ARM: cpuidle: Add a cpuidle ops structure to be used for DT

The current state of the different cpuidle drivers is the different PM
operations are passed via the platform_data using the platform driver
paradigm.

This approach allowed to split the low level PM code from the arch specific
and the generic cpuidle code.

Unfortunately there are complaints about this approach as, in the context of the
single kernel image, we have multiple drivers loaded in memory for nothing and
the platform driver is not adequate for cpuidle.

This patch provides a common interface via cpuidle ops for all new cpuidle
driver and a definition for the device tree.

It will allow with the next patches to a have a common definition with ARM64
and share the same cpuidle driver.

The code is optimized to use the __init section intensively in order to reduce
the memory footprint after the driver is initialized and unify the function
names with ARM64.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Kevin Hilman <khilman@linaro.org>
Acked-by: Rob Herring <robherring2@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Tested-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/arch/arm/include/asm/cpuidle.h b/arch/arm/include/asm/cpuidle.h
index 348dc817b9f38edb31526c5ae64c454cb8e76ca9..0f842492490280b9d0b50fd1b25935a51b5a4c9d 100644 (file)
--- a/arch/arm/include/asm/cpuidle.h
+++ b/arch/arm/include/asm/cpuidle.h
@@ -27,4 +27,25 @@ static inline int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
  */
 #define ARM_CPUIDLE_WFI_STATE ARM_CPUIDLE_WFI_STATE_PWR(UINT_MAX)
 
+struct device_node;
+
+struct cpuidle_ops {
+       int (*suspend)(int cpu, unsigned long arg);
+       int (*init)(struct device_node *, int cpu);
+};
+
+struct of_cpuidle_method {
+       const char *method;
+       struct cpuidle_ops *ops;
+};
+
+#define CPUIDLE_METHOD_OF_DECLARE(name, _method, _ops)                 \
+       static const struct of_cpuidle_method __cpuidle_method_of_table_##name \
+       __used __section(__cpuidle_method_of_table)                     \
+       = { .method = _method, .ops = _ops }
+
+extern int arm_cpuidle_suspend(int index);
+
+extern int arm_cpuidle_init(int cpu);
+
 #endif

diff --git a/arch/arm/kernel/cpuidle.c b/arch/arm/kernel/cpuidle.c
index 45969f89f05ca393742d1824e31a4162a4c7505d..2b0dae3cd0587994d9246be9b7493e400e0f920d 100644 (file)
--- a/arch/arm/kernel/cpuidle.c
+++ b/arch/arm/kernel/cpuidle.c
@@ -10,8 +10,17 @@
  */
 
 #include <linux/cpuidle.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <asm/cpuidle.h>
 
+extern struct of_cpuidle_method __cpuidle_method_of_table[];
+
+static const struct of_cpuidle_method __cpuidle_method_of_table_sentinel
+       __used __section(__cpuidle_method_of_table_end);
+
+static struct cpuidle_ops cpuidle_ops[NR_CPUS];
+
 int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
                struct cpuidle_driver *drv, int index)
 {
@@ -19,3 +28,66 @@ int arm_cpuidle_simple_enter(struct cpuidle_device *dev,
 
        return index;
 }
+
+int arm_cpuidle_suspend(int index)
+{
+       int ret = -EOPNOTSUPP;
+       int cpu = smp_processor_id();
+
+       if (cpuidle_ops[cpu].suspend)
+               ret = cpuidle_ops[cpu].suspend(cpu, index);
+
+       return ret;
+}
+
+static struct cpuidle_ops *__init arm_cpuidle_get_ops(const char *method)
+{
+       struct of_cpuidle_method *m = __cpuidle_method_of_table;
+
+       for (; m->method; m++)
+               if (!strcmp(m->method, method))
+                       return m->ops;
+
+       return NULL;
+}
+
+static int __init arm_cpuidle_read_ops(struct device_node *dn, int cpu)
+{
+       const char *enable_method;
+       struct cpuidle_ops *ops;
+
+       enable_method = of_get_property(dn, "enable-method", NULL);
+       if (!enable_method)
+               return -ENOENT;
+
+       ops = arm_cpuidle_get_ops(enable_method);
+       if (!ops) {
+               pr_warn("%s: unsupported enable-method property: %s\n",
+                       dn->full_name, enable_method);
+               return -EOPNOTSUPP;
+       }
+
+       cpuidle_ops[cpu] = *ops; /* structure copy */
+
+       pr_notice("cpuidle: enable-method property '%s'"
+                 " found operations\n", enable_method);
+
+       return 0;
+}
+
+int __init arm_cpuidle_init(int cpu)
+{
+       struct device_node *cpu_node = of_cpu_device_node_get(cpu);
+       int ret;
+
+       if (!cpu_node)
+               return -ENODEV;
+
+       ret = arm_cpuidle_read_ops(cpu_node, cpu);
+       if (!ret && cpuidle_ops[cpu].init)
+               ret = cpuidle_ops[cpu].init(cpu_node, cpu);
+
+       of_node_put(cpu_node);
+
+       return ret;
+}

diff --git a/arch/arm64/include/asm/cpuidle.h b/arch/arm64/include/asm/cpuidle.h
index c60643f14cda97e7ba6dd9676f10b133af4b0627..460a38bb84b9618a3b50452a2b16a935188962a9 100644 (file)
--- a/arch/arm64/include/asm/cpuidle.h
+++ b/arch/arm64/include/asm/cpuidle.h
@@ -17,5 +17,8 @@ static inline int cpu_suspend(unsigned long arg)
        return -EOPNOTSUPP;
 }
 #endif
-
+static inline int arm_cpuidle_suspend(int index)
+{
+       return cpu_suspend(index);
+}
 #endif

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index ac78910d7416c5f7f2a68cfbde0d950d58ab0d9c..91c09305106d3a51600aebbb4fc0e401a7014fde 100644 (file)
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -167,6 +167,7 @@
 #define IOMMU_OF_TABLES()      OF_TABLE(CONFIG_OF_IOMMU, iommu)
 #define RESERVEDMEM_OF_TABLES()        OF_TABLE(CONFIG_OF_RESERVED_MEM, reservedmem)
 #define CPU_METHOD_OF_TABLES() OF_TABLE(CONFIG_SMP, cpu_method)
+#define CPUIDLE_METHOD_OF_TABLES() OF_TABLE(CONFIG_CPU_IDLE, cpuidle_method)
 #define EARLYCON_OF_TABLES()   OF_TABLE(CONFIG_SERIAL_EARLYCON, earlycon)
 
 #define KERNEL_DTB()                                                   \
@@ -501,6 +502,7 @@
        CLKSRC_OF_TABLES()                                              \
        IOMMU_OF_TABLES()                                               \
        CPU_METHOD_OF_TABLES()                                          \
+       CPUIDLE_METHOD_OF_TABLES()                                      \
        KERNEL_DTB()                                                    \
        IRQCHIP_OF_MATCH_TABLE()                                        \
        EARLYCON_OF_TABLES()