linux/drivers/irqchip/irq-zevio.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 *  linux/drivers/irqchip/irq-zevio.c
   4 *
   5 *  Copyright (C) 2013 Daniel Tang <tangrs@tangrs.id.au>
   6 */
   7
   8#include <linux/io.h>
   9#include <linux/irq.h>
  10#include <linux/irqchip.h>
  11#include <linux/of.h>
  12#include <linux/of_address.h>
  13#include <linux/of_irq.h>
  14
  15#include <asm/mach/irq.h>
  16#include <asm/exception.h>
  17
  18#define IO_STATUS       0x000
  19#define IO_RAW_STATUS   0x004
  20#define IO_ENABLE       0x008
  21#define IO_DISABLE      0x00C
  22#define IO_CURRENT      0x020
  23#define IO_RESET        0x028
  24#define IO_MAX_PRIOTY   0x02C
  25
  26#define IO_IRQ_BASE     0x000
  27#define IO_FIQ_BASE     0x100
  28
  29#define IO_INVERT_SEL   0x200
  30#define IO_STICKY_SEL   0x204
  31#define IO_PRIORITY_SEL 0x300
  32
  33#define MAX_INTRS       32
  34#define FIQ_START       MAX_INTRS
  35
  36static struct irq_domain *zevio_irq_domain;
  37static void __iomem *zevio_irq_io;
  38
  39static void zevio_irq_ack(struct irq_data *irqd)
  40{
  41        struct irq_chip_generic *gc = irq_data_get_irq_chip_data(irqd);
  42        struct irq_chip_regs *regs = &irq_data_get_chip_type(irqd)->regs;
  43
  44        readl(gc->reg_base + regs->ack);
  45}
  46
  47static void __exception_irq_entry zevio_handle_irq(struct pt_regs *regs)
  48{
  49        int irqnr;
  50
  51        while (readl(zevio_irq_io + IO_STATUS)) {
  52                irqnr = readl(zevio_irq_io + IO_CURRENT);
  53                handle_domain_irq(zevio_irq_domain, irqnr, regs);
  54        }
  55}
  56
  57static void __init zevio_init_irq_base(void __iomem *base)
  58{
  59        /* Disable all interrupts */
  60        writel(~0, base + IO_DISABLE);
  61
  62        /* Accept interrupts of all priorities */
  63        writel(0xF, base + IO_MAX_PRIOTY);
  64
  65        /* Reset existing interrupts */
  66        readl(base + IO_RESET);
  67}
  68
  69static int __init zevio_of_init(struct device_node *node,
  70                                struct device_node *parent)
  71{
  72        unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
  73        struct irq_chip_generic *gc;
  74        int ret;
  75
  76        if (WARN_ON(zevio_irq_io || zevio_irq_domain))
  77                return -EBUSY;
  78
  79        zevio_irq_io = of_iomap(node, 0);
  80        BUG_ON(!zevio_irq_io);
  81
  82        /* Do not invert interrupt status bits */
  83        writel(~0, zevio_irq_io + IO_INVERT_SEL);
  84
  85        /* Disable sticky interrupts */
  86        writel(0, zevio_irq_io + IO_STICKY_SEL);
  87
  88        /* We don't use IRQ priorities. Set each IRQ to highest priority. */
  89        memset_io(zevio_irq_io + IO_PRIORITY_SEL, 0, MAX_INTRS * sizeof(u32));
  90
  91        /* Init IRQ and FIQ */
  92        zevio_init_irq_base(zevio_irq_io + IO_IRQ_BASE);
  93        zevio_init_irq_base(zevio_irq_io + IO_FIQ_BASE);
  94
  95        zevio_irq_domain = irq_domain_add_linear(node, MAX_INTRS,
  96                                                 &irq_generic_chip_ops, NULL);
  97        BUG_ON(!zevio_irq_domain);
  98
  99        ret = irq_alloc_domain_generic_chips(zevio_irq_domain, MAX_INTRS, 1,
 100                                             "zevio_intc", handle_level_irq,
 101                                             clr, 0, IRQ_GC_INIT_MASK_CACHE);
 102        BUG_ON(ret);
 103
 104        gc = irq_get_domain_generic_chip(zevio_irq_domain, 0);
 105        gc->reg_base                            = zevio_irq_io;
 106        gc->chip_types[0].chip.irq_ack          = zevio_irq_ack;
 107        gc->chip_types[0].chip.irq_mask         = irq_gc_mask_disable_reg;
 108        gc->chip_types[0].chip.irq_unmask       = irq_gc_unmask_enable_reg;
 109        gc->chip_types[0].regs.mask             = IO_IRQ_BASE + IO_ENABLE;
 110        gc->chip_types[0].regs.enable           = IO_IRQ_BASE + IO_ENABLE;
 111        gc->chip_types[0].regs.disable          = IO_IRQ_BASE + IO_DISABLE;
 112        gc->chip_types[0].regs.ack              = IO_IRQ_BASE + IO_RESET;
 113
 114        set_handle_irq(zevio_handle_irq);
 115
 116        pr_info("TI-NSPIRE classic IRQ controller\n");
 117        return 0;
 118}
 119
 120IRQCHIP_DECLARE(zevio_irq, "lsi,zevio-intc", zevio_of_init);
 121