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>

2 files changed, 20 insertions, 1 deletions

diff --git a/arch/arm/mach-tegra/flowctrl.h b/arch/arm/mach-tegra/flowctrl.h
index de0acb9ee323..c89aac60a143 100644
--- a/arch/arm/mach-tegra/flowctrl.h
+++ b/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
diff --git a/arch/arm/mach-tegra/pmc.c b/arch/arm/mach-tegra/pmc.c
index eb3fa4aee0e4..8345fcdcc9d5 100644
--- a/arch/arm/mach-tegra/pmc.c
+++ b/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);