arch/powerpc/platforms/iseries/lpevents.c

   1 /*
   2  * Copyright (C) 2001 Mike Corrigan  IBM Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  */
   9
  10 #include <linux/stddef.h>
  11 #include <linux/kernel.h>
  12 #include <linux/sched.h>
  13 #include <linux/bootmem.h>
  14 #include <linux/seq_file.h>
  15 #include <linux/proc_fs.h>
  16 #include <linux/module.h>
  17
  18 #include <asm/system.h>
  19 #include <asm/paca.h>
  20 #include <asm/firmware.h>
  21 #include <asm/iseries/it_lp_queue.h>
  22 #include <asm/iseries/hv_lp_event.h>
  23 #include <asm/iseries/hv_call_event.h>
  24 #include "it_lp_naca.h"
  25
  26 /*
  27  * The LpQueue is used to pass event data from the hypervisor to
  28  * the partition.  This is where I/O interrupt events are communicated.
  29  *
  30  * It is written to by the hypervisor so cannot end up in the BSS.
  31  */
  32 struct hvlpevent_queue hvlpevent_queue __attribute__((__section__(".data")));
  33
  34 DEFINE_PER_CPU(unsigned long[HvLpEvent_Type_NumTypes], hvlpevent_counts);
  35
  36 static char *event_types[HvLpEvent_Type_NumTypes] = {
  37         "Hypervisor",
  38         "Machine Facilities",
  39         "Session Manager",
  40         "SPD I/O",
  41         "Virtual Bus",
  42         "PCI I/O",
  43         "RIO I/O",
  44         "Virtual Lan",
  45         "Virtual I/O"
  46 };
  47
  48 /* Array of LpEvent handler functions */
  49 static LpEventHandler lpEventHandler[HvLpEvent_Type_NumTypes];
  50 static unsigned lpEventHandlerPaths[HvLpEvent_Type_NumTypes];
  51
  52 static struct HvLpEvent * get_next_hvlpevent(void)
  53 {
  54         struct HvLpEvent * event;
  55         event = (struct HvLpEvent *)hvlpevent_queue.hq_current_event;
  56
  57         if (hvlpevent_is_valid(event)) {
  58                 /* rmb() needed only for weakly consistent machines (regatta) */
  59                 rmb();
  60                 /* Set pointer to next potential event */
  61                 hvlpevent_queue.hq_current_event += ((event->xSizeMinus1 +
  62                                 IT_LP_EVENT_ALIGN) / IT_LP_EVENT_ALIGN) *
  63                                         IT_LP_EVENT_ALIGN;
  64
  65                 /* Wrap to beginning if no room at end */
  66                 if (hvlpevent_queue.hq_current_event >
  67                                 hvlpevent_queue.hq_last_event) {
  68                         hvlpevent_queue.hq_current_event =
  69                                 hvlpevent_queue.hq_event_stack;
  70                 }
  71         } else {
  72                 event = NULL;
  73         }
  74
  75         return event;
  76 }
  77
  78 static unsigned long spread_lpevents = NR_CPUS;
  79
  80 int hvlpevent_is_pending(void)
  81 {
  82         struct HvLpEvent *next_event;
  83
  84         if (smp_processor_id() >= spread_lpevents)
  85                 return 0;
  86
  87         next_event = (struct HvLpEvent *)hvlpevent_queue.hq_current_event;
  88
  89         return hvlpevent_is_valid(next_event) ||
  90                 hvlpevent_queue.hq_overflow_pending;
  91 }
  92
  93 static void hvlpevent_clear_valid(struct HvLpEvent * event)
  94 {
  95         /* Tell the Hypervisor that we're done with this event.
  96          * Also clear bits within this event that might look like valid bits.
  97          * ie. on 64-byte boundaries.
  98          */
  99         struct HvLpEvent *tmp;
 100         unsigned extra = ((event->xSizeMinus1 + IT_LP_EVENT_ALIGN) /
 101                                 IT_LP_EVENT_ALIGN) - 1;
 102
 103         switch (extra) {
 104         case 3:
 105                 tmp = (struct HvLpEvent*)((char*)event + 3 * IT_LP_EVENT_ALIGN);
 106                 hvlpevent_invalidate(tmp);
 107         case 2:
 108                 tmp = (struct HvLpEvent*)((char*)event + 2 * IT_LP_EVENT_ALIGN);
 109                 hvlpevent_invalidate(tmp);
 110         case 1:
 111                 tmp = (struct HvLpEvent*)((char*)event + 1 * IT_LP_EVENT_ALIGN);
 112                 hvlpevent_invalidate(tmp);
 113         }
 114
 115         mb();
 116
 117         hvlpevent_invalidate(event);
 118 }
 119
 120 void process_hvlpevents(void)
 121 {
 122         struct HvLpEvent * event;
 123
 124         /* If we have recursed, just return */
 125         if (!spin_trylock(&hvlpevent_queue.hq_lock))
 126                 return;
 127
 128         for (;;) {
 129                 event = get_next_hvlpevent();
 130                 if (event) {
 131                         /* Call appropriate handler here, passing
 132                          * a pointer to the LpEvent.  The handler
 133                          * must make a copy of the LpEvent if it
 134                          * needs it in a bottom half. (perhaps for
 135                          * an ACK)
 136                          *
 137                          *  Handlers are responsible for ACK processing
 138                          *
 139                          * The Hypervisor guarantees that LpEvents will
 140                          * only be delivered with types that we have
 141                          * registered for, so no type check is necessary
 142                          * here!
 143                          */
 144                         if (event->xType < HvLpEvent_Type_NumTypes)
 145                                 __get_cpu_var(hvlpevent_counts)[event->xType]++;
 146                         if (event->xType < HvLpEvent_Type_NumTypes &&
 147                                         lpEventHandler[event->xType])
 148                                 lpEventHandler[event->xType](event);
 149                         else
 150                                 printk(KERN_INFO "Unexpected Lp Event type=%d\n", event->xType );
 151
 152                         hvlpevent_clear_valid(event);
 153                 } else if (hvlpevent_queue.hq_overflow_pending)
 154                         /*
 155                          * No more valid events. If overflow events are
 156                          * pending process them
 157                          */
 158                         HvCallEvent_getOverflowLpEvents(hvlpevent_queue.hq_index);
 159                 else
 160                         break;
 161         }
 162
 163         spin_unlock(&hvlpevent_queue.hq_lock);
 164 }
 165
 166 static int set_spread_lpevents(char *str)
 167 {
 168         unsigned long val = simple_strtoul(str, NULL, 0);
 169
 170         /*
 171          * The parameter is the number of processors to share in processing
 172          * lp events.
 173          */
 174         if (( val > 0) && (val <= NR_CPUS)) {
 175                 spread_lpevents = val;
 176                 printk("lpevent processing spread over %ld processors\n", val);
 177         } else {
 178                 printk("invalid spread_lpevents %ld\n", val);
 179         }
 180
 181         return 1;
 182 }
 183 __setup("spread_lpevents=", set_spread_lpevents);
 184
 185 void __init setup_hvlpevent_queue(void)
 186 {
 187         void *eventStack;
 188
 189         spin_lock_init(&hvlpevent_queue.hq_lock);
 190
 191         /* Allocate a page for the Event Stack. */
 192         eventStack = alloc_bootmem_pages(IT_LP_EVENT_STACK_SIZE);
 193         memset(eventStack, 0, IT_LP_EVENT_STACK_SIZE);
 194
 195         /* Invoke the hypervisor to initialize the event stack */
 196         HvCallEvent_setLpEventStack(0, eventStack, IT_LP_EVENT_STACK_SIZE);
 197
 198         hvlpevent_queue.hq_event_stack = eventStack;
 199         hvlpevent_queue.hq_current_event = eventStack;
 200         hvlpevent_queue.hq_last_event = (char *)eventStack +
 201                 (IT_LP_EVENT_STACK_SIZE - IT_LP_EVENT_MAX_SIZE);
 202         hvlpevent_queue.hq_index = 0;
 203 }
 204
 205 /* Register a handler for an LpEvent type */
 206 int HvLpEvent_registerHandler(HvLpEvent_Type eventType, LpEventHandler handler)
 207 {
 208         if (eventType < HvLpEvent_Type_NumTypes) {
 209                 lpEventHandler[eventType] = handler;
 210                 return 0;
 211         }
 212         return 1;
 213 }
 214 EXPORT_SYMBOL(HvLpEvent_registerHandler);
 215
 216 int HvLpEvent_unregisterHandler(HvLpEvent_Type eventType)
 217 {
 218         might_sleep();
 219
 220         if (eventType < HvLpEvent_Type_NumTypes) {
 221                 if (!lpEventHandlerPaths[eventType]) {
 222                         lpEventHandler[eventType] = NULL;
 223                         /*
 224                          * We now sleep until all other CPUs have scheduled.
 225                          * This ensures that the deletion is seen by all
 226                          * other CPUs, and that the deleted handler isn't
 227                          * still running on another CPU when we return.
 228                          */
 229                         synchronize_rcu();
 230                         return 0;
 231                 }
 232         }
 233         return 1;
 234 }
 235 EXPORT_SYMBOL(HvLpEvent_unregisterHandler);
 236
 237 /*
 238  * lpIndex is the partition index of the target partition.
 239  * needed only for VirtualIo, VirtualLan and SessionMgr.  Zero
 240  * indicates to use our partition index - for the other types.
 241  */
 242 int HvLpEvent_openPath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 243 {
 244         if ((eventType < HvLpEvent_Type_NumTypes) &&
 245                         lpEventHandler[eventType]) {
 246                 if (lpIndex == 0)
 247                         lpIndex = itLpNaca.xLpIndex;
 248                 HvCallEvent_openLpEventPath(lpIndex, eventType);
 249                 ++lpEventHandlerPaths[eventType];
 250                 return 0;
 251         }
 252         return 1;
 253 }
 254
 255 int HvLpEvent_closePath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 256 {
 257         if ((eventType < HvLpEvent_Type_NumTypes) &&
 258                         lpEventHandler[eventType] &&
 259                         lpEventHandlerPaths[eventType]) {
 260                 if (lpIndex == 0)
 261                         lpIndex = itLpNaca.xLpIndex;
 262                 HvCallEvent_closeLpEventPath(lpIndex, eventType);
 263                 --lpEventHandlerPaths[eventType];
 264                 return 0;
 265         }
 266         return 1;
 267 }
 268
 269 static int proc_lpevents_show(struct seq_file *m, void *v)
 270 {
 271         int cpu, i;
 272         unsigned long sum;
 273         static unsigned long cpu_totals[NR_CPUS];
 274
 275         /* FIXME: do we care that there's no locking here? */
 276         sum = 0;
 277         for_each_online_cpu(cpu) {
 278                 cpu_totals[cpu] = 0;
 279                 for (i = 0; i < HvLpEvent_Type_NumTypes; i++) {
 280                         cpu_totals[cpu] += per_cpu(hvlpevent_counts, cpu)[i];
 281                 }
 282                 sum += cpu_totals[cpu];
 283         }
 284
 285         seq_printf(m, "LpEventQueue 0\n");
 286         seq_printf(m, "  events processed:\t%lu\n", sum);
 287
 288         for (i = 0; i < HvLpEvent_Type_NumTypes; ++i) {
 289                 sum = 0;
 290                 for_each_online_cpu(cpu) {
 291                         sum += per_cpu(hvlpevent_counts, cpu)[i];
 292                 }
 293
 294                 seq_printf(m, "    %-20s %10lu\n", event_types[i], sum);
 295         }
 296
 297         seq_printf(m, "\n  events processed by processor:\n");
 298
 299         for_each_online_cpu(cpu) {
 300                 seq_printf(m, "    CPU%02d  %10lu\n", cpu, cpu_totals[cpu]);
 301         }
 302
 303         return 0;
 304 }
 305
 306 static int proc_lpevents_open(struct inode *inode, struct file *file)
 307 {
 308         return single_open(file, proc_lpevents_show, NULL);
 309 }
 310
 311 static const struct file_operations proc_lpevents_operations = {
 312         .open           = proc_lpevents_open,
 313         .read           = seq_read,
 314         .llseek         = seq_lseek,
 315         .release        = single_release,
 316 };
 317
 318 static int __init proc_lpevents_init(void)
 319 {
 320         struct proc_dir_entry *e;
 321
 322         if (!firmware_has_feature(FW_FEATURE_ISERIES))
 323                 return 0;
 324
 325         e = create_proc_entry("iSeries/lpevents", S_IFREG|S_IRUGO, NULL);
 326         if (e)
 327                 e->proc_fops = &proc_lpevents_operations;
 328
 329         return 0;
 330 }
 331 __initcall(proc_lpevents_init);
 332