linux/arch/mips/sgi-ip30/ip30-smp.c

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// SPDX-License-Identifier: GPL-2.0
/*
* ip30-smp.c: SMP on IP30 architecture.
* Based off of the original IP30 SMP code, with inspiration from ip27-smp.c
* and smp-bmips.c.
*
* Copyright (C) 2005-2007 Stanislaw Skowronek <skylark@unaligned.org>
* 2006-2007, 2014-2015 Joshua Kinard <kumba@gentoo.org>
* 2009 Johannes Dickgreber <tanzy@gmx.de>
*/
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <asm/time.h>
#include <asm/sgi/heart.h>
#include "ip30-common.h"
#define MPCONF_MAGIC 0xbaddeed2
#define MPCONF_ADDR 0xa800000000000600L
#define MPCONF_SIZE 0x80
#define MPCONF(x) (MPCONF_ADDR + (x) * MPCONF_SIZE)
/* HEART can theoretically do 4 CPUs, but only 2 are physically possible */
#define MP_NCPU 2
struct mpconf {
u32 magic;
u32 prid;
u32 physid;
u32 virtid;
u32 scachesz;
u16 fanloads;
u16 res;
void *launch;
void *rendezvous;
u64 res2[3];
void *stackaddr;
void *lnch_parm;
void *rndv_parm;
u32 idleflag;
};
static void ip30_smp_send_ipi_single(int cpu, u32 action)
{
int irq;
switch (action) {
case SMP_RESCHEDULE_YOURSELF:
irq = HEART_L2_INT_RESCHED_CPU_0;
break;
case SMP_CALL_FUNCTION:
irq = HEART_L2_INT_CALL_CPU_0;
break;
default:
panic("IP30: Unknown action value in %s!\n", __func__);
}
irq += cpu;
/* Poke the other CPU -- it's got mail! */
heart_write(BIT_ULL(irq), &heart_regs->set_isr);
}
static void ip30_smp_send_ipi_mask(const struct cpumask *mask, u32 action)
{
u32 i;
for_each_cpu(i, mask)
ip30_smp_send_ipi_single(i, action);
}
static void __init ip30_smp_setup(void)
{
int i;
int ncpu = 0;
struct mpconf *mpc;
init_cpu_possible(cpumask_of(0));
/* Scan the MPCONF structure and enumerate available CPUs. */
for (i = 0; i < MP_NCPU; i++) {
mpc = (struct mpconf *)MPCONF(i);
if (mpc->magic == MPCONF_MAGIC) {
set_cpu_possible(i, true);
__cpu_number_map[i] = ++ncpu;
__cpu_logical_map[ncpu] = i;
pr_info("IP30: Slot: %d, PrID: %.8x, PhyID: %d, VirtID: %d\n",
i, mpc->prid, mpc->physid, mpc->virtid);
}
}
pr_info("IP30: Detected %d CPU(s) present.\n", ncpu);
/*
* Set the coherency algorithm to '5' (cacheable coherent
* exclusive on write). This is needed on IP30 SMP, especially
* for R14000 CPUs, otherwise, instruction bus errors will
* occur upon reaching userland.
*/
change_c0_config(CONF_CM_CMASK, CONF_CM_CACHABLE_COW);
}
static void __init ip30_smp_prepare_cpus(unsigned int max_cpus)
{
/* nothing to do here */
}
static int __init ip30_smp_boot_secondary(int cpu, struct task_struct *idle)
{
struct mpconf *mpc = (struct mpconf *)MPCONF(cpu);
/* Stack pointer (sp). */
mpc->stackaddr = (void *)__KSTK_TOS(idle);
/* Global pointer (gp). */
mpc->lnch_parm = task_thread_info(idle);
mb(); /* make sure stack and lparm are written */
/* Boot CPUx. */
mpc->launch = smp_bootstrap;
/* CPUx now executes smp_bootstrap, then ip30_smp_finish */
return 0;
}
static void __init ip30_smp_init_cpu(void)
{
ip30_per_cpu_init();
}
static void __init ip30_smp_finish(void)
{
enable_percpu_irq(get_c0_compare_int(), IRQ_TYPE_NONE);
local_irq_enable();
}
struct plat_smp_ops __read_mostly ip30_smp_ops = {
.send_ipi_single = ip30_smp_send_ipi_single,
.send_ipi_mask = ip30_smp_send_ipi_mask,
.smp_setup = ip30_smp_setup,
.prepare_cpus = ip30_smp_prepare_cpus,
.boot_secondary = ip30_smp_boot_secondary,
.init_secondary = ip30_smp_init_cpu,
.smp_finish = ip30_smp_finish,
.prepare_boot_cpu = ip30_smp_init_cpu,
};