[RFC PATCH v2 18/31] irqchip: Add kvx-core-intc core interupt controller driver

[Yann Sionneau <ysionneau@kalray.eu>]

From: Jules Maselbas <jmaselbas@kalray.eu>

Each kvx core includes a hardware interrupt controller (core INTC)
with the following features:
 - 32 independent interrupt sources
 - 4-bit priotity level
 - Individual interrupt enable bit
 - Interrupt status bit displaying the pending interrupts
 - Priority management between the 32 interrupts

Among those 32 interrupt sources, the first are hard-wired to hardware
sources. The remaining interrupt sources can be triggered via software
by directly writing to the ILR SFR.

The hard-wired interrupt sources are the following:
  0: Timer 0
  1: Timer 1
  2: Watchdog
  3: Performance Monitors
  4: APIC GIC line 0
  5: APIC GIC line 1
  6: APIC GIC line 2
  7: APIC GIC line 3
 12: SECC error from memory system
 13: Arithmetic exception (carry and IEEE 754 flags)
 16: Data Asynchronous Memory Error (DAME), raised for DECC/DSYS errors
 17: CLI (Cache Line Invalidation) for L1D or L1I following
     DECC/DSYS/Parity errors

The APIC GIC lines will be used to route interrupts coming from SoC
peripherals from outside the Cluster to the kvx core. Those peripherals
include USB host controller, eMMC/SD host controller, i2c, spi, PCIe,
IOMMUs etc...

Co-developed-by: Clement Leger <clement@clement-leger.fr>
Signed-off-by: Clement Leger <clement@clement-leger.fr>
Co-developed-by: Julian Vetter <jvetter@kalray.eu>
Signed-off-by: Julian Vetter <jvetter@kalray.eu>
Co-developed-by: Vincent Chardon <vincent.chardon@elsys-design.com>
Signed-off-by: Vincent Chardon <vincent.chardon@elsys-design.com>
Co-developed-by: Jules Maselbas <jmaselbas@kalray.eu>
Signed-off-by: Jules Maselbas <jmaselbas@kalray.eu>
Signed-off-by: Yann Sionneau <ysionneau@kalray.eu>
---

Notes:
    V1 -> V2: new patch
     - removed print on probe success

 drivers/irqchip/Kconfig             |  5 ++
 drivers/irqchip/Makefile            |  1 +
 drivers/irqchip/irq-kvx-core-intc.c | 80 +++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 drivers/irqchip/irq-kvx-core-intc.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 806adbc7b2a4..d242e02771e3 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -334,6 +334,11 @@ config MIPS_GIC
 	select IRQ_DOMAIN_HIERARCHY
 	select MIPS_CM
 
+config KVX_CORE_INTC
+	bool
+	depends on KVX
+	select IRQ_DOMAIN
+
 config KVX_APIC_GIC
 	bool
 	depends on KVX
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 7eaea87ca9ab..d931f2eb38b6 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_BCM7120_L2_IRQ)		+= irq-bcm7120-l2.o
 obj-$(CONFIG_BRCMSTB_L2_IRQ)		+= irq-brcmstb-l2.o
 obj-$(CONFIG_KEYSTONE_IRQ)		+= irq-keystone.o
 obj-$(CONFIG_MIPS_GIC)			+= irq-mips-gic.o
+obj-$(CONFIG_KVX_CORE_INTC)		+= irq-kvx-core-intc.o
 obj-$(CONFIG_KVX_APIC_GIC)		+= irq-kvx-apic-gic.o
 obj-$(CONFIG_KVX_ITGEN)			+= irq-kvx-itgen.o
 obj-$(CONFIG_KVX_APIC_MAILBOX)		+= irq-kvx-apic-mailbox.o
diff --git a/drivers/irqchip/irq-kvx-core-intc.c b/drivers/irqchip/irq-kvx-core-intc.c
new file mode 100644
index 000000000000..145f1248925b
--- /dev/null
+++ b/drivers/irqchip/irq-kvx-core-intc.c
@@ -0,0 +1,80 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2017-2023 Kalray Inc.
+ * Author(s): Clement Leger
+ */
+
+#define pr_fmt(fmt)	"kvx_core_intc: " fmt
+
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <asm/irq.h>
+
+#define KVX_CORE_INTC_IRQ	32
+
+
+static void kvx_irq_mask(struct irq_data *data)
+{
+	kvx_sfr_clear_bit(ILE, data->hwirq);
+}
+
+static void kvx_irq_unmask(struct irq_data *data)
+{
+	kvx_sfr_set_bit(ILE, data->hwirq);
+}
+
+static struct irq_chip kvx_irq_chip = {
+	.name           = "kvx core Intc",
+	.irq_mask	= kvx_irq_mask,
+	.irq_unmask	= kvx_irq_unmask,
+};
+
+static int kvx_irq_map(struct irq_domain *d, unsigned int irq,
+			 irq_hw_number_t hw)
+{
+	/* All interrupts for core are per cpu */
+	irq_set_percpu_devid(irq);
+	irq_set_chip_and_handler(irq, &kvx_irq_chip, handle_percpu_irq);
+
+	return 0;
+}
+
+static const struct irq_domain_ops kvx_irq_ops = {
+	.xlate = irq_domain_xlate_onecell,
+	.map = kvx_irq_map,
+};
+
+static int __init
+kvx_init_core_intc(struct device_node *intc, struct device_node *parent)
+{
+	struct irq_domain *root_domain;
+	uint32_t core_nr_irqs;
+
+	if (parent)
+		panic("DeviceTree core intc not a root irq controller\n");
+
+	if (of_property_read_u32(intc, "kalray,intc-nr-irqs", &core_nr_irqs))
+		core_nr_irqs = KVX_CORE_INTC_IRQ;
+
+	/* We only have up to 32 interrupts, according to IRQ-domain.txt,
+	 * linear is likely to be the best choice
+	 */
+	root_domain = irq_domain_add_linear(intc, core_nr_irqs,
+						&kvx_irq_ops, NULL);
+	if (!root_domain)
+		panic("root irq domain not avail\n");
+
+	/*
+	 * Needed for primary domain lookup to succeed
+	 * This is a primary irqchip, and can never have a parent
+	 */
+	irq_set_default_host(root_domain);
+
+	return 0;
+}
+
+IRQCHIP_DECLARE(kvx_core_intc, "kalray,kvx-core-intc", kvx_init_core_intc);
-- 
2.37.2