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          * SMTC/SMVP kernels manage VPE enable independently,
 131          * but uniprocessor kernels need to turn it on, even
 132          * if that wasn't the pre-dvpe() state.
 133          */
 134 #ifdef CONFIG_SMP
 135         evpe(vpeflags);
 136 #else
 137         evpe(EVPE_ENABLE);
 138 #endif
 139         emt(dmt_flag);
 140         local_irq_restore(flags);
 141
 142         list_for_each_entry(notifier, &v->notify, list)
 143                 notifier->start(VPE_MODULE_MINOR);
 144
 145         return 0;
 146 }
 147
 148 void cleanup_tc(struct tc *tc)
 149 {
 150         unsigned long flags;
 151         unsigned int mtflags, vpflags;
 152         int tmp;
 153
 154         local_irq_save(flags);
 155         mtflags = dmt();
 156         vpflags = dvpe();
 157         /* Put MVPE's into 'configuration state' */
 158         set_c0_mvpcontrol(MVPCONTROL_VPC);
 159
 160         settc(tc->index);
 161         tmp = read_tc_c0_tcstatus();
 162
 163         /* mark not allocated and not dynamically allocatable */
 164         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 165         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 166         write_tc_c0_tcstatus(tmp);
 167
 168         write_tc_c0_tchalt(TCHALT_H);
 169         mips_ihb();
 170
 171         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 172         evpe(vpflags);
 173         emt(mtflags);
 174         local_irq_restore(flags);
 175 }
 176
 177 /* module wrapper entry points */
 178 /* give me a vpe */
 179 void *vpe_alloc(void)
 180 {
 181         int i;
 182         struct vpe *v;
 183
 184         /* find a vpe */
 185         for (i = 1; i < MAX_VPES; i++) {
 186                 v = get_vpe(i);
 187                 if (v != NULL) {
 188                         v->state = VPE_STATE_INUSE;
 189                         return v;
 190                 }
 191         }
 192         return NULL;
 193 }
 194 EXPORT_SYMBOL(vpe_alloc);
 195
 196 /* start running from here */
 197 int vpe_start(void *vpe, unsigned long start)
 198 {
 199         struct vpe *v = vpe;
 200
 201         v->__start = start;
 202         return vpe_run(v);
 203 }
 204 EXPORT_SYMBOL(vpe_start);
 205
 206 /* halt it for now */
 207 int vpe_stop(void *vpe)
 208 {
 209         struct vpe *v = vpe;
 210         struct tc *t;
 211         unsigned int evpe_flags;
 212
 213         evpe_flags = dvpe();
 214
 215         t = list_entry(v->tc.next, struct tc, tc);
 216         if (t != NULL) {
 217                 settc(t->index);
 218                 write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 219         }
 220
 221         evpe(evpe_flags);
 222
 223         return 0;
 224 }
 225 EXPORT_SYMBOL(vpe_stop);
 226
 227 /* I've done with it thank you */
 228 int vpe_free(void *vpe)
 229 {
 230         struct vpe *v = vpe;
 231         struct tc *t;
 232         unsigned int evpe_flags;
 233
 234         t = list_entry(v->tc.next, struct tc, tc);
 235         if (t == NULL)
 236                 return -ENOEXEC;
 237
 238         evpe_flags = dvpe();
 239
 240         /* Put MVPE's into 'configuration state' */
 241         set_c0_mvpcontrol(MVPCONTROL_VPC);
 242
 243         settc(t->index);
 244         write_vpe_c0_vpeconf0(read_vpe_c0_vpeconf0() & ~VPECONF0_VPA);
 245
 246         /* halt the TC */
 247         write_tc_c0_tchalt(TCHALT_H);
 248         mips_ihb();
 249
 250         /* mark the TC unallocated */
 251         write_tc_c0_tcstatus(read_tc_c0_tcstatus() & ~TCSTATUS_A);
 252
 253         v->state = VPE_STATE_UNUSED;
 254
 255         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 256         evpe(evpe_flags);
 257
 258         return 0;
 259 }
 260 EXPORT_SYMBOL(vpe_free);
 261
 262 static ssize_t store_kill(struct device *dev, struct device_attribute *attr,
 263                           const char *buf, size_t len)
 264 {
 265         struct vpe *vpe = get_vpe(aprp_cpu_index());
 266         struct vpe_notifications *notifier;
 267
 268         list_for_each_entry(notifier, &vpe->notify, list)
 269                 notifier->stop(aprp_cpu_index());
 270
 271         release_progmem(vpe->load_addr);
 272         cleanup_tc(get_tc(aprp_cpu_index()));
 273         vpe_stop(vpe);
 274         vpe_free(vpe);
 275
 276         return len;
 277 }
 278 static DEVICE_ATTR(kill, S_IWUSR, NULL, store_kill);
 279
 280 static ssize_t ntcs_show(struct device *cd, struct device_attribute *attr,
 281                          char *buf)
 282 {
 283         struct vpe *vpe = get_vpe(aprp_cpu_index());
 284
 285         return sprintf(buf, "%d\n", vpe->ntcs);
 286 }
 287
 288 static ssize_t ntcs_store(struct device *dev, struct device_attribute *attr,
 289                           const char *buf, size_t len)
 290 {
 291         struct vpe *vpe = get_vpe(aprp_cpu_index());
 292         unsigned long new;
 293         int ret;
 294
 295         ret = kstrtoul(buf, 0, &new);
 296         if (ret < 0)
 297                 return ret;
 298
 299         if (new == 0 || new > (hw_tcs - aprp_cpu_index()))
 300                 return -EINVAL;
 301
 302         vpe->ntcs = new;
 303
 304         return len;
 305 }
 306 static DEVICE_ATTR_RW(ntcs);
 307
 308 static struct attribute *vpe_attrs[] = {
 309         &dev_attr_kill.attr,
 310         &dev_attr_ntcs.attr,
 311         NULL,
 312 };
 313 ATTRIBUTE_GROUPS(vpe);
 314
 315 static void vpe_device_release(struct device *cd)
 316 {
 317         kfree(cd);
 318 }
 319
 320 static struct class vpe_class = {
 321         .name = "vpe",
 322         .owner = THIS_MODULE,
 323         .dev_release = vpe_device_release,
 324         .dev_groups = vpe_groups,
 325 };
 326
 327 static struct device vpe_device;
 328
 329 int __init vpe_module_init(void)
 330 {
 331         unsigned int mtflags, vpflags;
 332         unsigned long flags, val;
 333         struct vpe *v = NULL;
 334         struct tc *t;
 335         int tc, err;
 336
 337         if (!cpu_has_mipsmt) {
 338                 pr_warn("VPE loader: not a MIPS MT capable processor\n");
 339                 return -ENODEV;
 340         }
 341
 342         if (vpelimit == 0) {
 343                 pr_warn("No VPEs reserved for AP/SP, not initialize VPE loader\n"
 344                         "Pass maxvpes=<n> argument as kernel argument\n");
 345
 346                 return -ENODEV;
 347         }
 348
 349         if (aprp_cpu_index() == 0) {
 350                 pr_warn("No TCs reserved for AP/SP, not initialize VPE loader\n"
 351                         "Pass maxtcs=<n> argument as kernel argument\n");
 352
 353                 return -ENODEV;
 354         }
 355
 356         major = register_chrdev(0, VPE_MODULE_NAME, &vpe_fops);
 357         if (major < 0) {
 358                 pr_warn("VPE loader: unable to register character device\n");
 359                 return major;
 360         }
 361
 362         err = class_register(&vpe_class);
 363         if (err) {
 364                 pr_err("vpe_class registration failed\n");
 365                 goto out_chrdev;
 366         }
 367
 368         device_initialize(&vpe_device);
 369         vpe_device.class        = &vpe_class,
 370         vpe_device.parent       = NULL,
 371         dev_set_name(&vpe_device, "vpe1");
 372         vpe_device.devt = MKDEV(major, VPE_MODULE_MINOR);
 373         err = device_add(&vpe_device);
 374         if (err) {
 375                 pr_err("Adding vpe_device failed\n");
 376                 goto out_class;
 377         }
 378
 379         local_irq_save(flags);
 380         mtflags = dmt();
 381         vpflags = dvpe();
 382
 383         /* Put MVPE's into 'configuration state' */
 384         set_c0_mvpcontrol(MVPCONTROL_VPC);
 385
 386         val = read_c0_mvpconf0();
 387         hw_tcs = (val & MVPCONF0_PTC) + 1;
 388         hw_vpes = ((val & MVPCONF0_PVPE) >> MVPCONF0_PVPE_SHIFT) + 1;
 389
 390         for (tc = aprp_cpu_index(); tc < hw_tcs; tc++) {
 391                 /*
 392                  * Must re-enable multithreading temporarily or in case we
 393                  * reschedule send IPIs or similar we might hang.
 394                  */
 395                 clear_c0_mvpcontrol(MVPCONTROL_VPC);
 396                 evpe(vpflags);
 397                 emt(mtflags);
 398                 local_irq_restore(flags);
 399                 t = alloc_tc(tc);
 400                 if (!t) {
 401                         err = -ENOMEM;
 402                         goto out_dev;
 403                 }
 404
 405                 local_irq_save(flags);
 406                 mtflags = dmt();
 407                 vpflags = dvpe();
 408                 set_c0_mvpcontrol(MVPCONTROL_VPC);
 409
 410                 /* VPE's */
 411                 if (tc < hw_tcs) {
 412                         settc(tc);
 413
 414                         v = alloc_vpe(tc);
 415                         if (v == NULL) {
 416                                 pr_warn("VPE: unable to allocate VPE\n");
 417                                 goto out_reenable;
 418                         }
 419
 420                         v->ntcs = hw_tcs - aprp_cpu_index();
 421
 422                         /* add the tc to the list of this vpe's tc's. */
 423                         list_add(&t->tc, &v->tc);
 424
 425                         /* deactivate all but vpe0 */
 426                         if (tc >= aprp_cpu_index()) {
 427                                 unsigned long tmp = read_vpe_c0_vpeconf0();
 428
 429                                 tmp &= ~VPECONF0_VPA;
 430
 431                                 /* master VPE */
 432                                 tmp |= VPECONF0_MVP;
 433                                 write_vpe_c0_vpeconf0(tmp);
 434                         }
 435
 436                         /* disable multi-threading with TC's */
 437                         write_vpe_c0_vpecontrol(read_vpe_c0_vpecontrol() &
 438                                                 ~VPECONTROL_TE);
 439
 440                         if (tc >= vpelimit) {
 441                                 /*
 442                                  * Set config to be the same as vpe0,
 443                                  * particularly kseg0 coherency alg
 444                                  */
 445                                 write_vpe_c0_config(read_c0_config());
 446                         }
 447                 }
 448
 449                 /* TC's */
 450                 t->pvpe = v;    /* set the parent vpe */
 451
 452                 if (tc >= aprp_cpu_index()) {
 453                         unsigned long tmp;
 454
 455                         settc(tc);
 456
 457                         /* Any TC that is bound to VPE0 gets left as is - in
 458                          * case we are running SMTC on VPE0. A TC that is bound
 459                          * to any other VPE gets bound to VPE0, ideally I'd like
 460                          * to make it homeless but it doesn't appear to let me
 461                          * bind a TC to a non-existent VPE. Which is perfectly
 462                          * reasonable.
 463                          *
 464                          * The (un)bound state is visible to an EJTAG probe so
 465                          * may notify GDB...
 466                          */
 467                         tmp = read_tc_c0_tcbind();
 468                         if (tmp & TCBIND_CURVPE) {
 469                                 /* tc is bound >vpe0 */
 470                                 write_tc_c0_tcbind(tmp & ~TCBIND_CURVPE);
 471
 472                                 t->pvpe = get_vpe(0);   /* set the parent vpe */
 473                         }
 474
 475                         /* halt the TC */
 476                         write_tc_c0_tchalt(TCHALT_H);
 477                         mips_ihb();
 478
 479                         tmp = read_tc_c0_tcstatus();
 480
 481                         /* mark not activated and not dynamically allocatable */
 482                         tmp &= ~(TCSTATUS_A | TCSTATUS_DA);
 483                         tmp |= TCSTATUS_IXMT;   /* interrupt exempt */
 484                         write_tc_c0_tcstatus(tmp);
 485                 }
 486         }
 487
 488 out_reenable:
 489         /* release config state */
 490         clear_c0_mvpcontrol(MVPCONTROL_VPC);
 491
 492         evpe(vpflags);
 493         emt(mtflags);
 494         local_irq_restore(flags);
 495
 496         return 0;
 497
 498 out_dev:
 499         device_del(&vpe_device);
 500
 501 out_class:
 502         class_unregister(&vpe_class);
 503
 504 out_chrdev:
 505         unregister_chrdev(major, VPE_MODULE_NAME);
 506
 507         return err;
 508 }
 509
 510 void __exit vpe_module_exit(void)
 511 {
 512         struct vpe *v, *n;
 513
 514         device_del(&vpe_device);
 515         class_unregister(&vpe_class);
 516         unregister_chrdev(major, VPE_MODULE_NAME);
 517
 518         /* No locking needed here */
 519         list_for_each_entry_safe(v, n, &vpecontrol.vpe_list, list) {
 520                 if (v->state != VPE_STATE_UNUSED)
 521                         release_vpe(v);
 522         }
 523 }