summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/smp-bmips.c
blob: df9e2bd9b2c292e0497cdd0daba5217589575c2c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
/*
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com)
 *
 * SMP support for BMIPS
 */

#include <linux/init.h>
#include <linux/sched.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/cpumask.h>
#include <linux/reboot.h>
#include <linux/io.h>
#include <linux/compiler.h>
#include <linux/linkage.h>
#include <linux/bug.h>
#include <linux/kernel.h>

#include <asm/time.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
#include <asm/bootinfo.h>
#include <asm/pmon.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/mipsregs.h>
#include <asm/bmips.h>
#include <asm/traps.h>
#include <asm/barrier.h>

static int __maybe_unused max_cpus = 1;

/* these may be configured by the platform code */
int bmips_smp_enabled = 1;
int bmips_cpu_offset;
cpumask_t bmips_booted_mask;

#ifdef CONFIG_SMP

/* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
unsigned long bmips_smp_boot_sp;
unsigned long bmips_smp_boot_gp;

static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
static void bmips5000_send_ipi_single(int cpu, unsigned int action);
static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);

/* SW interrupts 0,1 are used for interprocessor signaling */
#define IPI0_IRQ			(MIPS_CPU_IRQ_BASE + 0)
#define IPI1_IRQ			(MIPS_CPU_IRQ_BASE + 1)

#define CPUNUM(cpu, shift)		(((cpu) + bmips_cpu_offset) << (shift))
#define ACTION_CLR_IPI(cpu, ipi)	(0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
#define ACTION_SET_IPI(cpu, ipi)	(0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
#define ACTION_BOOT_THREAD(cpu)		(0x08 | CPUNUM(cpu, 0))

static void __init bmips_smp_setup(void)
{
	int i, cpu = 1, boot_cpu = 0;
	int cpu_hw_intr;

	switch (current_cpu_type()) {
	case CPU_BMIPS4350:
	case CPU_BMIPS4380:
		/* arbitration priority */
		clear_c0_brcm_cmt_ctrl(0x30);

		/* NBK and weak order flags */
		set_c0_brcm_config_0(0x30000);

		/* Find out if we are running on TP0 or TP1 */
		boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));

		/*
		 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
		 * thread
		 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
		 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
		 */
		if (boot_cpu == 0)
			cpu_hw_intr = 0x02;
		else
			cpu_hw_intr = 0x1d;

		change_c0_brcm_cmt_intr(0xf8018000,
					(cpu_hw_intr << 27) | (0x03 << 15));

		/* single core, 2 threads (2 pipelines) */
		max_cpus = 2;

		break;
	case CPU_BMIPS5000:
		/* enable raceless SW interrupts */
		set_c0_brcm_config(0x03 << 22);

		/* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
		change_c0_brcm_mode(0x1f << 27, 0x02 << 27);

		/* N cores, 2 threads per core */
		max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;

		/* clear any pending SW interrupts */
		for (i = 0; i < max_cpus; i++) {
			write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
			write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
		}

		break;
	default:
		max_cpus = 1;
	}

	if (!bmips_smp_enabled)
		max_cpus = 1;

	/* this can be overridden by the BSP */
	if (!board_ebase_setup)
		board_ebase_setup = &bmips_ebase_setup;

	__cpu_number_map[boot_cpu] = 0;
	__cpu_logical_map[0] = boot_cpu;

	for (i = 0; i < max_cpus; i++) {
		if (i != boot_cpu) {
			__cpu_number_map[i] = cpu;
			__cpu_logical_map[cpu] = i;
			cpu++;
		}
		set_cpu_possible(i, 1);
		set_cpu_present(i, 1);
	}
}

/*
 * IPI IRQ setup - runs on CPU0
 */
static void bmips_prepare_cpus(unsigned int max_cpus)
{
	irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);

	switch (current_cpu_type()) {
	case CPU_BMIPS4350:
	case CPU_BMIPS4380:
		bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
		break;
	case CPU_BMIPS5000:
		bmips_ipi_interrupt = bmips5000_ipi_interrupt;
		break;
	default:
		return;
	}

	if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
			"smp_ipi0", NULL))
		panic("Can't request IPI0 interrupt");
	if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
			"smp_ipi1", NULL))
		panic("Can't request IPI1 interrupt");
}

/*
 * Tell the hardware to boot CPUx - runs on CPU0
 */
static void bmips_boot_secondary(int cpu, struct task_struct *idle)
{
	bmips_smp_boot_sp = __KSTK_TOS(idle);
	bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
	mb();

	/*
	 * Initial boot sequence for secondary CPU:
	 *   bmips_reset_nmi_vec @ a000_0000 ->
	 *   bmips_smp_entry ->
	 *   plat_wired_tlb_setup (cached function call; optional) ->
	 *   start_secondary (cached jump)
	 *
	 * Warm restart sequence:
	 *   play_dead WAIT loop ->
	 *   bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
	 *   eret to play_dead ->
	 *   bmips_secondary_reentry ->
	 *   start_secondary
	 */

	pr_info("SMP: Booting CPU%d...\n", cpu);

	if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
		switch (current_cpu_type()) {
		case CPU_BMIPS4350:
		case CPU_BMIPS4380:
			bmips43xx_send_ipi_single(cpu, 0);
			break;
		case CPU_BMIPS5000:
			bmips5000_send_ipi_single(cpu, 0);
			break;
		}
	}
	else {
		switch (current_cpu_type()) {
		case CPU_BMIPS4350:
		case CPU_BMIPS4380:
			/* Reset slave TP1 if booting from TP0 */
			if (cpu_logical_map(cpu) == 1)
				set_c0_brcm_cmt_ctrl(0x01);
			break;
		case CPU_BMIPS5000:
			if (cpu & 0x01)
				write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
			else {
				/*
				 * core N thread 0 was already booted; just
				 * pulse the NMI line
				 */
				bmips_write_zscm_reg(0x210, 0xc0000000);
				udelay(10);
				bmips_write_zscm_reg(0x210, 0x00);
			}
			break;
		}
		cpumask_set_cpu(cpu, &bmips_booted_mask);
	}
}

/*
 * Early setup - runs on secondary CPU after cache probe
 */
static void bmips_init_secondary(void)
{
	/* move NMI vector to kseg0, in case XKS01 is enabled */

	void __iomem *cbr;
	unsigned long old_vec;
	unsigned long relo_vector;
	int boot_cpu;

	switch (current_cpu_type()) {
	case CPU_BMIPS4350:
	case CPU_BMIPS4380:
		cbr = BMIPS_GET_CBR();

		boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
		relo_vector = boot_cpu ? BMIPS_RELO_VECTOR_CONTROL_0 :
				  BMIPS_RELO_VECTOR_CONTROL_1;

		old_vec = __raw_readl(cbr + relo_vector);
		__raw_writel(old_vec & ~0x20000000, cbr + relo_vector);

		clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0);
		break;
	case CPU_BMIPS5000:
		write_c0_brcm_bootvec(read_c0_brcm_bootvec() &
			(smp_processor_id() & 0x01 ? ~0x20000000 : ~0x2000));

		write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0));
		break;
	}
}

/*
 * Late setup - runs on secondary CPU before entering the idle loop
 */
static void bmips_smp_finish(void)
{
	pr_info("SMP: CPU%d is running\n", smp_processor_id());

	/* make sure there won't be a timer interrupt for a little while */
	write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);

	irq_enable_hazard();
	set_c0_status(IE_SW0 | IE_SW1 | IE_IRQ1 | IE_IRQ5 | ST0_IE);
	irq_enable_hazard();
}

/*
 * BMIPS5000 raceless IPIs
 *
 * Each CPU has two inbound SW IRQs which are independent of all other CPUs.
 * IPI0 is used for SMP_RESCHEDULE_YOURSELF
 * IPI1 is used for SMP_CALL_FUNCTION
 */

static void bmips5000_send_ipi_single(int cpu, unsigned int action)
{
	write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION));
}

static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id)
{
	int action = irq - IPI0_IRQ;

	write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action));

	if (action == 0)
		scheduler_ipi();
	else
		smp_call_function_interrupt();

	return IRQ_HANDLED;
}

static void bmips5000_send_ipi_mask(const struct cpumask *mask,
	unsigned int action)
{
	unsigned int i;

	for_each_cpu(i, mask)
		bmips5000_send_ipi_single(i, action);
}

/*
 * BMIPS43xx racey IPIs
 *
 * We use one inbound SW IRQ for each CPU.
 *
 * A spinlock must be held in order to keep CPUx from accidentally clearing
 * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy.  The
 * same spinlock is used to protect the action masks.
 */

static DEFINE_SPINLOCK(ipi_lock);
static DEFINE_PER_CPU(int, ipi_action_mask);

static void bmips43xx_send_ipi_single(int cpu, unsigned int action)
{
	unsigned long flags;

	spin_lock_irqsave(&ipi_lock, flags);
	set_c0_cause(cpu ? C_SW1 : C_SW0);
	per_cpu(ipi_action_mask, cpu) |= action;
	irq_enable_hazard();
	spin_unlock_irqrestore(&ipi_lock, flags);
}

static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id)
{
	unsigned long flags;
	int action, cpu = irq - IPI0_IRQ;

	spin_lock_irqsave(&ipi_lock, flags);
	action = __get_cpu_var(ipi_action_mask);
	per_cpu(ipi_action_mask, cpu) = 0;
	clear_c0_cause(cpu ? C_SW1 : C_SW0);
	spin_unlock_irqrestore(&ipi_lock, flags);

	if (action & SMP_RESCHEDULE_YOURSELF)
		scheduler_ipi();
	if (action & SMP_CALL_FUNCTION)
		smp_call_function_interrupt();

	return IRQ_HANDLED;
}

static void bmips43xx_send_ipi_mask(const struct cpumask *mask,
	unsigned int action)
{
	unsigned int i;

	for_each_cpu(i, mask)
		bmips43xx_send_ipi_single(i, action);
}

#ifdef CONFIG_HOTPLUG_CPU

static int bmips_cpu_disable(void)
{
	unsigned int cpu = smp_processor_id();

	if (cpu == 0)
		return -EBUSY;

	pr_info("SMP: CPU%d is offline\n", cpu);

	set_cpu_online(cpu, false);
	cpu_clear(cpu, cpu_callin_map);

	local_flush_tlb_all();
	local_flush_icache_range(0, ~0);

	return 0;
}

static void bmips_cpu_die(unsigned int cpu)
{
}

void __ref play_dead(void)
{
	idle_task_exit();

	/* flush data cache */
	_dma_cache_wback_inv(0, ~0);

	/*
	 * Wakeup is on SW0 or SW1; disable everything else
	 * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux
	 * IRQ handlers; this clears ST0_IE and returns immediately.
	 */
	clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
	change_c0_status(IE_IRQ5 | IE_IRQ1 | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV,
		IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV);
	irq_disable_hazard();

	/*
	 * wait for SW interrupt from bmips_boot_secondary(), then jump
	 * back to start_secondary()
	 */
	__asm__ __volatile__(
	"	wait\n"
	"	j	bmips_secondary_reentry\n"
	: : : "memory");
}

#endif /* CONFIG_HOTPLUG_CPU */

struct plat_smp_ops bmips43xx_smp_ops = {
	.smp_setup		= bmips_smp_setup,
	.prepare_cpus		= bmips_prepare_cpus,
	.boot_secondary		= bmips_boot_secondary,
	.smp_finish		= bmips_smp_finish,
	.init_secondary		= bmips_init_secondary,
	.send_ipi_single	= bmips43xx_send_ipi_single,
	.send_ipi_mask		= bmips43xx_send_ipi_mask,
#ifdef CONFIG_HOTPLUG_CPU
	.cpu_disable		= bmips_cpu_disable,
	.cpu_die		= bmips_cpu_die,
#endif
};

struct plat_smp_ops bmips5000_smp_ops = {
	.smp_setup		= bmips_smp_setup,
	.prepare_cpus		= bmips_prepare_cpus,
	.boot_secondary		= bmips_boot_secondary,
	.smp_finish		= bmips_smp_finish,
	.init_secondary		= bmips_init_secondary,
	.send_ipi_single	= bmips5000_send_ipi_single,
	.send_ipi_mask		= bmips5000_send_ipi_mask,
#ifdef CONFIG_HOTPLUG_CPU
	.cpu_disable		= bmips_cpu_disable,
	.cpu_die		= bmips_cpu_die,
#endif
};

#endif /* CONFIG_SMP */

/***********************************************************************
 * BMIPS vector relocation
 * This is primarily used for SMP boot, but it is applicable to some
 * UP BMIPS systems as well.
 ***********************************************************************/

static void bmips_wr_vec(unsigned long dst, char *start, char *end)
{
	memcpy((void *)dst, start, end - start);
	dma_cache_wback((unsigned long)start, end - start);
	local_flush_icache_range(dst, dst + (end - start));
	instruction_hazard();
}

static inline void bmips_nmi_handler_setup(void)
{
	bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec,
		&bmips_reset_nmi_vec_end);
	bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec,
		&bmips_smp_int_vec_end);
}

void bmips_ebase_setup(void)
{
	unsigned long new_ebase = ebase;
	void __iomem __maybe_unused *cbr;

	BUG_ON(ebase != CKSEG0);

	switch (current_cpu_type()) {
	case CPU_BMIPS4350:
		/*
		 * BMIPS4350 cannot relocate the normal vectors, but it
		 * can relocate the BEV=1 vectors.  So CPU1 starts up at
		 * the relocated BEV=1, IV=0 general exception vector @
		 * 0xa000_0380.
		 *
		 * set_uncached_handler() is used here because:
		 *  - CPU1 will run this from uncached space
		 *  - None of the cacheflush functions are set up yet
		 */
		set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0,
			&bmips_smp_int_vec, 0x80);
		__sync();
		return;
	case CPU_BMIPS4380:
		/*
		 * 0x8000_0000: reset/NMI (initially in kseg1)
		 * 0x8000_0400: normal vectors
		 */
		new_ebase = 0x80000400;
		cbr = BMIPS_GET_CBR();
		__raw_writel(0x80080800, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
		__raw_writel(0xa0080800, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
		break;
	case CPU_BMIPS5000:
		/*
		 * 0x8000_0000: reset/NMI (initially in kseg1)
		 * 0x8000_1000: normal vectors
		 */
		new_ebase = 0x80001000;
		write_c0_brcm_bootvec(0xa0088008);
		write_c0_ebase(new_ebase);
		if (max_cpus > 2)
			bmips_write_zscm_reg(0xa0, 0xa008a008);
		break;
	default:
		return;
	}

	board_nmi_handler_setup = &bmips_nmi_handler_setup;
	ebase = new_ebase;
}

asmlinkage void __weak plat_wired_tlb_setup(void)
{
	/*
	 * Called when starting/restarting a secondary CPU.
	 * Kernel stacks and other important data might only be accessible
	 * once the wired entries are present.
	 */
}