Implement hysteresis like temperature up and down.

When die junction temperature reaches LIMIT1_UP set warning and start
lowering it by decreasing CPU frequency.
When temperature reaches LIMIT1_DOWN then get CPU back to max speed.
LIMIT_SHUTDOWN is hard limit to minimize power consumption by shutting down
as much as possible.
Those temperatures are all die junction temperatures. Ambient should be much
less than those (typically 50-60c).

arch/arm/mach-dove/hwmon.c

@@ -29,8 +29,14 @@
 #include <linux/list.h>
 #include <linux/platform_device.h>
 #include <linux/cpu.h>
+#include <linux/gpio.h>
 #include <asm/io.h>
+#include "mvOs.h"
+#include "pmu/mvPmu.h"
 #include "pmu/mvPmuRegs.h"
+#include "gpp/mvGppRegs.h"
+#include "ctrlEnv/mvCtrlEnvSpec.h"
+#include "ctrlEnv/sys/mvCpuIfRegs.h"
 
 #define DOVE_OVERHEAT_TEMP	105000		/* milidegree Celsius */
 #define DOVE_OVERHEAT_DELAY	0x700
@@ -47,6 +53,25 @@
 #define DOVE_TSEN_RAW2VOLT(x)  (((x) + 241)*100000/39619)
 
 #define LABEL "T-junction"
+
+/*
+ * Implement hysteresis like temperature up and down.
+ * When die junction temperature reaches LIMIT1_UP set warning and start
+ * lowering it by decreasing CPU frequency.
+ * When temperature reaches LIMIT1_DOWN then get CPU back to max speed.
+ * LIMIT_SHUTDOWN is hard limit to minimize power consumption by shutting down
+ * as much as possible.
+ * Those temperatures are all die junction temperatures. Ambient should be much
+ * less than those (typically 50-60c).
+ */
+#define LIMIT1_UP		105000 /* 100c */
+#define LIMIT1_DOWN		95000  /* 90c */
+#define LIMIT_SHUTDOWN		120000 /* 120c */
+
+/* External functions used for power management */
+extern MV_STATUS mvPmuCpuFreqScale (MV_PMU_CPU_SPEED cpuSpeed);
+extern MV_VOID mvPmuSramDeepIdle(MV_U32 ddrSelfRefresh);
+
 static struct device *hwmon_dev;
 unsigned int temp_min = DOVE_OVERCOOL_TEMP;
 unsigned int temp_max = DOVE_OVERHEAT_TEMP;
@@ -55,6 +80,7 @@ unsigned int temp_max = DOVE_OVERHEAT_TEMP;
 #define SENSOR_VOLT_CPU 2
 #define SENSOR_VOLT_CORE 3
 static int current_mode = 0;
+static struct timer_list thermal_check;
 
 typedef enum { 
 	SHOW_TEMP, 
@@ -240,6 +266,93 @@ static int dovetemp_read_volt(int mode)
 	return DOVE_TSEN_RAW2VOLT(reg);
 }
 
+static void local_cpu_freq_scale(MV_PMU_CPU_SPEED speed)
+{
+	MV_STATUS stat;
+	unsigned long ints;
+	u32 mc;
+	local_irq_save(ints);
+	mc = MV_REG_READ(CPU_MAIN_IRQ_MASK_HIGH_REG);
+	MV_REG_WRITE(CPU_MAIN_IRQ_MASK_HIGH_REG, (mc | 0x2));
+	stat = mvPmuCpuFreqScale (speed);
+	MV_REG_WRITE(CPU_MAIN_IRQ_MASK_HIGH_REG, mc);
+	local_irq_restore(ints);
+}
+/* Thermal check routine */
+static inline void dovetemp_checktemp(unsigned long data)
+{
+	static int warning_flag = 0;
+	int temp = dovetemp_read_temp();
+	u32 mc, mc2, reg;
+	unsigned long ints;
+	if (temp >= LIMIT_SHUTDOWN) {
+		/* Shutdown as much as possible */
+		printk (KERN_CRIT "Reached maximum thermal allowed. Shutting down\n");
+		local_irq_save(ints);
+		gpio_direction_output(1, 0); /* Disable external USB current limiter */
+		local_cpu_freq_scale(CPU_CLOCK_SLOW);
+		MV_REG_WRITE (0x0a2050, 0x009B1215); /* eSata - 40mA */
+		MV_REG_WRITE (0x0d0058, 0x0003007f); /* PEX clk - 10mA */
+		MV_REG_WRITE (0x072004, 0x00010800); /* SMI power down phy - ~20mA */
+		msleep(100);
+		MV_REG_WRITE (0x0720b0, 0x00000002); /* gigE digital part */
+		MV_REG_WRITE (0x0d0058, 0x0003007f); /* PEX clk + gig I/Os - 10mA */
+		/* disable GPU isolators */
+		reg = MV_REG_READ(PMU_ISO_CTRL_REG);
+		reg &= ~PMU_ISO_GPU_MASK;
+		MV_REG_WRITE(PMU_ISO_CTRL_REG, reg);
+		/* reset GPU unit */
+		reg = MV_REG_READ(PMU_SW_RST_CTRL_REG);
+		reg &= ~PMU_SW_RST_GPU_MASK;
+		MV_REG_WRITE(PMU_SW_RST_CTRL_REG, reg);
+		/* power off */
+		reg = MV_REG_READ(PMU_PWR_SUPLY_CTRL_REG);
+		reg |= PMU_PWR_GPU_PWR_DWN_MASK;
+		MV_REG_WRITE(PMU_PWR_SUPLY_CTRL_REG, reg);
+		reg = MV_REG_READ(0x0d0208);
+		reg &= ~0xf00;
+		reg |= 0x100; /* Set PWM GPIO to no-select */
+		MV_REG_WRITE(0x0d0208, reg);
+		reg = MV_REG_READ(0x0d0400);
+		reg |= (1 << 18);
+		MV_REG_WRITE(0x0d0400, reg);
+		MV_REG_WRITE (0x050400, 0xff000160); /* USB 0 phy shutdown */
+		MV_REG_WRITE (0x050400, 0xff000160); /* USB 1 phy shutdown */
+		MV_REG_WRITE (0x0d0038, 0xff3800c4); /* Clock gating of unused south bridge */
+		// Disable all interrupts besides uart0
+		mc = MV_REG_READ(CPU_MAIN_IRQ_MASK_REG);
+		mc2 = MV_REG_READ(CPU_MAIN_IRQ_MASK_HIGH_REG);
+		MV_REG_WRITE(CPU_MAIN_IRQ_MASK_REG, 0x80); /* disable all interrupts except UART0 */
+		MV_REG_WRITE(CPU_MAIN_IRQ_MASK_HIGH_REG, 0x0);
+		printk (KERN_CRIT "Just before entering deep sleep\n");
+		/* The following will put DDR in self-refresh mode */
+		mvPmuSramDeepIdle(0);
+		__asm__ __volatile__("wfi\n");
+		/* Should never reach here */
+		panic("Should never reach here function %s line %d\n",
+			__FUNCTION__,__LINE__);
+		local_irq_restore(ints);
+	}
+	if (temp >= LIMIT1_UP && !warning_flag) {
+		warning_flag = 1;
+		printk (KERN_WARNING "Die temperature exceeded limit (%d mili C)\n",
+			temp);
+		/* Limit CPU speed to DDR speed */
+		local_cpu_freq_scale (CPU_CLOCK_SLOW);
+	}
+	if (temp <= LIMIT1_DOWN && warning_flag) {
+		warning_flag = 0;
+		printk (KERN_INFO "Die temperature went below limit (%d mili C)\n",
+			temp);
+		/* Remove CPU speed limit */
+		local_cpu_freq_scale (CPU_CLOCK_TURBO);
+	}
+	if (warning_flag) {
+		/* Make sure external frequency scaling didn't change CPU freq */
+		local_cpu_freq_scale (CPU_CLOCK_SLOW);
+	}
+	mod_timer(&thermal_check, jiffies + (HZ));
+}
 /*
  * Sysfs stuff
  */
@@ -405,6 +518,11 @@ static int __devinit dovetemp_probe(struct platform_device *pdev)
 	}
 
 	printk(KERN_INFO "Dove hwmon thermal sensor initialized.\n");
+	init_timer(&thermal_check);
+	thermal_check.data = 0;
+	thermal_check.function = dovetemp_checktemp;
+	thermal_check.expires = jiffies + (HZ);
+	add_timer(&thermal_check);
 
 	return 0;