smp.c

  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * Copyright (C) 2001, 2002, 2003 Broadcom Corporation
  4 */
  5
  6#include <linux/init.h>
  7#include <linux/delay.h>
  8#include <linux/interrupt.h>
  9#include <linux/smp.h>
 10#include <linux/kernel_stat.h>
 11#include <linux/sched/task_stack.h>
 12
 13#include <asm/mmu_context.h>
 14#include <asm/io.h>
 15#include <asm/fw/cfe/cfe_api.h>
 16#include <asm/sibyte/sb1250.h>
 17#include <asm/sibyte/sb1250_regs.h>
 18#include <asm/sibyte/sb1250_int.h>
 19
 20static void *mailbox_set_regs[] = {
 21	IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_SET_CPU),
 22	IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_SET_CPU)
 23};
 24
 25static void *mailbox_clear_regs[] = {
 26	IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CLR_CPU),
 27	IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CLR_CPU)
 28};
 29
 30static void *mailbox_regs[] = {
 31	IOADDR(A_IMR_CPU0_BASE + R_IMR_MAILBOX_CPU),
 32	IOADDR(A_IMR_CPU1_BASE + R_IMR_MAILBOX_CPU)
 33};
 34
 35/*
 36 * SMP init and finish on secondary CPUs
 37 */
 38void sb1250_smp_init(void)
 39{
 40	unsigned int imask = STATUSF_IP4 | STATUSF_IP3 | STATUSF_IP2 |
 41		STATUSF_IP1 | STATUSF_IP0;
 42
 43	/* Set interrupt mask, but don't enable */
 44	change_c0_status(ST0_IM, imask);
 45}
 46
 47/*
 48 * These are routines for dealing with the sb1250 smp capabilities
 49 * independent of board/firmware
 50 */
 51
 52/*
 53 * Simple enough; everything is set up, so just poke the appropriate mailbox
 54 * register, and we should be set
 55 */
 56static void sb1250_send_ipi_single(int cpu, unsigned int action)
 57{
 58	__raw_writeq((((u64)action) << 48), mailbox_set_regs[cpu]);
 59}
 60
 61static inline void sb1250_send_ipi_mask(const struct cpumask *mask,
 62					unsigned int action)
 63{
 64	unsigned int i;
 65
 66	for_each_cpu(i, mask)
 67		sb1250_send_ipi_single(i, action);
 68}
 69
 70/*
 71 * Code to run on secondary just after probing the CPU
 72 */
 73static void sb1250_init_secondary(void)
 74{
 75	extern void sb1250_smp_init(void);
 76
 77	sb1250_smp_init();
 78}
 79
 80/*
 81 * Do any tidying up before marking online and running the idle
 82 * loop
 83 */
 84static void sb1250_smp_finish(void)
 85{
 86	extern void sb1250_clockevent_init(void);
 87
 88	sb1250_clockevent_init();
 89	local_irq_enable();
 90}
 91
 92/*
 93 * Setup the PC, SP, and GP of a secondary processor and start it
 94 * running!
 95 */
 96static int sb1250_boot_secondary(int cpu, struct task_struct *idle)
 97{
 98	int retval;
 99
100	retval = cfe_cpu_start(cpu_logical_map(cpu), &smp_bootstrap,
101			       __KSTK_TOS(idle),
102			       (unsigned long)task_thread_info(idle), 0);
103	if (retval != 0)
104		printk("cfe_start_cpu(%i) returned %i\n" , cpu, retval);
105	return retval;
106}
107
108/*
109 * Use CFE to find out how many CPUs are available, setting up
110 * cpu_possible_mask and the logical/physical mappings.
111 * XXXKW will the boot CPU ever not be physical 0?
112 *
113 * Common setup before any secondaries are started
114 */
115static void __init sb1250_smp_setup(void)
116{
117	int i, num;
118
119	init_cpu_possible(cpumask_of(0));
120	__cpu_number_map[0] = 0;
121	__cpu_logical_map[0] = 0;
122
123	for (i = 1, num = 0; i < NR_CPUS; i++) {
124		if (cfe_cpu_stop(i) == 0) {
125			set_cpu_possible(i, true);
126			__cpu_number_map[i] = ++num;
127			__cpu_logical_map[num] = i;
128		}
129	}
130	printk(KERN_INFO "Detected %i available secondary CPU(s)\n", num);
131}
132
133static void __init sb1250_prepare_cpus(unsigned int max_cpus)
134{
135}
136
137const struct plat_smp_ops sb_smp_ops = {
138	.send_ipi_single	= sb1250_send_ipi_single,
139	.send_ipi_mask		= sb1250_send_ipi_mask,
140	.init_secondary		= sb1250_init_secondary,
141	.smp_finish		= sb1250_smp_finish,
142	.boot_secondary		= sb1250_boot_secondary,
143	.smp_setup		= sb1250_smp_setup,
144	.prepare_cpus		= sb1250_prepare_cpus,
145};
146
147void sb1250_mailbox_interrupt(void)
148{
149	int cpu = smp_processor_id();
150	int irq = K_INT_MBOX_0;
151	unsigned int action;
152
153	kstat_incr_irq_this_cpu(irq);
154	/* Load the mailbox register to figure out what we're supposed to do */
155	action = (____raw_readq(mailbox_regs[cpu]) >> 48) & 0xffff;
156
157	/* Clear the mailbox to clear the interrupt */
158	____raw_writeq(((u64)action) << 48, mailbox_clear_regs[cpu]);
159
160	if (action & SMP_RESCHEDULE_YOURSELF)
161		scheduler_ipi();
162
163	if (action & SMP_CALL_FUNCTION) {
164		irq_enter();
165		generic_smp_call_function_interrupt();
166		irq_exit();
167	}
168}