--- /dev/null
+/*
+ * SMP support for BPA machines.
+ *
+ * Dave Engebretsen, Peter Bergner, and
+ * Mike Corrigan {engebret|bergner|mikec}@us.ibm.com
+ *
+ * Plus various changes from other IBM teams...
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#undef DEBUG
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/sched.h>
+#include <linux/smp.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/cache.h>
+#include <linux/err.h>
+#include <linux/sysdev.h>
+#include <linux/cpu.h>
+
+#include <asm/ptrace.h>
+#include <asm/atomic.h>
+#include <asm/irq.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/io.h>
+#include <asm/prom.h>
+#include <asm/smp.h>
+#include <asm/paca.h>
+#include <asm/time.h>
+#include <asm/machdep.h>
+#include <asm/cputable.h>
+#include <asm/firmware.h>
+#include <asm/system.h>
+#include <asm/rtas.h>
+
+#include "interrupt.h"
+
+#ifdef DEBUG
+#define DBG(fmt...) udbg_printf(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+/*
+ * The primary thread of each non-boot processor is recorded here before
+ * smp init.
+ */
+static cpumask_t of_spin_map;
+
+extern void pSeries_secondary_smp_init(unsigned long);
+
+/**
+ * smp_startup_cpu() - start the given cpu
+ *
+ * At boot time, there is nothing to do for primary threads which were
+ * started from Open Firmware. For anything else, call RTAS with the
+ * appropriate start location.
+ *
+ * Returns:
+ * 0 - failure
+ * 1 - success
+ */
+static inline int __devinit smp_startup_cpu(unsigned int lcpu)
+{
+ int status;
+ unsigned long start_here = __pa((u32)*((unsigned long *)
+ pSeries_secondary_smp_init));
+ unsigned int pcpu;
+ int start_cpu;
+
+ if (cpu_isset(lcpu, of_spin_map))
+ /* Already started by OF and sitting in spin loop */
+ return 1;
+
+ pcpu = get_hard_smp_processor_id(lcpu);
+
+ /* Fixup atomic count: it exited inside IRQ handler. */
+ paca[lcpu].__current->thread_info->preempt_count = 0;
+
+ /*
+ * If the RTAS start-cpu token does not exist then presume the
+ * cpu is already spinning.
+ */
+ start_cpu = rtas_token("start-cpu");
+ if (start_cpu == RTAS_UNKNOWN_SERVICE)
+ return 1;
+
+ status = rtas_call(start_cpu, 3, 1, NULL, pcpu, start_here, lcpu);
+ if (status != 0) {
+ printk(KERN_ERR "start-cpu failed: %i\n", status);
+ return 0;
+ }
+
+ return 1;
+}
+
+static void smp_iic_message_pass(int target, int msg)
+{
+ unsigned int i;
+
+ if (target < NR_CPUS) {
+ iic_cause_IPI(target, msg);
+ } else {
+ for_each_online_cpu(i) {
+ if (target == MSG_ALL_BUT_SELF
+ && i == smp_processor_id())
+ continue;
+ iic_cause_IPI(i, msg);
+ }
+ }
+}
+
+static int __init smp_iic_probe(void)
+{
+ iic_request_IPIs();
+
+ return cpus_weight(cpu_possible_map);
+}
+
+static void __devinit smp_iic_setup_cpu(int cpu)
+{
+ if (cpu != boot_cpuid)
+ iic_setup_cpu();
+}
+
+static DEFINE_SPINLOCK(timebase_lock);
+static unsigned long timebase = 0;
+
+static void __devinit cell_give_timebase(void)
+{
+ spin_lock(&timebase_lock);
+ rtas_call(rtas_token("freeze-time-base"), 0, 1, NULL);
+ timebase = get_tb();
+ spin_unlock(&timebase_lock);
+
+ while (timebase)
+ barrier();
+ rtas_call(rtas_token("thaw-time-base"), 0, 1, NULL);
+}
+
+static void __devinit cell_take_timebase(void)
+{
+ while (!timebase)
+ barrier();
+ spin_lock(&timebase_lock);
+ set_tb(timebase >> 32, timebase & 0xffffffff);
+ timebase = 0;
+ spin_unlock(&timebase_lock);
+}
+
+static void __devinit smp_cell_kick_cpu(int nr)
+{
+ BUG_ON(nr < 0 || nr >= NR_CPUS);
+
+ if (!smp_startup_cpu(nr))
+ return;
+
+ /*
+ * The processor is currently spinning, waiting for the
+ * cpu_start field to become non-zero After we set cpu_start,
+ * the processor will continue on to secondary_start
+ */
+ paca[nr].cpu_start = 1;
+}
+
+static int smp_cell_cpu_bootable(unsigned int nr)
+{
+ /* Special case - we inhibit secondary thread startup
+ * during boot if the user requests it. Odd-numbered
+ * cpus are assumed to be secondary threads.
+ */
+ if (system_state < SYSTEM_RUNNING &&
+ cpu_has_feature(CPU_FTR_SMT) &&
+ !smt_enabled_at_boot && nr % 2 != 0)
+ return 0;
+
+ return 1;
+}
+static struct smp_ops_t bpa_iic_smp_ops = {
+ .message_pass = smp_iic_message_pass,
+ .probe = smp_iic_probe,
+ .kick_cpu = smp_cell_kick_cpu,
+ .setup_cpu = smp_iic_setup_cpu,
+ .cpu_bootable = smp_cell_cpu_bootable,
+};
+
+/* This is called very early */
+void __init smp_init_cell(void)
+{
+ int i;
+
+ DBG(" -> smp_init_cell()\n");
+
+ smp_ops = &bpa_iic_smp_ops;
+
+ /* Mark threads which are still spinning in hold loops. */
+ if (cpu_has_feature(CPU_FTR_SMT)) {
+ for_each_present_cpu(i) {
+ if (i % 2 == 0)
+ /*
+ * Even-numbered logical cpus correspond to
+ * primary threads.
+ */
+ cpu_set(i, of_spin_map);
+ }
+ } else {
+ of_spin_map = cpu_present_map;
+ }
+
+ cpu_clear(boot_cpuid, of_spin_map);
+
+ /* Non-lpar has additional take/give timebase */
+ if (rtas_token("freeze-time-base") != RTAS_UNKNOWN_SERVICE) {
+ smp_ops->give_timebase = cell_give_timebase;
+ smp_ops->take_timebase = cell_take_timebase;
+ }
+
+ DBG(" <- smp_init_cell()\n");
+}
projects / GitHub / LineageOS / G12 / android_kernel_amlogic_linux-4.9.git / commitdiff