ARM: tegra: shut off the CPU rail when the last CPU in suspend

When the last CPU core in suspend, the CPU power rail can be turned off
by setting flags to flow controller. Then the flow controller will inform
PMC to turn off the CPU rail when the last CPU goes into suspend.

Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>

arch/arm/mach-tegra/flowctrl.h

@@ -35,6 +35,11 @@
 #define FLOW_CTRL_CPU0_CSR		0x8
 #define	FLOW_CTRL_CSR_INTR_FLAG		(1 << 15)
 #define FLOW_CTRL_CSR_EVENT_FLAG	(1 << 14)
+#define FLOW_CTRL_CSR_ENABLE_EXT_CRAIL	(1 << 13)
+#define FLOW_CTRL_CSR_ENABLE_EXT_NCPU	(1 << 12)
+#define FLOW_CTRL_CSR_ENABLE_EXT_MASK ( \
+		FLOW_CTRL_CSR_ENABLE_EXT_NCPU | \
+		FLOW_CTRL_CSR_ENABLE_EXT_CRAIL)
 #define FLOW_CTRL_CSR_ENABLE		(1 << 0)
 #define FLOW_CTRL_HALT_CPU1_EVENTS	0x14
 #define FLOW_CTRL_CPU1_CSR		0x18

arch/arm/mach-tegra/pmc.c

@@ -21,6 +21,7 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 
+#include "flowctrl.h"
 #include "fuse.h"
 #include "pm.h"
 #include "pmc.h"
@@ -195,13 +196,26 @@ enum tegra_suspend_mode tegra_pmc_get_suspend_mode(void)
 
 void tegra_pmc_pm_set(enum tegra_suspend_mode mode)
 {
-	u32 reg;
+	u32 reg, csr_reg;
 	unsigned long rate = 0;
 
 	reg = tegra_pmc_readl(PMC_CTRL);
 	reg |= TEGRA_POWER_CPU_PWRREQ_OE;
 	reg &= ~TEGRA_POWER_EFFECT_LP0;
 
+	switch (tegra_chip_id) {
+	case TEGRA20:
+	case TEGRA30:
+		break;
+	default:
+		/* Turn off CRAIL */
+		csr_reg = flowctrl_read_cpu_csr(0);
+		csr_reg &= ~FLOW_CTRL_CSR_ENABLE_EXT_MASK;
+		csr_reg |= FLOW_CTRL_CSR_ENABLE_EXT_CRAIL;
+		flowctrl_write_cpu_csr(0, csr_reg);
+		break;
+	}
+
 	switch (mode) {
 	case TEGRA_SUSPEND_LP2:
 		rate = clk_get_rate(tegra_pclk);