2 * Copyright (C) 2013 Imagination Technologies
3 * Author: Paul Burton <paul.burton@imgtec.com>
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License as published by the
7 * Free Software Foundation; either version 2 of the License, or (at your
8 * option) any later version.
11 #include <linux/delay.h>
13 #include <linux/irqchip/mips-gic.h>
14 #include <linux/sched.h>
15 #include <linux/slab.h>
16 #include <linux/smp.h>
17 #include <linux/types.h>
19 #include <asm/bcache.h>
20 #include <asm/mips-cm.h>
21 #include <asm/mips-cpc.h>
22 #include <asm/mips_mt.h>
23 #include <asm/mipsregs.h>
24 #include <asm/pm-cps.h>
25 #include <asm/r4kcache.h>
26 #include <asm/smp-cps.h>
30 static bool threads_disabled
;
31 static DECLARE_BITMAP(core_power
, NR_CPUS
);
33 struct core_boot_config
*mips_cps_core_bootcfg
;
35 static int __init
setup_nothreads(char *s
)
37 threads_disabled
= true;
40 early_param("nothreads", setup_nothreads
);
42 static unsigned core_vpe_count(unsigned core
)
49 if ((!IS_ENABLED(CONFIG_MIPS_MT_SMP
) || !cpu_has_mipsmt
)
50 && (!IS_ENABLED(CONFIG_CPU_MIPSR6
) || !cpu_has_vp
))
53 mips_cm_lock_other(core
, 0);
54 cfg
= read_gcr_co_config() & CM_GCR_Cx_CONFIG_PVPE_MSK
;
55 mips_cm_unlock_other();
56 return (cfg
>> CM_GCR_Cx_CONFIG_PVPE_SHF
) + 1;
59 static void __init
cps_smp_setup(void)
61 unsigned int ncores
, nvpes
, core_vpes
;
62 unsigned long core_entry
;
65 /* Detect & record VPE topology */
66 ncores
= mips_cm_numcores();
67 pr_info("%s topology ", cpu_has_mips_r6
? "VP" : "VPE");
68 for (c
= nvpes
= 0; c
< ncores
; c
++) {
69 core_vpes
= core_vpe_count(c
);
70 pr_cont("%c%u", c
? ',' : '{', core_vpes
);
72 /* Use the number of VPEs in core 0 for smp_num_siblings */
74 smp_num_siblings
= core_vpes
;
76 for (v
= 0; v
< min_t(int, core_vpes
, NR_CPUS
- nvpes
); v
++) {
77 cpu_data
[nvpes
+ v
].core
= c
;
78 #if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_CPU_MIPSR6)
79 cpu_data
[nvpes
+ v
].vpe_id
= v
;
85 pr_cont("} total %u\n", nvpes
);
87 /* Indicate present CPUs (CPU being synonymous with VPE) */
88 for (v
= 0; v
< min_t(unsigned, nvpes
, NR_CPUS
); v
++) {
89 set_cpu_possible(v
, true);
90 set_cpu_present(v
, true);
91 __cpu_number_map
[v
] = v
;
92 __cpu_logical_map
[v
] = v
;
95 /* Set a coherent default CCA (CWB) */
96 change_c0_config(CONF_CM_CMASK
, 0x5);
98 /* Core 0 is powered up (we're running on it) */
99 bitmap_set(core_power
, 0, 1);
101 /* Initialise core 0 */
102 mips_cps_core_init();
104 /* Make core 0 coherent with everything */
105 write_gcr_cl_coherence(0xff);
107 if (mips_cm_revision() >= CM_REV_CM3
) {
108 core_entry
= CKSEG1ADDR((unsigned long)mips_cps_core_entry
);
109 write_gcr_bev_base(core_entry
);
112 #ifdef CONFIG_MIPS_MT_FPAFF
113 /* If we have an FPU, enroll ourselves in the FPU-full mask */
115 cpumask_set_cpu(0, &mt_fpu_cpumask
);
116 #endif /* CONFIG_MIPS_MT_FPAFF */
119 static void __init
cps_prepare_cpus(unsigned int max_cpus
)
121 unsigned ncores
, core_vpes
, c
, cca
;
125 mips_mt_set_cpuoptions();
127 /* Detect whether the CCA is unsuited to multi-core SMP */
128 cca
= read_c0_config() & CONF_CM_CMASK
;
132 /* The CCA is coherent, multi-core is fine */
133 cca_unsuitable
= false;
137 /* CCA is not coherent, multi-core is not usable */
138 cca_unsuitable
= true;
141 /* Warn the user if the CCA prevents multi-core */
142 ncores
= mips_cm_numcores();
143 if (cca_unsuitable
&& ncores
> 1) {
144 pr_warn("Using only one core due to unsuitable CCA 0x%x\n",
147 for_each_present_cpu(c
) {
148 if (cpu_data
[c
].core
)
149 set_cpu_present(c
, false);
154 * Patch the start of mips_cps_core_entry to provide:
158 entry_code
= (u32
*)&mips_cps_core_entry
;
159 uasm_i_addiu(&entry_code
, 16, 0, cca
);
160 blast_dcache_range((unsigned long)&mips_cps_core_entry
,
161 (unsigned long)entry_code
);
162 bc_wback_inv((unsigned long)&mips_cps_core_entry
,
163 (void *)entry_code
- (void *)&mips_cps_core_entry
);
166 /* Allocate core boot configuration structs */
167 mips_cps_core_bootcfg
= kcalloc(ncores
, sizeof(*mips_cps_core_bootcfg
),
169 if (!mips_cps_core_bootcfg
) {
170 pr_err("Failed to allocate boot config for %u cores\n", ncores
);
174 /* Allocate VPE boot configuration structs */
175 for (c
= 0; c
< ncores
; c
++) {
176 core_vpes
= core_vpe_count(c
);
177 mips_cps_core_bootcfg
[c
].vpe_config
= kcalloc(core_vpes
,
178 sizeof(*mips_cps_core_bootcfg
[c
].vpe_config
),
180 if (!mips_cps_core_bootcfg
[c
].vpe_config
) {
181 pr_err("Failed to allocate %u VPE boot configs\n",
187 /* Mark this CPU as booted */
188 atomic_set(&mips_cps_core_bootcfg
[current_cpu_data
.core
].vpe_mask
,
189 1 << cpu_vpe_id(¤t_cpu_data
));
193 /* Clean up allocations */
194 if (mips_cps_core_bootcfg
) {
195 for (c
= 0; c
< ncores
; c
++)
196 kfree(mips_cps_core_bootcfg
[c
].vpe_config
);
197 kfree(mips_cps_core_bootcfg
);
198 mips_cps_core_bootcfg
= NULL
;
201 /* Effectively disable SMP by declaring CPUs not present */
202 for_each_possible_cpu(c
) {
205 set_cpu_present(c
, false);
209 static void boot_core(unsigned int core
, unsigned int vpe_id
)
211 u32 access
, stat
, seq_state
;
214 /* Select the appropriate core */
215 mips_cm_lock_other(core
, 0);
217 /* Set its reset vector */
218 write_gcr_co_reset_base(CKSEG1ADDR((unsigned long)mips_cps_core_entry
));
220 /* Ensure its coherency is disabled */
221 write_gcr_co_coherence(0);
223 /* Start it with the legacy memory map and exception base */
224 write_gcr_co_reset_ext_base(CM_GCR_RESET_EXT_BASE_UEB
);
226 /* Ensure the core can access the GCRs */
227 access
= read_gcr_access();
228 access
|= 1 << (CM_GCR_ACCESS_ACCESSEN_SHF
+ core
);
229 write_gcr_access(access
);
231 if (mips_cpc_present()) {
233 mips_cpc_lock_other(core
);
235 if (mips_cm_revision() >= CM_REV_CM3
) {
236 /* Run only the requested VP following the reset */
237 write_cpc_co_vp_stop(0xf);
238 write_cpc_co_vp_run(1 << vpe_id
);
241 * Ensure that the VP_RUN register is written before the
247 write_cpc_co_cmd(CPC_Cx_CMD_RESET
);
251 stat
= read_cpc_co_stat_conf();
252 seq_state
= stat
& CPC_Cx_STAT_CONF_SEQSTATE_MSK
;
254 /* U6 == coherent execution, ie. the core is up */
255 if (seq_state
== CPC_Cx_STAT_CONF_SEQSTATE_U6
)
258 /* Delay a little while before we start warning */
265 pr_warn("Waiting for core %u to start... STAT_CONF=0x%x\n",
270 mips_cpc_unlock_other();
272 /* Take the core out of reset */
273 write_gcr_co_reset_release(0);
276 mips_cm_unlock_other();
278 /* The core is now powered up */
279 bitmap_set(core_power
, core
, 1);
282 static void remote_vpe_boot(void *dummy
)
284 unsigned core
= current_cpu_data
.core
;
285 struct core_boot_config
*core_cfg
= &mips_cps_core_bootcfg
[core
];
287 mips_cps_boot_vpes(core_cfg
, cpu_vpe_id(¤t_cpu_data
));
290 static void cps_boot_secondary(int cpu
, struct task_struct
*idle
)
292 unsigned core
= cpu_data
[cpu
].core
;
293 unsigned vpe_id
= cpu_vpe_id(&cpu_data
[cpu
]);
294 struct core_boot_config
*core_cfg
= &mips_cps_core_bootcfg
[core
];
295 struct vpe_boot_config
*vpe_cfg
= &core_cfg
->vpe_config
[vpe_id
];
296 unsigned long core_entry
;
300 vpe_cfg
->pc
= (unsigned long)&smp_bootstrap
;
301 vpe_cfg
->sp
= __KSTK_TOS(idle
);
302 vpe_cfg
->gp
= (unsigned long)task_thread_info(idle
);
304 atomic_or(1 << cpu_vpe_id(&cpu_data
[cpu
]), &core_cfg
->vpe_mask
);
308 if (!test_bit(core
, core_power
)) {
309 /* Boot a VPE on a powered down core */
310 boot_core(core
, vpe_id
);
315 mips_cm_lock_other(core
, vpe_id
);
316 core_entry
= CKSEG1ADDR((unsigned long)mips_cps_core_entry
);
317 write_gcr_co_reset_base(core_entry
);
318 mips_cm_unlock_other();
321 if (core
!= current_cpu_data
.core
) {
322 /* Boot a VPE on another powered up core */
323 for (remote
= 0; remote
< NR_CPUS
; remote
++) {
324 if (cpu_data
[remote
].core
!= core
)
326 if (cpu_online(remote
))
329 BUG_ON(remote
>= NR_CPUS
);
331 err
= smp_call_function_single(remote
, remote_vpe_boot
,
334 panic("Failed to call remote CPU\n");
338 BUG_ON(!cpu_has_mipsmt
&& !cpu_has_vp
);
340 /* Boot a VPE on this core */
341 mips_cps_boot_vpes(core_cfg
, vpe_id
);
346 static void cps_init_secondary(void)
348 /* Disable MT - we only want to run 1 TC per VPE */
352 if (mips_cm_revision() >= CM_REV_CM3
) {
353 unsigned ident
= gic_read_local_vp_id();
356 * Ensure that our calculation of the VP ID matches up with
357 * what the GIC reports, otherwise we'll have configured
358 * interrupts incorrectly.
360 BUG_ON(ident
!= mips_cm_vp_id(smp_processor_id()));
364 clear_c0_status(ST0_IM
);
366 change_c0_status(ST0_IM
, STATUSF_IP2
| STATUSF_IP3
|
367 STATUSF_IP4
| STATUSF_IP5
|
368 STATUSF_IP6
| STATUSF_IP7
);
371 static void cps_smp_finish(void)
373 write_c0_compare(read_c0_count() + (8 * mips_hpt_frequency
/ HZ
));
375 #ifdef CONFIG_MIPS_MT_FPAFF
376 /* If we have an FPU, enroll ourselves in the FPU-full mask */
378 cpumask_set_cpu(smp_processor_id(), &mt_fpu_cpumask
);
379 #endif /* CONFIG_MIPS_MT_FPAFF */
384 #ifdef CONFIG_HOTPLUG_CPU
386 static int cps_cpu_disable(void)
388 unsigned cpu
= smp_processor_id();
389 struct core_boot_config
*core_cfg
;
394 if (!cps_pm_support_state(CPS_PM_POWER_GATED
))
397 core_cfg
= &mips_cps_core_bootcfg
[current_cpu_data
.core
];
398 atomic_sub(1 << cpu_vpe_id(¤t_cpu_data
), &core_cfg
->vpe_mask
);
399 smp_mb__after_atomic();
400 set_cpu_online(cpu
, false);
401 calculate_cpu_foreign_map();
402 cpumask_clear_cpu(cpu
, &cpu_callin_map
);
407 static DECLARE_COMPLETION(cpu_death_chosen
);
408 static unsigned cpu_death_sibling
;
416 unsigned int cpu
, core
, vpe_id
;
420 cpu
= smp_processor_id();
421 cpu_death
= CPU_DEATH_POWER
;
423 pr_debug("CPU%d going offline\n", cpu
);
425 if (cpu_has_mipsmt
|| cpu_has_vp
) {
426 core
= cpu_data
[cpu
].core
;
428 /* Look for another online VPE within the core */
429 for_each_online_cpu(cpu_death_sibling
) {
430 if (cpu_data
[cpu_death_sibling
].core
!= core
)
434 * There is an online VPE within the core. Just halt
435 * this TC and leave the core alone.
437 cpu_death
= CPU_DEATH_HALT
;
442 /* This CPU has chosen its way out */
443 complete(&cpu_death_chosen
);
445 if (cpu_death
== CPU_DEATH_HALT
) {
446 vpe_id
= cpu_vpe_id(&cpu_data
[cpu
]);
448 pr_debug("Halting core %d VP%d\n", core
, vpe_id
);
449 if (cpu_has_mipsmt
) {
451 write_c0_tchalt(TCHALT_H
);
452 instruction_hazard();
453 } else if (cpu_has_vp
) {
454 write_cpc_cl_vp_stop(1 << vpe_id
);
456 /* Ensure that the VP_STOP register is written */
460 pr_debug("Gating power to core %d\n", core
);
461 /* Power down the core */
462 cps_pm_enter_state(CPS_PM_POWER_GATED
);
465 /* This should never be reached */
466 panic("Failed to offline CPU %u", cpu
);
469 static void wait_for_sibling_halt(void *ptr_cpu
)
471 unsigned cpu
= (unsigned long)ptr_cpu
;
472 unsigned vpe_id
= cpu_vpe_id(&cpu_data
[cpu
]);
477 local_irq_save(flags
);
479 halted
= read_tc_c0_tchalt();
480 local_irq_restore(flags
);
481 } while (!(halted
& TCHALT_H
));
484 static void cps_cpu_die(unsigned int cpu
)
486 unsigned core
= cpu_data
[cpu
].core
;
487 unsigned int vpe_id
= cpu_vpe_id(&cpu_data
[cpu
]);
491 /* Wait for the cpu to choose its way out */
492 if (!wait_for_completion_timeout(&cpu_death_chosen
,
493 msecs_to_jiffies(5000))) {
494 pr_err("CPU%u: didn't offline\n", cpu
);
499 * Now wait for the CPU to actually offline. Without doing this that
500 * offlining may race with one or more of:
502 * - Onlining the CPU again.
503 * - Powering down the core if another VPE within it is offlined.
504 * - A sibling VPE entering a non-coherent state.
506 * In the non-MT halt case (ie. infinite loop) the CPU is doing nothing
507 * with which we could race, so do nothing.
509 if (cpu_death
== CPU_DEATH_POWER
) {
511 * Wait for the core to enter a powered down or clock gated
512 * state, the latter happening when a JTAG probe is connected
513 * in which case the CPC will refuse to power down the core.
516 mips_cm_lock_other(core
, 0);
517 mips_cpc_lock_other(core
);
518 stat
= read_cpc_co_stat_conf();
519 stat
&= CPC_Cx_STAT_CONF_SEQSTATE_MSK
;
520 mips_cpc_unlock_other();
521 mips_cm_unlock_other();
522 } while (stat
!= CPC_Cx_STAT_CONF_SEQSTATE_D0
&&
523 stat
!= CPC_Cx_STAT_CONF_SEQSTATE_D2
&&
524 stat
!= CPC_Cx_STAT_CONF_SEQSTATE_U2
);
526 /* Indicate the core is powered off */
527 bitmap_clear(core_power
, core
, 1);
528 } else if (cpu_has_mipsmt
) {
530 * Have a CPU with access to the offlined CPUs registers wait
531 * for its TC to halt.
533 err
= smp_call_function_single(cpu_death_sibling
,
534 wait_for_sibling_halt
,
535 (void *)(unsigned long)cpu
, 1);
537 panic("Failed to call remote sibling CPU\n");
538 } else if (cpu_has_vp
) {
540 mips_cm_lock_other(core
, vpe_id
);
541 stat
= read_cpc_co_vp_running();
542 mips_cm_unlock_other();
543 } while (stat
& (1 << vpe_id
));
547 #endif /* CONFIG_HOTPLUG_CPU */
549 static struct plat_smp_ops cps_smp_ops
= {
550 .smp_setup
= cps_smp_setup
,
551 .prepare_cpus
= cps_prepare_cpus
,
552 .boot_secondary
= cps_boot_secondary
,
553 .init_secondary
= cps_init_secondary
,
554 .smp_finish
= cps_smp_finish
,
555 .send_ipi_single
= mips_smp_send_ipi_single
,
556 .send_ipi_mask
= mips_smp_send_ipi_mask
,
557 #ifdef CONFIG_HOTPLUG_CPU
558 .cpu_disable
= cps_cpu_disable
,
559 .cpu_die
= cps_cpu_die
,
563 bool mips_cps_smp_in_use(void)
565 extern struct plat_smp_ops
*mp_ops
;
566 return mp_ops
== &cps_smp_ops
;
569 int register_cps_smp_ops(void)
571 if (!mips_cm_present()) {
572 pr_warn("MIPS CPS SMP unable to proceed without a CM\n");
576 /* check we have a GIC - we need one for IPIs */
577 if (!(read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX_MSK
)) {
578 pr_warn("MIPS CPS SMP unable to proceed without a GIC\n");
582 register_smp_ops(&cps_smp_ops
);