ARM: imx: add cpu idle support for i.MX6SLL

i.MX6SLL supports cpu idle with ARM power gated,
it can reuse i.MX6SX's cpu idle driver to support
below 3 states of cpu idle:

state0: WFI;
state1: WAIT mode with ARM power on;
state2: WAIT mode with ARM power off.

L2_PGE in GPC_CNTR needs to be cleared to support
state2 cpu idle.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/mach-imx/Makefile

@@ -25,8 +25,8 @@ obj-$(CONFIG_MXC_DEBUG_BOARD) += 3ds_debugboard.o
 ifeq ($(CONFIG_CPU_IDLE),y)
 obj-$(CONFIG_SOC_IMX5) += cpuidle-imx5.o
 obj-$(CONFIG_SOC_IMX6Q) += cpuidle-imx6q.o
-obj-$(CONFIG_SOC_IMX6SL) += cpuidle-imx6sl.o
-obj-$(CONFIG_SOC_IMX6SLL) += cpuidle-imx6sl.o
+obj-$(CONFIG_SOC_IMX6SL) += cpuidle-imx6sl.o cpuidle-imx6sx.o
+obj-$(CONFIG_SOC_IMX6SLL) += cpuidle-imx6sl.o cpuidle-imx6sx.o
 obj-$(CONFIG_SOC_IMX6SX) += cpuidle-imx6sx.o
 obj-$(CONFIG_SOC_IMX6UL) += cpuidle-imx6sx.o
 endif

arch/arm/mach-imx/cpuidle-imx6sx.c

@@ -103,6 +103,7 @@ int __init imx6sx_cpuidle_init(void)
 {
 	imx6_set_int_mem_clk_lpm(true);
 	imx6_enable_rbc(false);
+	imx_gpc_set_l2_mem_power_in_lpm(false);
 	/*
 	 * set ARM power up/down timing to the fastest,
 	 * sw2iso and sw can be set to one 32K cycle = 31us

arch/arm/mach-imx/mach-imx6sl.c

@@ -42,7 +42,10 @@ static void __init imx6sl_init_late(void)
 	if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ))
 		platform_device_register_simple("imx6q-cpufreq", -1, NULL, 0);
 
-	imx6sl_cpuidle_init();
+	if (cpu_is_imx6sl())
+		imx6sl_cpuidle_init();
+	else
+		imx6sx_cpuidle_init();
 }
 
 static void __init imx6sl_init_machine(void)