From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001
From: Daniel Baumann <daniel.baumann@progress-linux.org>
Date: Sun, 7 Apr 2024 20:49:45 +0200
Subject: Adding upstream version 6.1.76.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
---
 arch/mips/kernel/mips-cpc.c | 123 ++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 123 insertions(+)
 create mode 100644 arch/mips/kernel/mips-cpc.c

(limited to 'arch/mips/kernel/mips-cpc.c')

diff --git a/arch/mips/kernel/mips-cpc.c b/arch/mips/kernel/mips-cpc.c
new file mode 100644
index 000000000..3e386f7e1
--- /dev/null
+++ b/arch/mips/kernel/mips-cpc.c
@@ -0,0 +1,123 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2013 Imagination Technologies
+ * Author: Paul Burton <paul.burton@mips.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/errno.h>
+#include <linux/percpu.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/spinlock.h>
+
+#include <asm/mips-cps.h>
+
+void __iomem *mips_cpc_base;
+
+static DEFINE_PER_CPU_ALIGNED(spinlock_t, cpc_core_lock);
+
+static DEFINE_PER_CPU_ALIGNED(unsigned long, cpc_core_lock_flags);
+
+phys_addr_t __weak mips_cpc_default_phys_base(void)
+{
+	struct device_node *cpc_node;
+	struct resource res;
+	int err;
+
+	cpc_node = of_find_compatible_node(of_root, NULL, "mti,mips-cpc");
+	if (cpc_node) {
+		err = of_address_to_resource(cpc_node, 0, &res);
+		of_node_put(cpc_node);
+		if (!err)
+			return res.start;
+	}
+
+	return 0;
+}
+
+/**
+ * mips_cpc_phys_base - retrieve the physical base address of the CPC
+ *
+ * This function returns the physical base address of the Cluster Power
+ * Controller memory mapped registers, or 0 if no Cluster Power Controller
+ * is present.
+ */
+static phys_addr_t mips_cpc_phys_base(void)
+{
+	unsigned long cpc_base;
+
+	if (!mips_cm_present())
+		return 0;
+
+	if (!(read_gcr_cpc_status() & CM_GCR_CPC_STATUS_EX))
+		return 0;
+
+	/* If the CPC is already enabled, leave it so */
+	cpc_base = read_gcr_cpc_base();
+	if (cpc_base & CM_GCR_CPC_BASE_CPCEN)
+		return cpc_base & CM_GCR_CPC_BASE_CPCBASE;
+
+	/* Otherwise, use the default address */
+	cpc_base = mips_cpc_default_phys_base();
+	if (!cpc_base)
+		return cpc_base;
+
+	/* Enable the CPC, mapped at the default address */
+	write_gcr_cpc_base(cpc_base | CM_GCR_CPC_BASE_CPCEN);
+	return cpc_base;
+}
+
+int mips_cpc_probe(void)
+{
+	phys_addr_t addr;
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu)
+		spin_lock_init(&per_cpu(cpc_core_lock, cpu));
+
+	addr = mips_cpc_phys_base();
+	if (!addr)
+		return -ENODEV;
+
+	mips_cpc_base = ioremap(addr, 0x8000);
+	if (!mips_cpc_base)
+		return -ENXIO;
+
+	return 0;
+}
+
+void mips_cpc_lock_other(unsigned int core)
+{
+	unsigned int curr_core;
+
+	if (mips_cm_revision() >= CM_REV_CM3)
+		/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
+		return;
+
+	preempt_disable();
+	curr_core = cpu_core(&current_cpu_data);
+	spin_lock_irqsave(&per_cpu(cpc_core_lock, curr_core),
+			  per_cpu(cpc_core_lock_flags, curr_core));
+	write_cpc_cl_other(FIELD_PREP(CPC_Cx_OTHER_CORENUM, core));
+
+	/*
+	 * Ensure the core-other region reflects the appropriate core &
+	 * VP before any accesses to it occur.
+	 */
+	mb();
+}
+
+void mips_cpc_unlock_other(void)
+{
+	unsigned int curr_core;
+
+	if (mips_cm_revision() >= CM_REV_CM3)
+		/* Systems with CM >= 3 lock the CPC via mips_cm_lock_other */
+		return;
+
+	curr_core = cpu_core(&current_cpu_data);
+	spin_unlock_irqrestore(&per_cpu(cpc_core_lock, curr_core),
+			       per_cpu(cpc_core_lock_flags, curr_core));
+	preempt_enable();
+}
-- 
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