irqchip/riscv-intc: Allow drivers to directly discover INTC hwnode

Various RISC-V drivers (such as SBI IPI, SBI Timer, SBI PMU, and
KVM RISC-V) don't have associated DT node but these drivers need
standard per-CPU (local) interrupts defined by the RISC-V privileged
specification.

We add riscv_get_intc_hwnode() in arch/riscv which allows RISC-V
drivers not having DT node to discover INTC hwnode which in-turn
helps these drivers to map per-CPU (local) interrupts provided
by the INTC driver.

Signed-off-by: Anup Patel <apatel@ventanamicro.com>
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230328035223.1480939-3-apatel@ventanamicro.com

diff --git a/arch/riscv/include/asm/irq.h b/arch/riscv/include/asm/irq.h
index e4c435509983e544f73150ef4f6e7bd5a7267c85..43b9ebfbd94364f229f139ef0a0ed5c63c89dfc4 100644 (file)
--- a/arch/riscv/include/asm/irq.h
+++ b/arch/riscv/include/asm/irq.h
@@ -12,6 +12,10 @@
 
 #include <asm-generic/irq.h>
 
+void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void));
+
+struct fwnode_handle *riscv_get_intc_hwnode(void);
+
 extern void __init init_IRQ(void);
 
 #endif /* _ASM_RISCV_IRQ_H */

diff --git a/arch/riscv/kernel/irq.c b/arch/riscv/kernel/irq.c
index 7207fa08d78f86a26b0181c97c0c3761f4d49043..96d3171f0ca11ddb576ff59f72c7d09f7eb32b31 100644 (file)
--- a/arch/riscv/kernel/irq.c
+++ b/arch/riscv/kernel/irq.c
@@ -7,9 +7,27 @@
 
 #include <linux/interrupt.h>
 #include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/module.h>
 #include <linux/seq_file.h>
 #include <asm/smp.h>
 
+static struct fwnode_handle *(*__get_intc_node)(void);
+
+void riscv_set_intc_hwnode_fn(struct fwnode_handle *(*fn)(void))
+{
+       __get_intc_node = fn;
+}
+
+struct fwnode_handle *riscv_get_intc_hwnode(void)
+{
+       if (__get_intc_node)
+               return __get_intc_node();
+
+       return NULL;
+}
+EXPORT_SYMBOL_GPL(riscv_get_intc_hwnode);
+
 int arch_show_interrupts(struct seq_file *p, int prec)
 {
        show_ipi_stats(p, prec);

diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index 499e5f81b3fe33f913fc810aa11251c59021d86f..9066467e99e4e618f590d46ac45663e9c60611aa 100644 (file)
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -92,6 +92,11 @@ static const struct irq_domain_ops riscv_intc_domain_ops = {
        .xlate  = irq_domain_xlate_onecell,
 };
 
+static struct fwnode_handle *riscv_intc_hwnode(void)
+{
+       return intc_domain->fwnode;
+}
+
 static int __init riscv_intc_init(struct device_node *node,
                                  struct device_node *parent)
 {
@@ -126,6 +131,8 @@ static int __init riscv_intc_init(struct device_node *node,
                return rc;
        }
 
+       riscv_set_intc_hwnode_fn(riscv_intc_hwnode);
+
        cpuhp_setup_state(CPUHP_AP_IRQ_RISCV_STARTING,
                          "irqchip/riscv/intc:starting",
                          riscv_intc_cpu_starting,