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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#include <linux/irq.h>
30
31#include <asm/time.h>
32#include <asm/processor.h>
33#include <asm/bootinfo.h>
34#include <asm/cacheflush.h>
35#include <asm/tlbflush.h>
36#include <asm/mipsregs.h>
37#include <asm/bmips.h>
38#include <asm/traps.h>
39#include <asm/barrier.h>
40#include <asm/cpu-features.h>
41
42static int __maybe_unused max_cpus = 1;
43
44/* these may be configured by the platform code */
45int bmips_smp_enabled = 1;
46int bmips_cpu_offset;
47cpumask_t bmips_booted_mask;
48unsigned long bmips_tp1_irqs = IE_IRQ1;
49
50#define RESET_FROM_KSEG0 0x80080800
51#define RESET_FROM_KSEG1 0xa0080800
52
53static void bmips_set_reset_vec(int cpu, u32 val);
54
55#ifdef CONFIG_SMP
56
57/* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
58unsigned long bmips_smp_boot_sp;
59unsigned long bmips_smp_boot_gp;
60
61static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
62static void bmips5000_send_ipi_single(int cpu, unsigned int action);
63static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
64static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);
65
66/* SW interrupts 0,1 are used for interprocessor signaling */
67#define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0)
68#define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1)
69
70#define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift))
71#define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
72#define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
73#define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0))
74
75static void __init bmips_smp_setup(void)
76{
77 int i, cpu = 1, boot_cpu = 0;
78 int cpu_hw_intr;
79
80 switch (current_cpu_type()) {
81 case CPU_BMIPS4350:
82 case CPU_BMIPS4380:
83 /* arbitration priority */
84 clear_c0_brcm_cmt_ctrl(0x30);
85
86 /* NBK and weak order flags */
87 set_c0_brcm_config_0(0x30000);
88
89 /* Find out if we are running on TP0 or TP1 */
90 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
91
92 /*
93 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
94 * thread
95 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
96 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
97 */
98 if (boot_cpu == 0)
99 cpu_hw_intr = 0x02;
100 else
101 cpu_hw_intr = 0x1d;
102
103 change_c0_brcm_cmt_intr(0xf8018000,
104 (cpu_hw_intr << 27) | (0x03 << 15));
105
106 /* single core, 2 threads (2 pipelines) */
107 max_cpus = 2;
108
109 break;
110 case CPU_BMIPS5000:
111 /* enable raceless SW interrupts */
112 set_c0_brcm_config(0x03 << 22);
113
114 /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
115 change_c0_brcm_mode(0x1f << 27, 0x02 << 27);
116
117 /* N cores, 2 threads per core */
118 max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;
119
120 /* clear any pending SW interrupts */
121 for (i = 0; i < max_cpus; i++) {
122 write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
123 write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
124 }
125
126 break;
127 default:
128 max_cpus = 1;
129 }
130
131 if (!bmips_smp_enabled)
132 max_cpus = 1;
133
134 /* this can be overridden by the BSP */
135 if (!board_ebase_setup)
136 board_ebase_setup = &bmips_ebase_setup;
137
138 if (max_cpus > 1) {
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 } else {
152 __cpu_number_map[0] = boot_cpu;
153 __cpu_logical_map[0] = 0;
154 set_cpu_possible(0, 1);
155 set_cpu_present(0, 1);
156 }
157}
158
159/*
160 * IPI IRQ setup - runs on CPU0
161 */
162static void bmips_prepare_cpus(unsigned int max_cpus)
163{
164 irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);
165
166 switch (current_cpu_type()) {
167 case CPU_BMIPS4350:
168 case CPU_BMIPS4380:
169 bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
170 break;
171 case CPU_BMIPS5000:
172 bmips_ipi_interrupt = bmips5000_ipi_interrupt;
173 break;
174 default:
175 return;
176 }
177
178 if (request_irq(IPI0_IRQ, bmips_ipi_interrupt,
179 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi0", NULL))
180 panic("Can't request IPI0 interrupt");
181 if (request_irq(IPI1_IRQ, bmips_ipi_interrupt,
182 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi1", NULL))
183 panic("Can't request IPI1 interrupt");
184}
185
186/*
187 * Tell the hardware to boot CPUx - runs on CPU0
188 */
189static int bmips_boot_secondary(int cpu, struct task_struct *idle)
190{
191 bmips_smp_boot_sp = __KSTK_TOS(idle);
192 bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
193 mb();
194
195 /*
196 * Initial boot sequence for secondary CPU:
197 * bmips_reset_nmi_vec @ a000_0000 ->
198 * bmips_smp_entry ->
199 * plat_wired_tlb_setup (cached function call; optional) ->
200 * start_secondary (cached jump)
201 *
202 * Warm restart sequence:
203 * play_dead WAIT loop ->
204 * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
205 * eret to play_dead ->
206 * bmips_secondary_reentry ->
207 * start_secondary
208 */
209
210 pr_info("SMP: Booting CPU%d...\n", cpu);
211
212 if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
213 /* kseg1 might not exist if this CPU enabled XKS01 */
214 bmips_set_reset_vec(cpu, RESET_FROM_KSEG0);
215
216 switch (current_cpu_type()) {
217 case CPU_BMIPS4350:
218 case CPU_BMIPS4380:
219 bmips43xx_send_ipi_single(cpu, 0);
220 break;
221 case CPU_BMIPS5000:
222 bmips5000_send_ipi_single(cpu, 0);
223 break;
224 }
225 } else {
226 bmips_set_reset_vec(cpu, RESET_FROM_KSEG1);
227
228 switch (current_cpu_type()) {
229 case CPU_BMIPS4350:
230 case CPU_BMIPS4380:
231 /* Reset slave TP1 if booting from TP0 */
232 if (cpu_logical_map(cpu) == 1)
233 set_c0_brcm_cmt_ctrl(0x01);
234 break;
235 case CPU_BMIPS5000:
236 write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
237 break;
238 }
239 cpumask_set_cpu(cpu, &bmips_booted_mask);
240 }
241
242 return 0;
243}
244
245/*
246 * Early setup - runs on secondary CPU after cache probe
247 */
248static void bmips_init_secondary(void)
249{
250 bmips_cpu_setup();
251
252 switch (current_cpu_type()) {
253 case CPU_BMIPS4350:
254 case CPU_BMIPS4380:
255 clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0);
256 break;
257 case CPU_BMIPS5000:
258 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0));
259 cpu_set_core(¤t_cpu_data, (read_c0_brcm_config() >> 25) & 3);
260 break;
261 }
262}
263
264/*
265 * Late setup - runs on secondary CPU before entering the idle loop
266 */
267static void bmips_smp_finish(void)
268{
269 pr_info("SMP: CPU%d is running\n", smp_processor_id());
270
271 /* make sure there won't be a timer interrupt for a little while */
272 write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
273
274 irq_enable_hazard();
275 set_c0_status(IE_SW0 | IE_SW1 | bmips_tp1_irqs | IE_IRQ5 | ST0_IE);
276 irq_enable_hazard();
277}
278
279/*
280 * BMIPS5000 raceless IPIs
281 *
282 * Each CPU has two inbound SW IRQs which are independent of all other CPUs.
283 * IPI0 is used for SMP_RESCHEDULE_YOURSELF
284 * IPI1 is used for SMP_CALL_FUNCTION
285 */
286
287static void bmips5000_send_ipi_single(int cpu, unsigned int action)
288{
289 write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION));
290}
291
292static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id)
293{
294 int action = irq - IPI0_IRQ;
295
296 write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action));
297
298 if (action == 0)
299 scheduler_ipi();
300 else
301 generic_smp_call_function_interrupt();
302
303 return IRQ_HANDLED;
304}
305
306static void bmips5000_send_ipi_mask(const struct cpumask *mask,
307 unsigned int action)
308{
309 unsigned int i;
310
311 for_each_cpu(i, mask)
312 bmips5000_send_ipi_single(i, action);
313}
314
315/*
316 * BMIPS43xx racey IPIs
317 *
318 * We use one inbound SW IRQ for each CPU.
319 *
320 * A spinlock must be held in order to keep CPUx from accidentally clearing
321 * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy. The
322 * same spinlock is used to protect the action masks.
323 */
324
325static DEFINE_SPINLOCK(ipi_lock);
326static DEFINE_PER_CPU(int, ipi_action_mask);
327
328static void bmips43xx_send_ipi_single(int cpu, unsigned int action)
329{
330 unsigned long flags;
331
332 spin_lock_irqsave(&ipi_lock, flags);
333 set_c0_cause(cpu ? C_SW1 : C_SW0);
334 per_cpu(ipi_action_mask, cpu) |= action;
335 irq_enable_hazard();
336 spin_unlock_irqrestore(&ipi_lock, flags);
337}
338
339static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id)
340{
341 unsigned long flags;
342 int action, cpu = irq - IPI0_IRQ;
343
344 spin_lock_irqsave(&ipi_lock, flags);
345 action = __this_cpu_read(ipi_action_mask);
346 per_cpu(ipi_action_mask, cpu) = 0;
347 clear_c0_cause(cpu ? C_SW1 : C_SW0);
348 spin_unlock_irqrestore(&ipi_lock, flags);
349
350 if (action & SMP_RESCHEDULE_YOURSELF)
351 scheduler_ipi();
352 if (action & SMP_CALL_FUNCTION)
353 generic_smp_call_function_interrupt();
354
355 return IRQ_HANDLED;
356}
357
358static void bmips43xx_send_ipi_mask(const struct cpumask *mask,
359 unsigned int action)
360{
361 unsigned int i;
362
363 for_each_cpu(i, mask)
364 bmips43xx_send_ipi_single(i, action);
365}
366
367#ifdef CONFIG_HOTPLUG_CPU
368
369static int bmips_cpu_disable(void)
370{
371 unsigned int cpu = smp_processor_id();
372
373 pr_info("SMP: CPU%d is offline\n", cpu);
374
375 set_cpu_online(cpu, false);
376 calculate_cpu_foreign_map();
377 irq_migrate_all_off_this_cpu();
378 clear_c0_status(IE_IRQ5);
379
380 local_flush_tlb_all();
381 local_flush_icache_range(0, ~0);
382
383 return 0;
384}
385
386static void bmips_cpu_die(unsigned int cpu)
387{
388}
389
390void __ref play_dead(void)
391{
392 idle_task_exit();
393
394 /* flush data cache */
395 _dma_cache_wback_inv(0, ~0);
396
397 /*
398 * Wakeup is on SW0 or SW1; disable everything else
399 * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux
400 * IRQ handlers; this clears ST0_IE and returns immediately.
401 */
402 clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
403 change_c0_status(
404 IE_IRQ5 | bmips_tp1_irqs | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV,
405 IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV);
406 irq_disable_hazard();
407
408 /*
409 * wait for SW interrupt from bmips_boot_secondary(), then jump
410 * back to start_secondary()
411 */
412 __asm__ __volatile__(
413 " wait\n"
414 " j bmips_secondary_reentry\n"
415 : : : "memory");
416}
417
418#endif /* CONFIG_HOTPLUG_CPU */
419
420const struct plat_smp_ops bmips43xx_smp_ops = {
421 .smp_setup = bmips_smp_setup,
422 .prepare_cpus = bmips_prepare_cpus,
423 .boot_secondary = bmips_boot_secondary,
424 .smp_finish = bmips_smp_finish,
425 .init_secondary = bmips_init_secondary,
426 .send_ipi_single = bmips43xx_send_ipi_single,
427 .send_ipi_mask = bmips43xx_send_ipi_mask,
428#ifdef CONFIG_HOTPLUG_CPU
429 .cpu_disable = bmips_cpu_disable,
430 .cpu_die = bmips_cpu_die,
431#endif
432#ifdef CONFIG_KEXEC
433 .kexec_nonboot_cpu = kexec_nonboot_cpu_jump,
434#endif
435};
436
437const struct plat_smp_ops bmips5000_smp_ops = {
438 .smp_setup = bmips_smp_setup,
439 .prepare_cpus = bmips_prepare_cpus,
440 .boot_secondary = bmips_boot_secondary,
441 .smp_finish = bmips_smp_finish,
442 .init_secondary = bmips_init_secondary,
443 .send_ipi_single = bmips5000_send_ipi_single,
444 .send_ipi_mask = bmips5000_send_ipi_mask,
445#ifdef CONFIG_HOTPLUG_CPU
446 .cpu_disable = bmips_cpu_disable,
447 .cpu_die = bmips_cpu_die,
448#endif
449#ifdef CONFIG_KEXEC
450 .kexec_nonboot_cpu = kexec_nonboot_cpu_jump,
451#endif
452};
453
454#endif /* CONFIG_SMP */
455
456/***********************************************************************
457 * BMIPS vector relocation
458 * This is primarily used for SMP boot, but it is applicable to some
459 * UP BMIPS systems as well.
460 ***********************************************************************/
461
462static void bmips_wr_vec(unsigned long dst, char *start, char *end)
463{
464 memcpy((void *)dst, start, end - start);
465 dma_cache_wback(dst, end - start);
466 local_flush_icache_range(dst, dst + (end - start));
467 instruction_hazard();
468}
469
470static inline void bmips_nmi_handler_setup(void)
471{
472 bmips_wr_vec(BMIPS_NMI_RESET_VEC, bmips_reset_nmi_vec,
473 bmips_reset_nmi_vec_end);
474 bmips_wr_vec(BMIPS_WARM_RESTART_VEC, bmips_smp_int_vec,
475 bmips_smp_int_vec_end);
476}
477
478struct reset_vec_info {
479 int cpu;
480 u32 val;
481};
482
483static void bmips_set_reset_vec_remote(void *vinfo)
484{
485 struct reset_vec_info *info = vinfo;
486 int shift = info->cpu & 0x01 ? 16 : 0;
487 u32 mask = ~(0xffff << shift), val = info->val >> 16;
488
489 preempt_disable();
490 if (smp_processor_id() > 0) {
491 smp_call_function_single(0, &bmips_set_reset_vec_remote,
492 info, 1);
493 } else {
494 if (info->cpu & 0x02) {
495 /* BMIPS5200 "should" use mask/shift, but it's buggy */
496 bmips_write_zscm_reg(0xa0, (val << 16) | val);
497 bmips_read_zscm_reg(0xa0);
498 } else {
499 write_c0_brcm_bootvec((read_c0_brcm_bootvec() & mask) |
500 (val << shift));
501 }
502 }
503 preempt_enable();
504}
505
506static void bmips_set_reset_vec(int cpu, u32 val)
507{
508 struct reset_vec_info info;
509
510 if (current_cpu_type() == CPU_BMIPS5000) {
511 /* this needs to run from CPU0 (which is always online) */
512 info.cpu = cpu;
513 info.val = val;
514 bmips_set_reset_vec_remote(&info);
515 } else {
516 void __iomem *cbr = BMIPS_GET_CBR();
517
518 if (cpu == 0)
519 __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
520 else {
521 if (current_cpu_type() != CPU_BMIPS4380)
522 return;
523 __raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
524 }
525 }
526 __sync();
527 back_to_back_c0_hazard();
528}
529
530void bmips_ebase_setup(void)
531{
532 unsigned long new_ebase = ebase;
533
534 BUG_ON(ebase != CKSEG0);
535
536 switch (current_cpu_type()) {
537 case CPU_BMIPS4350:
538 /*
539 * BMIPS4350 cannot relocate the normal vectors, but it
540 * can relocate the BEV=1 vectors. So CPU1 starts up at
541 * the relocated BEV=1, IV=0 general exception vector @
542 * 0xa000_0380.
543 *
544 * set_uncached_handler() is used here because:
545 * - CPU1 will run this from uncached space
546 * - None of the cacheflush functions are set up yet
547 */
548 set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0,
549 &bmips_smp_int_vec, 0x80);
550 __sync();
551 return;
552 case CPU_BMIPS3300:
553 case CPU_BMIPS4380:
554 /*
555 * 0x8000_0000: reset/NMI (initially in kseg1)
556 * 0x8000_0400: normal vectors
557 */
558 new_ebase = 0x80000400;
559 bmips_set_reset_vec(0, RESET_FROM_KSEG0);
560 break;
561 case CPU_BMIPS5000:
562 /*
563 * 0x8000_0000: reset/NMI (initially in kseg1)
564 * 0x8000_1000: normal vectors
565 */
566 new_ebase = 0x80001000;
567 bmips_set_reset_vec(0, RESET_FROM_KSEG0);
568 write_c0_ebase(new_ebase);
569 break;
570 default:
571 return;
572 }
573
574 board_nmi_handler_setup = &bmips_nmi_handler_setup;
575 ebase = new_ebase;
576}
577
578asmlinkage void __weak plat_wired_tlb_setup(void)
579{
580 /*
581 * Called when starting/restarting a secondary CPU.
582 * Kernel stacks and other important data might only be accessible
583 * once the wired entries are present.
584 */
585}
586
587void bmips_cpu_setup(void)
588{
589 void __iomem __maybe_unused *cbr = BMIPS_GET_CBR();
590 u32 __maybe_unused cfg;
591
592 switch (current_cpu_type()) {
593 case CPU_BMIPS3300:
594 /* Set BIU to async mode */
595 set_c0_brcm_bus_pll(BIT(22));
596 __sync();
597
598 /* put the BIU back in sync mode */
599 clear_c0_brcm_bus_pll(BIT(22));
600
601 /* clear BHTD to enable branch history table */
602 clear_c0_brcm_reset(BIT(16));
603
604 /* Flush and enable RAC */
605 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
606 __raw_writel(cfg | 0x100, cbr + BMIPS_RAC_CONFIG);
607 __raw_readl(cbr + BMIPS_RAC_CONFIG);
608
609 cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
610 __raw_writel(cfg | 0xf, cbr + BMIPS_RAC_CONFIG);
611 __raw_readl(cbr + BMIPS_RAC_CONFIG);
612
613 cfg = __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
614 __raw_writel(cfg | 0x0fff0000, cbr + BMIPS_RAC_ADDRESS_RANGE);
615 __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
616 break;
617
618 case CPU_BMIPS4380:
619 /* CBG workaround for early BMIPS4380 CPUs */
620 switch (read_c0_prid()) {
621 case 0x2a040:
622 case 0x2a042:
623 case 0x2a044:
624 case 0x2a060:
625 cfg = __raw_readl(cbr + BMIPS_L2_CONFIG);
626 __raw_writel(cfg & ~0x07000000, cbr + BMIPS_L2_CONFIG);
627 __raw_readl(cbr + BMIPS_L2_CONFIG);
628 }
629
630 /* clear BHTD to enable branch history table */
631 clear_c0_brcm_config_0(BIT(21));
632
633 /* XI/ROTR enable */
634 set_c0_brcm_config_0(BIT(23));
635 set_c0_brcm_cmt_ctrl(BIT(15));
636 break;
637
638 case CPU_BMIPS5000:
639 /* enable RDHWR, BRDHWR */
640 set_c0_brcm_config(BIT(17) | BIT(21));
641
642 /* Disable JTB */
643 __asm__ __volatile__(
644 " .set noreorder\n"
645 " li $8, 0x5a455048\n"
646 " .word 0x4088b00f\n" /* mtc0 t0, $22, 15 */
647 " .word 0x4008b008\n" /* mfc0 t0, $22, 8 */
648 " li $9, 0x00008000\n"
649 " or $8, $8, $9\n"
650 " .word 0x4088b008\n" /* mtc0 t0, $22, 8 */
651 " sync\n"
652 " li $8, 0x0\n"
653 " .word 0x4088b00f\n" /* mtc0 t0, $22, 15 */
654 " .set reorder\n"
655 : : : "$8", "$9");
656
657 /* XI enable */
658 set_c0_brcm_config(BIT(27));
659
660 /* enable MIPS32R2 ROR instruction for XI TLB handlers */
661 __asm__ __volatile__(
662 " li $8, 0x5a455048\n"
663 " .word 0x4088b00f\n" /* mtc0 $8, $22, 15 */
664 " nop; nop; nop\n"
665 " .word 0x4008b008\n" /* mfc0 $8, $22, 8 */
666 " lui $9, 0x0100\n"
667 " or $8, $9\n"
668 " .word 0x4088b008\n" /* mtc0 $8, $22, 8 */
669 : : : "$8", "$9");
670 break;
671 }
672}
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/processor.h>
32#include <asm/bootinfo.h>
33#include <asm/cacheflush.h>
34#include <asm/tlbflush.h>
35#include <asm/mipsregs.h>
36#include <asm/bmips.h>
37#include <asm/traps.h>
38#include <asm/barrier.h>
39#include <asm/cpu-features.h>
40
41static int __maybe_unused max_cpus = 1;
42
43/* these may be configured by the platform code */
44int bmips_smp_enabled = 1;
45int bmips_cpu_offset;
46cpumask_t bmips_booted_mask;
47unsigned long bmips_tp1_irqs = IE_IRQ1;
48
49#define RESET_FROM_KSEG0 0x80080800
50#define RESET_FROM_KSEG1 0xa0080800
51
52static void bmips_set_reset_vec(int cpu, u32 val);
53
54#ifdef CONFIG_SMP
55
56/* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
57unsigned long bmips_smp_boot_sp;
58unsigned long bmips_smp_boot_gp;
59
60static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
61static void bmips5000_send_ipi_single(int cpu, unsigned int action);
62static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
63static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);
64
65/* SW interrupts 0,1 are used for interprocessor signaling */
66#define IPI0_IRQ (MIPS_CPU_IRQ_BASE + 0)
67#define IPI1_IRQ (MIPS_CPU_IRQ_BASE + 1)
68
69#define CPUNUM(cpu, shift) (((cpu) + bmips_cpu_offset) << (shift))
70#define ACTION_CLR_IPI(cpu, ipi) (0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
71#define ACTION_SET_IPI(cpu, ipi) (0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
72#define ACTION_BOOT_THREAD(cpu) (0x08 | CPUNUM(cpu, 0))
73
74static void __init bmips_smp_setup(void)
75{
76 int i, cpu = 1, boot_cpu = 0;
77 int cpu_hw_intr;
78
79 switch (current_cpu_type()) {
80 case CPU_BMIPS4350:
81 case CPU_BMIPS4380:
82 /* arbitration priority */
83 clear_c0_brcm_cmt_ctrl(0x30);
84
85 /* NBK and weak order flags */
86 set_c0_brcm_config_0(0x30000);
87
88 /* Find out if we are running on TP0 or TP1 */
89 boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
90
91 /*
92 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
93 * thread
94 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
95 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
96 */
97 if (boot_cpu == 0)
98 cpu_hw_intr = 0x02;
99 else
100 cpu_hw_intr = 0x1d;
101
102 change_c0_brcm_cmt_intr(0xf8018000,
103 (cpu_hw_intr << 27) | (0x03 << 15));
104
105 /* single core, 2 threads (2 pipelines) */
106 max_cpus = 2;
107
108 break;
109 case CPU_BMIPS5000:
110 /* enable raceless SW interrupts */
111 set_c0_brcm_config(0x03 << 22);
112
113 /* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
114 change_c0_brcm_mode(0x1f << 27, 0x02 << 27);
115
116 /* N cores, 2 threads per core */
117 max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;
118
119 /* clear any pending SW interrupts */
120 for (i = 0; i < max_cpus; i++) {
121 write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
122 write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
123 }
124
125 break;
126 default:
127 max_cpus = 1;
128 }
129
130 if (!bmips_smp_enabled)
131 max_cpus = 1;
132
133 /* this can be overridden by the BSP */
134 if (!board_ebase_setup)
135 board_ebase_setup = &bmips_ebase_setup;
136
137 __cpu_number_map[boot_cpu] = 0;
138 __cpu_logical_map[0] = boot_cpu;
139
140 for (i = 0; i < max_cpus; i++) {
141 if (i != boot_cpu) {
142 __cpu_number_map[i] = cpu;
143 __cpu_logical_map[cpu] = i;
144 cpu++;
145 }
146 set_cpu_possible(i, 1);
147 set_cpu_present(i, 1);
148 }
149}
150
151/*
152 * IPI IRQ setup - runs on CPU0
153 */
154static void bmips_prepare_cpus(unsigned int max_cpus)
155{
156 irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);
157
158 switch (current_cpu_type()) {
159 case CPU_BMIPS4350:
160 case CPU_BMIPS4380:
161 bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
162 break;
163 case CPU_BMIPS5000:
164 bmips_ipi_interrupt = bmips5000_ipi_interrupt;
165 break;
166 default:
167 return;
168 }
169
170 if (request_irq(IPI0_IRQ, bmips_ipi_interrupt,
171 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi0", NULL))
172 panic("Can't request IPI0 interrupt");
173 if (request_irq(IPI1_IRQ, bmips_ipi_interrupt,
174 IRQF_PERCPU | IRQF_NO_SUSPEND, "smp_ipi1", NULL))
175 panic("Can't request IPI1 interrupt");
176}
177
178/*
179 * Tell the hardware to boot CPUx - runs on CPU0
180 */
181static int bmips_boot_secondary(int cpu, struct task_struct *idle)
182{
183 bmips_smp_boot_sp = __KSTK_TOS(idle);
184 bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
185 mb();
186
187 /*
188 * Initial boot sequence for secondary CPU:
189 * bmips_reset_nmi_vec @ a000_0000 ->
190 * bmips_smp_entry ->
191 * plat_wired_tlb_setup (cached function call; optional) ->
192 * start_secondary (cached jump)
193 *
194 * Warm restart sequence:
195 * play_dead WAIT loop ->
196 * bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
197 * eret to play_dead ->
198 * bmips_secondary_reentry ->
199 * start_secondary
200 */
201
202 pr_info("SMP: Booting CPU%d...\n", cpu);
203
204 if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
205 /* kseg1 might not exist if this CPU enabled XKS01 */
206 bmips_set_reset_vec(cpu, RESET_FROM_KSEG0);
207
208 switch (current_cpu_type()) {
209 case CPU_BMIPS4350:
210 case CPU_BMIPS4380:
211 bmips43xx_send_ipi_single(cpu, 0);
212 break;
213 case CPU_BMIPS5000:
214 bmips5000_send_ipi_single(cpu, 0);
215 break;
216 }
217 } else {
218 bmips_set_reset_vec(cpu, RESET_FROM_KSEG1);
219
220 switch (current_cpu_type()) {
221 case CPU_BMIPS4350:
222 case CPU_BMIPS4380:
223 /* Reset slave TP1 if booting from TP0 */
224 if (cpu_logical_map(cpu) == 1)
225 set_c0_brcm_cmt_ctrl(0x01);
226 break;
227 case CPU_BMIPS5000:
228 write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
229 break;
230 }
231 cpumask_set_cpu(cpu, &bmips_booted_mask);
232 }
233
234 return 0;
235}
236
237/*
238 * Early setup - runs on secondary CPU after cache probe
239 */
240static void bmips_init_secondary(void)
241{
242 bmips_cpu_setup();
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}