arch/mips/kernel/smp-bmips.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) 2011 by Kevin Cernekee (cernekee@gmail.com)
   7  *
   8  * SMP support for BMIPS
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/sched.h>
  13 #include <linux/sched/hotplug.h>
  14 #include <linux/sched/task_stack.h>
  15 #include <linux/mm.h>
  16 #include <linux/delay.h>
  17 #include <linux/smp.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/spinlock.h>
  20 #include <linux/cpu.h>
  21 #include <linux/cpumask.h>
  22 #include <linux/reboot.h>
  23 #include <linux/io.h>
  24 #include <linux/compiler.h>
  25 #include <linux/linkage.h>
  26 #include <linux/bug.h>
  27 #include <linux/kernel.h>
  28 #include <linux/kexec.h>
  29
  30 #include <asm/time.h>
  31 #include <asm/pgtable.h>
  32 #include <asm/processor.h>
  33 #include <asm/bootinfo.h>
  34 #include <asm/pmon.h>
  35 #include <asm/cacheflush.h>
  36 #include <asm/tlbflush.h>
  37 #include <asm/mipsregs.h>
  38 #include <asm/bmips.h>
  39 #include <asm/traps.h>
  40 #include <asm/barrier.h>
  41 #include <asm/cpu-features.h>
  42
  43 static int __maybe_unused max_cpus = 1;
  44
  45 /* these may be configured by the platform code */
  46 int bmips_smp_enabled = 1;
  47 int bmips_cpu_offset;
  48 cpumask_t bmips_booted_mask;
  49 unsigned long bmips_tp1_irqs = IE_IRQ1;
  50
  51 #define RESET_FROM_KSEG0                0x80080800
  52 #define RESET_FROM_KSEG1                0xa0080800
  53
  54 static void bmips_set_reset_vec(int cpu, u32 val);
  55
  56 #ifdef CONFIG_SMP
  57
  58 /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
  59 unsigned long bmips_smp_boot_sp;
  60 unsigned long bmips_smp_boot_gp;
  61
  62 static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
  63 static void bmips5000_send_ipi_single(int cpu, unsigned int action);
  64 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
  65 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);
  66
  67 /* SW interrupts 0,1 are used for interprocessor signaling */
  68 #define IPI0_IRQ                        (MIPS_CPU_IRQ_BASE + 0)
  69 #define IPI1_IRQ                        (MIPS_CPU_IRQ_BASE + 1)
  70
  71 #define CPUNUM(cpu, shift)              (((cpu) + bmips_cpu_offset) << (shift))
  72 #define ACTION_CLR_IPI(cpu, ipi)        (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
  73 #define ACTION_SET_IPI(cpu, ipi)        (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
  74 #define ACTION_BOOT_THREAD(cpu)         (0x08 | CPUNUM(cpu, 0))
  75
  76 static void __init bmips_smp_setup(void)
  77 {
  78         int i, cpu = 1, boot_cpu = 0;
  79         int cpu_hw_intr;
  80
  81         switch (current_cpu_type()) {
  82         case CPU_BMIPS4350:
  83         case CPU_BMIPS4380:
  84                 /* arbitration priority */
  85                 clear_c0_brcm_cmt_ctrl(0x30);
  86
  87                 /* NBK and weak order flags */
  88                 set_c0_brcm_config_0(0x30000);
  89
  90                 /* Find out if we are running on TP0 or TP1 */
  91                 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
  92
  93                 /*
  94                  * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
  95                  * thread
  96                  * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
  97                  * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
  98                  */
  99                 if (boot_cpu == 0)
 100                         cpu_hw_intr = 0x02;
 101                 else
 102                         cpu_hw_intr = 0x1d;
 103
 104                 change_c0_brcm_cmt_intr(0xf8018000,
 105                                         (cpu_hw_intr << 27) | (0x03 << 15));
 106
 107                 /* single core, 2 threads (2 pipelines) */
 108                 max_cpus = 2;
 109
 110                 break;
 111         case CPU_BMIPS5000:
 112                 /* enable raceless SW interrupts */
 113                 set_c0_brcm_config(0x03 << 22);
 114
 115                 /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
 116                 change_c0_brcm_mode(0x1f << 27, 0x02 << 27);
 117
 118                 /* N cores, 2 threads per core */
 119                 max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;
 120
 121                 /* clear any pending SW interrupts */
 122                 for (i = 0; i < max_cpus; i++) {
 123                         write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
 124                         write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
 125                 }
 126
 127                 break;
 128         default:
 129                 max_cpus = 1;
 130         }
 131
 132         if (!bmips_smp_enabled)
 133                 max_cpus = 1;
 134
 135         /* this can be overridden by the BSP */
 136         if (!board_ebase_setup)
 137                 board_ebase_setup = &bmips_ebase_setup;
 138
 139         __cpu_number_map[boot_cpu] = 0;
 140         __cpu_logical_map[0] = boot_cpu;
 141
 142         for (i = 0; i < max_cpus; i++) {
 143                 if (i != boot_cpu) {
 144                         __cpu_number_map[i] = cpu;
 145                         __cpu_logical_map[cpu] = i;
 146                         cpu++;
 147                 }
 148                 set_cpu_possible(i, 1);
 149                 set_cpu_present(i, 1);
 150         }
 151 }
 152
 153 /*
 154  * IPI IRQ setup - runs on CPU0
 155  */
 156 static void bmips_prepare_cpus(unsigned int max_cpus)
 157 {
 158         irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);
 159
 160         switch (current_cpu_type()) {
 161         case CPU_BMIPS4350:
 162         case CPU_BMIPS4380:
 163                 bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
 164                 break;
 165         case CPU_BMIPS5000:
 166                 bmips_ipi_interrupt = bmips5000_ipi_interrupt;
 167                 break;
 168         default:
 169                 return;
 170         }
 171
 172         if (request_irq(IPI0_IRQ, bmips_ipi_interrupt,
 173                         IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi0", NULL))
 174                 panic("Can't request IPI0 interrupt");
 175         if (request_irq(IPI1_IRQ, bmips_ipi_interrupt,
 176                         IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi1", NULL))
 177                 panic("Can't request IPI1 interrupt");
 178 }
 179
 180 /*
 181  * Tell the hardware to boot CPUx - runs on CPU0
 182  */
 183 static int bmips_boot_secondary(int cpu, struct task_struct *idle)
 184 {
 185         bmips_smp_boot_sp = __KSTK_TOS(idle);
 186         bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
 187         mb();
 188
 189         /*
 190          * Initial boot sequence for secondary CPU:
 191          *   bmips_reset_nmi_vec @ a000_0000 ->
 192          *   bmips_smp_entry ->
 193          *   plat_wired_tlb_setup (cached function call; optional) ->
 194          *   start_secondary (cached jump)
 195          *
 196          * Warm restart sequence:
 197          *   play_dead WAIT loop ->
 198          *   bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
 199          *   eret to play_dead ->
 200          *   bmips_secondary_reentry ->
 201          *   start_secondary
 202          */
 203
 204         pr_info("SMP: Booting CPU%d...\n", cpu);
 205
 206         if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
 207                 /* kseg1 might not exist if this CPU enabled XKS01 */
 208                 bmips_set_reset_vec(cpu, RESET_FROM_KSEG0);
 209
 210                 switch (current_cpu_type()) {
 211                 case CPU_BMIPS4350:
 212                 case CPU_BMIPS4380:
 213                         bmips43xx_send_ipi_single(cpu, 0);
 214                         break;
 215                 case CPU_BMIPS5000:
 216                         bmips5000_send_ipi_single(cpu, 0);
 217                         break;
 218                 }
 219         } else {
 220                 bmips_set_reset_vec(cpu, RESET_FROM_KSEG1);
 221
 222                 switch (current_cpu_type()) {
 223                 case CPU_BMIPS4350:
 224                 case CPU_BMIPS4380:
 225                         /* Reset slave TP1 if booting from TP0 */
 226                         if (cpu_logical_map(cpu) == 1)
 227                                 set_c0_brcm_cmt_ctrl(0x01);
 228                         break;
 229                 case CPU_BMIPS5000:
 230                         write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
 231                         break;
 232                 }
 233                 cpumask_set_cpu(cpu, &bmips_booted_mask);
 234         }
 235
 236         return 0;
 237 }
 238
 239 /*
 240  * Early setup - runs on secondary CPU after cache probe
 241  */
 242 static void bmips_init_secondary(void)
 243 {
 244         switch (current_cpu_type()) {
 245         case CPU_BMIPS4350:
 246         case CPU_BMIPS4380:
 247                 clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0);
 248                 break;
 249         case CPU_BMIPS5000:
 250                 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0));
 251                 cpu_set_core(&current_cpu_data, (read_c0_brcm_config() >> 25) & 3);
 252                 break;
 253         }
 254 }
 255
 256 /*
 257  * Late setup - runs on secondary CPU before entering the idle loop
 258  */
 259 static void bmips_smp_finish(void)
 260 {
 261         pr_info("SMP: CPU%d is running\n", smp_processor_id());
 262
 263         /* make sure there won't be a timer interrupt for a little while */
 264         write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
 265
 266         irq_enable_hazard();
 267         set_c0_status(IE_SW0 | IE_SW1 | bmips_tp1_irqs | IE_IRQ5 | ST0_IE);
 268         irq_enable_hazard();
 269 }
 270
 271 /*
 272  * BMIPS5000 raceless IPIs
 273  *
 274  * Each CPU has two inbound SW IRQs which are independent of all other CPUs.
 275  * IPI0 is used for SMP_RESCHEDULE_YOURSELF
 276  * IPI1 is used for SMP_CALL_FUNCTION
 277  */
 278
 279 static void bmips5000_send_ipi_single(int cpu, unsigned int action)
 280 {
 281         write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION));
 282 }
 283
 284 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id)
 285 {
 286         int action = irq - IPI0_IRQ;
 287
 288         write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action));
 289
 290         if (action == 0)
 291                 scheduler_ipi();
 292         else
 293                 generic_smp_call_function_interrupt();
 294
 295         return IRQ_HANDLED;
 296 }
 297
 298 static void bmips5000_send_ipi_mask(const struct cpumask *mask,
 299         unsigned int action)
 300 {
 301         unsigned int i;
 302
 303         for_each_cpu(i, mask)
 304                 bmips5000_send_ipi_single(i, action);
 305 }
 306
 307 /*
 308  * BMIPS43xx racey IPIs
 309  *
 310  * We use one inbound SW IRQ for each CPU.
 311  *
 312  * A spinlock must be held in order to keep CPUx from accidentally clearing
 313  * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy.  The
 314  * same spinlock is used to protect the action masks.
 315  */
 316
 317 static DEFINE_SPINLOCK(ipi_lock);
 318 static DEFINE_PER_CPU(int, ipi_action_mask);
 319
 320 static void bmips43xx_send_ipi_single(int cpu, unsigned int action)
 321 {
 322         unsigned long flags;
 323
 324         spin_lock_irqsave(&ipi_lock, flags);
 325         set_c0_cause(cpu ? C_SW1 : C_SW0);
 326         per_cpu(ipi_action_mask, cpu) |= action;
 327         irq_enable_hazard();
 328         spin_unlock_irqrestore(&ipi_lock, flags);
 329 }
 330
 331 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id)
 332 {
 333         unsigned long flags;
 334         int action, cpu = irq - IPI0_IRQ;
 335
 336         spin_lock_irqsave(&ipi_lock, flags);
 337         action = __this_cpu_read(ipi_action_mask);
 338         per_cpu(ipi_action_mask, cpu) = 0;
 339         clear_c0_cause(cpu ? C_SW1 : C_SW0);
 340         spin_unlock_irqrestore(&ipi_lock, flags);
 341
 342         if (action & SMP_RESCHEDULE_YOURSELF)
 343                 scheduler_ipi();
 344         if (action & SMP_CALL_FUNCTION)
 345                 generic_smp_call_function_interrupt();
 346
 347         return IRQ_HANDLED;
 348 }
 349
 350 static void bmips43xx_send_ipi_mask(const struct cpumask *mask,
 351         unsigned int action)
 352 {
 353         unsigned int i;
 354
 355         for_each_cpu(i, mask)
 356                 bmips43xx_send_ipi_single(i, action);
 357 }
 358
 359 #ifdef CONFIG_HOTPLUG_CPU
 360
 361 static int bmips_cpu_disable(void)
 362 {
 363         unsigned int cpu = smp_processor_id();
 364
 365         if (cpu == 0)
 366                 return -EBUSY;
 367
 368         pr_info("SMP: CPU%d is offline\n", cpu);
 369
 370         set_cpu_online(cpu, false);
 371         calculate_cpu_foreign_map();
 372         irq_cpu_offline();
 373         clear_c0_status(IE_IRQ5);
 374
 375         local_flush_tlb_all();
 376         local_flush_icache_range(0, ~0);
 377
 378         return 0;
 379 }
 380
 381 static void bmips_cpu_die(unsigned int cpu)
 382 {
 383 }
 384
 385 void __ref play_dead(void)
 386 {
 387         idle_task_exit();
 388
 389         /* flush data cache */
 390         _dma_cache_wback_inv(0, ~0);
 391
 392         /*
 393          * Wakeup is on SW0 or SW1; disable everything else
 394          * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux
 395          * IRQ handlers; this clears ST0_IE and returns immediately.
 396          */
 397         clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
 398         change_c0_status(
 399                 IE_IRQ5 | bmips_tp1_irqs | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV,
 400                 IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV);
 401         irq_disable_hazard();
 402
 403         /*
 404          * wait for SW interrupt from bmips_boot_secondary(), then jump
 405          * back to start_secondary()
 406          */
 407         __asm__ __volatile__(
 408         "       wait\n"
 409         "       j       bmips_secondary_reentry\n"
 410         : : : "memory");
 411 }
 412
 413 #endif /* CONFIG_HOTPLUG_CPU */
 414
 415 const struct plat_smp_ops bmips43xx_smp_ops = {
 416         .smp_setup              = bmips_smp_setup,
 417         .prepare_cpus           = bmips_prepare_cpus,
 418         .boot_secondary         = bmips_boot_secondary,
 419         .smp_finish             = bmips_smp_finish,
 420         .init_secondary         = bmips_init_secondary,
 421         .send_ipi_single        = bmips43xx_send_ipi_single,
 422         .send_ipi_mask          = bmips43xx_send_ipi_mask,
 423 #ifdef CONFIG_HOTPLUG_CPU
 424         .cpu_disable            = bmips_cpu_disable,
 425         .cpu_die                = bmips_cpu_die,
 426 #endif
 427 #ifdef CONFIG_KEXEC
 428         .kexec_nonboot_cpu      = kexec_nonboot_cpu_jump,
 429 #endif
 430 };
 431
 432 const struct plat_smp_ops bmips5000_smp_ops = {
 433         .smp_setup              = bmips_smp_setup,
 434         .prepare_cpus           = bmips_prepare_cpus,
 435         .boot_secondary         = bmips_boot_secondary,
 436         .smp_finish             = bmips_smp_finish,
 437         .init_secondary         = bmips_init_secondary,
 438         .send_ipi_single        = bmips5000_send_ipi_single,
 439         .send_ipi_mask          = bmips5000_send_ipi_mask,
 440 #ifdef CONFIG_HOTPLUG_CPU
 441         .cpu_disable            = bmips_cpu_disable,
 442         .cpu_die                = bmips_cpu_die,
 443 #endif
 444 #ifdef CONFIG_KEXEC
 445         .kexec_nonboot_cpu      = kexec_nonboot_cpu_jump,
 446 #endif
 447 };
 448
 449 #endif /* CONFIG_SMP */
 450
 451 /***********************************************************************
 452  * BMIPS vector relocation
 453  * This is primarily used for SMP boot, but it is applicable to some
 454  * UP BMIPS systems as well.
 455  ***********************************************************************/
 456
 457 static void bmips_wr_vec(unsigned long dst, char *start, char *end)
 458 {
 459         memcpy((void *)dst, start, end - start);
 460         dma_cache_wback(dst, end - start);
 461         local_flush_icache_range(dst, dst + (end - start));
 462         instruction_hazard();
 463 }
 464
 465 static inline void bmips_nmi_handler_setup(void)
 466 {
 467         bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec,
 468                 &bmips_reset_nmi_vec_end);
 469         bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec,
 470                 &bmips_smp_int_vec_end);
 471 }
 472
 473 struct reset_vec_info {
 474         int cpu;
 475         u32 val;
 476 };
 477
 478 static void bmips_set_reset_vec_remote(void *vinfo)
 479 {
 480         struct reset_vec_info *info = vinfo;
 481         int shift = info->cpu & 0x01 ? 16 : 0;
 482         u32 mask = ~(0xffff << shift), val = info->val >> 16;
 483
 484         preempt_disable();
 485         if (smp_processor_id() > 0) {
 486                 smp_call_function_single(0, &bmips_set_reset_vec_remote,
 487                                          info, 1);
 488         } else {
 489                 if (info->cpu & 0x02) {
 490                         /* BMIPS5200 "should" use mask/shift, but it's buggy */
 491                         bmips_write_zscm_reg(0xa0, (val << 16) | val);
 492                         bmips_read_zscm_reg(0xa0);
 493                 } else {
 494                         write_c0_brcm_bootvec((read_c0_brcm_bootvec() & mask) |
 495                                               (val << shift));
 496                 }
 497         }
 498         preempt_enable();
 499 }
 500
 501 static void bmips_set_reset_vec(int cpu, u32 val)
 502 {
 503         struct reset_vec_info info;
 504
 505         if (current_cpu_type() == CPU_BMIPS5000) {
 506                 /* this needs to run from CPU0 (which is always online) */
 507                 info.cpu = cpu;
 508                 info.val = val;
 509                 bmips_set_reset_vec_remote(&info);
 510         } else {
 511                 void __iomem *cbr = BMIPS_GET_CBR();
 512
 513                 if (cpu == 0)
 514                         __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
 515                 else {
 516                         if (current_cpu_type() != CPU_BMIPS4380)
 517                                 return;
 518                         __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
 519                 }
 520         }
 521         __sync();
 522         back_to_back_c0_hazard();
 523 }
 524
 525 void bmips_ebase_setup(void)
 526 {
 527         unsigned long new_ebase = ebase;
 528
 529         BUG_ON(ebase != CKSEG0);
 530
 531         switch (current_cpu_type()) {
 532         case CPU_BMIPS4350:
 533                 /*
 534                  * BMIPS4350 cannot relocate the normal vectors, but it
 535                  * can relocate the BEV=1 vectors.  So CPU1 starts up at
 536                  * the relocated BEV=1, IV=0 general exception vector @
 537                  * 0xa000_0380.
 538                  *
 539                  * set_uncached_handler() is used here because:
 540                  *  - CPU1 will run this from uncached space
 541                  *  - None of the cacheflush functions are set up yet
 542                  */
 543                 set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0,
 544                         &bmips_smp_int_vec, 0x80);
 545                 __sync();
 546                 return;
 547         case CPU_BMIPS3300:
 548         case CPU_BMIPS4380:
 549                 /*
 550                  * 0x8000_0000: reset/NMI (initially in kseg1)
 551                  * 0x8000_0400: normal vectors
 552                  */
 553                 new_ebase = 0x80000400;
 554                 bmips_set_reset_vec(0, RESET_FROM_KSEG0);
 555                 break;
 556         case CPU_BMIPS5000:
 557                 /*
 558                  * 0x8000_0000: reset/NMI (initially in kseg1)
 559                  * 0x8000_1000: normal vectors
 560                  */
 561                 new_ebase = 0x80001000;
 562                 bmips_set_reset_vec(0, RESET_FROM_KSEG0);
 563                 write_c0_ebase(new_ebase);
 564                 break;
 565         default:
 566                 return;
 567         }
 568
 569         board_nmi_handler_setup = &bmips_nmi_handler_setup;
 570         ebase = new_ebase;
 571 }
 572
 573 asmlinkage void __weak plat_wired_tlb_setup(void)
 574 {
 575         /*
 576          * Called when starting/restarting a secondary CPU.
 577          * Kernel stacks and other important data might only be accessible
 578          * once the wired entries are present.
 579          */
 580 }
 581
 582 void bmips_cpu_setup(void)
 583 {
 584         void __iomem __maybe_unused *cbr = BMIPS_GET_CBR();
 585         u32 __maybe_unused cfg;
 586
 587         switch (current_cpu_type()) {
 588         case CPU_BMIPS3300:
 589                 /* Set BIU to async mode */
 590                 set_c0_brcm_bus_pll(BIT(22));
 591                 __sync();
 592
 593                 /* put the BIU back in sync mode */
 594                 clear_c0_brcm_bus_pll(BIT(22));
 595
 596                 /* clear BHTD to enable branch history table */
 597                 clear_c0_brcm_reset(BIT(16));
 598
 599                 /* Flush and enable RAC */
 600                 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
 601                 __raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG);
 602                 __raw_readl(cbr + BMIPS_RAC_CONFIG);
 603
 604                 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
 605                 __raw_writel(cfg | 0xf, cbr + BMIPS_RAC_CONFIG);
 606                 __raw_readl(cbr + BMIPS_RAC_CONFIG);
 607
 608                 cfg = __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
 609                 __raw_writel(cfg | 0x0fff0000, cbr + BMIPS_RAC_ADDRESS_RANGE);
 610                 __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
 611                 break;
 612
 613         case CPU_BMIPS4380:
 614                 /* CBG workaround for early BMIPS4380 CPUs */
 615                 switch (read_c0_prid()) {
 616                 case 0x2a040:
 617                 case 0x2a042:
 618                 case 0x2a044:
 619                 case 0x2a060:
 620                         cfg = __raw_readl(cbr + BMIPS_L2_CONFIG);
 621                         __raw_writel(cfg & ~0x07000000, cbr + BMIPS_L2_CONFIG);
 622                         __raw_readl(cbr + BMIPS_L2_CONFIG);
 623                 }
 624
 625                 /* clear BHTD to enable branch history table */
 626                 clear_c0_brcm_config_0(BIT(21));
 627
 628                 /* XI/ROTR enable */
 629                 set_c0_brcm_config_0(BIT(23));
 630                 set_c0_brcm_cmt_ctrl(BIT(15));
 631                 break;
 632
 633         case CPU_BMIPS5000:
 634                 /* enable RDHWR, BRDHWR */
 635                 set_c0_brcm_config(BIT(17) | BIT(21));
 636
 637                 /* Disable JTB */
 638                 __asm__ __volatile__(
 639                 "       .set    noreorder\n"
 640                 "       li      $8, 0x5a455048\n"
 641                 "       .word   0x4088b00f\n"   /* mtc0 t0, $22, 15 */
 642                 "       .word   0x4008b008\n"   /* mfc0 t0, $22, 8 */
 643                 "       li      $9, 0x00008000\n"
 644                 "       or      $8, $8, $9\n"
 645                 "       .word   0x4088b008\n"   /* mtc0 t0, $22, 8 */
 646                 "       sync\n"
 647                 "       li      $8, 0x0\n"
 648                 "       .word   0x4088b00f\n"   /* mtc0 t0, $22, 15 */
 649                 "       .set    reorder\n"
 650                 : : : "$8", "$9");
 651
 652                 /* XI enable */
 653                 set_c0_brcm_config(BIT(27));
 654
 655                 /* enable MIPS32R2 ROR instruction for XI TLB handlers */
 656                 __asm__ __volatile__(
 657                 "       li      $8, 0x5a455048\n"
 658                 "       .word   0x4088b00f\n"   /* mtc0 $8, $22, 15 */
 659                 "       nop; nop; nop\n"
 660                 "       .word   0x4008b008\n"   /* mfc0 $8, $22, 8 */
 661                 "       lui     $9, 0x0100\n"
 662                 "       or      $8, $9\n"
 663                 "       .word   0x4088b008\n"   /* mtc0 $8, $22, 8 */
 664                 : : : "$8", "$9");
 665                 break;
 666         }
 667 }