summaryrefslogtreecommitdiffstats
path: root/arch/mips/kernel/mips-cpc.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/mips/kernel/mips-cpc.c')
-rw-r--r--arch/mips/kernel/mips-cpc.c123
1 files changed, 123 insertions, 0 deletions
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();
+}