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>

3 files changed, 208 insertions, 0 deletions

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 383e7b70221d..8103f6f99dff 100644
--- a/drivers/irqchip/Kconfig
+++ b/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
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index fbd1ec8070ef..6b739ea27f85 100644
--- a/drivers/irqchip/Makefile
+++ b/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
diff --git a/drivers/irqchip/irq-csky-mpintc.c b/drivers/irqchip/irq-csky-mpintc.c
new file mode 100644
index 000000000000..c67c961ab6cc
--- /dev/null
+++ b/drivers/irqchip/irq-csky-mpintc.c
@@ -0,0 +1,198 @@
+// 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);