arch/powerpc/platforms/powernv/opal-irqchip.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * This file implements an irqchip for OPAL events. Whenever there is
   4  * an interrupt that is handled by OPAL we get passed a list of events
   5  * that Linux needs to do something about. These basically look like
   6  * interrupts to Linux so we implement an irqchip to handle them.
   7  *
   8  * Copyright Alistair Popple, IBM Corporation 2014.
   9  */
  10 #include <linux/bitops.h>
  11 #include <linux/irq.h>
  12 #include <linux/irqchip.h>
  13 #include <linux/irqdomain.h>
  14 #include <linux/interrupt.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/kthread.h>
  19 #include <linux/delay.h>
  20 #include <linux/slab.h>
  21 #include <linux/of_irq.h>
  22
  23 #include <asm/machdep.h>
  24 #include <asm/opal.h>
  25
  26 #include "powernv.h"
  27
  28 /* Maximum number of events supported by OPAL firmware */
  29 #define MAX_NUM_EVENTS 64
  30
  31 struct opal_event_irqchip {
  32         struct irq_chip irqchip;
  33         struct irq_domain *domain;
  34         unsigned long mask;
  35 };
  36 static struct opal_event_irqchip opal_event_irqchip;
  37 static u64 last_outstanding_events;
  38 static int opal_irq_count;
  39 static struct resource *opal_irqs;
  40
  41 void opal_handle_events(void)
  42 {
  43         __be64 events = 0;
  44         u64 e;
  45
  46         e = READ_ONCE(last_outstanding_events) & opal_event_irqchip.mask;
  47 again:
  48         while (e) {
  49                 int virq, hwirq;
  50
  51                 hwirq = fls64(e) - 1;
  52                 e &= ~BIT_ULL(hwirq);
  53
  54                 local_irq_disable();
  55                 virq = irq_find_mapping(opal_event_irqchip.domain, hwirq);
  56                 if (virq) {
  57                         irq_enter();
  58                         generic_handle_irq(virq);
  59                         irq_exit();
  60                 }
  61                 local_irq_enable();
  62
  63                 cond_resched();
  64         }
  65         last_outstanding_events = 0;
  66         if (opal_poll_events(&events) != OPAL_SUCCESS)
  67                 return;
  68         e = be64_to_cpu(events) & opal_event_irqchip.mask;
  69         if (e)
  70                 goto again;
  71 }
  72
  73 bool opal_have_pending_events(void)
  74 {
  75         if (last_outstanding_events & opal_event_irqchip.mask)
  76                 return true;
  77         return false;
  78 }
  79
  80 static void opal_event_mask(struct irq_data *d)
  81 {
  82         clear_bit(d->hwirq, &opal_event_irqchip.mask);
  83 }
  84
  85 static void opal_event_unmask(struct irq_data *d)
  86 {
  87         set_bit(d->hwirq, &opal_event_irqchip.mask);
  88         if (opal_have_pending_events())
  89                 opal_wake_poller();
  90 }
  91
  92 static int opal_event_set_type(struct irq_data *d, unsigned int flow_type)
  93 {
  94         /*
  95          * For now we only support level triggered events. The irq
  96          * handler will be called continuously until the event has
  97          * been cleared in OPAL.
  98          */
  99         if (flow_type != IRQ_TYPE_LEVEL_HIGH)
 100                 return -EINVAL;
 101
 102         return 0;
 103 }
 104
 105 static struct opal_event_irqchip opal_event_irqchip = {
 106         .irqchip = {
 107                 .name = "OPAL EVT",
 108                 .irq_mask = opal_event_mask,
 109                 .irq_unmask = opal_event_unmask,
 110                 .irq_set_type = opal_event_set_type,
 111         },
 112         .mask = 0,
 113 };
 114
 115 static int opal_event_map(struct irq_domain *d, unsigned int irq,
 116                         irq_hw_number_t hwirq)
 117 {
 118         irq_set_chip_data(irq, &opal_event_irqchip);
 119         irq_set_chip_and_handler(irq, &opal_event_irqchip.irqchip,
 120                                 handle_level_irq);
 121
 122         return 0;
 123 }
 124
 125 static irqreturn_t opal_interrupt(int irq, void *data)
 126 {
 127         __be64 events;
 128
 129         opal_handle_interrupt(virq_to_hw(irq), &events);
 130         last_outstanding_events = be64_to_cpu(events);
 131         if (opal_have_pending_events())
 132                 opal_wake_poller();
 133
 134         return IRQ_HANDLED;
 135 }
 136
 137 static int opal_event_match(struct irq_domain *h, struct device_node *node,
 138                             enum irq_domain_bus_token bus_token)
 139 {
 140         return irq_domain_get_of_node(h) == node;
 141 }
 142
 143 static int opal_event_xlate(struct irq_domain *h, struct device_node *np,
 144                            const u32 *intspec, unsigned int intsize,
 145                            irq_hw_number_t *out_hwirq, unsigned int *out_flags)
 146 {
 147         *out_hwirq = intspec[0];
 148         *out_flags = IRQ_TYPE_LEVEL_HIGH;
 149
 150         return 0;
 151 }
 152
 153 static const struct irq_domain_ops opal_event_domain_ops = {
 154         .match  = opal_event_match,
 155         .map    = opal_event_map,
 156         .xlate  = opal_event_xlate,
 157 };
 158
 159 void opal_event_shutdown(void)
 160 {
 161         unsigned int i;
 162
 163         /* First free interrupts, which will also mask them */
 164         for (i = 0; i < opal_irq_count; i++) {
 165                 if (!opal_irqs || !opal_irqs[i].start)
 166                         continue;
 167
 168                 if (in_interrupt() || irqs_disabled())
 169                         disable_irq_nosync(opal_irqs[i].start);
 170                 else
 171                         free_irq(opal_irqs[i].start, NULL);
 172
 173                 opal_irqs[i].start = 0;
 174         }
 175 }
 176
 177 int __init opal_event_init(void)
 178 {
 179         struct device_node *dn, *opal_node;
 180         bool old_style = false;
 181         int i, rc = 0;
 182
 183         opal_node = of_find_node_by_path("/ibm,opal");
 184         if (!opal_node) {
 185                 pr_warn("opal: Node not found\n");
 186                 return -ENODEV;
 187         }
 188
 189         /* If dn is NULL it means the domain won't be linked to a DT
 190          * node so therefore irq_of_parse_and_map(...) wont work. But
 191          * that shouldn't be problem because if we're running a
 192          * version of skiboot that doesn't have the dn then the
 193          * devices won't have the correct properties and will have to
 194          * fall back to the legacy method (opal_event_request(...))
 195          * anyway. */
 196         dn = of_find_compatible_node(NULL, NULL, "ibm,opal-event");
 197         opal_event_irqchip.domain = irq_domain_add_linear(dn, MAX_NUM_EVENTS,
 198                                 &opal_event_domain_ops, &opal_event_irqchip);
 199         of_node_put(dn);
 200         if (!opal_event_irqchip.domain) {
 201                 pr_warn("opal: Unable to create irq domain\n");
 202                 rc = -ENOMEM;
 203                 goto out;
 204         }
 205
 206         /* Look for new-style (standard) "interrupts" property */
 207         opal_irq_count = of_irq_count(opal_node);
 208
 209         /* Absent ? Look for the old one */
 210         if (opal_irq_count < 1) {
 211                 /* Get opal-interrupts property and names if present */
 212                 rc = of_property_count_u32_elems(opal_node, "opal-interrupts");
 213                 if (rc > 0)
 214                         opal_irq_count = rc;
 215                 old_style = true;
 216         }
 217
 218         /* No interrupts ? Bail out */
 219         if (!opal_irq_count)
 220                 goto out;
 221
 222         pr_debug("OPAL: Found %d interrupts reserved for OPAL using %s scheme\n",
 223                  opal_irq_count, old_style ? "old" : "new");
 224
 225         /* Allocate an IRQ resources array */
 226         opal_irqs = kcalloc(opal_irq_count, sizeof(struct resource), GFP_KERNEL);
 227         if (WARN_ON(!opal_irqs)) {
 228                 rc = -ENOMEM;
 229                 goto out;
 230         }
 231
 232         /* Build the resources array */
 233         if (old_style) {
 234                 /* Old style "opal-interrupts" property */
 235                 for (i = 0; i < opal_irq_count; i++) {
 236                         struct resource *r = &opal_irqs[i];
 237                         const char *name = NULL;
 238                         u32 hw_irq;
 239                         int virq;
 240
 241                         rc = of_property_read_u32_index(opal_node, "opal-interrupts",
 242                                                         i, &hw_irq);
 243                         if (WARN_ON(rc < 0)) {
 244                                 opal_irq_count = i;
 245                                 break;
 246                         }
 247                         of_property_read_string_index(opal_node, "opal-interrupts-names",
 248                                                       i, &name);
 249                         virq = irq_create_mapping(NULL, hw_irq);
 250                         if (!virq) {
 251                                 pr_warn("Failed to map OPAL irq 0x%x\n", hw_irq);
 252                                 continue;
 253                         }
 254                         r->start = r->end = virq;
 255                         r->flags = IORESOURCE_IRQ | IRQ_TYPE_LEVEL_LOW;
 256                         r->name = name;
 257                 }
 258         } else {
 259                 /* new style standard "interrupts" property */
 260                 rc = of_irq_to_resource_table(opal_node, opal_irqs, opal_irq_count);
 261                 if (WARN_ON(rc < 0)) {
 262                         opal_irq_count = 0;
 263                         kfree(opal_irqs);
 264                         goto out;
 265                 }
 266                 if (WARN_ON(rc < opal_irq_count))
 267                         opal_irq_count = rc;
 268         }
 269
 270         /* Install interrupt handlers */
 271         for (i = 0; i < opal_irq_count; i++) {
 272                 struct resource *r = &opal_irqs[i];
 273                 const char *name;
 274
 275                 /* Prefix name */
 276                 if (r->name && strlen(r->name))
 277                         name = kasprintf(GFP_KERNEL, "opal-%s", r->name);
 278                 else
 279                         name = kasprintf(GFP_KERNEL, "opal");
 280
 281                 /* Install interrupt handler */
 282                 rc = request_irq(r->start, opal_interrupt, r->flags & IRQD_TRIGGER_MASK,
 283                                  name, NULL);
 284                 if (rc) {
 285                         pr_warn("Error %d requesting OPAL irq %d\n", rc, (int)r->start);
 286                         continue;
 287                 }
 288         }
 289         rc = 0;
 290  out:
 291         of_node_put(opal_node);
 292         return rc;
 293 }
 294 machine_arch_initcall(powernv, opal_event_init);
 295
 296 /**
 297  * opal_event_request(unsigned int opal_event_nr) - Request an event
 298  * @opal_event_nr: the opal event number to request
 299  *
 300  * This routine can be used to find the linux virq number which can
 301  * then be passed to request_irq to assign a handler for a particular
 302  * opal event. This should only be used by legacy devices which don't
 303  * have proper device tree bindings. Most devices should use
 304  * irq_of_parse_and_map() instead.
 305  */
 306 int opal_event_request(unsigned int opal_event_nr)
 307 {
 308         if (WARN_ON_ONCE(!opal_event_irqchip.domain))
 309                 return 0;
 310
 311         return irq_create_mapping(opal_event_irqchip.domain, opal_event_nr);
 312 }
 313 EXPORT_SYMBOL(opal_event_request);