drivers/irqchip/irq-brcmstb-l2.c

   1 /*
   2  * Generic Broadcom Set Top Box Level 2 Interrupt controller driver
   3  *
   4  * Copyright (C) 2014 Broadcom Corporation
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #define pr_fmt(fmt)     KBUILD_MODNAME  ": " fmt
  17
  18 #include <linux/init.h>
  19 #include <linux/slab.h>
  20 #include <linux/module.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/of.h>
  24 #include <linux/of_irq.h>
  25 #include <linux/of_address.h>
  26 #include <linux/of_platform.h>
  27 #include <linux/interrupt.h>
  28 #include <linux/irq.h>
  29 #include <linux/io.h>
  30 #include <linux/irqdomain.h>
  31 #include <linux/irqchip.h>
  32 #include <linux/irqchip/chained_irq.h>
  33
  34 /* Register offsets in the L2 interrupt controller */
  35 #define CPU_STATUS      0x00
  36 #define CPU_SET         0x04
  37 #define CPU_CLEAR       0x08
  38 #define CPU_MASK_STATUS 0x0c
  39 #define CPU_MASK_SET    0x10
  40 #define CPU_MASK_CLEAR  0x14
  41
  42 /* L2 intc private data structure */
  43 struct brcmstb_l2_intc_data {
  44         int parent_irq;
  45         void __iomem *base;
  46         struct irq_domain *domain;
  47         bool can_wake;
  48         u32 saved_mask; /* for suspend/resume */
  49 };
  50
  51 static void brcmstb_l2_intc_irq_handle(struct irq_desc *desc)
  52 {
  53         struct brcmstb_l2_intc_data *b = irq_desc_get_handler_data(desc);
  54         struct irq_chip_generic *gc = irq_get_domain_generic_chip(b->domain, 0);
  55         struct irq_chip *chip = irq_desc_get_chip(desc);
  56         unsigned int irq;
  57         u32 status;
  58
  59         chained_irq_enter(chip, desc);
  60
  61         status = irq_reg_readl(gc, CPU_STATUS) &
  62                 ~(irq_reg_readl(gc, CPU_MASK_STATUS));
  63
  64         if (status == 0) {
  65                 raw_spin_lock(&desc->lock);
  66                 handle_bad_irq(desc);
  67                 raw_spin_unlock(&desc->lock);
  68                 goto out;
  69         }
  70
  71         do {
  72                 irq = ffs(status) - 1;
  73                 /* ack at our level */
  74                 irq_reg_writel(gc, 1 << irq, CPU_CLEAR);
  75                 status &= ~(1 << irq);
  76                 generic_handle_irq(irq_find_mapping(b->domain, irq));
  77         } while (status);
  78 out:
  79         chained_irq_exit(chip, desc);
  80 }
  81
  82 static void brcmstb_l2_intc_suspend(struct irq_data *d)
  83 {
  84         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
  85         struct brcmstb_l2_intc_data *b = gc->private;
  86
  87         irq_gc_lock(gc);
  88         /* Save the current mask */
  89         b->saved_mask = irq_reg_readl(gc, CPU_MASK_STATUS);
  90
  91         if (b->can_wake) {
  92                 /* Program the wakeup mask */
  93                 irq_reg_writel(gc, ~gc->wake_active, CPU_MASK_SET);
  94                 irq_reg_writel(gc, gc->wake_active, CPU_MASK_CLEAR);
  95         }
  96         irq_gc_unlock(gc);
  97 }
  98
  99 static void brcmstb_l2_intc_resume(struct irq_data *d)
 100 {
 101         struct irq_chip_generic *gc = irq_data_get_irq_chip_data(d);
 102         struct brcmstb_l2_intc_data *b = gc->private;
 103
 104         irq_gc_lock(gc);
 105         /* Clear unmasked non-wakeup interrupts */
 106         irq_reg_writel(gc, ~b->saved_mask & ~gc->wake_active, CPU_CLEAR);
 107
 108         /* Restore the saved mask */
 109         irq_reg_writel(gc, b->saved_mask, CPU_MASK_SET);
 110         irq_reg_writel(gc, ~b->saved_mask, CPU_MASK_CLEAR);
 111         irq_gc_unlock(gc);
 112 }
 113
 114 static int __init brcmstb_l2_intc_of_init(struct device_node *np,
 115                                           struct device_node *parent)
 116 {
 117         unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
 118         struct brcmstb_l2_intc_data *data;
 119         struct irq_chip_generic *gc;
 120         struct irq_chip_type *ct;
 121         int ret;
 122         unsigned int flags;
 123
 124         data = kzalloc(sizeof(*data), GFP_KERNEL);
 125         if (!data)
 126                 return -ENOMEM;
 127
 128         data->base = of_iomap(np, 0);
 129         if (!data->base) {
 130                 pr_err("failed to remap intc L2 registers\n");
 131                 ret = -ENOMEM;
 132                 goto out_free;
 133         }
 134
 135         /* Disable all interrupts by default */
 136         writel(0xffffffff, data->base + CPU_MASK_SET);
 137
 138         /* Wakeup interrupts may be retained from S5 (cold boot) */
 139         data->can_wake = of_property_read_bool(np, "brcm,irq-can-wake");
 140         if (!data->can_wake)
 141                 writel(0xffffffff, data->base + CPU_CLEAR);
 142
 143         data->parent_irq = irq_of_parse_and_map(np, 0);
 144         if (!data->parent_irq) {
 145                 pr_err("failed to find parent interrupt\n");
 146                 ret = -EINVAL;
 147                 goto out_unmap;
 148         }
 149
 150         data->domain = irq_domain_add_linear(np, 32,
 151                                 &irq_generic_chip_ops, NULL);
 152         if (!data->domain) {
 153                 ret = -ENOMEM;
 154                 goto out_unmap;
 155         }
 156
 157         /* MIPS chips strapped for BE will automagically configure the
 158          * peripheral registers for CPU-native byte order.
 159          */
 160         flags = 0;
 161         if (IS_ENABLED(CONFIG_MIPS) && IS_ENABLED(CONFIG_CPU_BIG_ENDIAN))
 162                 flags |= IRQ_GC_BE_IO;
 163
 164         /* Allocate a single Generic IRQ chip for this node */
 165         ret = irq_alloc_domain_generic_chips(data->domain, 32, 1,
 166                                 np->full_name, handle_edge_irq, clr, 0, flags);
 167         if (ret) {
 168                 pr_err("failed to allocate generic irq chip\n");
 169                 goto out_free_domain;
 170         }
 171
 172         /* Set the IRQ chaining logic */
 173         irq_set_chained_handler_and_data(data->parent_irq,
 174                                          brcmstb_l2_intc_irq_handle, data);
 175
 176         gc = irq_get_domain_generic_chip(data->domain, 0);
 177         gc->reg_base = data->base;
 178         gc->private = data;
 179         ct = gc->chip_types;
 180
 181         ct->chip.irq_ack = irq_gc_ack_set_bit;
 182         ct->regs.ack = CPU_CLEAR;
 183
 184         ct->chip.irq_mask = irq_gc_mask_disable_reg;
 185         ct->regs.disable = CPU_MASK_SET;
 186
 187         ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
 188         ct->regs.enable = CPU_MASK_CLEAR;
 189
 190         ct->chip.irq_suspend = brcmstb_l2_intc_suspend;
 191         ct->chip.irq_resume = brcmstb_l2_intc_resume;
 192
 193         if (data->can_wake) {
 194                 /* This IRQ chip can wake the system, set all child interrupts
 195                  * in wake_enabled mask
 196                  */
 197                 gc->wake_enabled = 0xffffffff;
 198                 ct->chip.irq_set_wake = irq_gc_set_wake;
 199         }
 200
 201         pr_info("registered L2 intc (mem: 0x%p, parent irq: %d)\n",
 202                         data->base, data->parent_irq);
 203
 204         return 0;
 205
 206 out_free_domain:
 207         irq_domain_remove(data->domain);
 208 out_unmap:
 209         iounmap(data->base);
 210 out_free:
 211         kfree(data);
 212         return ret;
 213 }
 214 IRQCHIP_DECLARE(brcmstb_l2_intc, "brcm,l2-intc", brcmstb_l2_intc_of_init);