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/export.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  restart:
 125         /* If we have recursed, just return */
 126         if (!spin_trylock(&hvlpevent_queue.hq_lock))
 127                 return;
 128
 129         for (;;) {
 130                 event = get_next_hvlpevent();
 131                 if (event) {
 132                         /* Call appropriate handler here, passing
 133                          * a pointer to the LpEvent.  The handler
 134                          * must make a copy of the LpEvent if it
 135                          * needs it in a bottom half. (perhaps for
 136                          * an ACK)
 137                          *
 138                          *  Handlers are responsible for ACK processing
 139                          *
 140                          * The Hypervisor guarantees that LpEvents will
 141                          * only be delivered with types that we have
 142                          * registered for, so no type check is necessary
 143                          * here!
 144                          */
 145                         if (event->xType < HvLpEvent_Type_NumTypes)
 146                                 __get_cpu_var(hvlpevent_counts)[event->xType]++;
 147                         if (event->xType < HvLpEvent_Type_NumTypes &&
 148                                         lpEventHandler[event->xType])
 149                                 lpEventHandler[event->xType](event);
 150                         else {
 151                                 u8 type = event->xType;
 152
 153                                 /*
 154                                  * Don't printk in the spinlock as printk
 155                                  * may require ack events form the HV to send
 156                                  * any characters there.
 157                                  */
 158                                 hvlpevent_clear_valid(event);
 159                                 spin_unlock(&hvlpevent_queue.hq_lock);
 160                                 printk(KERN_INFO
 161                                         "Unexpected Lp Event type=%d\n", type);
 162                                 goto restart;
 163                         }
 164
 165                         hvlpevent_clear_valid(event);
 166                 } else if (hvlpevent_queue.hq_overflow_pending)
 167                         /*
 168                          * No more valid events. If overflow events are
 169                          * pending process them
 170                          */
 171                         HvCallEvent_getOverflowLpEvents(hvlpevent_queue.hq_index);
 172                 else
 173                         break;
 174         }
 175
 176         spin_unlock(&hvlpevent_queue.hq_lock);
 177 }
 178
 179 static int set_spread_lpevents(char *str)
 180 {
 181         unsigned long val = simple_strtoul(str, NULL, 0);
 182
 183         /*
 184          * The parameter is the number of processors to share in processing
 185          * lp events.
 186          */
 187         if (( val > 0) && (val <= NR_CPUS)) {
 188                 spread_lpevents = val;
 189                 printk("lpevent processing spread over %ld processors\n", val);
 190         } else {
 191                 printk("invalid spread_lpevents %ld\n", val);
 192         }
 193
 194         return 1;
 195 }
 196 __setup("spread_lpevents=", set_spread_lpevents);
 197
 198 void __init setup_hvlpevent_queue(void)
 199 {
 200         void *eventStack;
 201
 202         spin_lock_init(&hvlpevent_queue.hq_lock);
 203
 204         /* Allocate a page for the Event Stack. */
 205         eventStack = alloc_bootmem_pages(IT_LP_EVENT_STACK_SIZE);
 206         memset(eventStack, 0, IT_LP_EVENT_STACK_SIZE);
 207
 208         /* Invoke the hypervisor to initialize the event stack */
 209         HvCallEvent_setLpEventStack(0, eventStack, IT_LP_EVENT_STACK_SIZE);
 210
 211         hvlpevent_queue.hq_event_stack = eventStack;
 212         hvlpevent_queue.hq_current_event = eventStack;
 213         hvlpevent_queue.hq_last_event = (char *)eventStack +
 214                 (IT_LP_EVENT_STACK_SIZE - IT_LP_EVENT_MAX_SIZE);
 215         hvlpevent_queue.hq_index = 0;
 216 }
 217
 218 /* Register a handler for an LpEvent type */
 219 int HvLpEvent_registerHandler(HvLpEvent_Type eventType, LpEventHandler handler)
 220 {
 221         if (eventType < HvLpEvent_Type_NumTypes) {
 222                 lpEventHandler[eventType] = handler;
 223                 return 0;
 224         }
 225         return 1;
 226 }
 227 EXPORT_SYMBOL(HvLpEvent_registerHandler);
 228
 229 int HvLpEvent_unregisterHandler(HvLpEvent_Type eventType)
 230 {
 231         might_sleep();
 232
 233         if (eventType < HvLpEvent_Type_NumTypes) {
 234                 if (!lpEventHandlerPaths[eventType]) {
 235                         lpEventHandler[eventType] = NULL;
 236                         /*
 237                          * We now sleep until all other CPUs have scheduled.
 238                          * This ensures that the deletion is seen by all
 239                          * other CPUs, and that the deleted handler isn't
 240                          * still running on another CPU when we return.
 241                          */
 242                         synchronize_sched();
 243                         return 0;
 244                 }
 245         }
 246         return 1;
 247 }
 248 EXPORT_SYMBOL(HvLpEvent_unregisterHandler);
 249
 250 /*
 251  * lpIndex is the partition index of the target partition.
 252  * needed only for VirtualIo, VirtualLan and SessionMgr.  Zero
 253  * indicates to use our partition index - for the other types.
 254  */
 255 int HvLpEvent_openPath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 256 {
 257         if ((eventType < HvLpEvent_Type_NumTypes) &&
 258                         lpEventHandler[eventType]) {
 259                 if (lpIndex == 0)
 260                         lpIndex = itLpNaca.xLpIndex;
 261                 HvCallEvent_openLpEventPath(lpIndex, eventType);
 262                 ++lpEventHandlerPaths[eventType];
 263                 return 0;
 264         }
 265         return 1;
 266 }
 267
 268 int HvLpEvent_closePath(HvLpEvent_Type eventType, HvLpIndex lpIndex)
 269 {
 270         if ((eventType < HvLpEvent_Type_NumTypes) &&
 271                         lpEventHandler[eventType] &&
 272                         lpEventHandlerPaths[eventType]) {
 273                 if (lpIndex == 0)
 274                         lpIndex = itLpNaca.xLpIndex;
 275                 HvCallEvent_closeLpEventPath(lpIndex, eventType);
 276                 --lpEventHandlerPaths[eventType];
 277                 return 0;
 278         }
 279         return 1;
 280 }
 281
 282 static int proc_lpevents_show(struct seq_file *m, void *v)
 283 {
 284         int cpu, i;
 285         unsigned long sum;
 286         static unsigned long cpu_totals[NR_CPUS];
 287
 288         /* FIXME: do we care that there's no locking here? */
 289         sum = 0;
 290         for_each_online_cpu(cpu) {
 291                 cpu_totals[cpu] = 0;
 292                 for (i = 0; i < HvLpEvent_Type_NumTypes; i++) {
 293                         cpu_totals[cpu] += per_cpu(hvlpevent_counts, cpu)[i];
 294                 }
 295                 sum += cpu_totals[cpu];
 296         }
 297
 298         seq_printf(m, "LpEventQueue 0\n");
 299         seq_printf(m, "  events processed:\t%lu\n", sum);
 300
 301         for (i = 0; i < HvLpEvent_Type_NumTypes; ++i) {
 302                 sum = 0;
 303                 for_each_online_cpu(cpu) {
 304                         sum += per_cpu(hvlpevent_counts, cpu)[i];
 305                 }
 306
 307                 seq_printf(m, "    %-20s %10lu\n", event_types[i], sum);
 308         }
 309
 310         seq_printf(m, "\n  events processed by processor:\n");
 311
 312         for_each_online_cpu(cpu) {
 313                 seq_printf(m, "    CPU%02d  %10lu\n", cpu, cpu_totals[cpu]);
 314         }
 315
 316         return 0;
 317 }
 318
 319 static int proc_lpevents_open(struct inode *inode, struct file *file)
 320 {
 321         return single_open(file, proc_lpevents_show, NULL);
 322 }
 323
 324 static const struct file_operations proc_lpevents_operations = {
 325         .open           = proc_lpevents_open,
 326         .read           = seq_read,
 327         .llseek         = seq_lseek,
 328         .release        = single_release,
 329 };
 330
 331 static int __init proc_lpevents_init(void)
 332 {
 333         if (!firmware_has_feature(FW_FEATURE_ISERIES))
 334                 return 0;
 335
 336         proc_create("iSeries/lpevents", S_IFREG|S_IRUGO, NULL,
 337                     &proc_lpevents_operations);
 338         return 0;
 339 }
 340 __initcall(proc_lpevents_init);
 341