12874c5fdSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later
219fe0475SArnd Bergmann /*
319fe0475SArnd Bergmann * SMP support for BPA machines.
419fe0475SArnd Bergmann *
519fe0475SArnd Bergmann * Dave Engebretsen, Peter Bergner, and
619fe0475SArnd Bergmann * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
719fe0475SArnd Bergmann *
819fe0475SArnd Bergmann * Plus various changes from other IBM teams...
919fe0475SArnd Bergmann */
1019fe0475SArnd Bergmann
1119fe0475SArnd Bergmann #undef DEBUG
1219fe0475SArnd Bergmann
1319fe0475SArnd Bergmann #include <linux/kernel.h>
1419fe0475SArnd Bergmann #include <linux/sched.h>
1519fe0475SArnd Bergmann #include <linux/smp.h>
1619fe0475SArnd Bergmann #include <linux/interrupt.h>
1719fe0475SArnd Bergmann #include <linux/delay.h>
1819fe0475SArnd Bergmann #include <linux/init.h>
1919fe0475SArnd Bergmann #include <linux/spinlock.h>
2019fe0475SArnd Bergmann #include <linux/cache.h>
2119fe0475SArnd Bergmann #include <linux/err.h>
22edbaa603SKay Sievers #include <linux/device.h>
2319fe0475SArnd Bergmann #include <linux/cpu.h>
2465fddcfcSMike Rapoport #include <linux/pgtable.h>
2519fe0475SArnd Bergmann
2619fe0475SArnd Bergmann #include <asm/ptrace.h>
2760063497SArun Sharma #include <linux/atomic.h>
2819fe0475SArnd Bergmann #include <asm/irq.h>
2919fe0475SArnd Bergmann #include <asm/page.h>
3019fe0475SArnd Bergmann #include <asm/io.h>
3119fe0475SArnd Bergmann #include <asm/smp.h>
3219fe0475SArnd Bergmann #include <asm/paca.h>
3319fe0475SArnd Bergmann #include <asm/machdep.h>
3419fe0475SArnd Bergmann #include <asm/cputable.h>
3519fe0475SArnd Bergmann #include <asm/firmware.h>
3619fe0475SArnd Bergmann #include <asm/rtas.h>
378d089085SBenjamin Herrenschmidt #include <asm/cputhreads.h>
382751b628SAnton Blanchard #include <asm/code-patching.h>
3919fe0475SArnd Bergmann
4019fe0475SArnd Bergmann #include "interrupt.h"
41aa39be09Swill schmidt #include <asm/udbg.h>
4219fe0475SArnd Bergmann
4319fe0475SArnd Bergmann #ifdef DEBUG
4419fe0475SArnd Bergmann #define DBG(fmt...) udbg_printf(fmt)
4519fe0475SArnd Bergmann #else
4619fe0475SArnd Bergmann #define DBG(fmt...)
4719fe0475SArnd Bergmann #endif
4819fe0475SArnd Bergmann
4919fe0475SArnd Bergmann /*
506a75a6b8SMilton Miller * The Primary thread of each non-boot processor was started from the OF client
516a75a6b8SMilton Miller * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
5219fe0475SArnd Bergmann */
5319fe0475SArnd Bergmann static cpumask_t of_spin_map;
5419fe0475SArnd Bergmann
5519fe0475SArnd Bergmann /**
5619fe0475SArnd Bergmann * smp_startup_cpu() - start the given cpu
5719fe0475SArnd Bergmann *
5819fe0475SArnd Bergmann * At boot time, there is nothing to do for primary threads which were
5919fe0475SArnd Bergmann * started from Open Firmware. For anything else, call RTAS with the
6019fe0475SArnd Bergmann * appropriate start location.
6119fe0475SArnd Bergmann *
6219fe0475SArnd Bergmann * Returns:
6319fe0475SArnd Bergmann * 0 - failure
6419fe0475SArnd Bergmann * 1 - success
6519fe0475SArnd Bergmann */
smp_startup_cpu(unsigned int lcpu)66cad5cef6SGreg Kroah-Hartman static inline int smp_startup_cpu(unsigned int lcpu)
6719fe0475SArnd Bergmann {
6819fe0475SArnd Bergmann int status;
692751b628SAnton Blanchard unsigned long start_here =
702751b628SAnton Blanchard __pa(ppc_function_entry(generic_secondary_smp_init));
7119fe0475SArnd Bergmann unsigned int pcpu;
7219fe0475SArnd Bergmann int start_cpu;
7319fe0475SArnd Bergmann
74104699c0SKOSAKI Motohiro if (cpumask_test_cpu(lcpu, &of_spin_map))
7519fe0475SArnd Bergmann /* Already started by OF and sitting in spin loop */
7619fe0475SArnd Bergmann return 1;
7719fe0475SArnd Bergmann
7819fe0475SArnd Bergmann pcpu = get_hard_smp_processor_id(lcpu);
7919fe0475SArnd Bergmann
8019fe0475SArnd Bergmann /*
8119fe0475SArnd Bergmann * If the RTAS start-cpu token does not exist then presume the
8219fe0475SArnd Bergmann * cpu is already spinning.
8319fe0475SArnd Bergmann */
84*08273c9fSNathan Lynch start_cpu = rtas_function_token(RTAS_FN_START_CPU);
8519fe0475SArnd Bergmann if (start_cpu == RTAS_UNKNOWN_SERVICE)
8619fe0475SArnd Bergmann return 1;
8719fe0475SArnd Bergmann
8819fe0475SArnd Bergmann status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu);
8919fe0475SArnd Bergmann if (status != 0) {
9019fe0475SArnd Bergmann printk(KERN_ERR "start-cpu failed: %i\n", status);
9119fe0475SArnd Bergmann return 0;
9219fe0475SArnd Bergmann }
9319fe0475SArnd Bergmann
9419fe0475SArnd Bergmann return 1;
9519fe0475SArnd Bergmann }
9619fe0475SArnd Bergmann
smp_cell_setup_cpu(int cpu)97cad5cef6SGreg Kroah-Hartman static void smp_cell_setup_cpu(int cpu)
9819fe0475SArnd Bergmann {
9919fe0475SArnd Bergmann if (cpu != boot_cpuid)
10019fe0475SArnd Bergmann iic_setup_cpu();
101960cedb4SArnd Bergmann
102960cedb4SArnd Bergmann /*
103960cedb4SArnd Bergmann * change default DABRX to allow user watchpoints
104960cedb4SArnd Bergmann */
105960cedb4SArnd Bergmann mtspr(SPRN_DABRX, DABRX_KERNEL | DABRX_USER);
10619fe0475SArnd Bergmann }
10719fe0475SArnd Bergmann
smp_cell_kick_cpu(int nr)108cad5cef6SGreg Kroah-Hartman static int smp_cell_kick_cpu(int nr)
10919fe0475SArnd Bergmann {
110c642af9cSSantosh Sivaraj if (nr < 0 || nr >= nr_cpu_ids)
111f8d0d5dcSSantosh Sivaraj return -EINVAL;
11219fe0475SArnd Bergmann
11319fe0475SArnd Bergmann if (!smp_startup_cpu(nr))
114de300974SMichael Ellerman return -ENOENT;
11519fe0475SArnd Bergmann
11619fe0475SArnd Bergmann /*
11719fe0475SArnd Bergmann * The processor is currently spinning, waiting for the
11819fe0475SArnd Bergmann * cpu_start field to become non-zero After we set cpu_start,
11919fe0475SArnd Bergmann * the processor will continue on to secondary_start
12019fe0475SArnd Bergmann */
121d2e60075SNicholas Piggin paca_ptrs[nr]->cpu_start = 1;
122de300974SMichael Ellerman
123de300974SMichael Ellerman return 0;
12419fe0475SArnd Bergmann }
12519fe0475SArnd Bergmann
12619fe0475SArnd Bergmann static struct smp_ops_t bpa_iic_smp_ops = {
127d5a1c193SMilton Miller .message_pass = iic_message_pass,
128a7f4ee1fSMichael Ellerman .probe = iic_request_IPIs,
12919fe0475SArnd Bergmann .kick_cpu = smp_cell_kick_cpu,
130960cedb4SArnd Bergmann .setup_cpu = smp_cell_setup_cpu,
13139fd4027SAndy Fleming .cpu_bootable = smp_generic_cpu_bootable,
13219fe0475SArnd Bergmann };
13319fe0475SArnd Bergmann
13419fe0475SArnd Bergmann /* This is called very early */
smp_init_cell(void)13519fe0475SArnd Bergmann void __init smp_init_cell(void)
13619fe0475SArnd Bergmann {
13719fe0475SArnd Bergmann int i;
13819fe0475SArnd Bergmann
13919fe0475SArnd Bergmann DBG(" -> smp_init_cell()\n");
14019fe0475SArnd Bergmann
14119fe0475SArnd Bergmann smp_ops = &bpa_iic_smp_ops;
14219fe0475SArnd Bergmann
14319fe0475SArnd Bergmann /* Mark threads which are still spinning in hold loops. */
14419fe0475SArnd Bergmann if (cpu_has_feature(CPU_FTR_SMT)) {
14519fe0475SArnd Bergmann for_each_present_cpu(i) {
1466a75a6b8SMilton Miller if (cpu_thread_in_core(i) == 0)
147104699c0SKOSAKI Motohiro cpumask_set_cpu(i, &of_spin_map);
14819fe0475SArnd Bergmann }
149104699c0SKOSAKI Motohiro } else
150104699c0SKOSAKI Motohiro cpumask_copy(&of_spin_map, cpu_present_mask);
15119fe0475SArnd Bergmann
152104699c0SKOSAKI Motohiro cpumask_clear_cpu(boot_cpuid, &of_spin_map);
15319fe0475SArnd Bergmann
15419fe0475SArnd Bergmann /* Non-lpar has additional take/give timebase */
155*08273c9fSNathan Lynch if (rtas_function_token(RTAS_FN_FREEZE_TIME_BASE) != RTAS_UNKNOWN_SERVICE) {
156c4007a2fSBenjamin Herrenschmidt smp_ops->give_timebase = rtas_give_timebase;
157c4007a2fSBenjamin Herrenschmidt smp_ops->take_timebase = rtas_take_timebase;
15819fe0475SArnd Bergmann }
15919fe0475SArnd Bergmann
16019fe0475SArnd Bergmann DBG(" <- smp_init_cell()\n");
16119fe0475SArnd Bergmann }
162