soc: samsung: Do not build ARMv7 PMU drivers on ARMv8

The Exynos Power Management Unit (PMU) drivers contain quite large
static arrays of register values necessary for given Exynos SoC to enter
low power mode.  All this data is useless for ARMv8 SoC like
Exynos5433, because the image will not be shared between ARMv7 and
ARMv8.

Add additional Kconfig symbol for selecting the SoC-specific driver
addons thus skipping the useless data in the final image (this is
similar approach to chosen for Exynos clock controller drivers):
 - exynos-pmu driver will be compiled on both architectures ARMv7
   and ARMv8,
 - additional driver_data for ARMv7 SoCs will not be built on ARMv8
   and a macro will return NULL for them in of_device_id - this should
   be safe as these compatibles cannot match on ARMv7 and driver
   anyway handles NULL driver_data,
 - on ARMv8 compile only exynos-pmu driver which exposes the
   syscon-regmap for PMU address space.

Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Reviewed-by: Alim Akhtar <alim.akhtar@samsung.com>

drivers/soc/samsung/Kconfig

@@ -8,7 +8,13 @@ if SOC_SAMSUNG
 
 config EXYNOS_PMU
 	bool "Exynos PMU controller driver" if COMPILE_TEST
-	depends on (ARM && ARCH_EXYNOS) || ((ARM || ARM64) && COMPILE_TEST)
+	depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST)
+	select EXYNOS_PMU_ARM_DRIVERS if ARM && ARCH_EXYNOS
+
+# There is no need to enable these drivers for ARMv8
+config EXYNOS_PMU_ARM_DRIVERS
+	bool "Exynos PMU ARMv7-specific driver extensions" if COMPILE_TEST
+	depends on EXYNOS_PMU
 
 config EXYNOS_PM_DOMAINS
 	bool "Exynos PM domains" if COMPILE_TEST

drivers/soc/samsung/Makefile

@@ -1,3 +1,5 @@
-obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o exynos3250-pmu.o exynos4-pmu.o \
+obj-$(CONFIG_EXYNOS_PMU)	+= exynos-pmu.o
+
+obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \
 					exynos5250-pmu.o exynos5420-pmu.o
 obj-$(CONFIG_EXYNOS_PM_DOMAINS) += pm_domains.o

drivers/soc/samsung/exynos-pmu.c

@@ -68,28 +68,38 @@ void exynos_sys_powerdown_conf(enum sys_powerdown mode)
 	}
 }
 
+/*
+ * Split the data between ARM architectures because it is relatively big
+ * and useless on other arch.
+ */
+#ifdef CONFIG_EXYNOS_PMU_ARM_DRIVERS
+#define exynos_pmu_data_arm_ptr(data)	(&data)
+#else
+#define exynos_pmu_data_arm_ptr(data)	NULL
+#endif
+
 /*
  * PMU platform driver and devicetree bindings.
  */
 static const struct of_device_id exynos_pmu_of_device_ids[] = {
 	{
 		.compatible = "samsung,exynos3250-pmu",
-		.data = &exynos3250_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos3250_pmu_data),
 	}, {
 		.compatible = "samsung,exynos4210-pmu",
-		.data = &exynos4210_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos4210_pmu_data),
 	}, {
 		.compatible = "samsung,exynos4212-pmu",
-		.data = &exynos4212_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos4212_pmu_data),
 	}, {
 		.compatible = "samsung,exynos4412-pmu",
-		.data = &exynos4412_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos4412_pmu_data),
 	}, {
 		.compatible = "samsung,exynos5250-pmu",
-		.data = &exynos5250_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos5250_pmu_data),
 	}, {
 		.compatible = "samsung,exynos5420-pmu",
-		.data = &exynos5420_pmu_data,
+		.data = exynos_pmu_data_arm_ptr(exynos5420_pmu_data),
 	}, {
 		.compatible = "samsung,exynos5433-pmu",
 	},

drivers/soc/samsung/exynos-pmu.h

@@ -31,6 +31,8 @@ struct exynos_pmu_data {
 };
 
 extern void __iomem *pmu_base_addr;
+
+#ifdef CONFIG_EXYNOS_PMU_ARM_DRIVERS
 /* list of all exported SoC specific data */
 extern const struct exynos_pmu_data exynos3250_pmu_data;
 extern const struct exynos_pmu_data exynos4210_pmu_data;
@@ -38,6 +40,7 @@ extern const struct exynos_pmu_data exynos4212_pmu_data;
 extern const struct exynos_pmu_data exynos4412_pmu_data;
 extern const struct exynos_pmu_data exynos5250_pmu_data;
 extern const struct exynos_pmu_data exynos5420_pmu_data;
+#endif
 
 extern void pmu_raw_writel(u32 val, u32 offset);
 extern u32 pmu_raw_readl(u32 offset);