!handler->enable_save)
- goto out_free_enable_reg;
+ return -ENOMEM;
+
done:
for (hwirq = 1; hwirq <= nr_irqs; hwirq++) {
plic_toggle(handler, hwirq, 0);
@@ -532,52 +560,50 @@ static int __init __plic_init(struct device_node *node,
nr_handlers++;
}

+ priv->irqdomain = irq_domain_create_linear(dev->fwnode, nr_irqs + 1,
+ &plic_irqdomain_ops, priv);
+ if (WARN_ON(!priv->irqdomain))
+ return -ENOMEM;
+
/*
* We can have multiple PLIC instances so setup cpuhp state
- * and register syscore operations only when context handler
- * for current/boot CPU is present.
+ * and register syscore operations only after context handlers
+ * of all online CPUs are initialized.
*/
- handler = this_cpu_ptr(&plic_handlers);
- if (handler->present && !plic_cpuhp_setup_done) {
+ cpuhp_setup = true;
+ for_each_online_cpu(cpu) {
+ handler = per_cpu_ptr(&plic_handlers, cpu);
+ if (!handler->present) {
+ cpuhp_setup = false;
+ break;
+ }
+ }
+ if (cpuhp_setup) {
cpuhp_setup_state(CPUHP_AP_IRQ_SIFIVE_PLIC_STARTING,
"irqchip/sifive/plic:starting",
plic_starting_cpu, plic_dying_cpu);
register_syscore_ops(&plic_irq_syscore_ops);
- plic_cpuhp_setup_done = true;
}

- pr_info("%pOFP: mapped %d interrupts with %d handlers for"
- " %d contexts.\n", node, nr_irqs, nr_handlers, nr_contexts);
+ dev_info(dev, "mapped %d interrupts with %d handlers for"
+ " %d contexts.\n", nr_irqs, nr_handlers, nr_contexts);
return 0;
-
-out_free_enable_reg:
- for_each_cpu(cpu, cpu_present_mask) {
- handler = per_cpu_ptr(&plic_handlers, cpu);
- kfree(handler->enable_save);
- }
-out_free_priority_reg:
- kfree(priv->prio_save);
-out_iounmap:
- iounmap(priv->regs);
-out_free_priv:
- kfree(priv);
- return error;
-}
-
-static int __init plic_init(struct device_node *node,
- struct device_node *parent)
-{
- return __plic_init(node, parent, 0);
}

-IRQCHIP_DECLARE(sifive_plic, "sifive,plic-1.0.0", plic_init);
-IRQCHIP_DECLARE(riscv_plic0, "riscv,plic0", plic_init); /* for legacy systems */
+static struct platform_driver plic_driver = {
+ .driver = {
+ .name = "riscv-plic",
+ .of_match_table = plic_match,
+ },
+ .probe = plic_probe,
+};

-static int __init plic_edge_init(struct device_node *node,
- struct device_node *parent)
+static int __init plic_init(void)
{
- return __plic_init(node, parent, BIT(PLIC_QUIRK_EDGE_INTERRUPT));
+ /*
+ * Register PLIC driver as early as possible so that PLIC
+ * platform device is probed as soon as it is created.
+ */
+ return platform_driver_register(&plic_driver);
}
-
-IRQCHIP_DECLARE(andestech_nceplic100, "andestech,nceplic100", plic_edge_init);
-IRQCHIP_DECLARE(thead_c900_plic, "thead,c900-plic", plic_edge_init);
+core_initcall(plic_init);