arch/powerpc/sysdev/uic.c

   1 /*
   2  * arch/powerpc/sysdev/uic.c
   3  *
   4  * IBM PowerPC 4xx Universal Interrupt Controller
   5  *
   6  * Copyright 2007 David Gibson <dwg@au1.ibm.com>, IBM Corporation.
   7  *
   8  * This program is free software; you can redistribute  it and/or modify it
   9  * under  the terms of  the GNU General  Public License as published by the
  10  * Free Software Foundation;  either version 2 of the  License, or (at your
  11  * option) any later version.
  12  */
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/errno.h>
  16 #include <linux/reboot.h>
  17 #include <linux/slab.h>
  18 #include <linux/stddef.h>
  19 #include <linux/sched.h>
  20 #include <linux/signal.h>
  21 #include <linux/device.h>
  22 #include <linux/spinlock.h>
  23 #include <linux/irq.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/kernel_stat.h>
  26 #include <asm/irq.h>
  27 #include <asm/io.h>
  28 #include <asm/prom.h>
  29 #include <asm/dcr.h>
  30
  31 #define NR_UIC_INTS     32
  32
  33 #define UIC_SR          0x0
  34 #define UIC_ER          0x2
  35 #define UIC_CR          0x3
  36 #define UIC_PR          0x4
  37 #define UIC_TR          0x5
  38 #define UIC_MSR         0x6
  39 #define UIC_VR          0x7
  40 #define UIC_VCR         0x8
  41
  42 struct uic *primary_uic;
  43
  44 struct uic {
  45         int index;
  46         int dcrbase;
  47
  48         raw_spinlock_t lock;
  49
  50         /* The remapper for this UIC */
  51         struct irq_domain       *irqhost;
  52 };
  53
  54 static void uic_unmask_irq(struct irq_data *d)
  55 {
  56         struct uic *uic = irq_data_get_irq_chip_data(d);
  57         unsigned int src = irqd_to_hwirq(d);
  58         unsigned long flags;
  59         u32 er, sr;
  60
  61         sr = 1 << (31-src);
  62         raw_spin_lock_irqsave(&uic->lock, flags);
  63         /* ack level-triggered interrupts here */
  64         if (irqd_is_level_type(d))
  65                 mtdcr(uic->dcrbase + UIC_SR, sr);
  66         er = mfdcr(uic->dcrbase + UIC_ER);
  67         er |= sr;
  68         mtdcr(uic->dcrbase + UIC_ER, er);
  69         raw_spin_unlock_irqrestore(&uic->lock, flags);
  70 }
  71
  72 static void uic_mask_irq(struct irq_data *d)
  73 {
  74         struct uic *uic = irq_data_get_irq_chip_data(d);
  75         unsigned int src = irqd_to_hwirq(d);
  76         unsigned long flags;
  77         u32 er;
  78
  79         raw_spin_lock_irqsave(&uic->lock, flags);
  80         er = mfdcr(uic->dcrbase + UIC_ER);
  81         er &= ~(1 << (31 - src));
  82         mtdcr(uic->dcrbase + UIC_ER, er);
  83         raw_spin_unlock_irqrestore(&uic->lock, flags);
  84 }
  85
  86 static void uic_ack_irq(struct irq_data *d)
  87 {
  88         struct uic *uic = irq_data_get_irq_chip_data(d);
  89         unsigned int src = irqd_to_hwirq(d);
  90         unsigned long flags;
  91
  92         raw_spin_lock_irqsave(&uic->lock, flags);
  93         mtdcr(uic->dcrbase + UIC_SR, 1 << (31-src));
  94         raw_spin_unlock_irqrestore(&uic->lock, flags);
  95 }
  96
  97 static void uic_mask_ack_irq(struct irq_data *d)
  98 {
  99         struct uic *uic = irq_data_get_irq_chip_data(d);
 100         unsigned int src = irqd_to_hwirq(d);
 101         unsigned long flags;
 102         u32 er, sr;
 103
 104         sr = 1 << (31-src);
 105         raw_spin_lock_irqsave(&uic->lock, flags);
 106         er = mfdcr(uic->dcrbase + UIC_ER);
 107         er &= ~sr;
 108         mtdcr(uic->dcrbase + UIC_ER, er);
 109         /* On the UIC, acking (i.e. clearing the SR bit)
 110          * a level irq will have no effect if the interrupt
 111          * is still asserted by the device, even if
 112          * the interrupt is already masked. Therefore
 113          * we only ack the egde interrupts here, while
 114          * level interrupts are ack'ed after the actual
 115          * isr call in the uic_unmask_irq()
 116          */
 117         if (!irqd_is_level_type(d))
 118                 mtdcr(uic->dcrbase + UIC_SR, sr);
 119         raw_spin_unlock_irqrestore(&uic->lock, flags);
 120 }
 121
 122 static int uic_set_irq_type(struct irq_data *d, unsigned int flow_type)
 123 {
 124         struct uic *uic = irq_data_get_irq_chip_data(d);
 125         unsigned int src = irqd_to_hwirq(d);
 126         unsigned long flags;
 127         int trigger, polarity;
 128         u32 tr, pr, mask;
 129
 130         switch (flow_type & IRQ_TYPE_SENSE_MASK) {
 131         case IRQ_TYPE_NONE:
 132                 uic_mask_irq(d);
 133                 return 0;
 134
 135         case IRQ_TYPE_EDGE_RISING:
 136                 trigger = 1; polarity = 1;
 137                 break;
 138         case IRQ_TYPE_EDGE_FALLING:
 139                 trigger = 1; polarity = 0;
 140                 break;
 141         case IRQ_TYPE_LEVEL_HIGH:
 142                 trigger = 0; polarity = 1;
 143                 break;
 144         case IRQ_TYPE_LEVEL_LOW:
 145                 trigger = 0; polarity = 0;
 146                 break;
 147         default:
 148                 return -EINVAL;
 149         }
 150
 151         mask = ~(1 << (31 - src));
 152
 153         raw_spin_lock_irqsave(&uic->lock, flags);
 154         tr = mfdcr(uic->dcrbase + UIC_TR);
 155         pr = mfdcr(uic->dcrbase + UIC_PR);
 156         tr = (tr & mask) | (trigger << (31-src));
 157         pr = (pr & mask) | (polarity << (31-src));
 158
 159         mtdcr(uic->dcrbase + UIC_PR, pr);
 160         mtdcr(uic->dcrbase + UIC_TR, tr);
 161
 162         raw_spin_unlock_irqrestore(&uic->lock, flags);
 163
 164         return 0;
 165 }
 166
 167 static struct irq_chip uic_irq_chip = {
 168         .name           = "UIC",
 169         .irq_unmask     = uic_unmask_irq,
 170         .irq_mask       = uic_mask_irq,
 171         .irq_mask_ack   = uic_mask_ack_irq,
 172         .irq_ack        = uic_ack_irq,
 173         .irq_set_type   = uic_set_irq_type,
 174 };
 175
 176 static int uic_host_map(struct irq_domain *h, unsigned int virq,
 177                         irq_hw_number_t hw)
 178 {
 179         struct uic *uic = h->host_data;
 180
 181         irq_set_chip_data(virq, uic);
 182         /* Despite the name, handle_level_irq() works for both level
 183          * and edge irqs on UIC.  FIXME: check this is correct */
 184         irq_set_chip_and_handler(virq, &uic_irq_chip, handle_level_irq);
 185
 186         /* Set default irq type */
 187         irq_set_irq_type(virq, IRQ_TYPE_NONE);
 188
 189         return 0;
 190 }
 191
 192 static const struct irq_domain_ops uic_host_ops = {
 193         .map    = uic_host_map,
 194         .xlate  = irq_domain_xlate_twocell,
 195 };
 196
 197 static void uic_irq_cascade(struct irq_desc *desc)
 198 {
 199         struct irq_chip *chip = irq_desc_get_chip(desc);
 200         struct irq_data *idata = irq_desc_get_irq_data(desc);
 201         struct uic *uic = irq_desc_get_handler_data(desc);
 202         u32 msr;
 203         int src;
 204         int subvirq;
 205
 206         raw_spin_lock(&desc->lock);
 207         if (irqd_is_level_type(idata))
 208                 chip->irq_mask(idata);
 209         else
 210                 chip->irq_mask_ack(idata);
 211         raw_spin_unlock(&desc->lock);
 212
 213         msr = mfdcr(uic->dcrbase + UIC_MSR);
 214         if (!msr) /* spurious interrupt */
 215                 goto uic_irq_ret;
 216
 217         src = 32 - ffs(msr);
 218
 219         subvirq = irq_linear_revmap(uic->irqhost, src);
 220         generic_handle_irq(subvirq);
 221
 222 uic_irq_ret:
 223         raw_spin_lock(&desc->lock);
 224         if (irqd_is_level_type(idata))
 225                 chip->irq_ack(idata);
 226         if (!irqd_irq_disabled(idata) && chip->irq_unmask)
 227                 chip->irq_unmask(idata);
 228         raw_spin_unlock(&desc->lock);
 229 }
 230
 231 static struct uic * __init uic_init_one(struct device_node *node)
 232 {
 233         struct uic *uic;
 234         const u32 *indexp, *dcrreg;
 235         int len;
 236
 237         BUG_ON(! of_device_is_compatible(node, "ibm,uic"));
 238
 239         uic = kzalloc(sizeof(*uic), GFP_KERNEL);
 240         if (! uic)
 241                 return NULL; /* FIXME: panic? */
 242
 243         raw_spin_lock_init(&uic->lock);
 244         indexp = of_get_property(node, "cell-index", &len);
 245         if (!indexp || (len != sizeof(u32))) {
 246                 printk(KERN_ERR "uic: Device node %s has missing or invalid "
 247                        "cell-index property\n", node->full_name);
 248                 return NULL;
 249         }
 250         uic->index = *indexp;
 251
 252         dcrreg = of_get_property(node, "dcr-reg", &len);
 253         if (!dcrreg || (len != 2*sizeof(u32))) {
 254                 printk(KERN_ERR "uic: Device node %s has missing or invalid "
 255                        "dcr-reg property\n", node->full_name);
 256                 return NULL;
 257         }
 258         uic->dcrbase = *dcrreg;
 259
 260         uic->irqhost = irq_domain_add_linear(node, NR_UIC_INTS, &uic_host_ops,
 261                                              uic);
 262         if (! uic->irqhost)
 263                 return NULL; /* FIXME: panic? */
 264
 265         /* Start with all interrupts disabled, level and non-critical */
 266         mtdcr(uic->dcrbase + UIC_ER, 0);
 267         mtdcr(uic->dcrbase + UIC_CR, 0);
 268         mtdcr(uic->dcrbase + UIC_TR, 0);
 269         /* Clear any pending interrupts, in case the firmware left some */
 270         mtdcr(uic->dcrbase + UIC_SR, 0xffffffff);
 271
 272         printk ("UIC%d (%d IRQ sources) at DCR 0x%x\n", uic->index,
 273                 NR_UIC_INTS, uic->dcrbase);
 274
 275         return uic;
 276 }
 277
 278 void __init uic_init_tree(void)
 279 {
 280         struct device_node *np;
 281         struct uic *uic;
 282         const u32 *interrupts;
 283
 284         /* First locate and initialize the top-level UIC */
 285         for_each_compatible_node(np, NULL, "ibm,uic") {
 286                 interrupts = of_get_property(np, "interrupts", NULL);
 287                 if (!interrupts)
 288                         break;
 289         }
 290
 291         BUG_ON(!np); /* uic_init_tree() assumes there's a UIC as the
 292                       * top-level interrupt controller */
 293         primary_uic = uic_init_one(np);
 294         if (!primary_uic)
 295                 panic("Unable to initialize primary UIC %s\n", np->full_name);
 296
 297         irq_set_default_host(primary_uic->irqhost);
 298         of_node_put(np);
 299
 300         /* The scan again for cascaded UICs */
 301         for_each_compatible_node(np, NULL, "ibm,uic") {
 302                 interrupts = of_get_property(np, "interrupts", NULL);
 303                 if (interrupts) {
 304                         /* Secondary UIC */
 305                         int cascade_virq;
 306
 307                         uic = uic_init_one(np);
 308                         if (! uic)
 309                                 panic("Unable to initialize a secondary UIC %s\n",
 310                                       np->full_name);
 311
 312                         cascade_virq = irq_of_parse_and_map(np, 0);
 313
 314                         irq_set_handler_data(cascade_virq, uic);
 315                         irq_set_chained_handler(cascade_virq, uic_irq_cascade);
 316
 317                         /* FIXME: setup critical cascade?? */
 318                 }
 319         }
 320 }
 321
 322 /* Return an interrupt vector or 0 if no interrupt is pending. */
 323 unsigned int uic_get_irq(void)
 324 {
 325         u32 msr;
 326         int src;
 327
 328         BUG_ON(! primary_uic);
 329
 330         msr = mfdcr(primary_uic->dcrbase + UIC_MSR);
 331         src = 32 - ffs(msr);
 332
 333         return irq_linear_revmap(primary_uic->irqhost, src);
 334 }