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/irqchip.h>
  31 #include <linux/irqdomain.h>
  32 #include <linux/interrupt.h>
  33 #include <linux/bitops.h>
  34
  35 #include <linux/of.h>
  36 #include <linux/of_irq.h>
  37 #include <linux/of_address.h>
  38
  39 #include <asm/irq.h>
  40 #include <asm/exception.h>
  41 #include <asm/mach/irq.h>
  42
  43 #define VT8500_ICPC_IRQ         0x20
  44 #define VT8500_ICPC_FIQ         0x24
  45 #define VT8500_ICDC             0x40            /* Destination Control 64*u32 */
  46 #define VT8500_ICIS             0x80            /* Interrupt status, 16*u32 */
  47
  48 /* ICPC */
  49 #define ICPC_MASK               0x3F
  50 #define ICPC_ROTATE             BIT(6)
  51
  52 /* IC_DCTR */
  53 #define ICDC_IRQ                0x00
  54 #define ICDC_FIQ                0x01
  55 #define ICDC_DSS0               0x02
  56 #define ICDC_DSS1               0x03
  57 #define ICDC_DSS2               0x04
  58 #define ICDC_DSS3               0x05
  59 #define ICDC_DSS4               0x06
  60 #define ICDC_DSS5               0x07
  61
  62 #define VT8500_INT_DISABLE      0
  63 #define VT8500_INT_ENABLE       BIT(3)
  64
  65 #define VT8500_TRIGGER_HIGH     0
  66 #define VT8500_TRIGGER_RISING   BIT(5)
  67 #define VT8500_TRIGGER_FALLING  BIT(6)
  68 #define VT8500_EDGE             ( VT8500_TRIGGER_RISING \
  69                                 | VT8500_TRIGGER_FALLING)
  70
  71 /* vt8500 has 1 intc, wm8505 and wm8650 have 2 */
  72 #define VT8500_INTC_MAX         2
  73
  74 struct vt8500_irq_data {
  75         void __iomem            *base;          /* IO Memory base address */
  76         struct irq_domain       *domain;        /* Domain for this controller */
  77 };
  78
  79 /* Global variable for accessing io-mem addresses */
  80 static struct vt8500_irq_data intc[VT8500_INTC_MAX];
  81 static u32 active_cnt = 0;
  82
  83 static void vt8500_irq_mask(struct irq_data *d)
  84 {
  85         struct vt8500_irq_data *priv = d->domain->host_data;
  86         void __iomem *base = priv->base;
  87         void __iomem *stat_reg = base + VT8500_ICIS + (d->hwirq < 32 ? 0 : 4);
  88         u8 edge, dctr;
  89         u32 status;
  90
  91         edge = readb(base + VT8500_ICDC + d->hwirq) & VT8500_EDGE;
  92         if (edge) {
  93                 status = readl(stat_reg);
  94
  95                 status |= (1 << (d->hwirq & 0x1f));
  96                 writel(status, stat_reg);
  97         } else {
  98                 dctr = readb(base + VT8500_ICDC + d->hwirq);
  99                 dctr &= ~VT8500_INT_ENABLE;
 100                 writeb(dctr, base + VT8500_ICDC + d->hwirq);
 101         }
 102 }
 103
 104 static void vt8500_irq_unmask(struct irq_data *d)
 105 {
 106         struct vt8500_irq_data *priv = d->domain->host_data;
 107         void __iomem *base = priv->base;
 108         u8 dctr;
 109
 110         dctr = readb(base + VT8500_ICDC + d->hwirq);
 111         dctr |= VT8500_INT_ENABLE;
 112         writeb(dctr, base + VT8500_ICDC + d->hwirq);
 113 }
 114
 115 static int vt8500_irq_set_type(struct irq_data *d, unsigned int flow_type)
 116 {
 117         struct vt8500_irq_data *priv = d->domain->host_data;
 118         void __iomem *base = priv->base;
 119         u8 dctr;
 120
 121         dctr = readb(base + VT8500_ICDC + d->hwirq);
 122         dctr &= ~VT8500_EDGE;
 123
 124         switch (flow_type) {
 125         case IRQF_TRIGGER_LOW:
 126                 return -EINVAL;
 127         case IRQF_TRIGGER_HIGH:
 128                 dctr |= VT8500_TRIGGER_HIGH;
 129                 irq_set_handler_locked(d, handle_level_irq);
 130                 break;
 131         case IRQF_TRIGGER_FALLING:
 132                 dctr |= VT8500_TRIGGER_FALLING;
 133                 irq_set_handler_locked(d, handle_edge_irq);
 134                 break;
 135         case IRQF_TRIGGER_RISING:
 136                 dctr |= VT8500_TRIGGER_RISING;
 137                 irq_set_handler_locked(d, handle_edge_irq);
 138                 break;
 139         }
 140         writeb(dctr, base + VT8500_ICDC + d->hwirq);
 141
 142         return 0;
 143 }
 144
 145 static struct irq_chip vt8500_irq_chip = {
 146         .name = "vt8500",
 147         .irq_ack = vt8500_irq_mask,
 148         .irq_mask = vt8500_irq_mask,
 149         .irq_unmask = vt8500_irq_unmask,
 150         .irq_set_type = vt8500_irq_set_type,
 151 };
 152
 153 static void __init vt8500_init_irq_hw(void __iomem *base)
 154 {
 155         u32 i;
 156
 157         /* Enable rotating priority for IRQ */
 158         writel(ICPC_ROTATE, base + VT8500_ICPC_IRQ);
 159         writel(0x00, base + VT8500_ICPC_FIQ);
 160
 161         /* Disable all interrupts and route them to IRQ */
 162         for (i = 0; i < 64; i++)
 163                 writeb(VT8500_INT_DISABLE | ICDC_IRQ, base + VT8500_ICDC + i);
 164 }
 165
 166 static int vt8500_irq_map(struct irq_domain *h, unsigned int virq,
 167                                                         irq_hw_number_t hw)
 168 {
 169         irq_set_chip_and_handler(virq, &vt8500_irq_chip, handle_level_irq);
 170
 171         return 0;
 172 }
 173
 174 static const struct irq_domain_ops vt8500_irq_domain_ops = {
 175         .map = vt8500_irq_map,
 176         .xlate = irq_domain_xlate_onecell,
 177 };
 178
 179 static void __exception_irq_entry vt8500_handle_irq(struct pt_regs *regs)
 180 {
 181         u32 stat, i;
 182         int irqnr;
 183         void __iomem *base;
 184
 185         /* Loop through each active controller */
 186         for (i=0; i<active_cnt; i++) {
 187                 base = intc[i].base;
 188                 irqnr = readl_relaxed(base) & 0x3F;
 189                 /*
 190                   Highest Priority register default = 63, so check that this
 191                   is a real interrupt by checking the status register
 192                 */
 193                 if (irqnr == 63) {
 194                         stat = readl_relaxed(base + VT8500_ICIS + 4);
 195                         if (!(stat & BIT(31)))
 196                                 continue;
 197                 }
 198
 199                 handle_domain_irq(intc[i].domain, irqnr, regs);
 200         }
 201 }
 202
 203 static int __init vt8500_irq_init(struct device_node *node,
 204                                   struct device_node *parent)
 205 {
 206         int irq, i;
 207         struct device_node *np = node;
 208
 209         if (active_cnt == VT8500_INTC_MAX) {
 210                 pr_err("%s: Interrupt controllers > VT8500_INTC_MAX\n",
 211                                                                 __func__);
 212                 goto out;
 213         }
 214
 215         intc[active_cnt].base = of_iomap(np, 0);
 216         intc[active_cnt].domain = irq_domain_add_linear(node, 64,
 217                         &vt8500_irq_domain_ops, &intc[active_cnt]);
 218
 219         if (!intc[active_cnt].base) {
 220                 pr_err("%s: Unable to map IO memory\n", __func__);
 221                 goto out;
 222         }
 223
 224         if (!intc[active_cnt].domain) {
 225                 pr_err("%s: Unable to add irq domain!\n", __func__);
 226                 goto out;
 227         }
 228
 229         set_handle_irq(vt8500_handle_irq);
 230
 231         vt8500_init_irq_hw(intc[active_cnt].base);
 232
 233         pr_info("vt8500-irq: Added interrupt controller\n");
 234
 235         active_cnt++;
 236
 237         /* check if this is a slaved controller */
 238         if (of_irq_count(np) != 0) {
 239                 /* check that we have the correct number of interrupts */
 240                 if (of_irq_count(np) != 8) {
 241                         pr_err("%s: Incorrect IRQ map for slaved controller\n",
 242                                         __func__);
 243                         return -EINVAL;
 244                 }
 245
 246                 for (i = 0; i < 8; i++) {
 247                         irq = irq_of_parse_and_map(np, i);
 248                         enable_irq(irq);
 249                 }
 250
 251                 pr_info("vt8500-irq: Enabled slave->parent interrupts\n");
 252         }
 253 out:
 254         return 0;
 255 }
 256
 257 IRQCHIP_DECLARE(vt8500_irq, "via,vt8500-intc", vt8500_irq_init);