[PATCH v8 03/10] irqchip/riscv-intc: Introduce Andes hart-level interrupt controller

From: Yu Chien Peter Lin
Date: Mon Jan 29 2024 - 04:30:55 EST

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Add support for the Andes hart-level interrupt controller. This
controller provides interrupt mask/unmask functions to access the
custom register (SLIE) where the non-standard S-mode local interrupt
enable bits are located. The base of custom interrupt number is set
to 256.

To share the riscv_intc_domain_map() with the generic RISC-V INTC and
ACPI, add a chip parameter to riscv_intc_init_common(), so it can be
passed to the irq_domain_set_info() as a private data.

Andes hart-level interrupt controller requires the "andestech,cpu-intc"
compatible string to be present in interrupt-controller of cpu node to
enable the use of custom local interrupt source.
e.g.,

cpu0: cpu@0 {
compatible = "andestech,ax45mp", "riscv";
...
cpu0-intc: interrupt-controller {
#interrupt-cells = <0x01>;
compatible = "andestech,cpu-intc", "riscv,cpu-intc";
interrupt-controller;
};
};

Signed-off-by: Yu Chien Peter Lin <peterlin@xxxxxxxxxxxxx>
Reviewed-by: Randolph <randolph@xxxxxxxxxxxxx>
Reviewed-by: Anup Patel <anup@xxxxxxxxxxxxxx>
---
Changes v1 -> v2:
- New patch
Changes v2 -> v3:
- Return -ENXIO if no valid compatible INTC found
- Allow falling back to generic RISC-V INTC
Changes v3 -> v4: (Suggested by Thomas [1])
- Add comment to andes irq chip function
- Refine code flow to share with generic RISC-V INTC and ACPI
- Move Andes specific definitions to include/linux/soc/andes/irq.h
Changes v4 -> v5: (Suggested by Thomas)
- Fix commit message
- Subtract ANDES_SLI_CAUSE_BASE from d->hwirq to calculate the value of mask
- Do not set chip_data to the chip itself with irq_domain_set_info()
- Follow reverse fir tree order variable declarations
Changes v5 -> v6:
- To follow the naming on datasheet, rename ANDES_RV_IRQ_PMU to ANDES_RV_IRQ_PMOVI
- Initialize the riscv_intc_* global variables for Andes INTC (Suggested by Anup)
- Use BITS_PER_LONG to compute the bit mask of SIE/SLIE as they are 64-bit registers (32-bit for RV32)
Changes v6 -> v7:
- No change
Changes v7 -> v8:
- Include Reviewed-by tags from Anup

[1] https://patchwork.kernel.org/project/linux-riscv/patch/20231019135723.3657156-1-peterlin@xxxxxxxxxxxxx/
---
drivers/irqchip/irq-riscv-intc.c | 66 +++++++++++++++++++++++++++-----
include/linux/soc/andes/irq.h | 18 +++++++++
2 files changed, 74 insertions(+), 10 deletions(-)
create mode 100644 include/linux/soc/andes/irq.h

diff --git a/drivers/irqchip/irq-riscv-intc.c b/drivers/irqchip/irq-riscv-intc.c
index b13a16b164c9..7064857f1f1d 100644
--- a/drivers/irqchip/irq-riscv-intc.c
+++ b/drivers/irqchip/irq-riscv-intc.c
@@ -17,6 +17,7 @@
#include <linux/module.h>
#include <linux/of.h>
#include <linux/smp.h>
+#include <linux/soc/andes/irq.h>

static struct irq_domain *intc_domain;
static unsigned int riscv_intc_nr_irqs __ro_after_init;
@@ -49,6 +50,31 @@ static void riscv_intc_irq_unmask(struct irq_data *d)
csr_set(CSR_IE, BIT(d->hwirq));
}

+static void andes_intc_irq_mask(struct irq_data *d)
+{
+ /*
+ * Andes specific S-mode local interrupt causes (hwirq)
+ * are defined as (256 + n) and controlled by n-th bit
+ * of SLIE.
+ */
+ unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
+
+ if (d->hwirq < ANDES_SLI_CAUSE_BASE)
+ csr_clear(CSR_IE, mask);
+ else
+ csr_clear(ANDES_CSR_SLIE, mask);
+}
+
+static void andes_intc_irq_unmask(struct irq_data *d)
+{
+ unsigned int mask = BIT(d->hwirq % BITS_PER_LONG);
+
+ if (d->hwirq < ANDES_SLI_CAUSE_BASE)
+ csr_set(CSR_IE, mask);
+ else
+ csr_set(ANDES_CSR_SLIE, mask);
+}
+
static void riscv_intc_irq_eoi(struct irq_data *d)
{
/*
@@ -72,12 +98,21 @@ static struct irq_chip riscv_intc_chip = {
.irq_eoi = riscv_intc_irq_eoi,
};

+static struct irq_chip andes_intc_chip = {
+ .name = "RISC-V INTC",
+ .irq_mask = andes_intc_irq_mask,
+ .irq_unmask = andes_intc_irq_unmask,
+ .irq_eoi = riscv_intc_irq_eoi,
+};
+
static int riscv_intc_domain_map(struct irq_domain *d, unsigned int irq,
irq_hw_number_t hwirq)
{
+ struct irq_chip *chip = d->host_data;
+
irq_set_percpu_devid(irq);
- irq_domain_set_info(d, irq, hwirq, &riscv_intc_chip, d->host_data,
- handle_percpu_devid_irq, NULL, NULL);
+ irq_domain_set_info(d, irq, hwirq, chip, NULL, handle_percpu_devid_irq,
+ NULL, NULL);

return 0;
}
@@ -123,11 +158,12 @@ static struct fwnode_handle *riscv_intc_hwnode(void)
return intc_domain->fwnode;
}

-static int __init riscv_intc_init_common(struct fwnode_handle *fn)
+static int __init riscv_intc_init_common(struct fwnode_handle *fn,
+ struct irq_chip *chip)
{
int rc;

- intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, NULL);
+ intc_domain = irq_domain_create_tree(fn, &riscv_intc_domain_ops, chip);
if (!intc_domain) {
pr_err("unable to add IRQ domain\n");
return -ENXIO;
@@ -152,8 +188,9 @@ static int __init riscv_intc_init_common(struct fwnode_handle *fn)
static int __init riscv_intc_init(struct device_node *node,
struct device_node *parent)
{
- int rc;
+ struct irq_chip *chip;
unsigned long hartid;
+ int rc;

rc = riscv_of_parent_hartid(node, &hartid);
if (rc < 0) {
@@ -178,14 +215,23 @@ static int __init riscv_intc_init(struct device_node *node,
return 0;
}

- riscv_intc_nr_irqs = BITS_PER_LONG;
- riscv_intc_custom_base = riscv_intc_nr_irqs;
- riscv_intc_custom_nr_irqs = 0;
+ if (of_device_is_compatible(node, "andestech,cpu-intc")) {
+ riscv_intc_nr_irqs = BITS_PER_LONG;
+ riscv_intc_custom_base = ANDES_SLI_CAUSE_BASE;
+ riscv_intc_custom_nr_irqs = ANDES_RV_IRQ_LAST;
+ chip = &andes_intc_chip;
+ } else {
+ riscv_intc_nr_irqs = BITS_PER_LONG;
+ riscv_intc_custom_base = riscv_intc_nr_irqs;
+ riscv_intc_custom_nr_irqs = 0;
+ chip = &riscv_intc_chip;
+ }

- return riscv_intc_init_common(of_node_to_fwnode(node));
+ return riscv_intc_init_common(of_node_to_fwnode(node), chip);
}

IRQCHIP_DECLARE(riscv, "riscv,cpu-intc", riscv_intc_init);
+IRQCHIP_DECLARE(andes, "andestech,cpu-intc", riscv_intc_init);

#ifdef CONFIG_ACPI

@@ -212,7 +258,7 @@ static int __init riscv_intc_acpi_init(union acpi_subtable_headers *header,
return -ENOMEM;
}

- return riscv_intc_init_common(fn);
+ return riscv_intc_init_common(fn, &riscv_intc_chip);
}

IRQCHIP_ACPI_DECLARE(riscv_intc, ACPI_MADT_TYPE_RINTC, NULL,
diff --git a/include/linux/soc/andes/irq.h b/include/linux/soc/andes/irq.h
new file mode 100644
index 000000000000..edc3182d6e66
--- /dev/null
+++ b/include/linux/soc/andes/irq.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (C) 2023 Andes Technology Corporation
+ */
+#ifndef __ANDES_IRQ_H
+#define __ANDES_IRQ_H
+
+/* Andes PMU irq number */
+#define ANDES_RV_IRQ_PMOVI 18
+#define ANDES_RV_IRQ_LAST ANDES_RV_IRQ_PMOVI
+#define ANDES_SLI_CAUSE_BASE 256
+
+/* Andes PMU related registers */
+#define ANDES_CSR_SLIE 0x9c4
+#define ANDES_CSR_SLIP 0x9c5
+#define ANDES_CSR_SCOUNTEROF 0x9d4
+
+#endif /* __ANDES_IRQ_H */
--
2.34.1

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