xref: /linux/arch/mips/kernel/smp-bmips.c (revision f594d0b9b34aeb8e3ffa524eaa8a4085afb56d22)
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 #include <asm/cpu-features.h>
39 
40 static int __maybe_unused max_cpus = 1;
41 
42 /* these may be configured by the platform code */
43 int bmips_smp_enabled = 1;
44 int bmips_cpu_offset;
45 cpumask_t bmips_booted_mask;
46 unsigned long bmips_tp1_irqs = IE_IRQ1;
47 
48 #define RESET_FROM_KSEG0		0x80080800
49 #define RESET_FROM_KSEG1		0xa0080800
50 
51 static void bmips_set_reset_vec(int cpu, u32 val);
52 
53 #ifdef CONFIG_SMP
54 
55 /* initial $sp, $gp - used by arch/mips/kernel/bmips_vec.S */
56 unsigned long bmips_smp_boot_sp;
57 unsigned long bmips_smp_boot_gp;
58 
59 static void bmips43xx_send_ipi_single(int cpu, unsigned int action);
60 static void bmips5000_send_ipi_single(int cpu, unsigned int action);
61 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id);
62 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id);
63 
64 /* SW interrupts 0,1 are used for interprocessor signaling */
65 #define IPI0_IRQ			(MIPS_CPU_IRQ_BASE + 0)
66 #define IPI1_IRQ			(MIPS_CPU_IRQ_BASE + 1)
67 
68 #define CPUNUM(cpu, shift)		(((cpu) + bmips_cpu_offset) << (shift))
69 #define ACTION_CLR_IPI(cpu, ipi)	(0x2000 | CPUNUM(cpu, 9) | ((ipi) << 8))
70 #define ACTION_SET_IPI(cpu, ipi)	(0x3000 | CPUNUM(cpu, 9) | ((ipi) << 8))
71 #define ACTION_BOOT_THREAD(cpu)		(0x08 | CPUNUM(cpu, 0))
72 
73 static void __init bmips_smp_setup(void)
74 {
75 	int i, cpu = 1, boot_cpu = 0;
76 	int cpu_hw_intr;
77 
78 	switch (current_cpu_type()) {
79 	case CPU_BMIPS4350:
80 	case CPU_BMIPS4380:
81 		/* arbitration priority */
82 		clear_c0_brcm_cmt_ctrl(0x30);
83 
84 		/* NBK and weak order flags */
85 		set_c0_brcm_config_0(0x30000);
86 
87 		/* Find out if we are running on TP0 or TP1 */
88 		boot_cpu = !!(read_c0_brcm_cmt_local() & (1 << 31));
89 
90 		/*
91 		 * MIPS interrupts 0,1 (SW INT 0,1) cross over to the other
92 		 * thread
93 		 * MIPS interrupt 2 (HW INT 0) is the CPU0 L1 controller output
94 		 * MIPS interrupt 3 (HW INT 1) is the CPU1 L1 controller output
95 		 */
96 		if (boot_cpu == 0)
97 			cpu_hw_intr = 0x02;
98 		else
99 			cpu_hw_intr = 0x1d;
100 
101 		change_c0_brcm_cmt_intr(0xf8018000,
102 					(cpu_hw_intr << 27) | (0x03 << 15));
103 
104 		/* single core, 2 threads (2 pipelines) */
105 		max_cpus = 2;
106 
107 		break;
108 	case CPU_BMIPS5000:
109 		/* enable raceless SW interrupts */
110 		set_c0_brcm_config(0x03 << 22);
111 
112 		/* route HW interrupt 0 to CPU0, HW interrupt 1 to CPU1 */
113 		change_c0_brcm_mode(0x1f << 27, 0x02 << 27);
114 
115 		/* N cores, 2 threads per core */
116 		max_cpus = (((read_c0_brcm_config() >> 6) & 0x03) + 1) << 1;
117 
118 		/* clear any pending SW interrupts */
119 		for (i = 0; i < max_cpus; i++) {
120 			write_c0_brcm_action(ACTION_CLR_IPI(i, 0));
121 			write_c0_brcm_action(ACTION_CLR_IPI(i, 1));
122 		}
123 
124 		break;
125 	default:
126 		max_cpus = 1;
127 	}
128 
129 	if (!bmips_smp_enabled)
130 		max_cpus = 1;
131 
132 	/* this can be overridden by the BSP */
133 	if (!board_ebase_setup)
134 		board_ebase_setup = &bmips_ebase_setup;
135 
136 	__cpu_number_map[boot_cpu] = 0;
137 	__cpu_logical_map[0] = boot_cpu;
138 
139 	for (i = 0; i < max_cpus; i++) {
140 		if (i != boot_cpu) {
141 			__cpu_number_map[i] = cpu;
142 			__cpu_logical_map[cpu] = i;
143 			cpu++;
144 		}
145 		set_cpu_possible(i, 1);
146 		set_cpu_present(i, 1);
147 	}
148 }
149 
150 /*
151  * IPI IRQ setup - runs on CPU0
152  */
153 static void bmips_prepare_cpus(unsigned int max_cpus)
154 {
155 	irqreturn_t (*bmips_ipi_interrupt)(int irq, void *dev_id);
156 
157 	switch (current_cpu_type()) {
158 	case CPU_BMIPS4350:
159 	case CPU_BMIPS4380:
160 		bmips_ipi_interrupt = bmips43xx_ipi_interrupt;
161 		break;
162 	case CPU_BMIPS5000:
163 		bmips_ipi_interrupt = bmips5000_ipi_interrupt;
164 		break;
165 	default:
166 		return;
167 	}
168 
169 	if (request_irq(IPI0_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
170 			"smp_ipi0", NULL))
171 		panic("Can't request IPI0 interrupt");
172 	if (request_irq(IPI1_IRQ, bmips_ipi_interrupt, IRQF_PERCPU,
173 			"smp_ipi1", NULL))
174 		panic("Can't request IPI1 interrupt");
175 }
176 
177 /*
178  * Tell the hardware to boot CPUx - runs on CPU0
179  */
180 static void bmips_boot_secondary(int cpu, struct task_struct *idle)
181 {
182 	bmips_smp_boot_sp = __KSTK_TOS(idle);
183 	bmips_smp_boot_gp = (unsigned long)task_thread_info(idle);
184 	mb();
185 
186 	/*
187 	 * Initial boot sequence for secondary CPU:
188 	 *   bmips_reset_nmi_vec @ a000_0000 ->
189 	 *   bmips_smp_entry ->
190 	 *   plat_wired_tlb_setup (cached function call; optional) ->
191 	 *   start_secondary (cached jump)
192 	 *
193 	 * Warm restart sequence:
194 	 *   play_dead WAIT loop ->
195 	 *   bmips_smp_int_vec @ BMIPS_WARM_RESTART_VEC ->
196 	 *   eret to play_dead ->
197 	 *   bmips_secondary_reentry ->
198 	 *   start_secondary
199 	 */
200 
201 	pr_info("SMP: Booting CPU%d...\n", cpu);
202 
203 	if (cpumask_test_cpu(cpu, &bmips_booted_mask)) {
204 		/* kseg1 might not exist if this CPU enabled XKS01 */
205 		bmips_set_reset_vec(cpu, RESET_FROM_KSEG0);
206 
207 		switch (current_cpu_type()) {
208 		case CPU_BMIPS4350:
209 		case CPU_BMIPS4380:
210 			bmips43xx_send_ipi_single(cpu, 0);
211 			break;
212 		case CPU_BMIPS5000:
213 			bmips5000_send_ipi_single(cpu, 0);
214 			break;
215 		}
216 	} else {
217 		bmips_set_reset_vec(cpu, RESET_FROM_KSEG1);
218 
219 		switch (current_cpu_type()) {
220 		case CPU_BMIPS4350:
221 		case CPU_BMIPS4380:
222 			/* Reset slave TP1 if booting from TP0 */
223 			if (cpu_logical_map(cpu) == 1)
224 				set_c0_brcm_cmt_ctrl(0x01);
225 			break;
226 		case CPU_BMIPS5000:
227 			write_c0_brcm_action(ACTION_BOOT_THREAD(cpu));
228 			break;
229 		}
230 		cpumask_set_cpu(cpu, &bmips_booted_mask);
231 	}
232 }
233 
234 /*
235  * Early setup - runs on secondary CPU after cache probe
236  */
237 static void bmips_init_secondary(void)
238 {
239 	switch (current_cpu_type()) {
240 	case CPU_BMIPS4350:
241 	case CPU_BMIPS4380:
242 		clear_c0_cause(smp_processor_id() ? C_SW1 : C_SW0);
243 		break;
244 	case CPU_BMIPS5000:
245 		write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), 0));
246 		current_cpu_data.core = (read_c0_brcm_config() >> 25) & 3;
247 		break;
248 	}
249 }
250 
251 /*
252  * Late setup - runs on secondary CPU before entering the idle loop
253  */
254 static void bmips_smp_finish(void)
255 {
256 	pr_info("SMP: CPU%d is running\n", smp_processor_id());
257 
258 	/* make sure there won't be a timer interrupt for a little while */
259 	write_c0_compare(read_c0_count() + mips_hpt_frequency / HZ);
260 
261 	irq_enable_hazard();
262 	set_c0_status(IE_SW0 | IE_SW1 | bmips_tp1_irqs | IE_IRQ5 | ST0_IE);
263 	irq_enable_hazard();
264 }
265 
266 /*
267  * BMIPS5000 raceless IPIs
268  *
269  * Each CPU has two inbound SW IRQs which are independent of all other CPUs.
270  * IPI0 is used for SMP_RESCHEDULE_YOURSELF
271  * IPI1 is used for SMP_CALL_FUNCTION
272  */
273 
274 static void bmips5000_send_ipi_single(int cpu, unsigned int action)
275 {
276 	write_c0_brcm_action(ACTION_SET_IPI(cpu, action == SMP_CALL_FUNCTION));
277 }
278 
279 static irqreturn_t bmips5000_ipi_interrupt(int irq, void *dev_id)
280 {
281 	int action = irq - IPI0_IRQ;
282 
283 	write_c0_brcm_action(ACTION_CLR_IPI(smp_processor_id(), action));
284 
285 	if (action == 0)
286 		scheduler_ipi();
287 	else
288 		generic_smp_call_function_interrupt();
289 
290 	return IRQ_HANDLED;
291 }
292 
293 static void bmips5000_send_ipi_mask(const struct cpumask *mask,
294 	unsigned int action)
295 {
296 	unsigned int i;
297 
298 	for_each_cpu(i, mask)
299 		bmips5000_send_ipi_single(i, action);
300 }
301 
302 /*
303  * BMIPS43xx racey IPIs
304  *
305  * We use one inbound SW IRQ for each CPU.
306  *
307  * A spinlock must be held in order to keep CPUx from accidentally clearing
308  * an incoming IPI when it writes CP0 CAUSE to raise an IPI on CPUy.  The
309  * same spinlock is used to protect the action masks.
310  */
311 
312 static DEFINE_SPINLOCK(ipi_lock);
313 static DEFINE_PER_CPU(int, ipi_action_mask);
314 
315 static void bmips43xx_send_ipi_single(int cpu, unsigned int action)
316 {
317 	unsigned long flags;
318 
319 	spin_lock_irqsave(&ipi_lock, flags);
320 	set_c0_cause(cpu ? C_SW1 : C_SW0);
321 	per_cpu(ipi_action_mask, cpu) |= action;
322 	irq_enable_hazard();
323 	spin_unlock_irqrestore(&ipi_lock, flags);
324 }
325 
326 static irqreturn_t bmips43xx_ipi_interrupt(int irq, void *dev_id)
327 {
328 	unsigned long flags;
329 	int action, cpu = irq - IPI0_IRQ;
330 
331 	spin_lock_irqsave(&ipi_lock, flags);
332 	action = __this_cpu_read(ipi_action_mask);
333 	per_cpu(ipi_action_mask, cpu) = 0;
334 	clear_c0_cause(cpu ? C_SW1 : C_SW0);
335 	spin_unlock_irqrestore(&ipi_lock, flags);
336 
337 	if (action & SMP_RESCHEDULE_YOURSELF)
338 		scheduler_ipi();
339 	if (action & SMP_CALL_FUNCTION)
340 		generic_smp_call_function_interrupt();
341 
342 	return IRQ_HANDLED;
343 }
344 
345 static void bmips43xx_send_ipi_mask(const struct cpumask *mask,
346 	unsigned int action)
347 {
348 	unsigned int i;
349 
350 	for_each_cpu(i, mask)
351 		bmips43xx_send_ipi_single(i, action);
352 }
353 
354 #ifdef CONFIG_HOTPLUG_CPU
355 
356 static int bmips_cpu_disable(void)
357 {
358 	unsigned int cpu = smp_processor_id();
359 
360 	if (cpu == 0)
361 		return -EBUSY;
362 
363 	pr_info("SMP: CPU%d is offline\n", cpu);
364 
365 	set_cpu_online(cpu, false);
366 	calculate_cpu_foreign_map();
367 	cpumask_clear_cpu(cpu, &cpu_callin_map);
368 	clear_c0_status(IE_IRQ5);
369 
370 	local_flush_tlb_all();
371 	local_flush_icache_range(0, ~0);
372 
373 	return 0;
374 }
375 
376 static void bmips_cpu_die(unsigned int cpu)
377 {
378 }
379 
380 void __ref play_dead(void)
381 {
382 	idle_task_exit();
383 
384 	/* flush data cache */
385 	_dma_cache_wback_inv(0, ~0);
386 
387 	/*
388 	 * Wakeup is on SW0 or SW1; disable everything else
389 	 * Use BEV !IV (BMIPS_WARM_RESTART_VEC) to avoid the regular Linux
390 	 * IRQ handlers; this clears ST0_IE and returns immediately.
391 	 */
392 	clear_c0_cause(CAUSEF_IV | C_SW0 | C_SW1);
393 	change_c0_status(
394 		IE_IRQ5 | bmips_tp1_irqs | IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV,
395 		IE_SW0 | IE_SW1 | ST0_IE | ST0_BEV);
396 	irq_disable_hazard();
397 
398 	/*
399 	 * wait for SW interrupt from bmips_boot_secondary(), then jump
400 	 * back to start_secondary()
401 	 */
402 	__asm__ __volatile__(
403 	"	wait\n"
404 	"	j	bmips_secondary_reentry\n"
405 	: : : "memory");
406 }
407 
408 #endif /* CONFIG_HOTPLUG_CPU */
409 
410 struct plat_smp_ops bmips43xx_smp_ops = {
411 	.smp_setup		= bmips_smp_setup,
412 	.prepare_cpus		= bmips_prepare_cpus,
413 	.boot_secondary		= bmips_boot_secondary,
414 	.smp_finish		= bmips_smp_finish,
415 	.init_secondary		= bmips_init_secondary,
416 	.send_ipi_single	= bmips43xx_send_ipi_single,
417 	.send_ipi_mask		= bmips43xx_send_ipi_mask,
418 #ifdef CONFIG_HOTPLUG_CPU
419 	.cpu_disable		= bmips_cpu_disable,
420 	.cpu_die		= bmips_cpu_die,
421 #endif
422 };
423 
424 struct plat_smp_ops bmips5000_smp_ops = {
425 	.smp_setup		= bmips_smp_setup,
426 	.prepare_cpus		= bmips_prepare_cpus,
427 	.boot_secondary		= bmips_boot_secondary,
428 	.smp_finish		= bmips_smp_finish,
429 	.init_secondary		= bmips_init_secondary,
430 	.send_ipi_single	= bmips5000_send_ipi_single,
431 	.send_ipi_mask		= bmips5000_send_ipi_mask,
432 #ifdef CONFIG_HOTPLUG_CPU
433 	.cpu_disable		= bmips_cpu_disable,
434 	.cpu_die		= bmips_cpu_die,
435 #endif
436 };
437 
438 #endif /* CONFIG_SMP */
439 
440 /***********************************************************************
441  * BMIPS vector relocation
442  * This is primarily used for SMP boot, but it is applicable to some
443  * UP BMIPS systems as well.
444  ***********************************************************************/
445 
446 static void bmips_wr_vec(unsigned long dst, char *start, char *end)
447 {
448 	memcpy((void *)dst, start, end - start);
449 	dma_cache_wback(dst, end - start);
450 	local_flush_icache_range(dst, dst + (end - start));
451 	instruction_hazard();
452 }
453 
454 static inline void bmips_nmi_handler_setup(void)
455 {
456 	bmips_wr_vec(BMIPS_NMI_RESET_VEC, &bmips_reset_nmi_vec,
457 		&bmips_reset_nmi_vec_end);
458 	bmips_wr_vec(BMIPS_WARM_RESTART_VEC, &bmips_smp_int_vec,
459 		&bmips_smp_int_vec_end);
460 }
461 
462 struct reset_vec_info {
463 	int cpu;
464 	u32 val;
465 };
466 
467 static void bmips_set_reset_vec_remote(void *vinfo)
468 {
469 	struct reset_vec_info *info = vinfo;
470 	int shift = info->cpu & 0x01 ? 16 : 0;
471 	u32 mask = ~(0xffff << shift), val = info->val >> 16;
472 
473 	preempt_disable();
474 	if (smp_processor_id() > 0) {
475 		smp_call_function_single(0, &bmips_set_reset_vec_remote,
476 					 info, 1);
477 	} else {
478 		if (info->cpu & 0x02) {
479 			/* BMIPS5200 "should" use mask/shift, but it's buggy */
480 			bmips_write_zscm_reg(0xa0, (val << 16) | val);
481 			bmips_read_zscm_reg(0xa0);
482 		} else {
483 			write_c0_brcm_bootvec((read_c0_brcm_bootvec() & mask) |
484 					      (val << shift));
485 		}
486 	}
487 	preempt_enable();
488 }
489 
490 static void bmips_set_reset_vec(int cpu, u32 val)
491 {
492 	struct reset_vec_info info;
493 
494 	if (current_cpu_type() == CPU_BMIPS5000) {
495 		/* this needs to run from CPU0 (which is always online) */
496 		info.cpu = cpu;
497 		info.val = val;
498 		bmips_set_reset_vec_remote(&info);
499 	} else {
500 		void __iomem *cbr = BMIPS_GET_CBR();
501 
502 		if (cpu == 0)
503 			__raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_0);
504 		else {
505 			if (current_cpu_type() != CPU_BMIPS4380)
506 				return;
507 			__raw_writel(val, cbr + BMIPS_RELO_VECTOR_CONTROL_1);
508 		}
509 	}
510 	__sync();
511 	back_to_back_c0_hazard();
512 }
513 
514 void bmips_ebase_setup(void)
515 {
516 	unsigned long new_ebase = ebase;
517 
518 	BUG_ON(ebase != CKSEG0);
519 
520 	switch (current_cpu_type()) {
521 	case CPU_BMIPS4350:
522 		/*
523 		 * BMIPS4350 cannot relocate the normal vectors, but it
524 		 * can relocate the BEV=1 vectors.  So CPU1 starts up at
525 		 * the relocated BEV=1, IV=0 general exception vector @
526 		 * 0xa000_0380.
527 		 *
528 		 * set_uncached_handler() is used here because:
529 		 *  - CPU1 will run this from uncached space
530 		 *  - None of the cacheflush functions are set up yet
531 		 */
532 		set_uncached_handler(BMIPS_WARM_RESTART_VEC - CKSEG0,
533 			&bmips_smp_int_vec, 0x80);
534 		__sync();
535 		return;
536 	case CPU_BMIPS3300:
537 	case CPU_BMIPS4380:
538 		/*
539 		 * 0x8000_0000: reset/NMI (initially in kseg1)
540 		 * 0x8000_0400: normal vectors
541 		 */
542 		new_ebase = 0x80000400;
543 		bmips_set_reset_vec(0, RESET_FROM_KSEG0);
544 		break;
545 	case CPU_BMIPS5000:
546 		/*
547 		 * 0x8000_0000: reset/NMI (initially in kseg1)
548 		 * 0x8000_1000: normal vectors
549 		 */
550 		new_ebase = 0x80001000;
551 		bmips_set_reset_vec(0, RESET_FROM_KSEG0);
552 		write_c0_ebase(new_ebase);
553 		break;
554 	default:
555 		return;
556 	}
557 
558 	board_nmi_handler_setup = &bmips_nmi_handler_setup;
559 	ebase = new_ebase;
560 }
561 
562 asmlinkage void __weak plat_wired_tlb_setup(void)
563 {
564 	/*
565 	 * Called when starting/restarting a secondary CPU.
566 	 * Kernel stacks and other important data might only be accessible
567 	 * once the wired entries are present.
568 	 */
569 }
570 
571 void __init bmips_cpu_setup(void)
572 {
573 	void __iomem __maybe_unused *cbr = BMIPS_GET_CBR();
574 	u32 __maybe_unused cfg;
575 
576 	switch (current_cpu_type()) {
577 	case CPU_BMIPS3300:
578 		/* Set BIU to async mode */
579 		set_c0_brcm_bus_pll(BIT(22));
580 		__sync();
581 
582 		/* put the BIU back in sync mode */
583 		clear_c0_brcm_bus_pll(BIT(22));
584 
585 		/* clear BHTD to enable branch history table */
586 		clear_c0_brcm_reset(BIT(16));
587 
588 		/* Flush and enable RAC */
589 		cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
590 		__raw_writel(cfg | 0x100, BMIPS_RAC_CONFIG);
591 		__raw_readl(cbr + BMIPS_RAC_CONFIG);
592 
593 		cfg = __raw_readl(cbr + BMIPS_RAC_CONFIG);
594 		__raw_writel(cfg | 0xf, BMIPS_RAC_CONFIG);
595 		__raw_readl(cbr + BMIPS_RAC_CONFIG);
596 
597 		cfg = __raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
598 		__raw_writel(cfg | 0x0fff0000, cbr + BMIPS_RAC_ADDRESS_RANGE);
599 		__raw_readl(cbr + BMIPS_RAC_ADDRESS_RANGE);
600 		break;
601 
602 	case CPU_BMIPS4380:
603 		/* CBG workaround for early BMIPS4380 CPUs */
604 		switch (read_c0_prid()) {
605 		case 0x2a040:
606 		case 0x2a042:
607 		case 0x2a044:
608 		case 0x2a060:
609 			cfg = __raw_readl(cbr + BMIPS_L2_CONFIG);
610 			__raw_writel(cfg & ~0x07000000, cbr + BMIPS_L2_CONFIG);
611 			__raw_readl(cbr + BMIPS_L2_CONFIG);
612 		}
613 
614 		/* clear BHTD to enable branch history table */
615 		clear_c0_brcm_config_0(BIT(21));
616 
617 		/* XI/ROTR enable */
618 		set_c0_brcm_config_0(BIT(23));
619 		set_c0_brcm_cmt_ctrl(BIT(15));
620 		break;
621 
622 	case CPU_BMIPS5000:
623 		/* enable RDHWR, BRDHWR */
624 		set_c0_brcm_config(BIT(17) | BIT(21));
625 
626 		/* Disable JTB */
627 		__asm__ __volatile__(
628 		"	.set	noreorder\n"
629 		"	li	$8, 0x5a455048\n"
630 		"	.word	0x4088b00f\n"	/* mtc0	t0, $22, 15 */
631 		"	.word	0x4008b008\n"	/* mfc0	t0, $22, 8 */
632 		"	li	$9, 0x00008000\n"
633 		"	or	$8, $8, $9\n"
634 		"	.word	0x4088b008\n"	/* mtc0	t0, $22, 8 */
635 		"	sync\n"
636 		"	li	$8, 0x0\n"
637 		"	.word	0x4088b00f\n"	/* mtc0	t0, $22, 15 */
638 		"	.set	reorder\n"
639 		: : : "$8", "$9");
640 
641 		/* XI enable */
642 		set_c0_brcm_config(BIT(27));
643 
644 		/* enable MIPS32R2 ROR instruction for XI TLB handlers */
645 		__asm__ __volatile__(
646 		"	li	$8, 0x5a455048\n"
647 		"	.word	0x4088b00f\n"	/* mtc0 $8, $22, 15 */
648 		"	nop; nop; nop\n"
649 		"	.word	0x4008b008\n"	/* mfc0 $8, $22, 8 */
650 		"	lui	$9, 0x0100\n"
651 		"	or	$8, $9\n"
652 		"	.word	0x4088b008\n"	/* mtc0 $8, $22, 8 */
653 		: : : "$8", "$9");
654 		break;
655 	}
656 }
657