From ace9429bb58fd418f0c81d4c2835699bddf6bde6 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Thu, 11 Apr 2024 10:27:49 +0200
Subject: Adding upstream version 6.6.15.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/powerpc/platforms/cell/smp.c | 161 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 arch/powerpc/platforms/cell/smp.c

(limited to 'arch/powerpc/platforms/cell/smp.c')

diff --git a/arch/powerpc/platforms/cell/smp.c b/arch/powerpc/platforms/cell/smp.c
new file mode 100644
index 0000000000..30394c6f88
--- /dev/null
+++ b/arch/powerpc/platforms/cell/smp.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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...
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.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/device.h>
+#include <linux/cpu.h>
+#include <linux/pgtable.h>
+
+#include <asm/ptrace.h>
+#include <linux/atomic.h>
+#include <asm/irq.h>
+#include <asm/page.h>
+#include <asm/io.h>
+#include <asm/smp.h>
+#include <asm/paca.h>
+#include <asm/machdep.h>
+#include <asm/cputable.h>
+#include <asm/firmware.h>
+#include <asm/rtas.h>
+#include <asm/cputhreads.h>
+#include <asm/code-patching.h>
+
+#include "interrupt.h"
+#include <asm/udbg.h>
+
+#ifdef DEBUG
+#define DBG(fmt...) udbg_printf(fmt)
+#else
+#define DBG(fmt...)
+#endif
+
+/*
+ * The Primary thread of each non-boot processor was started from the OF client
+ * interface by prom_hold_cpus and is spinning on secondary_hold_spinloop.
+ */
+static cpumask_t of_spin_map;
+
+/**
+ * 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 smp_startup_cpu(unsigned int lcpu)
+{
+	int status;
+	unsigned long start_here =
+			__pa(ppc_function_entry(generic_secondary_smp_init));
+	unsigned int pcpu;
+	int start_cpu;
+
+	if (cpumask_test_cpu(lcpu, &of_spin_map))
+		/* Already started by OF and sitting in spin loop */
+		return 1;
+
+	pcpu = get_hard_smp_processor_id(lcpu);
+
+	/*
+	 * If the RTAS start-cpu token does not exist then presume the
+	 * cpu is already spinning.
+	 */
+	start_cpu = rtas_function_token(RTAS_FN_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_cell_setup_cpu(int cpu)
+{
+	if (cpu != boot_cpuid)
+		iic_setup_cpu();
+
+	/*
+	 * change default DABRX to allow user watchpoints
+	 */
+	mtspr(SPRN_DABRX, DABRX_KERNEL | DABRX_USER);
+}
+
+static int smp_cell_kick_cpu(int nr)
+{
+	if (nr < 0 || nr >= nr_cpu_ids)
+		return -EINVAL;
+
+	if (!smp_startup_cpu(nr))
+		return -ENOENT;
+
+	/*
+	 * 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_ptrs[nr]->cpu_start = 1;
+
+	return 0;
+}
+
+static struct smp_ops_t bpa_iic_smp_ops = {
+	.message_pass	= iic_message_pass,
+	.probe		= iic_request_IPIs,
+	.kick_cpu	= smp_cell_kick_cpu,
+	.setup_cpu	= smp_cell_setup_cpu,
+	.cpu_bootable	= smp_generic_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 (cpu_thread_in_core(i) == 0)
+				cpumask_set_cpu(i, &of_spin_map);
+		}
+	} else
+		cpumask_copy(&of_spin_map, cpu_present_mask);
+
+	cpumask_clear_cpu(boot_cpuid, &of_spin_map);
+
+	/* Non-lpar has additional take/give timebase */
+	if (rtas_function_token(RTAS_FN_FREEZE_TIME_BASE) != RTAS_UNKNOWN_SERVICE) {
+		smp_ops->give_timebase = rtas_give_timebase;
+		smp_ops->take_timebase = rtas_take_timebase;
+	}
+
+	DBG(" <- smp_init_cell()\n");
+}
-- 
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