target/linux/ipq806x/patches/0008-ARM-Introduce-CPU_METHOD_OF_DECLARE-for-cpu-hotplug-.patch

   1 From 48f17325fef9cbebc5cb39aa78f4c1caff5d7b16 Mon Sep 17 00:00:00 2001
   2 From: Stephen Boyd <sboyd@codeaurora.org>
   3 Date: Wed, 30 Oct 2013 18:21:09 -0700
   4 Subject: [PATCH 008/182] ARM: Introduce CPU_METHOD_OF_DECLARE() for cpu
   5  hotplug/smp
   6
   7 The goal of multi-platform kernels is to remove the need for mach
   8 directories and machine descriptors. To further that goal,
   9 introduce CPU_METHOD_OF_DECLARE() to allow cpu hotplug/smp
  10 support to be separated from the machine descriptors.
  11 Implementers should specify an enable-method property in their
  12 cpus node and then implement a matching set of smp_ops in their
  13 hotplug/smp code, wiring it up with the CPU_METHOD_OF_DECLARE()
  14 macro. When the kernel is compiled we'll collect all the
  15 enable-method smp_ops into one section for use at boot.
  16
  17 At boot time we'll look for an enable-method in each cpu node and
  18 try to match that against all known CPU enable methods in the
  19 kernel. If there are no enable-methods in the cpu nodes we
  20 fallback to the cpus node and try to use any enable-method found
  21 there. If that doesn't work we fall back to the old way of using
  22 the machine descriptor.
  23
  24 Acked-by: Mark Rutland <mark.rutland@arm.com>
  25 Cc: Russell King <linux@arm.linux.org.uk>
  26 Cc: <devicetree@vger.kernel.org>
  27 Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
  28 Signed-off-by: Kumar Gala <galak@codeaurora.org>
  29 ---
  30  arch/arm/include/asm/smp.h        |    9 +++++++++
  31  arch/arm/kernel/devtree.c         |   40 +++++++++++++++++++++++++++++++++++++
  32  include/asm-generic/vmlinux.lds.h |   10 ++++++++++
  33  3 files changed, 59 insertions(+)
  34
  35 diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h
  36 index 22a3b9b..772435b 100644
  37 --- a/arch/arm/include/asm/smp.h
  38 +++ b/arch/arm/include/asm/smp.h
  39 @@ -114,6 +114,15 @@ struct smp_operations {
  40  #endif
  41  };
  42
  43 +struct of_cpu_method {
  44 +       const char *method;
  45 +       struct smp_operations *ops;
  46 +};
  47 +
  48 +#define CPU_METHOD_OF_DECLARE(name, _method, _ops)                     \
  49 +       static const struct of_cpu_method __cpu_method_of_table_##name  \
  50 +               __used __section(__cpu_method_of_table)                 \
  51 +               = { .method = _method, .ops = _ops }
  52  /*
  53   * set platform specific SMP operations
  54   */
  55 diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
  56 index f751714..c7419a5 100644
  57 --- a/arch/arm/kernel/devtree.c
  58 +++ b/arch/arm/kernel/devtree.c
  59 @@ -18,6 +18,7 @@
  60  #include <linux/of_fdt.h>
  61  #include <linux/of_irq.h>
  62  #include <linux/of_platform.h>
  63 +#include <linux/smp.h>
  64
  65  #include <asm/cputype.h>
  66  #include <asm/setup.h>
  67 @@ -63,6 +64,34 @@ void __init arm_dt_memblock_reserve(void)
  68         }
  69  }
  70
  71 +#ifdef CONFIG_SMP
  72 +extern struct of_cpu_method __cpu_method_of_table_begin[];
  73 +extern struct of_cpu_method __cpu_method_of_table_end[];
  74 +
  75 +static int __init set_smp_ops_by_method(struct device_node *node)
  76 +{
  77 +       const char *method;
  78 +       struct of_cpu_method *m = __cpu_method_of_table_begin;
  79 +
  80 +       if (of_property_read_string(node, "enable-method", &method))
  81 +               return 0;
  82 +
  83 +       for (; m < __cpu_method_of_table_end; m++)
  84 +               if (!strcmp(m->method, method)) {
  85 +                       smp_set_ops(m->ops);
  86 +                       return 1;
  87 +               }
  88 +
  89 +       return 0;
  90 +}
  91 +#else
  92 +static inline int set_smp_ops_by_method(struct device_node *node)
  93 +{
  94 +       return 1;
  95 +}
  96 +#endif
  97 +
  98 +
  99  /*
 100   * arm_dt_init_cpu_maps - Function retrieves cpu nodes from the device tree
 101   * and builds the cpu logical map array containing MPIDR values related to
 102 @@ -79,6 +108,7 @@ void __init arm_dt_init_cpu_maps(void)
 103          * read as 0.
 104          */
 105         struct device_node *cpu, *cpus;
 106 +       int found_method = 0;
 107         u32 i, j, cpuidx = 1;
 108         u32 mpidr = is_smp() ? read_cpuid_mpidr() & MPIDR_HWID_BITMASK : 0;
 109
 110 @@ -150,8 +180,18 @@ void __init arm_dt_init_cpu_maps(void)
 111                 }
 112
 113                 tmp_map[i] = hwid;
 114 +
 115 +               if (!found_method)
 116 +                       found_method = set_smp_ops_by_method(cpu);
 117         }
 118
 119 +       /*
 120 +        * Fallback to an enable-method in the cpus node if nothing found in
 121 +        * a cpu node.
 122 +        */
 123 +       if (!found_method)
 124 +               set_smp_ops_by_method(cpus);
 125 +
 126         if (!bootcpu_valid) {
 127                 pr_warn("DT missing boot CPU MPIDR[23:0], fall back to default cpu_logical_map\n");
 128                 return;
 129 diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
 130 index bc2121f..bd02ca7 100644
 131 --- a/include/asm-generic/vmlinux.lds.h
 132 +++ b/include/asm-generic/vmlinux.lds.h
 133 @@ -167,6 +167,15 @@
 134  #define CLK_OF_TABLES()
 135  #endif
 136
 137 +#ifdef CONFIG_SMP
 138 +#define CPU_METHOD_OF_TABLES() . = ALIGN(8);                               \
 139 +                          VMLINUX_SYMBOL(__cpu_method_of_table_begin) = .; \
 140 +                          *(__cpu_method_of_table)                         \
 141 +                          VMLINUX_SYMBOL(__cpu_method_of_table_end) = .;
 142 +#else
 143 +#define CPU_METHOD_OF_TABLES()
 144 +#endif
 145 +
 146  #define KERNEL_DTB()                                                   \
 147         STRUCT_ALIGN();                                                 \
 148         VMLINUX_SYMBOL(__dtb_start) = .;                                \
 149 @@ -491,6 +500,7 @@
 150         MEM_DISCARD(init.rodata)                                        \
 151         CLK_OF_TABLES()                                                 \
 152         CLKSRC_OF_TABLES()                                              \
 153 +       CPU_METHOD_OF_TABLES()                                          \
 154         KERNEL_DTB()                                                    \
 155         IRQCHIP_OF_MATCH_TABLE()
 156
 157 --
 158 1.7.10.4
 159