drivers/irqchip/irq-aspeed-vic.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  *  Copyright (C) 2015 - Ben Herrenschmidt, IBM Corp.
   4  *
   5  *  Driver for Aspeed "new" VIC as found in SoC generation 3 and later
   6  *
   7  *  Based on irq-vic.c:
   8  *
   9  *  Copyright (C) 1999 - 2003 ARM Limited
  10  *  Copyright (C) 2000 Deep Blue Solutions Ltd
  11  */
  12
  13 #include <linux/export.h>
  14 #include <linux/init.h>
  15 #include <linux/list.h>
  16 #include <linux/io.h>
  17 #include <linux/irq.h>
  18 #include <linux/irqchip.h>
  19 #include <linux/irqchip/chained_irq.h>
  20 #include <linux/irqdomain.h>
  21 #include <linux/of.h>
  22 #include <linux/of_address.h>
  23 #include <linux/of_irq.h>
  24 #include <linux/syscore_ops.h>
  25 #include <linux/device.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/exception.h>
  29 #include <asm/irq.h>
  30
  31 /* These definitions correspond to the "new mapping" of the
  32  * register set that interleaves "high" and "low". The offsets
  33  * below are for the "low" register, add 4 to get to the high one
  34  */
  35 #define AVIC_IRQ_STATUS         0x00
  36 #define AVIC_FIQ_STATUS         0x08
  37 #define AVIC_RAW_STATUS         0x10
  38 #define AVIC_INT_SELECT         0x18
  39 #define AVIC_INT_ENABLE         0x20
  40 #define AVIC_INT_ENABLE_CLR     0x28
  41 #define AVIC_INT_TRIGGER        0x30
  42 #define AVIC_INT_TRIGGER_CLR    0x38
  43 #define AVIC_INT_SENSE          0x40
  44 #define AVIC_INT_DUAL_EDGE      0x48
  45 #define AVIC_INT_EVENT          0x50
  46 #define AVIC_EDGE_CLR           0x58
  47 #define AVIC_EDGE_STATUS        0x60
  48
  49 #define NUM_IRQS                64
  50
  51 struct aspeed_vic {
  52         void __iomem            *base;
  53         u32                     edge_sources[2];
  54         struct irq_domain       *dom;
  55 };
  56 static struct aspeed_vic *system_avic;
  57
  58 static void vic_init_hw(struct aspeed_vic *vic)
  59 {
  60         u32 sense;
  61
  62         /* Disable all interrupts */
  63         writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR);
  64         writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR + 4);
  65
  66         /* Make sure no soft trigger is on */
  67         writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR);
  68         writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR + 4);
  69
  70         /* Set everything to be IRQ */
  71         writel(0, vic->base + AVIC_INT_SELECT);
  72         writel(0, vic->base + AVIC_INT_SELECT + 4);
  73
  74         /* Some interrupts have a programmable high/low level trigger
  75          * (4 GPIO direct inputs), for now we assume this was configured
  76          * by firmware. We read which ones are edge now.
  77          */
  78         sense = readl(vic->base + AVIC_INT_SENSE);
  79         vic->edge_sources[0] = ~sense;
  80         sense = readl(vic->base + AVIC_INT_SENSE + 4);
  81         vic->edge_sources[1] = ~sense;
  82
  83         /* Clear edge detection latches */
  84         writel(0xffffffff, vic->base + AVIC_EDGE_CLR);
  85         writel(0xffffffff, vic->base + AVIC_EDGE_CLR + 4);
  86 }
  87
  88 static void __exception_irq_entry avic_handle_irq(struct pt_regs *regs)
  89 {
  90         struct aspeed_vic *vic = system_avic;
  91         u32 stat, irq;
  92
  93         for (;;) {
  94                 irq = 0;
  95                 stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS);
  96                 if (!stat) {
  97                         stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS + 4);
  98                         irq = 32;
  99                 }
 100                 if (stat == 0)
 101                         break;
 102                 irq += ffs(stat) - 1;
 103                 generic_handle_domain_irq(vic->dom, irq);
 104         }
 105 }
 106
 107 static void avic_ack_irq(struct irq_data *d)
 108 {
 109         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 110         unsigned int sidx = d->hwirq >> 5;
 111         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 112
 113         /* Clear edge latch for edge interrupts, nop for level */
 114         if (vic->edge_sources[sidx] & sbit)
 115                 writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
 116 }
 117
 118 static void avic_mask_irq(struct irq_data *d)
 119 {
 120         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 121         unsigned int sidx = d->hwirq >> 5;
 122         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 123
 124         writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
 125 }
 126
 127 static void avic_unmask_irq(struct irq_data *d)
 128 {
 129         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 130         unsigned int sidx = d->hwirq >> 5;
 131         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 132
 133         writel(sbit, vic->base + AVIC_INT_ENABLE + sidx * 4);
 134 }
 135
 136 /* For level irq, faster than going through a nop "ack" and mask */
 137 static void avic_mask_ack_irq(struct irq_data *d)
 138 {
 139         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 140         unsigned int sidx = d->hwirq >> 5;
 141         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 142
 143         /* First mask */
 144         writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
 145
 146         /* Then clear edge latch for edge interrupts */
 147         if (vic->edge_sources[sidx] & sbit)
 148                 writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
 149 }
 150
 151 static struct irq_chip avic_chip = {
 152         .name           = "AVIC",
 153         .irq_ack        = avic_ack_irq,
 154         .irq_mask       = avic_mask_irq,
 155         .irq_unmask     = avic_unmask_irq,
 156         .irq_mask_ack   = avic_mask_ack_irq,
 157 };
 158
 159 static int avic_map(struct irq_domain *d, unsigned int irq,
 160                     irq_hw_number_t hwirq)
 161 {
 162         struct aspeed_vic *vic = d->host_data;
 163         unsigned int sidx = hwirq >> 5;
 164         unsigned int sbit = 1u << (hwirq & 0x1f);
 165
 166         /* Check if interrupt exists */
 167         if (sidx > 1)
 168                 return -EPERM;
 169
 170         if (vic->edge_sources[sidx] & sbit)
 171                 irq_set_chip_and_handler(irq, &avic_chip, handle_edge_irq);
 172         else
 173                 irq_set_chip_and_handler(irq, &avic_chip, handle_level_irq);
 174         irq_set_chip_data(irq, vic);
 175         irq_set_probe(irq);
 176         return 0;
 177 }
 178
 179 static const struct irq_domain_ops avic_dom_ops = {
 180         .map = avic_map,
 181         .xlate = irq_domain_xlate_onetwocell,
 182 };
 183
 184 static int __init avic_of_init(struct device_node *node,
 185                                struct device_node *parent)
 186 {
 187         void __iomem *regs;
 188         struct aspeed_vic *vic;
 189
 190         if (WARN(parent, "non-root Aspeed VIC not supported"))
 191                 return -EINVAL;
 192         if (WARN(system_avic, "duplicate Aspeed VIC not supported"))
 193                 return -EINVAL;
 194
 195         regs = of_iomap(node, 0);
 196         if (WARN_ON(!regs))
 197                 return -EIO;
 198
 199         vic = kzalloc(sizeof(struct aspeed_vic), GFP_KERNEL);
 200         if (WARN_ON(!vic)) {
 201                 iounmap(regs);
 202                 return -ENOMEM;
 203         }
 204         vic->base = regs;
 205
 206         /* Initialize sources, all masked */
 207         vic_init_hw(vic);
 208
 209         /* Ready to receive interrupts */
 210         system_avic = vic;
 211         set_handle_irq(avic_handle_irq);
 212
 213         /* Register our domain */
 214         vic->dom = irq_domain_add_simple(node, NUM_IRQS, 0,
 215                                          &avic_dom_ops, vic);
 216
 217         return 0;
 218 }
 219
 220 IRQCHIP_DECLARE(ast2400_vic, "aspeed,ast2400-vic", avic_of_init);
 221 IRQCHIP_DECLARE(ast2500_vic, "aspeed,ast2500-vic", avic_of_init);