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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
43static int __maybe_unused max_cpus = 1;
44
45/* these may be configured by the platform code */
46int bmips_smp_enabled = 1;
47int bmips_cpu_offset;
48cpumask_t bmips_booted_mask;
49unsigned long bmips_tp1_irqs = IE_IRQ1;
50
51#define RESET_FROM_KSEG0 0x80080800
52#define RESET_FROM_KSEG1 0xa0080800
53
54static 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 */
59unsigned long bmips_smp_boot_sp;
60unsigned long bmips_smp_boot_gp;
61
62static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
63static void bmips5000_send_ipi_single(int cpu, unsigned int action);
64static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
65static 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
76static 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 */
156static 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 */
183static 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 */
242static 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(¤t_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 */
259static 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
279static 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
284static 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
298static 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
317static DEFINE_SPINLOCK(ipi_lock);
318static DEFINE_PER_CPU(int, ipi_action_mask);
319
320static 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
331static 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
350static 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
361static 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
381static void bmips_cpu_die(unsigned int cpu)
382{
383}
384
385void __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
415const 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
432const 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
457static 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
465static 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
473struct reset_vec_info {
474 int cpu;
475 u32 val;
476};
477
478static 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
501static 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
525void 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
573asmlinkage 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
582void 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}
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/mm.h>
14#include <linux/delay.h>
15#include <linux/smp.h>
16#include <linux/interrupt.h>
17#include <linux/spinlock.h>
18#include <linux/cpu.h>
19#include <linux/cpumask.h>
20#include <linux/reboot.h>
21#include <linux/io.h>
22#include <linux/compiler.h>
23#include <linux/linkage.h>
24#include <linux/bug.h>
25#include <linux/kernel.h>
26
27#include <asm/time.h>
28#include <asm/pgtable.h>
29#include <asm/processor.h>
30#include <asm/bootinfo.h>
31#include <asm/pmon.h>
32#include <asm/cacheflush.h>
33#include <asm/tlbflush.h>
34#include <asm/mipsregs.h>
35#include <asm/bmips.h>
36#include <asm/traps.h>
37#include <asm/barrier.h>
38
39static int __maybe_unused max_cpus = 1;
40
41/* these may be configured by the platform code */
42int bmips_smp_enabled = 1;
43int bmips_cpu_offset;
44cpumask_t bmips_booted_mask;
45
46#ifdef CONFIG_SMP
47
48/* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
49unsigned long bmips_smp_boot_sp;
50unsigned long bmips_smp_boot_gp;
51
52static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
53static void bmips5000_send_ipi_single(int cpu, unsigned int action);
54static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
55static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);
56
57/* SW interrupts 0,1 are used for interprocessor signaling */
58#define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0)
59#define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1)
60
61#define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift))
62#define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
63#define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
64#define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0))
65
66static void __init bmips_smp_setup(void)
67{
68 int i, cpu = 1, boot_cpu = 0;
69 int cpu_hw_intr;
70
71 switch (current_cpu_type()) {
72 case CPU_BMIPS4350:
73 case CPU_BMIPS4380:
74 /* arbitration priority */
75 clear_c0_brcm_cmt_ctrl(0x30);
76
77 /* NBK and weak order flags */
78 set_c0_brcm_config_0(0x30000);
79
80 /* Find out if we are running on TP0 or TP1 */
81 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
82
83 /*
84 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
85 * thread
86 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
87 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
88 */
89 if (boot_cpu == 0)
90 cpu_hw_intr = 0x02;
91 else
92 cpu_hw_intr = 0x1d;
93
94 change_c0_brcm_cmt_intr(0xf8018000,
95 (cpu_hw_intr << 27) | (0x03 << 15));
96
97 /* single core, 2 threads (2 pipelines) */
98 max_cpus = 2;
99
100 break;
101 case CPU_BMIPS5000:
102 /* enable raceless SW interrupts */
103 set_c0_brcm_config(0x03 << 22);
104
105 /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
106 change_c0_brcm_mode(0x1f << 27, 0x02 << 27);
107
108 /* N cores, 2 threads per core */
109 max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;
110
111 /* clear any pending SW interrupts */
112 for (i = 0; i < max_cpus; i++) {
113 write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
114 write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
115 }
116
117 break;
118 default:
119 max_cpus = 1;
120 }
121
122 if (!bmips_smp_enabled)
123 max_cpus = 1;
124
125 /* this can be overridden by the BSP */
126 if (!board_ebase_setup)
127 board_ebase_setup = &bmips_ebase_setup;
128
129 __cpu_number_map[boot_cpu] = 0;
130 __cpu_logical_map[0] = boot_cpu;
131
132 for (i = 0; i < max_cpus; i++) {
133 if (i != boot_cpu) {
134 __cpu_number_map[i] = cpu;
135 __cpu_logical_map[cpu] = i;
136 cpu++;
137 }
138 set_cpu_possible(i, 1);
139 set_cpu_present(i, 1);
140 }
141}
142
143/*
144 * IPI IRQ setup - runs on CPU0
145 */
146static void bmips_prepare_cpus(unsigned int max_cpus)
147{
148 irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);
149
150 switch (current_cpu_type()) {
151 case CPU_BMIPS4350:
152 case CPU_BMIPS4380:
153 bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
154 break;
155 case CPU_BMIPS5000:
156 bmips_ipi_interrupt = bmips5000_ipi_interrupt;
157 break;
158 default:
159 return;
160 }
161
162 if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
163 "smp_ipi0", NULL))
164 panic("Can't request IPI0 interrupt");
165 if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
166 "smp_ipi1", NULL))
167 panic("Can't request IPI1 interrupt");
168}
169
170/*
171 * Tell the hardware to boot CPUx - runs on CPU0
172 */
173static void bmips_boot_secondary(int cpu, struct task_struct *idle)
174{
175 bmips_smp_boot_sp = __KSTK_TOS(idle);
176 bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
177 mb();
178
179 /*
180 * Initial boot sequence for secondary CPU:
181 * bmips_reset_nmi_vec @ a000_0000 ->
182 * bmips_smp_entry ->
183 * plat_wired_tlb_setup (cached function call; optional) ->
184 * start_secondary (cached jump)
185 *
186 * Warm restart sequence:
187 * play_dead WAIT loop ->
188 * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
189 * eret to play_dead ->
190 * bmips_secondary_reentry ->
191 * start_secondary
192 */
193
194 pr_info("SMP: Booting CPU%d...\n", cpu);
195
196 if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
197 switch (current_cpu_type()) {
198 case CPU_BMIPS4350:
199 case CPU_BMIPS4380:
200 bmips43xx_send_ipi_single(cpu, 0);
201 break;
202 case CPU_BMIPS5000:
203 bmips5000_send_ipi_single(cpu, 0);
204 break;
205 }
206 }
207 else {
208 switch (current_cpu_type()) {
209 case CPU_BMIPS4350:
210 case CPU_BMIPS4380:
211 /* Reset slave TP1 if booting from TP0 */
212 if (cpu_logical_map(cpu) == 1)
213 set_c0_brcm_cmt_ctrl(0x01);
214 break;
215 case CPU_BMIPS5000:
216 if (cpu & 0x01)
217 write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
218 else {
219 /*
220 * core N thread 0 was already booted; just
221 * pulse the NMI line
222 */
223 bmips_write_zscm_reg(0x210, 0xc0000000);
224 udelay(10);
225 bmips_write_zscm_reg(0x210, 0x00);
226 }
227 break;
228 }
229 cpumask_set_cpu(cpu, &bmips_booted_mask);
230 }
231}
232
233/*
234 * Early setup - runs on secondary CPU after cache probe
235 */
236static void bmips_init_secondary(void)
237{
238 /* move NMI vector to kseg0, in case XKS01 is enabled */
239
240 void __iomem *cbr;
241 unsigned long old_vec;
242 unsigned long relo_vector;
243 int boot_cpu;
244
245 switch (current_cpu_type()) {
246 case CPU_BMIPS4350:
247 case CPU_BMIPS4380:
248 cbr = BMIPS_GET_CBR();
249
250 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
251 relo_vector = boot_cpu ? BMIPS_RELO_VECTOR_CONTROL_0 :
252 BMIPS_RELO_VECTOR_CONTROL_1;
253
254 old_vec = __raw_readl(cbr + relo_vector);
255 __raw_writel(old_vec & ~0x20000000, cbr + relo_vector);
256
257 clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0);
258 break;
259 case CPU_BMIPS5000:
260 write_c0_brcm_bootvec(read_c0_brcm_bootvec() &
261 (smp_processor_id() & 0x01 ? ~0x20000000 : ~0x2000));
262
263 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0));
264 break;
265 }
266}
267
268/*
269 * Late setup - runs on secondary CPU before entering the idle loop
270 */
271static void bmips_smp_finish(void)
272{
273 pr_info("SMP: CPU%d is running\n", smp_processor_id());
274
275 /* make sure there won't be a timer interrupt for a little while */
276 write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
277
278 irq_enable_hazard();
279 set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ1 | IE_IRQ5 | ST0_IE);
280 irq_enable_hazard();
281}
282
283/*
284 * Runs on CPU0 after all CPUs have been booted
285 */
286static void bmips_cpus_done(void)
287{
288}
289
290/*
291 * BMIPS5000 raceless IPIs
292 *
293 * Each CPU has two inbound SW IRQs which are independent of all other CPUs.
294 * IPI0 is used for SMP_RESCHEDULE_YOURSELF
295 * IPI1 is used for SMP_CALL_FUNCTION
296 */
297
298static void bmips5000_send_ipi_single(int cpu, unsigned int action)
299{
300 write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION));
301}
302
303static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id)
304{
305 int action = irq - IPI0_IRQ;
306
307 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action));
308
309 if (action == 0)
310 scheduler_ipi();
311 else
312 smp_call_function_interrupt();
313
314 return IRQ_HANDLED;
315}
316
317static void bmips5000_send_ipi_mask(const struct cpumask *mask,
318 unsigned int action)
319{
320 unsigned int i;
321
322 for_each_cpu(i, mask)
323 bmips5000_send_ipi_single(i, action);
324}
325
326/*
327 * BMIPS43xx racey IPIs
328 *
329 * We use one inbound SW IRQ for each CPU.
330 *
331 * A spinlock must be held in order to keep CPUx from accidentally clearing
332 * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy. The
333 * same spinlock is used to protect the action masks.
334 */
335
336static DEFINE_SPINLOCK(ipi_lock);
337static DEFINE_PER_CPU(int, ipi_action_mask);
338
339static void bmips43xx_send_ipi_single(int cpu, unsigned int action)
340{
341 unsigned long flags;
342
343 spin_lock_irqsave(&ipi_lock, flags);
344 set_c0_cause(cpu ? C_SW1 : C_SW0);
345 per_cpu(ipi_action_mask, cpu) |= action;
346 irq_enable_hazard();
347 spin_unlock_irqrestore(&ipi_lock, flags);
348}
349
350static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id)
351{
352 unsigned long flags;
353 int action, cpu = irq - IPI0_IRQ;
354
355 spin_lock_irqsave(&ipi_lock, flags);
356 action = __get_cpu_var(ipi_action_mask);
357 per_cpu(ipi_action_mask, cpu) = 0;
358 clear_c0_cause(cpu ? C_SW1 : C_SW0);
359 spin_unlock_irqrestore(&ipi_lock, flags);
360
361 if (action & SMP_RESCHEDULE_YOURSELF)
362 scheduler_ipi();
363 if (action & SMP_CALL_FUNCTION)
364 smp_call_function_interrupt();
365
366 return IRQ_HANDLED;
367}
368
369static void bmips43xx_send_ipi_mask(const struct cpumask *mask,
370 unsigned int action)
371{
372 unsigned int i;
373
374 for_each_cpu(i, mask)
375 bmips43xx_send_ipi_single(i, action);
376}
377
378#ifdef CONFIG_HOTPLUG_CPU
379
380static int bmips_cpu_disable(void)
381{
382 unsigned int cpu = smp_processor_id();
383
384 if (cpu == 0)
385 return -EBUSY;
386
387 pr_info("SMP: CPU%d is offline\n", cpu);
388
389 set_cpu_online(cpu, false);
390 cpu_clear(cpu, cpu_callin_map);
391
392 local_flush_tlb_all();
393 local_flush_icache_range(0, ~0);
394
395 return 0;
396}
397
398static void bmips_cpu_die(unsigned int cpu)
399{
400}
401
402void __ref play_dead(void)
403{
404 idle_task_exit();
405
406 /* flush data cache */
407 _dma_cache_wback_inv(0, ~0);
408
409 /*
410 * Wakeup is on SW0 or SW1; disable everything else
411 * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux
412 * IRQ handlers; this clears ST0_IE and returns immediately.
413 */
414 clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
415 change_c0_status(IE_IRQ5 | IE_IRQ1 | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV,
416 IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV);
417 irq_disable_hazard();
418
419 /*
420 * wait for SW interrupt from bmips_boot_secondary(), then jump
421 * back to start_secondary()
422 */
423 __asm__ __volatile__(
424 " wait\n"
425 " j bmips_secondary_reentry\n"
426 : : : "memory");
427}
428
429#endif /* CONFIG_HOTPLUG_CPU */
430
431struct plat_smp_ops bmips43xx_smp_ops = {
432 .smp_setup = bmips_smp_setup,
433 .prepare_cpus = bmips_prepare_cpus,
434 .boot_secondary = bmips_boot_secondary,
435 .smp_finish = bmips_smp_finish,
436 .init_secondary = bmips_init_secondary,
437 .cpus_done = bmips_cpus_done,
438 .send_ipi_single = bmips43xx_send_ipi_single,
439 .send_ipi_mask = bmips43xx_send_ipi_mask,
440#ifdef CONFIG_HOTPLUG_CPU
441 .cpu_disable = bmips_cpu_disable,
442 .cpu_die = bmips_cpu_die,
443#endif
444};
445
446struct plat_smp_ops bmips5000_smp_ops = {
447 .smp_setup = bmips_smp_setup,
448 .prepare_cpus = bmips_prepare_cpus,
449 .boot_secondary = bmips_boot_secondary,
450 .smp_finish = bmips_smp_finish,
451 .init_secondary = bmips_init_secondary,
452 .cpus_done = bmips_cpus_done,
453 .send_ipi_single = bmips5000_send_ipi_single,
454 .send_ipi_mask = bmips5000_send_ipi_mask,
455#ifdef CONFIG_HOTPLUG_CPU
456 .cpu_disable = bmips_cpu_disable,
457 .cpu_die = bmips_cpu_die,
458#endif
459};
460
461#endif /* CONFIG_SMP */
462
463/***********************************************************************
464 * BMIPS vector relocation
465 * This is primarily used for SMP boot, but it is applicable to some
466 * UP BMIPS systems as well.
467 ***********************************************************************/
468
469static void bmips_wr_vec(unsigned long dst, char *start, char *end)
470{
471 memcpy((void *)dst, start, end - start);
472 dma_cache_wback((unsigned long)start, end - start);
473 local_flush_icache_range(dst, dst + (end - start));
474 instruction_hazard();
475}
476
477static inline void bmips_nmi_handler_setup(void)
478{
479 bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec,
480 &bmips_reset_nmi_vec_end);
481 bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec,
482 &bmips_smp_int_vec_end);
483}
484
485void bmips_ebase_setup(void)
486{
487 unsigned long new_ebase = ebase;
488 void __iomem __maybe_unused *cbr;
489
490 BUG_ON(ebase != CKSEG0);
491
492 switch (current_cpu_type()) {
493 case CPU_BMIPS4350:
494 /*
495 * BMIPS4350 cannot relocate the normal vectors, but it
496 * can relocate the BEV=1 vectors. So CPU1 starts up at
497 * the relocated BEV=1, IV=0 general exception vector @
498 * 0xa000_0380.
499 *
500 * set_uncached_handler() is used here because:
501 * - CPU1 will run this from uncached space
502 * - None of the cacheflush functions are set up yet
503 */
504 set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0,
505 &bmips_smp_int_vec, 0x80);
506 __sync();
507 return;
508 case CPU_BMIPS4380:
509 /*
510 * 0x8000_0000: reset/NMI (initially in kseg1)
511 * 0x8000_0400: normal vectors
512 */
513 new_ebase = 0x80000400;
514 cbr = BMIPS_GET_CBR();
515 __raw_writel(0x80080800, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
516 __raw_writel(0xa0080800, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
517 break;
518 case CPU_BMIPS5000:
519 /*
520 * 0x8000_0000: reset/NMI (initially in kseg1)
521 * 0x8000_1000: normal vectors
522 */
523 new_ebase = 0x80001000;
524 write_c0_brcm_bootvec(0xa0088008);
525 write_c0_ebase(new_ebase);
526 if (max_cpus > 2)
527 bmips_write_zscm_reg(0xa0, 0xa008a008);
528 break;
529 default:
530 return;
531 }
532
533 board_nmi_handler_setup = &bmips_nmi_handler_setup;
534 ebase = new_ebase;
535}
536
537asmlinkage void __weak plat_wired_tlb_setup(void)
538{
539 /*
540 * Called when starting/restarting a secondary CPU.
541 * Kernel stacks and other important data might only be accessible
542 * once the wired entries are present.
543 */
544}