1 files changed, 519 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
new file mode 100644
index 000000000..40aa58206
--- /dev/null
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -0,0 +1,519 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Author: Andy Fleming <afleming@freescale.com>
+ * 	   Kumar Gala <galak@kernel.crashing.org>
+ *
+ * Copyright 2006-2008, 2011-2012, 2015 Freescale Semiconductor Inc.
+ */
+
+#include <linux/stddef.h>
+#include <linux/kernel.h>
+#include <linux/sched/hotplug.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/of.h>
+#include <linux/kexec.h>
+#include <linux/highmem.h>
+#include <linux/cpu.h>
+#include <linux/fsl/guts.h>
+#include <linux/pgtable.h>
+
+#include <asm/machdep.h>
+#include <asm/page.h>
+#include <asm/mpic.h>
+#include <asm/cacheflush.h>
+#include <asm/dbell.h>
+#include <asm/code-patching.h>
+#include <asm/cputhreads.h>
+#include <asm/fsl_pm.h>
+
+#include <sysdev/fsl_soc.h>
+#include <sysdev/mpic.h>
+#include "smp.h"
+
+struct epapr_spin_table {
+	u32	addr_h;
+	u32	addr_l;
+	u32	r3_h;
+	u32	r3_l;
+	u32	reserved;
+	u32	pir;
+};
+
+static u64 timebase;
+static int tb_req;
+static int tb_valid;
+
+static void mpc85xx_give_timebase(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	hard_irq_disable();
+
+	while (!tb_req)
+		barrier();
+	tb_req = 0;
+
+	qoriq_pm_ops->freeze_time_base(true);
+#ifdef CONFIG_PPC64
+	/*
+	 * e5500/e6500 have a workaround for erratum A-006958 in place
+	 * that will reread the timebase until TBL is non-zero.
+	 * That would be a bad thing when the timebase is frozen.
+	 *
+	 * Thus, we read it manually, and instead of checking that
+	 * TBL is non-zero, we ensure that TB does not change.  We don't
+	 * do that for the main mftb implementation, because it requires
+	 * a scratch register
+	 */
+	{
+		u64 prev;
+
+		asm volatile("mfspr %0, %1" : "=r" (timebase) :
+			     "i" (SPRN_TBRL));
+
+		do {
+			prev = timebase;
+			asm volatile("mfspr %0, %1" : "=r" (timebase) :
+				     "i" (SPRN_TBRL));
+		} while (prev != timebase);
+	}
+#else
+	timebase = get_tb();
+#endif
+	mb();
+	tb_valid = 1;
+
+	while (tb_valid)
+		barrier();
+
+	qoriq_pm_ops->freeze_time_base(false);
+
+	local_irq_restore(flags);
+}
+
+static void mpc85xx_take_timebase(void)
+{
+	unsigned long flags;
+
+	local_irq_save(flags);
+	hard_irq_disable();
+
+	tb_req = 1;
+	while (!tb_valid)
+		barrier();
+
+	set_tb(timebase >> 32, timebase & 0xffffffff);
+	isync();
+	tb_valid = 0;
+
+	local_irq_restore(flags);
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void smp_85xx_cpu_offline_self(void)
+{
+	unsigned int cpu = smp_processor_id();
+
+	local_irq_disable();
+	hard_irq_disable();
+	/* mask all irqs to prevent cpu wakeup */
+	qoriq_pm_ops->irq_mask(cpu);
+
+	idle_task_exit();
+
+	mtspr(SPRN_TCR, 0);
+	mtspr(SPRN_TSR, mfspr(SPRN_TSR));
+
+	generic_set_cpu_dead(cpu);
+
+	cur_cpu_spec->cpu_down_flush();
+
+	qoriq_pm_ops->cpu_die(cpu);
+
+	while (1)
+		;
+}
+
+static void qoriq_cpu_kill(unsigned int cpu)
+{
+	int i;
+
+	for (i = 0; i < 500; i++) {
+		if (is_cpu_dead(cpu)) {
+#ifdef CONFIG_PPC64
+			paca_ptrs[cpu]->cpu_start = 0;
+#endif
+			return;
+		}
+		msleep(20);
+	}
+	pr_err("CPU%d didn't die...\n", cpu);
+}
+#endif
+
+/*
+ * To keep it compatible with old boot program which uses
+ * cache-inhibit spin table, we need to flush the cache
+ * before accessing spin table to invalidate any staled data.
+ * We also need to flush the cache after writing to spin
+ * table to push data out.
+ */
+static inline void flush_spin_table(void *spin_table)
+{
+	flush_dcache_range((ulong)spin_table,
+		(ulong)spin_table + sizeof(struct epapr_spin_table));
+}
+
+static inline u32 read_spin_table_addr_l(void *spin_table)
+{
+	flush_dcache_range((ulong)spin_table,
+		(ulong)spin_table + sizeof(struct epapr_spin_table));
+	return in_be32(&((struct epapr_spin_table *)spin_table)->addr_l);
+}
+
+#ifdef CONFIG_PPC64
+static void wake_hw_thread(void *info)
+{
+	void fsl_secondary_thread_init(void);
+	unsigned long inia;
+	int cpu = *(const int *)info;
+
+	inia = ppc_function_entry(fsl_secondary_thread_init);
+	book3e_start_thread(cpu_thread_in_core(cpu), inia);
+}
+#endif
+
+static int smp_85xx_start_cpu(int cpu)
+{
+	int ret = 0;
+	struct device_node *np;
+	const u64 *cpu_rel_addr;
+	unsigned long flags;
+	int ioremappable;
+	int hw_cpu = get_hard_smp_processor_id(cpu);
+	struct epapr_spin_table __iomem *spin_table;
+
+	np = of_get_cpu_node(cpu, NULL);
+	cpu_rel_addr = of_get_property(np, "cpu-release-addr", NULL);
+	if (!cpu_rel_addr) {
+		pr_err("No cpu-release-addr for cpu %d\n", cpu);
+		return -ENOENT;
+	}
+
+	/*
+	 * A secondary core could be in a spinloop in the bootpage
+	 * (0xfffff000), somewhere in highmem, or somewhere in lowmem.
+	 * The bootpage and highmem can be accessed via ioremap(), but
+	 * we need to directly access the spinloop if its in lowmem.
+	 */
+	ioremappable = *cpu_rel_addr > virt_to_phys(high_memory - 1);
+
+	/* Map the spin table */
+	if (ioremappable)
+		spin_table = ioremap_coherent(*cpu_rel_addr,
+					      sizeof(struct epapr_spin_table));
+	else
+		spin_table = phys_to_virt(*cpu_rel_addr);
+
+	local_irq_save(flags);
+	hard_irq_disable();
+
+	if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
+		qoriq_pm_ops->cpu_up_prepare(cpu);
+
+	/* if cpu is not spinning, reset it */
+	if (read_spin_table_addr_l(spin_table) != 1) {
+		/*
+		 * We don't set the BPTR register here since it already points
+		 * to the boot page properly.
+		 */
+		mpic_reset_core(cpu);
+
+		/*
+		 * wait until core is ready...
+		 * We need to invalidate the stale data, in case the boot
+		 * loader uses a cache-inhibited spin table.
+		 */
+		if (!spin_event_timeout(
+				read_spin_table_addr_l(spin_table) == 1,
+				10000, 100)) {
+			pr_err("timeout waiting for cpu %d to reset\n",
+				hw_cpu);
+			ret = -EAGAIN;
+			goto err;
+		}
+	}
+
+	flush_spin_table(spin_table);
+	out_be32(&spin_table->pir, hw_cpu);
+#ifdef CONFIG_PPC64
+	out_be64((u64 *)(&spin_table->addr_h),
+		__pa(ppc_function_entry(generic_secondary_smp_init)));
+#else
+#ifdef CONFIG_PHYS_ADDR_T_64BIT
+	/*
+	 * We need also to write addr_h to spin table for systems
+	 * in which their physical memory start address was configured
+	 * to above 4G, otherwise the secondary core can not get
+	 * correct entry to start from.
+	 */
+	out_be32(&spin_table->addr_h, __pa(__early_start) >> 32);
+#endif
+	out_be32(&spin_table->addr_l, __pa(__early_start));
+#endif
+	flush_spin_table(spin_table);
+err:
+	local_irq_restore(flags);
+
+	if (ioremappable)
+		iounmap(spin_table);
+
+	return ret;
+}
+
+static int smp_85xx_kick_cpu(int nr)
+{
+	int ret = 0;
+#ifdef CONFIG_PPC64
+	int primary = nr;
+#endif
+
+	WARN_ON(nr < 0 || nr >= num_possible_cpus());
+
+	pr_debug("kick CPU #%d\n", nr);
+
+#ifdef CONFIG_PPC64
+	if (threads_per_core == 2) {
+		if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT)))
+			return -ENOENT;
+
+		booting_thread_hwid = cpu_thread_in_core(nr);
+		primary = cpu_first_thread_sibling(nr);
+
+		if (qoriq_pm_ops && qoriq_pm_ops->cpu_up_prepare)
+			qoriq_pm_ops->cpu_up_prepare(nr);
+
+		/*
+		 * If either thread in the core is online, use it to start
+		 * the other.
+		 */
+		if (cpu_online(primary)) {
+			smp_call_function_single(primary,
+					wake_hw_thread, &nr, 1);
+			goto done;
+		} else if (cpu_online(primary + 1)) {
+			smp_call_function_single(primary + 1,
+					wake_hw_thread, &nr, 1);
+			goto done;
+		}
+
+		/*
+		 * If getting here, it means both threads in the core are
+		 * offline. So start the primary thread, then it will start
+		 * the thread specified in booting_thread_hwid, the one
+		 * corresponding to nr.
+		 */
+
+	} else if (threads_per_core == 1) {
+		/*
+		 * If one core has only one thread, set booting_thread_hwid to
+		 * an invalid value.
+		 */
+		booting_thread_hwid = INVALID_THREAD_HWID;
+
+	} else if (threads_per_core > 2) {
+		pr_err("Do not support more than 2 threads per CPU.");
+		return -EINVAL;
+	}
+
+	ret = smp_85xx_start_cpu(primary);
+	if (ret)
+		return ret;
+
+done:
+	paca_ptrs[nr]->cpu_start = 1;
+	generic_set_cpu_up(nr);
+
+	return ret;
+#else
+	ret = smp_85xx_start_cpu(nr);
+	if (ret)
+		return ret;
+
+	generic_set_cpu_up(nr);
+
+	return ret;
+#endif
+}
+
+struct smp_ops_t smp_85xx_ops = {
+	.cause_nmi_ipi = NULL,
+	.kick_cpu = smp_85xx_kick_cpu,
+	.cpu_bootable = smp_generic_cpu_bootable,
+#ifdef CONFIG_HOTPLUG_CPU
+	.cpu_disable	= generic_cpu_disable,
+	.cpu_die	= generic_cpu_die,
+#endif
+#if defined(CONFIG_KEXEC_CORE) && !defined(CONFIG_PPC64)
+	.give_timebase	= smp_generic_give_timebase,
+	.take_timebase	= smp_generic_take_timebase,
+#endif
+};
+
+#ifdef CONFIG_KEXEC_CORE
+#ifdef CONFIG_PPC32
+atomic_t kexec_down_cpus = ATOMIC_INIT(0);
+
+static void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
+{
+	local_irq_disable();
+
+	if (secondary) {
+		cur_cpu_spec->cpu_down_flush();
+		atomic_inc(&kexec_down_cpus);
+		/* loop forever */
+		while (1);
+	}
+}
+
+static void mpc85xx_smp_kexec_down(void *arg)
+{
+	if (ppc_md.kexec_cpu_down)
+		ppc_md.kexec_cpu_down(0,1);
+}
+#else
+static void mpc85xx_smp_kexec_cpu_down(int crash_shutdown, int secondary)
+{
+	int cpu = smp_processor_id();
+	int sibling = cpu_last_thread_sibling(cpu);
+	bool notified = false;
+	int disable_cpu;
+	int disable_threadbit = 0;
+	long start = mftb();
+	long now;
+
+	local_irq_disable();
+	hard_irq_disable();
+	mpic_teardown_this_cpu(secondary);
+
+	if (cpu == crashing_cpu && cpu_thread_in_core(cpu) != 0) {
+		/*
+		 * We enter the crash kernel on whatever cpu crashed,
+		 * even if it's a secondary thread.  If that's the case,
+		 * disable the corresponding primary thread.
+		 */
+		disable_threadbit = 1;
+		disable_cpu = cpu_first_thread_sibling(cpu);
+	} else if (sibling != crashing_cpu &&
+		   cpu_thread_in_core(cpu) == 0 &&
+		   cpu_thread_in_core(sibling) != 0) {
+		disable_threadbit = 2;
+		disable_cpu = sibling;
+	}
+
+	if (disable_threadbit) {
+		while (paca_ptrs[disable_cpu]->kexec_state < KEXEC_STATE_REAL_MODE) {
+			barrier();
+			now = mftb();
+			if (!notified && now - start > 1000000) {
+				pr_info("%s/%d: waiting for cpu %d to enter KEXEC_STATE_REAL_MODE (%d)\n",
+					__func__, smp_processor_id(),
+					disable_cpu,
+					paca_ptrs[disable_cpu]->kexec_state);
+				notified = true;
+			}
+		}
+
+		if (notified) {
+			pr_info("%s: cpu %d done waiting\n",
+				__func__, disable_cpu);
+		}
+
+		mtspr(SPRN_TENC, disable_threadbit);
+		while (mfspr(SPRN_TENSR) & disable_threadbit)
+			cpu_relax();
+	}
+}
+#endif
+
+static void mpc85xx_smp_machine_kexec(struct kimage *image)
+{
+#ifdef CONFIG_PPC32
+	int timeout = INT_MAX;
+	int i, num_cpus = num_present_cpus();
+
+	if (image->type == KEXEC_TYPE_DEFAULT)
+		smp_call_function(mpc85xx_smp_kexec_down, NULL, 0);
+
+	while ( (atomic_read(&kexec_down_cpus) != (num_cpus - 1)) &&
+		( timeout > 0 ) )
+	{
+		timeout--;
+	}
+
+	if ( !timeout )
+		printk(KERN_ERR "Unable to bring down secondary cpu(s)");
+
+	for_each_online_cpu(i)
+	{
+		if ( i == smp_processor_id() ) continue;
+		mpic_reset_core(i);
+	}
+#endif
+
+	default_machine_kexec(image);
+}
+#endif /* CONFIG_KEXEC_CORE */
+
+static void smp_85xx_setup_cpu(int cpu_nr)
+{
+	mpic_setup_this_cpu();
+}
+
+void __init mpc85xx_smp_init(void)
+{
+	struct device_node *np;
+
+
+	np = of_find_node_by_type(NULL, "open-pic");
+	if (np) {
+		smp_85xx_ops.probe = smp_mpic_probe;
+		smp_85xx_ops.setup_cpu = smp_85xx_setup_cpu;
+		smp_85xx_ops.message_pass = smp_mpic_message_pass;
+	} else
+		smp_85xx_ops.setup_cpu = NULL;
+
+	if (cpu_has_feature(CPU_FTR_DBELL)) {
+		/*
+		 * If left NULL, .message_pass defaults to
+		 * smp_muxed_ipi_message_pass
+		 */
+		smp_85xx_ops.message_pass = NULL;
+		smp_85xx_ops.cause_ipi = doorbell_global_ipi;
+		smp_85xx_ops.probe = NULL;
+	}
+
+#ifdef CONFIG_FSL_CORENET_RCPM
+	/* Assign a value to qoriq_pm_ops on PPC_E500MC */
+	fsl_rcpm_init();
+#else
+	/* Assign a value to qoriq_pm_ops on !PPC_E500MC */
+	mpc85xx_setup_pmc();
+#endif
+	if (qoriq_pm_ops) {
+		smp_85xx_ops.give_timebase = mpc85xx_give_timebase;
+		smp_85xx_ops.take_timebase = mpc85xx_take_timebase;
+#ifdef CONFIG_HOTPLUG_CPU
+		smp_85xx_ops.cpu_offline_self = smp_85xx_cpu_offline_self;
+		smp_85xx_ops.cpu_die = qoriq_cpu_kill;
+#endif
+	}
+	smp_ops = &smp_85xx_ops;
+
+#ifdef CONFIG_KEXEC_CORE
+	ppc_md.kexec_cpu_down = mpc85xx_smp_kexec_cpu_down;
+	ppc_md.machine_kexec = mpc85xx_smp_machine_kexec;
+#endif
+}