thermal/drivers/core: Add init section table for self-encapsulation

Currently the governors are declared in their respective files but they
export their [un]register functions which in turn call the [un]register
governors core's functions. That implies a cyclic dependency which is
not desirable. There is a way to self-encapsulate the governors by letting
them to declare themselves in a __init section table.

Define the table in the asm generic linker description like the other
tables and provide the specific macros to deal with.

Reviewed-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>

diff --git a/drivers/thermal/thermal_core.h b/drivers/thermal/thermal_core.h
index 0df190e..06778ce 100644 (file)
--- a/drivers/thermal/thermal_core.h
+++ b/drivers/thermal/thermal_core.h
@@ -15,6 +15,21 @@
 /* Initial state of a cooling device during binding */
 #define THERMAL_NO_TARGET -1UL
 
+/* Init section thermal table */
+extern struct thermal_governor *__governor_thermal_table[];
+extern struct thermal_governor *__governor_thermal_table_end[];
+
+#define THERMAL_TABLE_ENTRY(table, name)                       \
+       static typeof(name) *__thermal_table_entry_##name       \
+       __used __section(__##table##_thermal_table) = &name
+
+#define THERMAL_GOVERNOR_DECLARE(name) THERMAL_TABLE_ENTRY(governor, name)
+
+#define for_each_governor_table(__governor)            \
+       for (__governor = __governor_thermal_table;     \
+            __governor < __governor_thermal_table_end; \
+            __governor++)
+
 /*
  * This structure is used to describe the behavior of
  * a certain cooling device on a certain trip point

diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h
index 088987e..5a06822 100644 (file)
--- a/include/asm-generic/vmlinux.lds.h
+++ b/include/asm-generic/vmlinux.lds.h
@@ -239,6 +239,16 @@
 #define ACPI_PROBE_TABLE(name)
 #endif
 
+#ifdef CONFIG_THERMAL
+#define THERMAL_TABLE(name)                                            \
+       . = ALIGN(8);                                                   \
+       __##name##_thermal_table = .;                                   \
+       KEEP(*(__##name##_thermal_table))                               \
+       __##name##_thermal_table_end = .;
+#else
+#define THERMAL_TABLE(name)
+#endif
+
 #define KERNEL_DTB()                                                   \
        STRUCT_ALIGN();                                                 \
        __dtb_start = .;                                                \
@@ -608,6 +618,7 @@
        IRQCHIP_OF_MATCH_TABLE()                                        \
        ACPI_PROBE_TABLE(irqchip)                                       \
        ACPI_PROBE_TABLE(timer)                                         \
+       THERMAL_TABLE(governor)                                         \
        EARLYCON_TABLE()                                                \
        LSM_TABLE()