[PATCH V3 6/7] ARM: tegra30: flowctrl: add cpu_suspend_exter/exit function

[Joseph Lo]

The flow controller can help CPU to go into suspend mode (powered-down
state). When CPU go into powered-down state, it needs some careful
settings before getting into and after leaving. The enter and exit
functions do that by configuring appropriate mode for flow controller.

Signed-off-by: Joseph Lo <josephl at nvidia.com>
---
V3:
* update the commit message
V2:
* no change
---
 arch/arm/mach-tegra/flowctrl.c |   47 ++++++++++++++++++++++++++++++++++++++++
 arch/arm/mach-tegra/flowctrl.h |    8 ++++++
 2 files changed, 55 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-tegra/flowctrl.c b/arch/arm/mach-tegra/flowctrl.c
index f07488e..5967b08 100644
--- a/arch/arm/mach-tegra/flowctrl.c
+++ b/arch/arm/mach-tegra/flowctrl.c
@@ -21,6 +21,7 @@
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/io.h>
+#include <linux/cpumask.h>
 
 #include <mach/iomap.h>
 
@@ -51,6 +52,14 @@ static void flowctrl_update(u8 offset, u32 value)
 	readl_relaxed(addr);
 }
 
+u32 flowctrl_read_cpu_csr(unsigned int cpuid)
+{
+	u8 offset = flowctrl_offset_cpu_csr[cpuid];
+	void __iomem *addr = IO_ADDRESS(TEGRA_FLOW_CTRL_BASE) + offset;
+
+	return readl(addr);
+}
+
 void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value)
 {
 	return flowctrl_update(flowctrl_offset_cpu_csr[cpuid], value);
@@ -60,3 +69,41 @@ void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value)
 {
 	return flowctrl_update(flowctrl_offset_halt_cpu[cpuid], value);
 }
+
+void flowctrl_cpu_suspend_enter(unsigned int cpuid)
+{
+	unsigned int reg;
+	int i;
+
+	reg = flowctrl_read_cpu_csr(cpuid);
+	reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;	/* clear wfe bitmap */
+	reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;	/* clear wfi bitmap */
+	reg |= FLOW_CTRL_CSR_INTR_FLAG;			/* clear intr flag */
+	reg |= FLOW_CTRL_CSR_EVENT_FLAG;		/* clear event flag */
+	reg |= TEGRA30_FLOW_CTRL_CSR_WFI_CPU0 << cpuid;	/* pwr gating on wfi */
+	reg |= FLOW_CTRL_CSR_ENABLE;			/* pwr gating */
+	flowctrl_write_cpu_csr(cpuid, reg);
+
+	for (i = 0; i < num_possible_cpus(); i++) {
+		if (i == cpuid)
+			continue;
+		reg = flowctrl_read_cpu_csr(i);
+		reg |= FLOW_CTRL_CSR_EVENT_FLAG;
+		reg |= FLOW_CTRL_CSR_INTR_FLAG;
+		flowctrl_write_cpu_csr(i, reg);
+	}
+}
+
+void flowctrl_cpu_suspend_exit(unsigned int cpuid)
+{
+	unsigned int reg;
+
+	/* Disable powergating via flow controller for CPU0 */
+	reg = flowctrl_read_cpu_csr(cpuid);
+	reg &= ~TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP;	/* clear wfe bitmap */
+	reg &= ~TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP;	/* clear wfi bitmap */
+	reg &= ~FLOW_CTRL_CSR_ENABLE;			/* clear enable */
+	reg |= FLOW_CTRL_CSR_INTR_FLAG;			/* clear intr */
+	reg |= FLOW_CTRL_CSR_EVENT_FLAG;		/* clear event */
+	flowctrl_write_cpu_csr(cpuid, reg);
+}
diff --git a/arch/arm/mach-tegra/flowctrl.h b/arch/arm/mach-tegra/flowctrl.h
index 1942817..0798dec 100644
--- a/arch/arm/mach-tegra/flowctrl.h
+++ b/arch/arm/mach-tegra/flowctrl.h
@@ -34,9 +34,17 @@
 #define FLOW_CTRL_HALT_CPU1_EVENTS	0x14
 #define FLOW_CTRL_CPU1_CSR		0x18
 
+#define TEGRA30_FLOW_CTRL_CSR_WFI_CPU0		(1 << 8)
+#define TEGRA30_FLOW_CTRL_CSR_WFE_BITMAP	(0xF << 4)
+#define TEGRA30_FLOW_CTRL_CSR_WFI_BITMAP	(0xF << 8)
+
 #ifndef __ASSEMBLY__
+u32 flowctrl_read_cpu_csr(unsigned int cpuid);
 void flowctrl_write_cpu_csr(unsigned int cpuid, u32 value);
 void flowctrl_write_cpu_halt(unsigned int cpuid, u32 value);
+
+void flowctrl_cpu_suspend_enter(unsigned int cpuid);
+void flowctrl_cpu_suspend_exit(unsigned int cpuid);
 #endif
 
 #endif
-- 
1.7.0.4