drivers/irqchip/irq-goldfish-pic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for MIPS Goldfish Programmable Interrupt Controller.
   4  *
   5  * Author: Miodrag Dinic <miodrag.dinic@mips.com>
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/interrupt.h>
  11 #include <linux/irq.h>
  12 #include <linux/irqchip.h>
  13 #include <linux/irqchip/chained_irq.h>
  14 #include <linux/irqdomain.h>
  15 #include <linux/of_address.h>
  16 #include <linux/of_irq.h>
  17
  18 #define GFPIC_NR_IRQS                   32
  19
  20 /* 8..39 Cascaded Goldfish PIC interrupts */
  21 #define GFPIC_IRQ_BASE                  8
  22
  23 #define GFPIC_REG_IRQ_PENDING           0x04
  24 #define GFPIC_REG_IRQ_DISABLE_ALL       0x08
  25 #define GFPIC_REG_IRQ_DISABLE           0x0c
  26 #define GFPIC_REG_IRQ_ENABLE            0x10
  27
  28 struct goldfish_pic_data {
  29         void __iomem *base;
  30         struct irq_domain *irq_domain;
  31 };
  32
  33 static void goldfish_pic_cascade(struct irq_desc *desc)
  34 {
  35         struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
  36         struct irq_chip *host_chip = irq_desc_get_chip(desc);
  37         u32 pending, hwirq, virq;
  38
  39         chained_irq_enter(host_chip, desc);
  40
  41         pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
  42         while (pending) {
  43                 hwirq = __fls(pending);
  44                 virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
  45                 generic_handle_irq(virq);
  46                 pending &= ~(1 << hwirq);
  47         }
  48
  49         chained_irq_exit(host_chip, desc);
  50 }
  51
  52 static const struct irq_domain_ops goldfish_irq_domain_ops = {
  53         .xlate = irq_domain_xlate_onecell,
  54 };
  55
  56 static int __init goldfish_pic_of_init(struct device_node *of_node,
  57                                        struct device_node *parent)
  58 {
  59         struct goldfish_pic_data *gfpic;
  60         struct irq_chip_generic *gc;
  61         struct irq_chip_type *ct;
  62         unsigned int parent_irq;
  63         int ret = 0;
  64
  65         gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
  66         if (!gfpic) {
  67                 ret = -ENOMEM;
  68                 goto out_err;
  69         }
  70
  71         parent_irq = irq_of_parse_and_map(of_node, 0);
  72         if (!parent_irq) {
  73                 pr_err("Failed to map parent IRQ!\n");
  74                 ret = -EINVAL;
  75                 goto out_free;
  76         }
  77
  78         gfpic->base = of_iomap(of_node, 0);
  79         if (!gfpic->base) {
  80                 pr_err("Failed to map base address!\n");
  81                 ret = -ENOMEM;
  82                 goto out_unmap_irq;
  83         }
  84
  85         /* Mask interrupts. */
  86         writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
  87
  88         gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
  89                                     handle_level_irq);
  90         if (!gc) {
  91                 pr_err("Failed to allocate chip structures!\n");
  92                 ret = -ENOMEM;
  93                 goto out_iounmap;
  94         }
  95
  96         ct = gc->chip_types;
  97         ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
  98         ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
  99         ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
 100         ct->chip.irq_mask = irq_gc_mask_disable_reg;
 101
 102         irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
 103                                IRQ_NOPROBE | IRQ_LEVEL, 0);
 104
 105         gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
 106                                                   GFPIC_IRQ_BASE, 0,
 107                                                   &goldfish_irq_domain_ops,
 108                                                   NULL);
 109         if (!gfpic->irq_domain) {
 110                 pr_err("Failed to add irqdomain!\n");
 111                 ret = -ENOMEM;
 112                 goto out_destroy_generic_chip;
 113         }
 114
 115         irq_set_chained_handler_and_data(parent_irq,
 116                                          goldfish_pic_cascade, gfpic);
 117
 118         pr_info("Successfully registered.\n");
 119         return 0;
 120
 121 out_destroy_generic_chip:
 122         irq_destroy_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS),
 123                                  IRQ_NOPROBE | IRQ_LEVEL, 0);
 124 out_iounmap:
 125         iounmap(gfpic->base);
 126 out_unmap_irq:
 127         irq_dispose_mapping(parent_irq);
 128 out_free:
 129         kfree(gfpic);
 130 out_err:
 131         pr_err("Failed to initialize! (errno = %d)\n", ret);
 132         return ret;
 133 }
 134
 135 IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);