This controller appeared on Loongson-1 family MCUs
including Loongson-1B and Loongson-1C.

Signed-off-by: Jiaxun Yang <jiaxun.y...@flygoat.com>
---
 drivers/irqchip/Kconfig    |   9 ++
 drivers/irqchip/Makefile   |   1 +
 drivers/irqchip/irq-ls1x.c | 194 +++++++++++++++++++++++++++++++++++++
 3 files changed, 204 insertions(+)
 create mode 100644 drivers/irqchip/irq-ls1x.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 3d1e60779078..5dcb5456cd14 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -406,6 +406,15 @@ config IMX_IRQSTEER
        help
          Support for the i.MX IRQSTEER interrupt multiplexer/remapper.
 
+config LS1X_IRQ
+       bool "Loongson-1 Interrupt Controller"
+       depends on MACH_LOONGSON32
+       default y
+       select IRQ_DOMAIN
+       select GENERIC_IRQ_CHIP
+       help
+         Support for the Loongson-1 platform Interrupt Controller.
+
 endmenu
 
 config SIFIVE_PLIC
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index c93713d24b86..7acd0e36d0b4 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -94,3 +94,4 @@ obj-$(CONFIG_CSKY_APB_INTC)           += irq-csky-apb-intc.o
 obj-$(CONFIG_SIFIVE_PLIC)              += irq-sifive-plic.o
 obj-$(CONFIG_IMX_IRQSTEER)             += irq-imx-irqsteer.o
 obj-$(CONFIG_MADERA_IRQ)               += irq-madera.o
+obj-$(CONFIG_LS1X_IRQ)                 += irq-ls1x.o
diff --git a/drivers/irqchip/irq-ls1x.c b/drivers/irqchip/irq-ls1x.c
new file mode 100644
index 000000000000..f8ca738ed25c
--- /dev/null
+++ b/drivers/irqchip/irq-ls1x.c
@@ -0,0 +1,194 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ *  Copyright (C) 2019, Jiaxun Yang <jiaxun.y...@flygoat.com>
+ *  Loongson-1 platform IRQ support
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/irqchip.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <asm/io.h>
+
+#include <asm/mach-loongson32/irq.h>
+
+struct ls_intc_data {
+       void __iomem *base;
+       unsigned int chip;
+};
+
+#define MAX_CHIPS      5
+#define LS_REG_INTC_STATUS     0x00
+#define LS_REG_INTC_EN 0x04
+#define LS_REG_INTC_SET        0x08
+#define LS_REG_INTC_CLR        0x0c
+#define LS_REG_INTC_POL 0x10
+#define LS_REG_INTC_EDGE 0x14
+#define CHIP_SIZE              0x18
+
+static irqreturn_t intc_cascade(int irq, void *data)
+{
+       struct ls_intc_data *intc = irq_get_handler_data(irq);
+       uint32_t irq_reg;
+
+       irq_reg = readl(intc->base + (CHIP_SIZE * intc->chip)
+                                       + LS_REG_INTC_STATUS);
+       generic_handle_irq(__fls(irq_reg) + (intc->chip * 32) + LS1X_IRQ_BASE);
+
+       return IRQ_HANDLED;
+}
+
+static void ls_intc_set_bit(
+       struct irq_chip_generic *gc, unsigned int offset,
+       u32 mask, bool set)
+{
+       if (set)
+               writel(readl(gc->reg_base + offset) |
+               mask, gc->reg_base + offset);
+       else
+               writel(readl(gc->reg_base + offset) &
+               ~mask, gc->reg_base + offset);
+}
+
+static int ls_intc_set_type(struct irq_data *data, unsigned int type)
+{
+       struct irq_chip_generic *gc = irq_data_get_irq_chip_data(data);
+       u32 mask = data->mask;
+
+       switch (type) {
+       case IRQ_TYPE_LEVEL_HIGH:
+               ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, false);
+               ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, true);
+               break;
+       case IRQ_TYPE_LEVEL_LOW:
+               ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, false);
+               ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, false);
+               break;
+       case IRQ_TYPE_EDGE_RISING:
+               ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, true);
+               ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, true);
+               break;
+       case IRQ_TYPE_EDGE_FALLING:
+               ls_intc_set_bit(gc, LS_REG_INTC_EDGE, mask, true);
+               ls_intc_set_bit(gc, LS_REG_INTC_POL, mask, false);
+               break;
+       case IRQ_TYPE_NONE:
+               break;
+       default:
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+
+static struct irqaction intc_cascade_action = {
+       .handler = intc_cascade,
+       .name = "intc cascade interrupt",
+};
+
+static int __init ls_intc_of_init(struct device_node *node,
+                                      unsigned int num_chips)
+{
+       struct ls_intc_data *intc[MAX_CHIPS];
+       struct irq_chip_generic *gc;
+       struct irq_chip_type *ct;
+       struct irq_domain *domain;
+       void __iomem *base;
+       int parent_irq[MAX_CHIPS], err = 0;
+       unsigned int i = 0;
+
+       base = of_iomap(node, 0);
+       if (!base)
+               return -ENODEV;
+
+       for (i = 0; i < num_chips; i++) {
+               /* Mask all irqs */
+               writel(0x0, base + (i * CHIP_SIZE) +
+                      LS_REG_INTC_EN);
+
+               /* Set all irqs to high level triggered */
+               writel(0xffffffff, base + (i * CHIP_SIZE) +
+                      LS_REG_INTC_POL);
+
+               intc[i] = kzalloc(sizeof(*intc[i]), GFP_KERNEL);
+               if (!intc[i]) {
+                       err = -ENOMEM;
+                       goto out_err;
+               }
+
+               intc[i]->base = base;
+               intc[i]->chip = i;
+
+               parent_irq[i] = irq_of_parse_and_map(node, i);
+               if (!parent_irq[i]) {
+                       pr_warn("unable to get parent irq for irqchip %u", i);
+                       kfree(intc[i]);
+                       intc[i] = NULL;
+                       err = -EINVAL;
+                       goto out_err;
+               }
+
+               err = irq_set_handler_data(parent_irq[i], intc[i]);
+               if (err)
+                       goto out_err;
+
+               gc = irq_alloc_generic_chip("INTC", 1,
+                                           LS1X_IRQ_BASE + (i * 32),
+                                           base + (i * CHIP_SIZE),
+                                           handle_level_irq);
+
+               ct = gc->chip_types;
+               ct->regs.mask = LS_REG_INTC_EN;
+               ct->regs.ack = LS_REG_INTC_CLR;
+               ct->chip.irq_unmask = irq_gc_mask_set_bit;
+               ct->chip.irq_mask = irq_gc_mask_clr_bit;
+               ct->chip.irq_ack = irq_gc_ack_set_bit;
+               ct->chip.irq_set_type = ls_intc_set_type;
+
+               irq_setup_generic_chip(gc, IRQ_MSK(32), 0, 0,
+                                      IRQ_NOPROBE | IRQ_LEVEL);
+       }
+
+       domain = irq_domain_add_legacy(node, num_chips * 32, LS1X_IRQ_BASE, 0,
+                                      &irq_domain_simple_ops, NULL);
+       if (!domain) {
+               pr_warn("unable to register IRQ domain\n");
+               err = -EINVAL;
+               goto out_err;
+       }
+
+       for (i = 0; i < num_chips; i++)
+               setup_irq(parent_irq[i], &intc_cascade_action);
+
+       return 0;
+
+out_err:
+       for (i = 0; i < MAX_CHIPS; i++) {
+               if (intc[i]) {
+                       kfree(intc[i]);
+                       irq_dispose_mapping(parent_irq[i]);
+               } else {
+                       break;
+               }
+       }
+       return err;
+}
+
+static int __init intc_4chip_of_init(struct device_node *node,
+                                    struct device_node *parent)
+{
+       return ls_intc_of_init(node, 4);
+}
+IRQCHIP_DECLARE(ls1b_intc, "loongson,ls1b-intc", intc_4chip_of_init);
+
+static int __init intc_5chip_of_init(struct device_node *node,
+       struct device_node *parent)
+{
+       return ls_intc_of_init(node, 5);
+}
+IRQCHIP_DECLARE(ls1c_intc, "loongson,ls1c-intc", intc_5chip_of_init);
-- 
2.20.1

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