arch/mips/kernel/vpe-mt.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2004, 2005 MIPS Technologies, Inc.  All rights reserved.
   7  * Copyright (C) 2013 Imagination Technologies Ltd.
   8  */
   9 #include <linux/kernel.h>
  10 #include <linux/device.h>
  11 #include <linux/fs.h>
  12 #include <linux/slab.h>
  13 #include <linux/export.h>
  14
  15 #include <asm/mipsregs.h>
  16 #include <asm/mipsmtregs.h>
  17 #include <asm/mips_mt.h>
  18 #include <asm/vpe.h>
  19
  20 static int major;
  21
  22 /* The number of TCs and VPEs physically available on the core */
  23 static int hw_tcs, hw_vpes;
  24
  25 /* We are prepared so configure and start the VPE... */
  26 int vpe_run(struct vpe *v)
  27 {
  28         unsigned long flags, val, dmt_flag;
  29         struct vpe_notifications *notifier;
  30         unsigned int vpeflags;
  31         struct tc *t;
  32
  33         /* check we are the Master VPE */
  34         local_irq_save(flags);
  35         val = read_c0_vpeconf0();
  36         if (!(val & VPECONF0_MVP)) {
  37                 pr_warn("VPE loader: only Master VPE's are able to config MT\n");
  38                 local_irq_restore(flags);
  39
  40                 return -1;
  41         }
  42
  43         dmt_flag = dmt();
  44         vpeflags = dvpe();
  45
  46         if (list_empty(&v->tc)) {
  47                 evpe(vpeflags);
  48                 emt(dmt_flag);
  49                 local_irq_restore(flags);
  50
  51                 pr_warn("VPE loader: No TC's associated with VPE %d\n",
  52                         v->minor);
  53
  54                 return -ENOEXEC;
  55         }
  56
  57         t = list_first_entry(&v->tc, struct tc, tc);
  58
  59         /* Put MVPE's into 'configuration state' */
  60         set_c0_mvpcontrol(MVPCONTROL_VPC);
  61
  62         settc(t->index);
  63
  64         /* should check it is halted, and not activated */
  65         if ((read_tc_c0_tcstatus() & TCSTATUS_A) ||
  66            !(read_tc_c0_tchalt() & TCHALT_H)) {
  67                 evpe(vpeflags);
  68                 emt(dmt_flag);
  69                 local_irq_restore(flags);
  70
  71                 pr_warn("VPE loader: TC %d is already active!\n",
  72                         t->index);
  73
  74                 return -ENOEXEC;
  75         }
  76
  77         /*
  78          * Write the address we want it to start running from in the TCPC
  79          * register.
  80          */
  81         write_tc_c0_tcrestart((unsigned long)v->__start);
  82         write_tc_c0_tccontext((unsigned long)0);
  83
  84         /*
  85          * Mark the TC as activated, not interrupt exempt and not dynamically
  86          * allocatable
  87          */
  88         val = read_tc_c0_tcstatus();
  89         val = (val & ~(TCSTATUS_DA | TCSTATUS_IXMT)) | TCSTATUS_A;
  90         write_tc_c0_tcstatus(val);
  91
  92         write_tc_c0_tchalt(read_tc_c0_tchalt() & ~TCHALT_H);
  93
  94         /*
  95          * We don't pass the memsize here, so VPE programs need to be
  96          * compiled with DFLT_STACK_SIZE and DFLT_HEAP_SIZE defined.
  97          */
  98         mttgpr($7, 0);
  99         mttgpr($6, v->ntcs);
 100
 101         /* set up VPE1 */
 102         /*
 103          * bind the TC to VPE 1 as late as possible so we only have the final
 104          * VPE registers to set up, and so an EJTAG probe can trigger on it
 105          */
 106         write_tc_c0_tcbind((read_tc_c0_tcbind() & ~TCBIND_CURVPE) | 1);
 107
 108         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~(VPECONF0_VPA));
 109
 110         back_to_back_c0_hazard();
 111
 112         /* Set up the XTC bit in vpeconf0 to point at our tc */
 113         write_vpe_c0_vpeconf0((read_vpe_c0_vpeconf0() & ~(VPECONF0_XTC))
 114                               | (t->index << VPECONF0_XTC_SHIFT));
 115
 116         back_to_back_c0_hazard();
 117
 118         /* enable this VPE */
 119         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
 120
 121         /* clear out any left overs from a previous program */
 122         write_vpe_c0_status(0);
 123         write_vpe_c0_cause(0);
 124
 125         /* take system out of configuration state */
 126         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 127
 128         /*
 129          * SMVP kernels manage VPE enable independently, but uniprocessor
 130          * kernels need to turn it on, even if that wasn't the pre-dvpe() state.
 131          */
 132 #ifdef CONFIG_SMP
 133         evpe(vpeflags);
 134 #else
 135         evpe(EVPE_ENABLE);
 136 #endif
 137         emt(dmt_flag);
 138         local_irq_restore(flags);
 139
 140         list_for_each_entry(notifier, &v->notify, list)
 141                 notifier->start(VPE_MODULE_MINOR);
 142
 143         return 0;
 144 }
 145
 146 void cleanup_tc(struct tc *tc)
 147 {
 148         unsigned long flags;
 149         unsigned int mtflags, vpflags;
 150         int tmp;
 151
 152         local_irq_save(flags);
 153         mtflags = dmt();
 154         vpflags = dvpe();
 155         /* Put MVPE's into 'configuration state' */
 156         set_c0_mvpcontrol(MVPCONTROL_VPC);
 157
 158         settc(tc->index);
 159         tmp = read_tc_c0_tcstatus();
 160
 161         /* mark not allocated and not dynamically allocatable */
 162         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 163         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 164         write_tc_c0_tcstatus(tmp);
 165
 166         write_tc_c0_tchalt(TCHALT_H);
 167         mips_ihb();
 168
 169         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 170         evpe(vpflags);
 171         emt(mtflags);
 172         local_irq_restore(flags);
 173 }
 174
 175 /* module wrapper entry points */
 176 /* give me a vpe */
 177 void *vpe_alloc(void)
 178 {
 179         int i;
 180         struct vpe *v;
 181
 182         /* find a vpe */
 183         for (i = 1; i < MAX_VPES; i++) {
 184                 v = get_vpe(i);
 185                 if (v != NULL) {
 186                         v->state = VPE_STATE_INUSE;
 187                         return v;
 188                 }
 189         }
 190         return NULL;
 191 }
 192 EXPORT_SYMBOL(vpe_alloc);
 193
 194 /* start running from here */
 195 int vpe_start(void *vpe, unsigned long start)
 196 {
 197         struct vpe *v = vpe;
 198
 199         v->__start = start;
 200         return vpe_run(v);
 201 }
 202 EXPORT_SYMBOL(vpe_start);
 203
 204 /* halt it for now */
 205 int vpe_stop(void *vpe)
 206 {
 207         struct vpe *v = vpe;
 208         struct tc *t;
 209         unsigned int evpe_flags;
 210
 211         evpe_flags = dvpe();
 212
 213         t = list_entry(v->tc.next, struct tc, tc);
 214         if (t != NULL) {
 215                 settc(t->index);
 216                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 217         }
 218
 219         evpe(evpe_flags);
 220
 221         return 0;
 222 }
 223 EXPORT_SYMBOL(vpe_stop);
 224
 225 /* I've done with it thank you */
 226 int vpe_free(void *vpe)
 227 {
 228         struct vpe *v = vpe;
 229         struct tc *t;
 230         unsigned int evpe_flags;
 231
 232         t = list_entry(v->tc.next, struct tc, tc);
 233         if (t == NULL)
 234                 return -ENOEXEC;
 235
 236         evpe_flags = dvpe();
 237
 238         /* Put MVPE's into 'configuration state' */
 239         set_c0_mvpcontrol(MVPCONTROL_VPC);
 240
 241         settc(t->index);
 242         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 243
 244         /* halt the TC */
 245         write_tc_c0_tchalt(TCHALT_H);
 246         mips_ihb();
 247
 248         /* mark the TC unallocated */
 249         write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
 250
 251         v->state = VPE_STATE_UNUSED;
 252
 253         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 254         evpe(evpe_flags);
 255
 256         return 0;
 257 }
 258 EXPORT_SYMBOL(vpe_free);
 259
 260 static ssize_t store_kill(struct device *dev, struct device_attribute *attr,
 261                           const char *buf, size_t len)
 262 {
 263         struct vpe *vpe = get_vpe(aprp_cpu_index());
 264         struct vpe_notifications *notifier;
 265
 266         list_for_each_entry(notifier, &vpe->notify, list)
 267                 notifier->stop(aprp_cpu_index());
 268
 269         release_progmem(vpe->load_addr);
 270         cleanup_tc(get_tc(aprp_cpu_index()));
 271         vpe_stop(vpe);
 272         vpe_free(vpe);
 273
 274         return len;
 275 }
 276 static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
 277
 278 static ssize_t ntcs_show(struct device *cd, struct device_attribute *attr,
 279                          char *buf)
 280 {
 281         struct vpe *vpe = get_vpe(aprp_cpu_index());
 282
 283         return sprintf(buf, "%d\n", vpe->ntcs);
 284 }
 285
 286 static ssize_t ntcs_store(struct device *dev, struct device_attribute *attr,
 287                           const char *buf, size_t len)
 288 {
 289         struct vpe *vpe = get_vpe(aprp_cpu_index());
 290         unsigned long new;
 291         int ret;
 292
 293         ret = kstrtoul(buf, 0, &new);
 294         if (ret < 0)
 295                 return ret;
 296
 297         if (new == 0 || new > (hw_tcs - aprp_cpu_index()))
 298                 return -EINVAL;
 299
 300         vpe->ntcs = new;
 301
 302         return len;
 303 }
 304 static DEVICE_ATTR_RW(ntcs);
 305
 306 static struct attribute *vpe_attrs[] = {
 307         &dev_attr_kill.attr,
 308         &dev_attr_ntcs.attr,
 309         NULL,
 310 };
 311 ATTRIBUTE_GROUPS(vpe);
 312
 313 static void vpe_device_release(struct device *cd)
 314 {
 315 }
 316
 317 static struct class vpe_class = {
 318         .name = "vpe",
 319         .dev_release = vpe_device_release,
 320         .dev_groups = vpe_groups,
 321 };
 322
 323 static struct device vpe_device;
 324
 325 int __init vpe_module_init(void)
 326 {
 327         unsigned int mtflags, vpflags;
 328         unsigned long flags, val;
 329         struct vpe *v = NULL;
 330         struct tc *t;
 331         int tc, err;
 332
 333         if (!cpu_has_mipsmt) {
 334                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
 335                 return -ENODEV;
 336         }
 337
 338         if (vpelimit == 0) {
 339                 pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
 340                         "Pass maxvpes=<n> argument as kernel argument\n");
 341
 342                 return -ENODEV;
 343         }
 344
 345         if (aprp_cpu_index() == 0) {
 346                 pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
 347                         "Pass maxtcs=<n> argument as kernel argument\n");
 348
 349                 return -ENODEV;
 350         }
 351
 352         major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
 353         if (major < 0) {
 354                 pr_warn("VPE loader: unable to register character device\n");
 355                 return major;
 356         }
 357
 358         err = class_register(&vpe_class);
 359         if (err) {
 360                 pr_err("vpe_class registration failed\n");
 361                 goto out_chrdev;
 362         }
 363
 364         device_initialize(&vpe_device);
 365         vpe_device.class        = &vpe_class;
 366         vpe_device.parent       = NULL;
 367         dev_set_name(&vpe_device, "vpe1");
 368         vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
 369         err = device_add(&vpe_device);
 370         if (err) {
 371                 pr_err("Adding vpe_device failed\n");
 372                 goto out_class;
 373         }
 374
 375         local_irq_save(flags);
 376         mtflags = dmt();
 377         vpflags = dvpe();
 378
 379         /* Put MVPE's into 'configuration state' */
 380         set_c0_mvpcontrol(MVPCONTROL_VPC);
 381
 382         val = read_c0_mvpconf0();
 383         hw_tcs = (val & MVPCONF0_PTC) + 1;
 384         hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 385
 386         for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
 387                 /*
 388                  * Must re-enable multithreading temporarily or in case we
 389                  * reschedule send IPIs or similar we might hang.
 390                  */
 391                 clear_c0_mvpcontrol(MVPCONTROL_VPC);
 392                 evpe(vpflags);
 393                 emt(mtflags);
 394                 local_irq_restore(flags);
 395                 t = alloc_tc(tc);
 396                 if (!t) {
 397                         err = -ENOMEM;
 398                         goto out_dev;
 399                 }
 400
 401                 local_irq_save(flags);
 402                 mtflags = dmt();
 403                 vpflags = dvpe();
 404                 set_c0_mvpcontrol(MVPCONTROL_VPC);
 405
 406                 /* VPE's */
 407                 if (tc < hw_tcs) {
 408                         settc(tc);
 409
 410                         v = alloc_vpe(tc);
 411                         if (v == NULL) {
 412                                 pr_warn("VPE: unable to allocate VPE\n");
 413                                 goto out_reenable;
 414                         }
 415
 416                         v->ntcs = hw_tcs - aprp_cpu_index();
 417
 418                         /* add the tc to the list of this vpe's tc's. */
 419                         list_add(&t->tc, &v->tc);
 420
 421                         /* deactivate all but vpe0 */
 422                         if (tc >= aprp_cpu_index()) {
 423                                 unsigned long tmp = read_vpe_c0_vpeconf0();
 424
 425                                 tmp &= ~VPECONF0_VPA;
 426
 427                                 /* master VPE */
 428                                 tmp |= VPECONF0_MVP;
 429                                 write_vpe_c0_vpeconf0(tmp);
 430                         }
 431
 432                         /* disable multi-threading with TC's */
 433                         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
 434                                                 ~VPECONTROL_TE);
 435
 436                         if (tc >= vpelimit) {
 437                                 /*
 438                                  * Set config to be the same as vpe0,
 439                                  * particularly kseg0 coherency alg
 440                                  */
 441                                 write_vpe_c0_config(read_c0_config());
 442                         }
 443                 }
 444
 445                 /* TC's */
 446                 t->pvpe = v;    /* set the parent vpe */
 447
 448                 if (tc >= aprp_cpu_index()) {
 449                         unsigned long tmp;
 450
 451                         settc(tc);
 452
 453                         /*
 454                          * A TC that is bound to any other VPE gets bound to
 455                          * VPE0, ideally I'd like to make it homeless but it
 456                          * doesn't appear to let me bind a TC to a non-existent
 457                          * VPE. Which is perfectly reasonable.
 458                          *
 459                          * The (un)bound state is visible to an EJTAG probe so
 460                          * may notify GDB...
 461                          */
 462                         tmp = read_tc_c0_tcbind();
 463                         if (tmp & TCBIND_CURVPE) {
 464                                 /* tc is bound >vpe0 */
 465                                 write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
 466
 467                                 t->pvpe = get_vpe(0);   /* set the parent vpe */
 468                         }
 469
 470                         /* halt the TC */
 471                         write_tc_c0_tchalt(TCHALT_H);
 472                         mips_ihb();
 473
 474                         tmp = read_tc_c0_tcstatus();
 475
 476                         /* mark not activated and not dynamically allocatable */
 477                         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 478                         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 479                         write_tc_c0_tcstatus(tmp);
 480                 }
 481         }
 482
 483 out_reenable:
 484         /* release config state */
 485         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 486
 487         evpe(vpflags);
 488         emt(mtflags);
 489         local_irq_restore(flags);
 490
 491         return 0;
 492
 493 out_dev:
 494         device_del(&vpe_device);
 495
 496 out_class:
 497         put_device(&vpe_device);
 498         class_unregister(&vpe_class);
 499
 500 out_chrdev:
 501         unregister_chrdev(major, VPE_MODULE_NAME);
 502
 503         return err;
 504 }
 505
 506 void __exit vpe_module_exit(void)
 507 {
 508         struct vpe *v, *n;
 509
 510         device_unregister(&vpe_device);
 511         class_unregister(&vpe_class);
 512         unregister_chrdev(major, VPE_MODULE_NAME);
 513
 514         /* No locking needed here */
 515         list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
 516                 if (v->state != VPE_STATE_UNUSED)
 517                         release_vpe(v);
 518         }
 519 }