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150 lines
4.4 KiB
150 lines
4.4 KiB
From 48f17325fef9cbebc5cb39aa78f4c1caff5d7b16 Mon Sep 17 00:00:00 2001
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From: Stephen Boyd <sboyd@codeaurora.org>
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Date: Wed, 30 Oct 2013 18:21:09 -0700
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Subject: [PATCH 008/182] ARM: Introduce CPU_METHOD_OF_DECLARE() for cpu
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hotplug/smp
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The goal of multi-platform kernels is to remove the need for mach
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directories and machine descriptors. To further that goal,
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introduce CPU_METHOD_OF_DECLARE() to allow cpu hotplug/smp
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support to be separated from the machine descriptors.
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Implementers should specify an enable-method property in their
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cpus node and then implement a matching set of smp_ops in their
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hotplug/smp code, wiring it up with the CPU_METHOD_OF_DECLARE()
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macro. When the kernel is compiled we'll collect all the
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enable-method smp_ops into one section for use at boot.
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At boot time we'll look for an enable-method in each cpu node and
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try to match that against all known CPU enable methods in the
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kernel. If there are no enable-methods in the cpu nodes we
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fallback to the cpus node and try to use any enable-method found
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there. If that doesn't work we fall back to the old way of using
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the machine descriptor.
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Acked-by: Mark Rutland <mark.rutland@arm.com>
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Cc: Russell King <linux@arm.linux.org.uk>
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Cc: <devicetree@vger.kernel.org>
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Signed-off-by: Kumar Gala <galak@codeaurora.org>
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---
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arch/arm/include/asm/smp.h | 9 +++++++++
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arch/arm/kernel/devtree.c | 40 +++++++++++++++++++++++++++++++++++++
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include/asm-generic/vmlinux.lds.h | 10 ++++++++++
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3 files changed, 59 insertions(+)
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--- a/arch/arm/include/asm/smp.h
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+++ b/arch/arm/include/asm/smp.h
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@@ -114,6 +114,15 @@ struct smp_operations {
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#endif
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};
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+struct of_cpu_method {
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+ const char *method;
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+ struct smp_operations *ops;
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+};
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+
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+#define CPU_METHOD_OF_DECLARE(name, _method, _ops) \
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+ static const struct of_cpu_method __cpu_method_of_table_##name \
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+ __used __section(__cpu_method_of_table) \
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+ = { .method = _method, .ops = _ops }
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/*
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* set platform specific SMP operations
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*/
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--- a/arch/arm/kernel/devtree.c
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+++ b/arch/arm/kernel/devtree.c
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@@ -18,6 +18,7 @@
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#include <linux/of_fdt.h>
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#include <linux/of_irq.h>
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#include <linux/of_platform.h>
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+#include <linux/smp.h>
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#include <asm/cputype.h>
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#include <asm/setup.h>
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@@ -63,6 +64,34 @@ void __init arm_dt_memblock_reserve(void
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}
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}
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+#ifdef CONFIG_SMP
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+extern struct of_cpu_method __cpu_method_of_table_begin[];
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+extern struct of_cpu_method __cpu_method_of_table_end[];
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+
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+static int __init set_smp_ops_by_method(struct device_node *node)
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+{
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+ const char *method;
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+ struct of_cpu_method *m = __cpu_method_of_table_begin;
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+
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+ if (of_property_read_string(node, "enable-method", &method))
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+ return 0;
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+
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+ for (; m < __cpu_method_of_table_end; m++)
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+ if (!strcmp(m->method, method)) {
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+ smp_set_ops(m->ops);
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+ return 1;
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+ }
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+
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+ return 0;
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+}
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+#else
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+static inline int set_smp_ops_by_method(struct device_node *node)
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+{
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+ return 1;
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+}
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+#endif
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+
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+
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/*
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* arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
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* and builds the cpu logical map array containing MPIDR values related to
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@@ -79,6 +108,7 @@ void __init arm_dt_init_cpu_maps(void)
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* read as 0.
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*/
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struct device_node *cpu, *cpus;
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+ int found_method = 0;
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u32 i, j, cpuidx = 1;
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u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
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@@ -150,8 +180,18 @@ void __init arm_dt_init_cpu_maps(void)
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}
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tmp_map[i] = hwid;
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+
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+ if (!found_method)
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+ found_method = set_smp_ops_by_method(cpu);
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}
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+ /*
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+ * Fallback to an enable-method in the cpus node if nothing found in
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+ * a cpu node.
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+ */
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+ if (!found_method)
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+ set_smp_ops_by_method(cpus);
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+
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if (!bootcpu_valid) {
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pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
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return;
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--- a/include/asm-generic/vmlinux.lds.h
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+++ b/include/asm-generic/vmlinux.lds.h
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@@ -177,6 +177,15 @@
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#define CLK_OF_TABLES()
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#endif
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+#ifdef CONFIG_SMP
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+#define CPU_METHOD_OF_TABLES() . = ALIGN(8); \
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+ VMLINUX_SYMBOL(__cpu_method_of_table_begin) = .; \
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+ *(__cpu_method_of_table) \
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+ VMLINUX_SYMBOL(__cpu_method_of_table_end) = .;
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+#else
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+#define CPU_METHOD_OF_TABLES()
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+#endif
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+
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#define KERNEL_DTB() \
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STRUCT_ALIGN(); \
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VMLINUX_SYMBOL(__dtb_start) = .; \
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@@ -502,6 +511,7 @@
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MEM_DISCARD(init.rodata) \
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CLK_OF_TABLES() \
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CLKSRC_OF_TABLES() \
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+ CPU_METHOD_OF_TABLES() \
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KERNEL_DTB() \
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IRQCHIP_OF_MATCH_TABLE()
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