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          * The sde-kit passes 'memsize' to __start in $a3, so set something
  96          * here...  Or set $a3 to zero and define DFLT_STACK_SIZE and
  97          * DFLT_HEAP_SIZE when you compile your program
  98          */
  99         mttgpr(6, v->ntcs);
 100         mttgpr(7, physical_memsize);
 101
 102         /* set up VPE1 */
 103         /*
 104          * bind the TC to VPE 1 as late as possible so we only have the final
 105          * VPE registers to set up, and so an EJTAG probe can trigger on it
 106          */
 107         write_tc_c0_tcbind((read_tc_c0_tcbind() & ~TCBIND_CURVPE) | 1);
 108
 109         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~(VPECONF0_VPA));
 110
 111         back_to_back_c0_hazard();
 112
 113         /* Set up the XTC bit in vpeconf0 to point at our tc */
 114         write_vpe_c0_vpeconf0((read_vpe_c0_vpeconf0() & ~(VPECONF0_XTC))
 115                               | (t->index << VPECONF0_XTC_SHIFT));
 116
 117         back_to_back_c0_hazard();
 118
 119         /* enable this VPE */
 120         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() | VPECONF0_VPA);
 121
 122         /* clear out any left overs from a previous program */
 123         write_vpe_c0_status(0);
 124         write_vpe_c0_cause(0);
 125
 126         /* take system out of configuration state */
 127         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 128
 129         /*
 130          * SMVP kernels manage VPE enable independently, but uniprocessor
 131          * kernels need to turn it on, even if that wasn't the pre-dvpe() state.
 132          */
 133 #ifdef CONFIG_SMP
 134         evpe(vpeflags);
 135 #else
 136         evpe(EVPE_ENABLE);
 137 #endif
 138         emt(dmt_flag);
 139         local_irq_restore(flags);
 140
 141         list_for_each_entry(notifier, &v->notify, list)
 142                 notifier->start(VPE_MODULE_MINOR);
 143
 144         return 0;
 145 }
 146
 147 void cleanup_tc(struct tc *tc)
 148 {
 149         unsigned long flags;
 150         unsigned int mtflags, vpflags;
 151         int tmp;
 152
 153         local_irq_save(flags);
 154         mtflags = dmt();
 155         vpflags = dvpe();
 156         /* Put MVPE's into 'configuration state' */
 157         set_c0_mvpcontrol(MVPCONTROL_VPC);
 158
 159         settc(tc->index);
 160         tmp = read_tc_c0_tcstatus();
 161
 162         /* mark not allocated and not dynamically allocatable */
 163         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 164         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 165         write_tc_c0_tcstatus(tmp);
 166
 167         write_tc_c0_tchalt(TCHALT_H);
 168         mips_ihb();
 169
 170         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 171         evpe(vpflags);
 172         emt(mtflags);
 173         local_irq_restore(flags);
 174 }
 175
 176 /* module wrapper entry points */
 177 /* give me a vpe */
 178 void *vpe_alloc(void)
 179 {
 180         int i;
 181         struct vpe *v;
 182
 183         /* find a vpe */
 184         for (i = 1; i < MAX_VPES; i++) {
 185                 v = get_vpe(i);
 186                 if (v != NULL) {
 187                         v->state = VPE_STATE_INUSE;
 188                         return v;
 189                 }
 190         }
 191         return NULL;
 192 }
 193 EXPORT_SYMBOL(vpe_alloc);
 194
 195 /* start running from here */
 196 int vpe_start(void *vpe, unsigned long start)
 197 {
 198         struct vpe *v = vpe;
 199
 200         v->__start = start;
 201         return vpe_run(v);
 202 }
 203 EXPORT_SYMBOL(vpe_start);
 204
 205 /* halt it for now */
 206 int vpe_stop(void *vpe)
 207 {
 208         struct vpe *v = vpe;
 209         struct tc *t;
 210         unsigned int evpe_flags;
 211
 212         evpe_flags = dvpe();
 213
 214         t = list_entry(v->tc.next, struct tc, tc);
 215         if (t != NULL) {
 216                 settc(t->index);
 217                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 218         }
 219
 220         evpe(evpe_flags);
 221
 222         return 0;
 223 }
 224 EXPORT_SYMBOL(vpe_stop);
 225
 226 /* I've done with it thank you */
 227 int vpe_free(void *vpe)
 228 {
 229         struct vpe *v = vpe;
 230         struct tc *t;
 231         unsigned int evpe_flags;
 232
 233         t = list_entry(v->tc.next, struct tc, tc);
 234         if (t == NULL)
 235                 return -ENOEXEC;
 236
 237         evpe_flags = dvpe();
 238
 239         /* Put MVPE's into 'configuration state' */
 240         set_c0_mvpcontrol(MVPCONTROL_VPC);
 241
 242         settc(t->index);
 243         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 244
 245         /* halt the TC */
 246         write_tc_c0_tchalt(TCHALT_H);
 247         mips_ihb();
 248
 249         /* mark the TC unallocated */
 250         write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
 251
 252         v->state = VPE_STATE_UNUSED;
 253
 254         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 255         evpe(evpe_flags);
 256
 257         return 0;
 258 }
 259 EXPORT_SYMBOL(vpe_free);
 260
 261 static ssize_t store_kill(struct device *dev, struct device_attribute *attr,
 262                           const char *buf, size_t len)
 263 {
 264         struct vpe *vpe = get_vpe(aprp_cpu_index());
 265         struct vpe_notifications *notifier;
 266
 267         list_for_each_entry(notifier, &vpe->notify, list)
 268                 notifier->stop(aprp_cpu_index());
 269
 270         release_progmem(vpe->load_addr);
 271         cleanup_tc(get_tc(aprp_cpu_index()));
 272         vpe_stop(vpe);
 273         vpe_free(vpe);
 274
 275         return len;
 276 }
 277 static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
 278
 279 static ssize_t ntcs_show(struct device *cd, struct device_attribute *attr,
 280                          char *buf)
 281 {
 282         struct vpe *vpe = get_vpe(aprp_cpu_index());
 283
 284         return sprintf(buf, "%d\n", vpe->ntcs);
 285 }
 286
 287 static ssize_t ntcs_store(struct device *dev, struct device_attribute *attr,
 288                           const char *buf, size_t len)
 289 {
 290         struct vpe *vpe = get_vpe(aprp_cpu_index());
 291         unsigned long new;
 292         int ret;
 293
 294         ret = kstrtoul(buf, 0, &new);
 295         if (ret < 0)
 296                 return ret;
 297
 298         if (new == 0 || new > (hw_tcs - aprp_cpu_index()))
 299                 return -EINVAL;
 300
 301         vpe->ntcs = new;
 302
 303         return len;
 304 }
 305 static DEVICE_ATTR_RW(ntcs);
 306
 307 static struct attribute *vpe_attrs[] = {
 308         &dev_attr_kill.attr,
 309         &dev_attr_ntcs.attr,
 310         NULL,
 311 };
 312 ATTRIBUTE_GROUPS(vpe);
 313
 314 static void vpe_device_release(struct device *cd)
 315 {
 316         kfree(cd);
 317 }
 318
 319 static struct class vpe_class = {
 320         .name = "vpe",
 321         .owner = THIS_MODULE,
 322         .dev_release = vpe_device_release,
 323         .dev_groups = vpe_groups,
 324 };
 325
 326 static struct device vpe_device;
 327
 328 int __init vpe_module_init(void)
 329 {
 330         unsigned int mtflags, vpflags;
 331         unsigned long flags, val;
 332         struct vpe *v = NULL;
 333         struct tc *t;
 334         int tc, err;
 335
 336         if (!cpu_has_mipsmt) {
 337                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
 338                 return -ENODEV;
 339         }
 340
 341         if (vpelimit == 0) {
 342                 pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
 343                         "Pass maxvpes=<n> argument as kernel argument\n");
 344
 345                 return -ENODEV;
 346         }
 347
 348         if (aprp_cpu_index() == 0) {
 349                 pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
 350                         "Pass maxtcs=<n> argument as kernel argument\n");
 351
 352                 return -ENODEV;
 353         }
 354
 355         major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
 356         if (major < 0) {
 357                 pr_warn("VPE loader: unable to register character device\n");
 358                 return major;
 359         }
 360
 361         err = class_register(&vpe_class);
 362         if (err) {
 363                 pr_err("vpe_class registration failed\n");
 364                 goto out_chrdev;
 365         }
 366
 367         device_initialize(&vpe_device);
 368         vpe_device.class        = &vpe_class,
 369         vpe_device.parent       = NULL,
 370         dev_set_name(&vpe_device, "vpe1");
 371         vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
 372         err = device_add(&vpe_device);
 373         if (err) {
 374                 pr_err("Adding vpe_device failed\n");
 375                 goto out_class;
 376         }
 377
 378         local_irq_save(flags);
 379         mtflags = dmt();
 380         vpflags = dvpe();
 381
 382         /* Put MVPE's into 'configuration state' */
 383         set_c0_mvpcontrol(MVPCONTROL_VPC);
 384
 385         val = read_c0_mvpconf0();
 386         hw_tcs = (val & MVPCONF0_PTC) + 1;
 387         hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 388
 389         for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
 390                 /*
 391                  * Must re-enable multithreading temporarily or in case we
 392                  * reschedule send IPIs or similar we might hang.
 393                  */
 394                 clear_c0_mvpcontrol(MVPCONTROL_VPC);
 395                 evpe(vpflags);
 396                 emt(mtflags);
 397                 local_irq_restore(flags);
 398                 t = alloc_tc(tc);
 399                 if (!t) {
 400                         err = -ENOMEM;
 401                         goto out_dev;
 402                 }
 403
 404                 local_irq_save(flags);
 405                 mtflags = dmt();
 406                 vpflags = dvpe();
 407                 set_c0_mvpcontrol(MVPCONTROL_VPC);
 408
 409                 /* VPE's */
 410                 if (tc < hw_tcs) {
 411                         settc(tc);
 412
 413                         v = alloc_vpe(tc);
 414                         if (v == NULL) {
 415                                 pr_warn("VPE: unable to allocate VPE\n");
 416                                 goto out_reenable;
 417                         }
 418
 419                         v->ntcs = hw_tcs - aprp_cpu_index();
 420
 421                         /* add the tc to the list of this vpe's tc's. */
 422                         list_add(&t->tc, &v->tc);
 423
 424                         /* deactivate all but vpe0 */
 425                         if (tc >= aprp_cpu_index()) {
 426                                 unsigned long tmp = read_vpe_c0_vpeconf0();
 427
 428                                 tmp &= ~VPECONF0_VPA;
 429
 430                                 /* master VPE */
 431                                 tmp |= VPECONF0_MVP;
 432                                 write_vpe_c0_vpeconf0(tmp);
 433                         }
 434
 435                         /* disable multi-threading with TC's */
 436                         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
 437                                                 ~VPECONTROL_TE);
 438
 439                         if (tc >= vpelimit) {
 440                                 /*
 441                                  * Set config to be the same as vpe0,
 442                                  * particularly kseg0 coherency alg
 443                                  */
 444                                 write_vpe_c0_config(read_c0_config());
 445                         }
 446                 }
 447
 448                 /* TC's */
 449                 t->pvpe = v;    /* set the parent vpe */
 450
 451                 if (tc >= aprp_cpu_index()) {
 452                         unsigned long tmp;
 453
 454                         settc(tc);
 455
 456                         /*
 457                          * A TC that is bound to any other VPE gets bound to
 458                          * VPE0, ideally I'd like to make it homeless but it
 459                          * doesn't appear to let me bind a TC to a non-existent
 460                          * VPE. Which is perfectly reasonable.
 461                          *
 462                          * The (un)bound state is visible to an EJTAG probe so
 463                          * may notify GDB...
 464                          */
 465                         tmp = read_tc_c0_tcbind();
 466                         if (tmp & TCBIND_CURVPE) {
 467                                 /* tc is bound >vpe0 */
 468                                 write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
 469
 470                                 t->pvpe = get_vpe(0);   /* set the parent vpe */
 471                         }
 472
 473                         /* halt the TC */
 474                         write_tc_c0_tchalt(TCHALT_H);
 475                         mips_ihb();
 476
 477                         tmp = read_tc_c0_tcstatus();
 478
 479                         /* mark not activated and not dynamically allocatable */
 480                         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 481                         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 482                         write_tc_c0_tcstatus(tmp);
 483                 }
 484         }
 485
 486 out_reenable:
 487         /* release config state */
 488         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 489
 490         evpe(vpflags);
 491         emt(mtflags);
 492         local_irq_restore(flags);
 493
 494         return 0;
 495
 496 out_dev:
 497         device_del(&vpe_device);
 498
 499 out_class:
 500         class_unregister(&vpe_class);
 501
 502 out_chrdev:
 503         unregister_chrdev(major, VPE_MODULE_NAME);
 504
 505         return err;
 506 }
 507
 508 void __exit vpe_module_exit(void)
 509 {
 510         struct vpe *v, *n;
 511
 512         device_del(&vpe_device);
 513         class_unregister(&vpe_class);
 514         unregister_chrdev(major, VPE_MODULE_NAME);
 515
 516         /* No locking needed here */
 517         list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
 518                 if (v->state != VPE_STATE_UNUSED)
 519                         release_vpe(v);
 520         }
 521 }