drivers/irqchip/irq-aspeed-vic.c

   1 /*
   2  *  Copyright (C) 2015 - Ben Herrenschmidt, IBM Corp.
   3  *
   4  *  Driver for Aspeed "new" VIC as found in SoC generation 3 and later
   5  *
   6  *  Based on irq-vic.c:
   7  *
   8  *  Copyright (C) 1999 - 2003 ARM Limited
   9  *  Copyright (C) 2000 Deep Blue Solutions Ltd
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  */
  22
  23 #include <linux/export.h>
  24 #include <linux/init.h>
  25 #include <linux/list.h>
  26 #include <linux/io.h>
  27 #include <linux/irq.h>
  28 #include <linux/irqchip.h>
  29 #include <linux/irqchip/chained_irq.h>
  30 #include <linux/irqdomain.h>
  31 #include <linux/of.h>
  32 #include <linux/of_address.h>
  33 #include <linux/of_irq.h>
  34 #include <linux/syscore_ops.h>
  35 #include <linux/device.h>
  36 #include <linux/slab.h>
  37
  38 #include <asm/exception.h>
  39 #include <asm/irq.h>
  40
  41 /* These definitions correspond to the "new mapping" of the
  42  * register set that interleaves "high" and "low". The offsets
  43  * below are for the "low" register, add 4 to get to the high one
  44  */
  45 #define AVIC_IRQ_STATUS         0x00
  46 #define AVIC_FIQ_STATUS         0x08
  47 #define AVIC_RAW_STATUS         0x10
  48 #define AVIC_INT_SELECT         0x18
  49 #define AVIC_INT_ENABLE         0x20
  50 #define AVIC_INT_ENABLE_CLR     0x28
  51 #define AVIC_INT_TRIGGER        0x30
  52 #define AVIC_INT_TRIGGER_CLR    0x38
  53 #define AVIC_INT_SENSE          0x40
  54 #define AVIC_INT_DUAL_EDGE      0x48
  55 #define AVIC_INT_EVENT          0x50
  56 #define AVIC_EDGE_CLR           0x58
  57 #define AVIC_EDGE_STATUS        0x60
  58
  59 #define NUM_IRQS                64
  60
  61 struct aspeed_vic {
  62         void __iomem            *base;
  63         u32                     edge_sources[2];
  64         struct irq_domain       *dom;
  65 };
  66 static struct aspeed_vic *system_avic;
  67
  68 static void vic_init_hw(struct aspeed_vic *vic)
  69 {
  70         u32 sense;
  71
  72         /* Disable all interrupts */
  73         writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR);
  74         writel(0xffffffff, vic->base + AVIC_INT_ENABLE_CLR + 4);
  75
  76         /* Make sure no soft trigger is on */
  77         writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR);
  78         writel(0xffffffff, vic->base + AVIC_INT_TRIGGER_CLR + 4);
  79
  80         /* Set everything to be IRQ */
  81         writel(0, vic->base + AVIC_INT_SELECT);
  82         writel(0, vic->base + AVIC_INT_SELECT + 4);
  83
  84         /* Some interrupts have a programable high/low level trigger
  85          * (4 GPIO direct inputs), for now we assume this was configured
  86          * by firmware. We read which ones are edge now.
  87          */
  88         sense = readl(vic->base + AVIC_INT_SENSE);
  89         vic->edge_sources[0] = ~sense;
  90         sense = readl(vic->base + AVIC_INT_SENSE + 4);
  91         vic->edge_sources[1] = ~sense;
  92
  93         /* Clear edge detection latches */
  94         writel(0xffffffff, vic->base + AVIC_EDGE_CLR);
  95         writel(0xffffffff, vic->base + AVIC_EDGE_CLR + 4);
  96 }
  97
  98 static void __exception_irq_entry avic_handle_irq(struct pt_regs *regs)
  99 {
 100         struct aspeed_vic *vic = system_avic;
 101         u32 stat, irq;
 102
 103         for (;;) {
 104                 irq = 0;
 105                 stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS);
 106                 if (!stat) {
 107                         stat = readl_relaxed(vic->base + AVIC_IRQ_STATUS + 4);
 108                         irq = 32;
 109                 }
 110                 if (stat == 0)
 111                         break;
 112                 irq += ffs(stat) - 1;
 113                 handle_domain_irq(vic->dom, irq, regs);
 114         }
 115 }
 116
 117 static void avic_ack_irq(struct irq_data *d)
 118 {
 119         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 120         unsigned int sidx = d->hwirq >> 5;
 121         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 122
 123         /* Clear edge latch for edge interrupts, nop for level */
 124         if (vic->edge_sources[sidx] & sbit)
 125                 writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
 126 }
 127
 128 static void avic_mask_irq(struct irq_data *d)
 129 {
 130         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 131         unsigned int sidx = d->hwirq >> 5;
 132         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 133
 134         writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
 135 }
 136
 137 static void avic_unmask_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         writel(sbit, vic->base + AVIC_INT_ENABLE + sidx * 4);
 144 }
 145
 146 /* For level irq, faster than going through a nop "ack" and mask */
 147 static void avic_mask_ack_irq(struct irq_data *d)
 148 {
 149         struct aspeed_vic *vic = irq_data_get_irq_chip_data(d);
 150         unsigned int sidx = d->hwirq >> 5;
 151         unsigned int sbit = 1u << (d->hwirq & 0x1f);
 152
 153         /* First mask */
 154         writel(sbit, vic->base + AVIC_INT_ENABLE_CLR + sidx * 4);
 155
 156         /* Then clear edge latch for edge interrupts */
 157         if (vic->edge_sources[sidx] & sbit)
 158                 writel(sbit, vic->base + AVIC_EDGE_CLR + sidx * 4);
 159 }
 160
 161 static struct irq_chip avic_chip = {
 162         .name           = "AVIC",
 163         .irq_ack        = avic_ack_irq,
 164         .irq_mask       = avic_mask_irq,
 165         .irq_unmask     = avic_unmask_irq,
 166         .irq_mask_ack   = avic_mask_ack_irq,
 167 };
 168
 169 static int avic_map(struct irq_domain *d, unsigned int irq,
 170                     irq_hw_number_t hwirq)
 171 {
 172         struct aspeed_vic *vic = d->host_data;
 173         unsigned int sidx = hwirq >> 5;
 174         unsigned int sbit = 1u << (hwirq & 0x1f);
 175
 176         /* Check if interrupt exists */
 177         if (sidx > 1)
 178                 return -EPERM;
 179
 180         if (vic->edge_sources[sidx] & sbit)
 181                 irq_set_chip_and_handler(irq, &avic_chip, handle_edge_irq);
 182         else
 183                 irq_set_chip_and_handler(irq, &avic_chip, handle_level_irq);
 184         irq_set_chip_data(irq, vic);
 185         irq_set_probe(irq);
 186         return 0;
 187 }
 188
 189 static const struct irq_domain_ops avic_dom_ops = {
 190         .map = avic_map,
 191         .xlate = irq_domain_xlate_onetwocell,
 192 };
 193
 194 static int __init avic_of_init(struct device_node *node,
 195                                struct device_node *parent)
 196 {
 197         void __iomem *regs;
 198         struct aspeed_vic *vic;
 199
 200         if (WARN(parent, "non-root Aspeed VIC not supported"))
 201                 return -EINVAL;
 202         if (WARN(system_avic, "duplicate Aspeed VIC not supported"))
 203                 return -EINVAL;
 204
 205         regs = of_iomap(node, 0);
 206         if (WARN_ON(!regs))
 207                 return -EIO;
 208
 209         vic = kzalloc(sizeof(struct aspeed_vic), GFP_KERNEL);
 210         if (WARN_ON(!vic)) {
 211                 iounmap(regs);
 212                 return -ENOMEM;
 213         }
 214         vic->base = regs;
 215
 216         /* Initialize soures, all masked */
 217         vic_init_hw(vic);
 218
 219         /* Ready to receive interrupts */
 220         system_avic = vic;
 221         set_handle_irq(avic_handle_irq);
 222
 223         /* Register our domain */
 224         vic->dom = irq_domain_add_simple(node, NUM_IRQS, 0,
 225                                          &avic_dom_ops, vic);
 226
 227         return 0;
 228 }
 229
 230 IRQCHIP_DECLARE(ast2400_vic, "aspeed,ast2400-vic", avic_of_init);
 231 IRQCHIP_DECLARE(ast2500_vic, "aspeed,ast2500-vic", avic_of_init);