ARM: tegra30: clocks: add CPU low-power function into tegra_cpu_car_ops

Add suspend, resume and rail_off_ready API into tegra_cpu_car_ops. These
functions were used for CPU powered-down state maintenance. One thing
needs to notice the rail_off_ready API only availalbe for cpu_g cluster
not cpu_lp cluster.

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

2 files changed, 145 insertions, 0 deletions

diff --git a/arch/arm/mach-tegra/tegra30_clocks.c b/arch/arm/mach-tegra/tegra30_clocks.c
index f5b453f4bf4d..efc000e32e1c 100644
--- a/arch/arm/mach-tegra/tegra30_clocks.c
+++ b/arch/arm/mach-tegra/tegra30_clocks.c
@@ -31,6 +31,8 @@
 
 #include <asm/clkdev.h>
 
+#include <mach/powergate.h>
+
 #include "clock.h"
 #include "fuse.h"
 #include "iomap.h"
@@ -309,6 +311,31 @@
 #define CPU_CLOCK(cpu)  (0x1 << (8 + cpu))
 #define CPU_RESET(cpu)  (0x1111ul << (cpu))
 
+#define CLK_RESET_CCLK_BURST    0x20
+#define CLK_RESET_CCLK_DIVIDER  0x24
+#define CLK_RESET_PLLX_BASE     0xe0
+#define CLK_RESET_PLLX_MISC     0xe4
+
+#define CLK_RESET_SOURCE_CSITE  0x1d4
+
+#define CLK_RESET_CCLK_BURST_POLICY_SHIFT       28
+#define CLK_RESET_CCLK_RUN_POLICY_SHIFT         4
+#define CLK_RESET_CCLK_IDLE_POLICY_SHIFT        0
+#define CLK_RESET_CCLK_IDLE_POLICY              1
+#define CLK_RESET_CCLK_RUN_POLICY               2
+#define CLK_RESET_CCLK_BURST_POLICY_PLLX        8
+
+#ifdef CONFIG_PM_SLEEP
+static struct cpu_clk_suspend_context {
+        u32 pllx_misc;
+        u32 pllx_base;
+
+        u32 cpu_burst;
+        u32 clk_csite_src;
+        u32 cclk_divider;
+} tegra30_cpu_clk_sctx;
+#endif
+
 /**
 * Structure defining the fields for USB UTMI clocks Parameters.
 */
@@ -2386,12 +2413,93 @@ static void tegra30_disable_cpu_clock(u32 cpu)
                reg_clk_base + TEGRA_CLK_RST_CONTROLLER_CLK_CPU_CMPLX);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static bool tegra30_cpu_rail_off_ready(void)
+{
+        unsigned int cpu_rst_status;
+        int cpu_pwr_status;
+
+        cpu_rst_status = readl(reg_clk_base +
+                               TEGRA30_CLK_RST_CONTROLLER_CPU_CMPLX_STATUS);
+        cpu_pwr_status = tegra_powergate_is_powered(TEGRA_POWERGATE_CPU1) ||
+                         tegra_powergate_is_powered(TEGRA_POWERGATE_CPU2) ||
+                         tegra_powergate_is_powered(TEGRA_POWERGATE_CPU3);
+
+        if (((cpu_rst_status & 0xE) != 0xE) || cpu_pwr_status)
+                return false;
+
+        return true;
+}
+
+static void tegra30_cpu_clock_suspend(void)
+{
+        /* switch coresite to clk_m, save off original source */
+        tegra30_cpu_clk_sctx.clk_csite_src =
+                                readl(reg_clk_base + CLK_RESET_SOURCE_CSITE);
+        writel(3<<30, reg_clk_base + CLK_RESET_SOURCE_CSITE);
+
+        tegra30_cpu_clk_sctx.cpu_burst =
+                                readl(reg_clk_base + CLK_RESET_CCLK_BURST);
+        tegra30_cpu_clk_sctx.pllx_base =
+                                readl(reg_clk_base + CLK_RESET_PLLX_BASE);
+        tegra30_cpu_clk_sctx.pllx_misc =
+                                readl(reg_clk_base + CLK_RESET_PLLX_MISC);
+        tegra30_cpu_clk_sctx.cclk_divider =
+                                readl(reg_clk_base + CLK_RESET_CCLK_DIVIDER);
+}
+
+static void tegra30_cpu_clock_resume(void)
+{
+        unsigned int reg, policy;
+
+        /* Is CPU complex already running on PLLX? */
+        reg = readl(reg_clk_base + CLK_RESET_CCLK_BURST);
+        policy = (reg >> CLK_RESET_CCLK_BURST_POLICY_SHIFT) & 0xF;
+
+        if (policy == CLK_RESET_CCLK_IDLE_POLICY)
+                reg = (reg >> CLK_RESET_CCLK_IDLE_POLICY_SHIFT) & 0xF;
+        else if (policy == CLK_RESET_CCLK_RUN_POLICY)
+                reg = (reg >> CLK_RESET_CCLK_RUN_POLICY_SHIFT) & 0xF;
+        else
+                BUG();
+
+        if (reg != CLK_RESET_CCLK_BURST_POLICY_PLLX) {
+                /* restore PLLX settings if CPU is on different PLL */
+                writel(tegra30_cpu_clk_sctx.pllx_misc,
+                                        reg_clk_base + CLK_RESET_PLLX_MISC);
+                writel(tegra30_cpu_clk_sctx.pllx_base,
+                                        reg_clk_base + CLK_RESET_PLLX_BASE);
+
+                /* wait for PLL stabilization if PLLX was enabled */
+                if (tegra30_cpu_clk_sctx.pllx_base & (1 << 30))
+                        udelay(300);
+        }
+
+        /*
+         * Restore original burst policy setting for calls resulting from CPU
+         * LP2 in idle or system suspend.
+         */
+        writel(tegra30_cpu_clk_sctx.cclk_divider,
+                                        reg_clk_base + CLK_RESET_CCLK_DIVIDER);
+        writel(tegra30_cpu_clk_sctx.cpu_burst,
+                                        reg_clk_base + CLK_RESET_CCLK_BURST);
+
+        writel(tegra30_cpu_clk_sctx.clk_csite_src,
+                                        reg_clk_base + CLK_RESET_SOURCE_CSITE);
+}
+#endif
+
 static struct tegra_cpu_car_ops tegra30_cpu_car_ops = {
         .wait_for_reset = tegra30_wait_cpu_in_reset,
         .put_in_reset   = tegra30_put_cpu_in_reset,
         .out_of_reset   = tegra30_cpu_out_of_reset,
         .enable_clock   = tegra30_enable_cpu_clock,
         .disable_clock  = tegra30_disable_cpu_clock,
+#ifdef CONFIG_PM_SLEEP
+        .rail_off_ready = tegra30_cpu_rail_off_ready,
+        .suspend        = tegra30_cpu_clock_suspend,
+        .resume         = tegra30_cpu_clock_resume,
+#endif
 };
 
 void __init tegra30_cpu_car_ops_init(void)
diff --git a/arch/arm/mach-tegra/tegra_cpu_car.h b/arch/arm/mach-tegra/tegra_cpu_car.h
index 30d063ad2bef..9764d31032b7 100644
--- a/arch/arm/mach-tegra/tegra_cpu_car.h
+++ b/arch/arm/mach-tegra/tegra_cpu_car.h
@@ -30,6 +30,12 @@
  *      CPU clock un-gate
  * disable_clock:
  *      CPU clock gate
+ * rail_off_ready:
+ *      CPU is ready for rail off
+ * suspend:
+ *      save the clock settings when CPU go into low-power state
+ * resume:
+ *      restore the clock settings when CPU exit low-power state
  */
 struct tegra_cpu_car_ops {
         void (*wait_for_reset)(u32 cpu);
@@ -37,6 +43,11 @@ struct tegra_cpu_car_ops {
         void (*out_of_reset)(u32 cpu);
         void (*enable_clock)(u32 cpu);
         void (*disable_clock)(u32 cpu);
+#ifdef CONFIG_PM_SLEEP
+        bool (*rail_off_ready)(void);
+        void (*suspend)(void);
+        void (*resume)(void);
+#endif
 };
 
 extern struct tegra_cpu_car_ops *tegra_cpu_car_ops;
@@ -81,6 +92,32 @@ static inline void tegra_disable_cpu_clock(u32 cpu)
         tegra_cpu_car_ops->disable_clock(cpu);
 }
 
+#ifdef CONFIG_PM_SLEEP
+static inline bool tegra_cpu_rail_off_ready(void)
+{
+        if (WARN_ON(!tegra_cpu_car_ops->rail_off_ready))
+                return false;
+
+        return tegra_cpu_car_ops->rail_off_ready();
+}
+
+static inline void tegra_cpu_clock_suspend(void)
+{
+        if (WARN_ON(!tegra_cpu_car_ops->suspend))
+                return;
+
+        tegra_cpu_car_ops->suspend();
+}
+
+static inline void tegra_cpu_clock_resume(void)
+{
+        if (WARN_ON(!tegra_cpu_car_ops->resume))
+                return;
+
+        tegra_cpu_car_ops->resume();
+}
+#endif
+
 void tegra20_cpu_car_ops_init(void);
 void tegra30_cpu_car_ops_init(void);