1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Author: Andy Fleming <afleming@freescale.com>
4 * 	   Kumar Gala <galak@kernel.crashing.org>
5 *
6 * Copyright 2006-2008, 2011-2012, 2015 Freescale Semiconductor Inc.
7 */
8
9#include <linux/stddef.h>
10#include <linux/kernel.h>
11#include <linux/sched/hotplug.h>
12#include <linux/init.h>
13#include <linux/delay.h>
14#include <linux/of.h>
15#include <linux/kexec.h>
16#include <linux/highmem.h>
17#include <linux/cpu.h>
18#include <linux/fsl/guts.h>
19#include <linux/pgtable.h>
20
21#include <asm/machdep.h>
22#include <asm/page.h>
23#include <asm/mpic.h>
24#include <asm/cacheflush.h>
25#include <asm/dbell.h>
26#include <asm/code-patching.h>
27#include <asm/cputhreads.h>
28#include <asm/fsl_pm.h>
29
30#include <sysdev/fsl_soc.h>
31#include <sysdev/mpic.h>
32#include "smp.h"
33
34struct epapr_spin_table {
35	u32	addr_h;
36	u32	addr_l;
37	u32	r3_h;
38	u32	r3_l;
39	u32	reserved;
40	u32	pir;
41};
42
43static u64 timebase;
44static int tb_req;
45static int tb_valid;
46
47static void mpc85xx_give_timebase(void)
48{
49	unsigned long flags;
50
51	local_irq_save(flags);
52	hard_irq_disable();
53
54	while (!tb_req)
55		barrier();
56	tb_req = 0;
57
58	qoriq_pm_ops->freeze_time_base(true);
59#ifdef CONFIG_PPC64
60	/*
61	 * e5500/e6500 have a workaround for erratum A-006958 in place
62	 * that will reread the timebase until TBL is non-zero.
63	 * That would be a bad thing when the timebase is frozen.
64	 *
65	 * Thus, we read it manually, and instead of checking that
66	 * TBL is non-zero, we ensure that TB does not change.  We don't
67	 * do that for the main mftb implementation, because it requires
68	 * a scratch register
69	 */
70	{
71		u64 prev;
72
73		asm volatile("mfspr %0, %1" : "=r" (timebase) :
74			     "i" (SPRN_TBRL));
75
76		do {
77			prev = timebase;
78			asm volatile("mfspr %0, %1" : "=r" (timebase) :
79				     "i" (SPRN_TBRL));
80		} while (prev != timebase);
81	}
82#else
83	timebase = get_tb();
84#endif
85	mb();
86	tb_valid = 1;
87
88	while (tb_valid)
89		barrier();
90
91	qoriq_pm_ops->freeze_time_base(false);
92
93	local_irq_restore(flags);
94}
95
96static void mpc85xx_take_timebase(void)
97{
98	unsigned long flags;
99
100	local_irq_save(flags);
101	hard_irq_disable();
102
103	tb_req = 1;
104	while (!tb_valid)
105		barrier();
106
107	set_tb(timebase >> 32, timebase & 0xffffffff);
108	isync();
109	tb_valid = 0;
110
111	local_irq_restore(flags);
112}
113
114#ifdef CONFIG_HOTPLUG_CPU
115static void smp_85xx_cpu_offline_self(void)
116{
117	unsigned int cpu = smp_processor_id();
118
119	local_irq_disable();
120	hard_irq_disable();
121	/* mask all irqs to prevent cpu wakeup */
122	qoriq_pm_ops->irq_mask(cpu);
123
124	idle_task_exit();
125
126	mtspr(SPRN_TCR, 0);
127	mtspr(SPRN_TSR, mfspr(SPRN_TSR));
128
129	generic_set_cpu_dead(cpu);
130
131	cur_cpu_spec->cpu_down_flush();
132
133	qoriq_pm_ops->cpu_die(cpu);
134
135	while (1)
136		;
137}
138
139static void qoriq_cpu_kill(unsigned int cpu)
140{
141	int i;
142
143	for (i = 0; i < 500; i++) {
144		if (is_cpu_dead(cpu)) {
145#ifdef CONFIG_PPC64
146			paca_ptrs[cpu]->cpu_start = 0;
147#endif
148			return;
149		}
150		msleep(20);
151	}
152	pr_err("CPU%d didn't die...\n", cpu);
153}
154#endif
155
156/*
157 * To keep it compatible with old boot program which uses
158 * cache-inhibit spin table, we need to flush the cache
159 * before accessing spin table to invalidate any staled data.
160 * We also need to flush the cache after writing to spin
161 * table to push data out.
162 */
163static inline void flush_spin_table(void *spin_table)
164{
165	flush_dcache_range((ulong)spin_table,
166		(ulong)spin_table + sizeof(struct epapr_spin_table));
167}
168
169static inline u32 read_spin_table_addr_l(void *spin_table)
170{
171	flush_dcache_range((ulong)spin_table,
172		(ulong)spin_table + sizeof(struct epapr_spin_table));
173	return in_be32(&((struct epapr_spin_table *)spin_table)->addr_l);
174}
175
176#ifdef CONFIG_PPC64
177static void wake_hw_thread(void *info)
178{
179	void fsl_secondary_thread_init(void);
180	unsigned long inia;
181	int cpu = *(const int *)info;
182
183	inia = ppc_function_entry(fsl_secondary_thread_init);
184	book3e_start_thread(cpu_thread_in_core(cpu), inia);
185}
186#endif
187
188static int smp_85xx_start_cpu(int cpu)
189{
190	int ret = 0;
191	struct device_node *np;
192	const u64 *cpu_rel_addr;
193	unsigned long flags;
194	int ioremappable;
195	int hw_cpu = get_hard_smp_processor_id(cpu);
196	struct epapr_spin_table __iomem *spin_table;
197
198	np = of_get_cpu_node(cpu, NULL);
199	cpu_rel_addr = of_get_property(np, "cpu-release-addr", NULL);
200	if (!cpu_rel_addr) {
201		pr_err("No cpu-release-addr for cpu %d\n", cpu);
202		return -ENOENT;
203	}
204
205	/*
206	 * A secondary core could be in a spinloop in the bootpage
207	 * (0xfffff000), somewhere in highmem, or somewhere in lowmem.
208	 * The bootpage and highmem can be accessed via ioremap(), but
209	 * we need to directly access the spinloop if its in lowmem.
210	 */
211	ioremappable = *cpu_rel_addr > virt_to_phys(high_memory - 1);
212
213	/* Map the spin table */
214	if (ioremappable)
215		spin_table = ioremap_coherent(*cpu_rel_addr,
216					      sizeof(struct epapr_spin_table));
217	else
218		spin_table = phys_to_virt(*cpu_rel_addr);
219
220	local_irq_save(flags);
221	hard_irq_disable();
222
223	if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
224		qoriq_pm_ops->cpu_up_prepare(cpu);
225
226	/* if cpu is not spinning, reset it */
227	if (read_spin_table_addr_l(spin_table) != 1) {
228		/*
229		 * We don't set the BPTR register here since it already points
230		 * to the boot page properly.
231		 */
232		mpic_reset_core(cpu);
233
234		/*
235		 * wait until core is ready...
236		 * We need to invalidate the stale data, in case the boot
237		 * loader uses a cache-inhibited spin table.
238		 */
239		if (!spin_event_timeout(
240				read_spin_table_addr_l(spin_table) == 1,
241				10000, 100)) {
242			pr_err("timeout waiting for cpu %d to reset\n",
243				hw_cpu);
244			ret = -EAGAIN;
245			goto err;
246		}
247	}
248
249	flush_spin_table(spin_table);
250	out_be32(&spin_table->pir, hw_cpu);
251#ifdef CONFIG_PPC64
252	out_be64((u64 *)(&spin_table->addr_h),
253		__pa(ppc_function_entry(generic_secondary_smp_init)));
254#else
255#ifdef CONFIG_PHYS_ADDR_T_64BIT
256	/*
257	 * We need also to write addr_h to spin table for systems
258	 * in which their physical memory start address was configured
259	 * to above 4G, otherwise the secondary core can not get
260	 * correct entry to start from.
261	 */
262	out_be32(&spin_table->addr_h, __pa(__early_start) >> 32);
263#endif
264	out_be32(&spin_table->addr_l, __pa(__early_start));
265#endif
266	flush_spin_table(spin_table);
267err:
268	local_irq_restore(flags);
269
270	if (ioremappable)
271		iounmap(spin_table);
272
273	return ret;
274}
275
276static int smp_85xx_kick_cpu(int nr)
277{
278	int ret = 0;
279#ifdef CONFIG_PPC64
280	int primary = nr;
281#endif
282
283	WARN_ON(nr < 0 || nr >= num_possible_cpus());
284
285	pr_debug("kick CPU #%d\n", nr);
286
287#ifdef CONFIG_PPC64
288	if (threads_per_core == 2) {
289		if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT)))
290			return -ENOENT;
291
292		booting_thread_hwid = cpu_thread_in_core(nr);
293		primary = cpu_first_thread_sibling(nr);
294
295		if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
296			qoriq_pm_ops->cpu_up_prepare(nr);
297
298		/*
299		 * If either thread in the core is online, use it to start
300		 * the other.
301		 */
302		if (cpu_online(primary)) {
303			smp_call_function_single(primary,
304					wake_hw_thread, &nr, 1);
305			goto done;
306		} else if (cpu_online(primary + 1)) {
307			smp_call_function_single(primary + 1,
308					wake_hw_thread, &nr, 1);
309			goto done;
310		}
311
312		/*
313		 * If getting here, it means both threads in the core are
314		 * offline. So start the primary thread, then it will start
315		 * the thread specified in booting_thread_hwid, the one
316		 * corresponding to nr.
317		 */
318
319	} else if (threads_per_core == 1) {
320		/*
321		 * If one core has only one thread, set booting_thread_hwid to
322		 * an invalid value.
323		 */
324		booting_thread_hwid = INVALID_THREAD_HWID;
325
326	} else if (threads_per_core > 2) {
327		pr_err("Do not support more than 2 threads per CPU.");
328		return -EINVAL;
329	}
330
331	ret = smp_85xx_start_cpu(primary);
332	if (ret)
333		return ret;
334
335done:
336	paca_ptrs[nr]->cpu_start = 1;
337	generic_set_cpu_up(nr);
338
339	return ret;
340#else
341	ret = smp_85xx_start_cpu(nr);
342	if (ret)
343		return ret;
344
345	generic_set_cpu_up(nr);
346
347	return ret;
348#endif
349}
350
351struct smp_ops_t smp_85xx_ops = {
352	.cause_nmi_ipi = NULL,
353	.kick_cpu = smp_85xx_kick_cpu,
354	.cpu_bootable = smp_generic_cpu_bootable,
355#ifdef CONFIG_HOTPLUG_CPU
356	.cpu_disable	= generic_cpu_disable,
357	.cpu_die	= generic_cpu_die,
358#endif
359#if defined(CONFIG_KEXEC_CORE) && !defined(CONFIG_PPC64)
360	.give_timebase	= smp_generic_give_timebase,
361	.take_timebase	= smp_generic_take_timebase,
362#endif
363};
364
365#ifdef CONFIG_KEXEC_CORE
366#ifdef CONFIG_PPC32
367atomic_t kexec_down_cpus = ATOMIC_INIT(0);
368
369static void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
370{
371	local_irq_disable();
372
373	if (secondary) {
374		cur_cpu_spec->cpu_down_flush();
375		atomic_inc(&kexec_down_cpus);
376		/* loop forever */
377		while (1);
378	}
379}
380
381static void mpc85xx_smp_kexec_down(void *arg)
382{
383	if (ppc_md.kexec_cpu_down)
384		ppc_md.kexec_cpu_down(0,1);
385}
386#else
387static void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
388{
389	int cpu = smp_processor_id();
390	int sibling = cpu_last_thread_sibling(cpu);
391	bool notified = false;
392	int disable_cpu;
393	int disable_threadbit = 0;
394	long start = mftb();
395	long now;
396
397	local_irq_disable();
398	hard_irq_disable();
399	mpic_teardown_this_cpu(secondary);
400
401	if (cpu == crashing_cpu && cpu_thread_in_core(cpu) != 0) {
402		/*
403		 * We enter the crash kernel on whatever cpu crashed,
404		 * even if it's a secondary thread.  If that's the case,
405		 * disable the corresponding primary thread.
406		 */
407		disable_threadbit = 1;
408		disable_cpu = cpu_first_thread_sibling(cpu);
409	} else if (sibling != crashing_cpu &&
410		   cpu_thread_in_core(cpu) == 0 &&
411		   cpu_thread_in_core(sibling) != 0) {
412		disable_threadbit = 2;
413		disable_cpu = sibling;
414	}
415
416	if (disable_threadbit) {
417		while (paca_ptrs[disable_cpu]->kexec_state < KEXEC_STATE_REAL_MODE) {
418			barrier();
419			now = mftb();
420			if (!notified && now - start > 1000000) {
421				pr_info("%s/%d: waiting for cpu %d to enter KEXEC_STATE_REAL_MODE (%d)\n",
422					__func__, smp_processor_id(),
423					disable_cpu,
424					paca_ptrs[disable_cpu]->kexec_state);
425				notified = true;
426			}
427		}
428
429		if (notified) {
430			pr_info("%s: cpu %d done waiting\n",
431				__func__, disable_cpu);
432		}
433
434		mtspr(SPRN_TENC, disable_threadbit);
435		while (mfspr(SPRN_TENSR) & disable_threadbit)
436			cpu_relax();
437	}
438}
439#endif
440
441static void mpc85xx_smp_machine_kexec(struct kimage *image)
442{
443#ifdef CONFIG_PPC32
444	int timeout = INT_MAX;
445	int i, num_cpus = num_present_cpus();
446
447	if (image->type == KEXEC_TYPE_DEFAULT)
448		smp_call_function(mpc85xx_smp_kexec_down, NULL, 0);
449
450	while ( (atomic_read(&kexec_down_cpus) != (num_cpus - 1)) &&
451		( timeout > 0 ) )
452	{
453		timeout--;
454	}
455
456	if ( !timeout )
457		printk(KERN_ERR "Unable to bring down secondary cpu(s)");
458
459	for_each_online_cpu(i)
460	{
461		if ( i == smp_processor_id() ) continue;
462		mpic_reset_core(i);
463	}
464#endif
465
466	default_machine_kexec(image);
467}
468#endif /* CONFIG_KEXEC_CORE */
469
470static void smp_85xx_setup_cpu(int cpu_nr)
471{
472	mpic_setup_this_cpu();
473}
474
475void __init mpc85xx_smp_init(void)
476{
477	struct device_node *np;
478
479
480	np = of_find_node_by_type(NULL, "open-pic");
481	if (np) {
482		smp_85xx_ops.probe = smp_mpic_probe;
483		smp_85xx_ops.setup_cpu = smp_85xx_setup_cpu;
484		smp_85xx_ops.message_pass = smp_mpic_message_pass;
485	} else
486		smp_85xx_ops.setup_cpu = NULL;
487
488	if (cpu_has_feature(CPU_FTR_DBELL)) {
489		/*
490		 * If left NULL, .message_pass defaults to
491		 * smp_muxed_ipi_message_pass
492		 */
493		smp_85xx_ops.message_pass = NULL;
494		smp_85xx_ops.cause_ipi = doorbell_global_ipi;
495		smp_85xx_ops.probe = NULL;
496	}
497
498#ifdef CONFIG_FSL_CORENET_RCPM
499	/* Assign a value to qoriq_pm_ops on PPC_E500MC */
500	fsl_rcpm_init();
501#else
502	/* Assign a value to qoriq_pm_ops on !PPC_E500MC */
503	mpc85xx_setup_pmc();
504#endif
505	if (qoriq_pm_ops) {
506		smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
507		smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
508#ifdef CONFIG_HOTPLUG_CPU
509		smp_85xx_ops.cpu_offline_self = smp_85xx_cpu_offline_self;
510		smp_85xx_ops.cpu_die = qoriq_cpu_kill;
511#endif
512	}
513	smp_ops = &smp_85xx_ops;
514
515#ifdef CONFIG_KEXEC_CORE
516	ppc_md.kexec_cpu_down = mpc85xx_smp_kexec_cpu_down;
517	ppc_md.machine_kexec = mpc85xx_smp_machine_kexec;
518#endif
519}
520