irqchip: add C-SKY SMP interrupt controller

The driver is for C-SKY SMP interrupt controller. It support 16
soft-irqs, 16 private-irqs, and 992 max external-irqs, a total of
1024 interrupts.

C-SKY CPU 807/810/860 SMP/non-SMP could use it.
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

drivers/irqchip/Kconfig

@@ -371,6 +371,15 @@ config QCOM_PDC
 	  Power Domain Controller driver to manage and configure wakeup
 	  IRQs for Qualcomm Technologies Inc (QTI) mobile chips.
 
+config CSKY_MPINTC
+	bool "C-SKY Multi Processor Interrupt Controller"
+	depends on CSKY
+	help
+	  Say yes here to enable C-SKY SMP interrupt controller driver used
+	  for C-SKY SMP system.
+	  In fact it's not mmio map in hw and it use ld/st to visit the
+	  controller's register inside CPU.
+
 endmenu
 
 config SIFIVE_PLIC

drivers/irqchip/Makefile

@@ -87,4 +87,5 @@ obj-$(CONFIG_MESON_IRQ_GPIO)		+= irq-meson-gpio.o
 obj-$(CONFIG_GOLDFISH_PIC) 		+= irq-goldfish-pic.o
 obj-$(CONFIG_NDS32)			+= irq-ativic32.o
 obj-$(CONFIG_QCOM_PDC)			+= qcom-pdc.o
+obj-$(CONFIG_CSKY_MPINTC)		+= irq-csky-mpintc.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o

drivers/irqchip/irq-csky-mpintc.c

+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/module.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip.h>
+#include <linux/irq.h>
+#include <linux/interrupt.h>
+#include <linux/smp.h>
+#include <linux/io.h>
+#include <asm/irq.h>
+#include <asm/traps.h>
+#include <asm/reg_ops.h>
+
+static struct irq_domain *root_domain;
+static void __iomem *INTCG_base;
+static void __iomem *INTCL_base;
+
+#define IPI_IRQ		15
+#define INTC_IRQS	256
+#define COMM_IRQ_BASE	32
+
+#define INTCG_SIZE	0x8000
+#define INTCL_SIZE	0x1000
+
+#define INTCG_ICTLR	0x0
+#define INTCG_CICFGR	0x100
+#define INTCG_CIDSTR	0x1000
+
+#define INTCL_PICTLR	0x0
+#define INTCL_SIGR	0x60
+#define INTCL_HPPIR	0x68
+#define INTCL_RDYIR	0x6c
+#define INTCL_SENR	0xa0
+#define INTCL_CENR	0xa4
+#define INTCL_CACR	0xb4
+
+static DEFINE_PER_CPU(void __iomem *, intcl_reg);
+
+static void csky_mpintc_handler(struct pt_regs *regs)
+{
+	void __iomem *reg_base = this_cpu_read(intcl_reg);
+
+	do {
+		handle_domain_irq(root_domain,
+				  readl_relaxed(reg_base + INTCL_RDYIR),
+				  regs);
+	} while (readl_relaxed(reg_base + INTCL_HPPIR) & BIT(31));
+}
+
+static void csky_mpintc_enable(struct irq_data *d)
+{
+	void __iomem *reg_base = this_cpu_read(intcl_reg);
+
+	writel_relaxed(d->hwirq, reg_base + INTCL_SENR);
+}
+
+static void csky_mpintc_disable(struct irq_data *d)
+{
+	void __iomem *reg_base = this_cpu_read(intcl_reg);
+
+	writel_relaxed(d->hwirq, reg_base + INTCL_CENR);
+}
+
+static void csky_mpintc_eoi(struct irq_data *d)
+{
+	void __iomem *reg_base = this_cpu_read(intcl_reg);
+
+	writel_relaxed(d->hwirq, reg_base + INTCL_CACR);
+}
+
+#ifdef CONFIG_SMP
+static int csky_irq_set_affinity(struct irq_data *d,
+				 const struct cpumask *mask_val,
+				 bool force)
+{
+	unsigned int cpu;
+	unsigned int offset = 4 * (d->hwirq - COMM_IRQ_BASE);
+
+	if (!force)
+		cpu = cpumask_any_and(mask_val, cpu_online_mask);
+	else
+		cpu = cpumask_first(mask_val);
+
+	if (cpu >= nr_cpu_ids)
+		return -EINVAL;
+
+	/* Enable interrupt destination */
+	cpu |= BIT(31);
+
+	writel_relaxed(cpu, INTCG_base + INTCG_CIDSTR + offset);
+
+	irq_data_update_effective_affinity(d, cpumask_of(cpu));
+
+	return IRQ_SET_MASK_OK_DONE;
+}
+#endif
+
+static struct irq_chip csky_irq_chip = {
+	.name           = "C-SKY SMP Intc",
+	.irq_eoi	= csky_mpintc_eoi,
+	.irq_enable	= csky_mpintc_enable,
+	.irq_disable	= csky_mpintc_disable,
+#ifdef CONFIG_SMP
+	.irq_set_affinity = csky_irq_set_affinity,
+#endif
+};
+
+static int csky_irqdomain_map(struct irq_domain *d, unsigned int irq,
+			      irq_hw_number_t hwirq)
+{
+	if (hwirq < COMM_IRQ_BASE) {
+		irq_set_percpu_devid(irq);
+		irq_set_chip_and_handler(irq, &csky_irq_chip,
+					 handle_percpu_irq);
+	} else {
+		irq_set_chip_and_handler(irq, &csky_irq_chip,
+					 handle_fasteoi_irq);
+	}
+
+	return 0;
+}
+
+static const struct irq_domain_ops csky_irqdomain_ops = {
+	.map	= csky_irqdomain_map,
+	.xlate	= irq_domain_xlate_onecell,
+};
+
+#ifdef CONFIG_SMP
+static void csky_mpintc_send_ipi(const struct cpumask *mask)
+{
+	void __iomem *reg_base = this_cpu_read(intcl_reg);
+
+	/*
+	 * INTCL_SIGR[3:0] INTID
+	 * INTCL_SIGR[8:15] CPUMASK
+	 */
+	writel_relaxed((*cpumask_bits(mask)) << 8 | IPI_IRQ,
+					reg_base + INTCL_SIGR);
+}
+#endif
+
+/* C-SKY multi processor interrupt controller */
+static int __init
+csky_mpintc_init(struct device_node *node, struct device_node *parent)
+{
+	int ret;
+	unsigned int cpu, nr_irq;
+#ifdef CONFIG_SMP
+	unsigned int ipi_irq;
+#endif
+
+	if (parent)
+		return 0;
+
+	ret = of_property_read_u32(node, "csky,num-irqs", &nr_irq);
+	if (ret < 0)
+		nr_irq = INTC_IRQS;
+
+	if (INTCG_base == NULL) {
+		INTCG_base = ioremap(mfcr("cr<31, 14>"),
+				     INTCL_SIZE*nr_cpu_ids + INTCG_SIZE);
+		if (INTCG_base == NULL)
+			return -EIO;
+
+		INTCL_base = INTCG_base + INTCG_SIZE;
+
+		writel_relaxed(BIT(0), INTCG_base + INTCG_ICTLR);
+	}
+
+	root_domain = irq_domain_add_linear(node, nr_irq, &csky_irqdomain_ops,
+					    NULL);
+	if (!root_domain)
+		return -ENXIO;
+
+	/* for every cpu */
+	for_each_present_cpu(cpu) {
+		per_cpu(intcl_reg, cpu) = INTCL_base + (INTCL_SIZE * cpu);
+		writel_relaxed(BIT(0), per_cpu(intcl_reg, cpu) + INTCL_PICTLR);
+	}
+
+	set_handle_irq(&csky_mpintc_handler);
+
+#ifdef CONFIG_SMP
+	ipi_irq = irq_create_mapping(root_domain, IPI_IRQ);
+	if (!ipi_irq)
+		return -EIO;
+
+	set_send_ipi(&csky_mpintc_send_ipi, ipi_irq);
+#endif
+
+	return 0;
+}
+IRQCHIP_DECLARE(csky_mpintc, "csky,mpintc", csky_mpintc_init);