kernel/drivers/irqchip/irq-vt8500.c

   1 /*
   2  *  arch/arm/mach-vt8500/irq.c
   3  *
   4  *  Copyright (C) 2012 Tony Prisk <linux@prisktech.co.nz>
   5  *  Copyright (C) 2010 Alexey Charkov <alchark@gmail.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, write to the Free Software
  19  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  20  */
  21
  22 /*
  23  * This file is copied and modified from the original irq.c provided by
  24  * Alexey Charkov. Minor changes have been made for Device Tree Support.
  25  */
  26
  27 #include <linux/slab.h>
  28 #include <linux/io.h>
  29 #include <linux/irq.h>
  30 #include <linux/irqdomain.h>
  31 #include <linux/interrupt.h>
  32 #include <linux/bitops.h>
  33
  34 #include <linux/of.h>
  35 #include <linux/of_irq.h>
  36 #include <linux/of_address.h>
  37
  38 #include <asm/irq.h>
  39 #include <asm/exception.h>
  40 #include <asm/mach/irq.h>
  41
  42 #include "irqchip.h"
  43
  44 #define VT8500_ICPC_IRQ         0x20
  45 #define VT8500_ICPC_FIQ         0x24
  46 #define VT8500_ICDC             0x40            /* Destination Control 64*u32 */
  47 #define VT8500_ICIS             0x80            /* Interrupt status, 16*u32 */
  48
  49 /* ICPC */
  50 #define ICPC_MASK               0x3F
  51 #define ICPC_ROTATE             BIT(6)
  52
  53 /* IC_DCTR */
  54 #define ICDC_IRQ                0x00
  55 #define ICDC_FIQ                0x01
  56 #define ICDC_DSS0               0x02
  57 #define ICDC_DSS1               0x03
  58 #define ICDC_DSS2               0x04
  59 #define ICDC_DSS3               0x05
  60 #define ICDC_DSS4               0x06
  61 #define ICDC_DSS5               0x07
  62
  63 #define VT8500_INT_DISABLE      0
  64 #define VT8500_INT_ENABLE       BIT(3)
  65
  66 #define VT8500_TRIGGER_HIGH     0
  67 #define VT8500_TRIGGER_RISING   BIT(5)
  68 #define VT8500_TRIGGER_FALLING  BIT(6)
  69 #define VT8500_EDGE             ( VT8500_TRIGGER_RISING \
  70                                 | VT8500_TRIGGER_FALLING)
  71
  72 /* vt8500 has 1 intc, wm8505 and wm8650 have 2 */
  73 #define VT8500_INTC_MAX         2
  74
  75 struct vt8500_irq_data {
  76         void __iomem            *base;          /* IO Memory base address */
  77         struct irq_domain       *domain;        /* Domain for this controller */
  78 };
  79
  80 /* Global variable for accessing io-mem addresses */
  81 static struct vt8500_irq_data intc[VT8500_INTC_MAX];
  82 static u32 active_cnt = 0;
  83
  84 static void vt8500_irq_mask(struct irq_data *d)
  85 {
  86         struct vt8500_irq_data *priv = d->domain->host_data;
  87         void __iomem *base = priv->base;
  88         void __iomem *stat_reg = base + VT8500_ICIS + (d->hwirq < 32 ? 0 : 4);
  89         u8 edge, dctr;
  90         u32 status;
  91
  92         edge = readb(base + VT8500_ICDC + d->hwirq) & VT8500_EDGE;
  93         if (edge) {
  94                 status = readl(stat_reg);
  95
  96                 status |= (1 << (d->hwirq & 0x1f));
  97                 writel(status, stat_reg);
  98         } else {
  99                 dctr = readb(base + VT8500_ICDC + d->hwirq);
 100                 dctr &= ~VT8500_INT_ENABLE;
 101                 writeb(dctr, base + VT8500_ICDC + d->hwirq);
 102         }
 103 }
 104
 105 static void vt8500_irq_unmask(struct irq_data *d)
 106 {
 107         struct vt8500_irq_data *priv = d->domain->host_data;
 108         void __iomem *base = priv->base;
 109         u8 dctr;
 110
 111         dctr = readb(base + VT8500_ICDC + d->hwirq);
 112         dctr |= VT8500_INT_ENABLE;
 113         writeb(dctr, base + VT8500_ICDC + d->hwirq);
 114 }
 115
 116 static int vt8500_irq_set_type(struct irq_data *d, unsigned int flow_type)
 117 {
 118         struct vt8500_irq_data *priv = d->domain->host_data;
 119         void __iomem *base = priv->base;
 120         u8 dctr;
 121
 122         dctr = readb(base + VT8500_ICDC + d->hwirq);
 123         dctr &= ~VT8500_EDGE;
 124
 125         switch (flow_type) {
 126         case IRQF_TRIGGER_LOW:
 127                 return -EINVAL;
 128         case IRQF_TRIGGER_HIGH:
 129                 dctr |= VT8500_TRIGGER_HIGH;
 130                 __irq_set_handler_locked(d->irq, handle_level_irq);
 131                 break;
 132         case IRQF_TRIGGER_FALLING:
 133                 dctr |= VT8500_TRIGGER_FALLING;
 134                 __irq_set_handler_locked(d->irq, handle_edge_irq);
 135                 break;
 136         case IRQF_TRIGGER_RISING:
 137                 dctr |= VT8500_TRIGGER_RISING;
 138                 __irq_set_handler_locked(d->irq, handle_edge_irq);
 139                 break;
 140         }
 141         writeb(dctr, base + VT8500_ICDC + d->hwirq);
 142
 143         return 0;
 144 }
 145
 146 static struct irq_chip vt8500_irq_chip = {
 147         .name = "vt8500",
 148         .irq_ack = vt8500_irq_mask,
 149         .irq_mask = vt8500_irq_mask,
 150         .irq_unmask = vt8500_irq_unmask,
 151         .irq_set_type = vt8500_irq_set_type,
 152 };
 153
 154 static void __init vt8500_init_irq_hw(void __iomem *base)
 155 {
 156         u32 i;
 157
 158         /* Enable rotating priority for IRQ */
 159         writel(ICPC_ROTATE, base + VT8500_ICPC_IRQ);
 160         writel(0x00, base + VT8500_ICPC_FIQ);
 161
 162         /* Disable all interrupts and route them to IRQ */
 163         for (i = 0; i < 64; i++)
 164                 writeb(VT8500_INT_DISABLE | ICDC_IRQ, base + VT8500_ICDC + i);
 165 }
 166
 167 static int vt8500_irq_map(struct irq_domain *h, unsigned int virq,
 168                                                         irq_hw_number_t hw)
 169 {
 170         irq_set_chip_and_handler(virq, &vt8500_irq_chip, handle_level_irq);
 171         set_irq_flags(virq, IRQF_VALID);
 172
 173         return 0;
 174 }
 175
 176 static struct irq_domain_ops vt8500_irq_domain_ops = {
 177         .map = vt8500_irq_map,
 178         .xlate = irq_domain_xlate_onecell,
 179 };
 180
 181 static void __exception_irq_entry vt8500_handle_irq(struct pt_regs *regs)
 182 {
 183         u32 stat, i;
 184         int irqnr;
 185         void __iomem *base;
 186
 187         /* Loop through each active controller */
 188         for (i=0; i<active_cnt; i++) {
 189                 base = intc[i].base;
 190                 irqnr = readl_relaxed(base) & 0x3F;
 191                 /*
 192                   Highest Priority register default = 63, so check that this
 193                   is a real interrupt by checking the status register
 194                 */
 195                 if (irqnr == 63) {
 196                         stat = readl_relaxed(base + VT8500_ICIS + 4);
 197                         if (!(stat & BIT(31)))
 198                                 continue;
 199                 }
 200
 201                 handle_domain_irq(intc[i].domain, irqnr, regs);
 202         }
 203 }
 204
 205 static int __init vt8500_irq_init(struct device_node *node,
 206                                   struct device_node *parent)
 207 {
 208         int irq, i;
 209         struct device_node *np = node;
 210
 211         if (active_cnt == VT8500_INTC_MAX) {
 212                 pr_err("%s: Interrupt controllers > VT8500_INTC_MAX\n",
 213                                                                 __func__);
 214                 goto out;
 215         }
 216
 217         intc[active_cnt].base = of_iomap(np, 0);
 218         intc[active_cnt].domain = irq_domain_add_linear(node, 64,
 219                         &vt8500_irq_domain_ops, &intc[active_cnt]);
 220
 221         if (!intc[active_cnt].base) {
 222                 pr_err("%s: Unable to map IO memory\n", __func__);
 223                 goto out;
 224         }
 225
 226         if (!intc[active_cnt].domain) {
 227                 pr_err("%s: Unable to add irq domain!\n", __func__);
 228                 goto out;
 229         }
 230
 231         set_handle_irq(vt8500_handle_irq);
 232
 233         vt8500_init_irq_hw(intc[active_cnt].base);
 234
 235         pr_info("vt8500-irq: Added interrupt controller\n");
 236
 237         active_cnt++;
 238
 239         /* check if this is a slaved controller */
 240         if (of_irq_count(np) != 0) {
 241                 /* check that we have the correct number of interrupts */
 242                 if (of_irq_count(np) != 8) {
 243                         pr_err("%s: Incorrect IRQ map for slaved controller\n",
 244                                         __func__);
 245                         return -EINVAL;
 246                 }
 247
 248                 for (i = 0; i < 8; i++) {
 249                         irq = irq_of_parse_and_map(np, i);
 250                         enable_irq(irq);
 251                 }
 252
 253                 pr_info("vt8500-irq: Enabled slave->parent interrupts\n");
 254         }
 255 out:
 256         return 0;
 257 }
 258
 259 IRQCHIP_DECLARE(vt8500_irq, "via,vt8500-intc", vt8500_irq_init);