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 <[email protected]> Signed-off-by: Daniel Lezcano <[email protected]> Signed-off-by: Zhang Rui <[email protected]>
jbg · Jun 27, 2019 · 980af75 · 980af75
1 parent 4b972a0
commit 980af75
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diff --git 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
@@ -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()