+static u32 __data thermal_calib;
+
+#define FACTOR0 10000000
+#define FACTOR1 15976
+#define FACTOR2 4297157
+
+int raw_to_celsius(unsigned int raw, unsigned int raw_25c, unsigned int raw_hot,
+ unsigned int hot_temp)
+{
+ int temperature;
+
+ if (raw_hot != 0 && hot_temp != 0) {
+ unsigned int raw_n40c, ratio;
+
+ ratio = ((raw_25c - raw_hot) * 100) / (hot_temp - 25);
+ raw_n40c = raw_25c + (13 * ratio) / 20;
+ if (raw <= raw_n40c)
+ temperature = (raw_n40c - raw) * 100 / ratio - 40;
+ else
+ temperature = TEMPERATURE_MIN;
+ } else {
+ u64 temp64 = FACTOR0;
+ unsigned int c1, c2;
+ /*
+ * Derived from linear interpolation:
+ * slope = 0.4297157 - (0.0015976 * 25C fuse)
+ * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
+ * (Nmeas - n1) / (Tmeas - t1) = slope
+ * We want to reduce this down to the minimum computation necessary
+ * for each temperature read. Also, we want Tmeas in millicelsius
+ * and we don't want to lose precision from integer division. So...
+ * Tmeas = (Nmeas - n1) / slope + t1
+ * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
+ * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
+ * Let constant c1 = (-1000 / slope)
+ * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
+ * Let constant c2 = n1 *c1 + 1000 * t1
+ * milli_Tmeas = c2 - Nmeas * c1
+ */
+ temp64 *= 1000;
+ do_div(temp64, FACTOR1 * raw_25c - FACTOR2);
+ c1 = temp64;
+ c2 = raw_25c * c1 + 1000 * 25;
+ temperature = (c2 - raw * c1) / 1000;
+ }
+ return temperature;
+}
+
+int read_cpu_temperature(void)
+{
+ unsigned int reg, tmp, i;
+ unsigned int raw_25c, raw_hot, hot_temp;
+ int temperature;
+ struct anatop_regs *const anatop = (void *)ANATOP_BASE_ADDR;
+ struct mx6_ocotp_regs *const ocotp_regs = (void *)OCOTP_BASE_ADDR;
+
+ if (!thermal_calib) {
+ ocotp_clk_enable();
+ writel(1, &ocotp_regs->hw_ocotp_read_ctrl);
+ thermal_calib = readl(&ocotp_regs->hw_ocotp_ana1);
+ writel(0, &ocotp_regs->hw_ocotp_read_ctrl);
+ ocotp_clk_disable();
+ }
+
+ if (thermal_calib == 0 || thermal_calib == 0xffffffff)
+ return TEMPERATURE_MIN;
+
+ /* Fuse data layout:
+ * [31:20] sensor value @ 25C
+ * [19:8] sensor value of hot
+ * [7:0] hot temperature value */
+ raw_25c = thermal_calib >> 20;
+ raw_hot = (thermal_calib & 0xfff00) >> 8;
+ hot_temp = thermal_calib & 0xff;
+
+ /* now we only using single measure, every time we measure
+ * the temperature, we will power on/off the anadig module
+ */
+ writel(BM_ANADIG_TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr);
+ writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set);
+
+ /* write measure freq */
+ writel(327, &anatop->tempsense1);
+ writel(BM_ANADIG_TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr);
+ writel(BM_ANADIG_TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
+ writel(BM_ANADIG_TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set);
+
+ /* average the temperature value over multiple readings */
+ for (i = 0; i < TEMP_AVG_COUNT; i++) {
+ static int failed;
+ int limit = 100;
+
+ while ((readl(&anatop->tempsense0) &
+ BM_ANADIG_TEMPSENSE0_FINISHED) == 0) {
+ udelay(10000);
+ if (--limit < 0)
+ break;
+ }
+ if ((readl(&anatop->tempsense0) &
+ BM_ANADIG_TEMPSENSE0_FINISHED) == 0) {
+ if (!failed) {
+ printf("Failed to read temp sensor\n");
+ failed = 1;
+ }
+ return 0;
+ }
+ failed = 0;
+ reg = (readl(&anatop->tempsense0) &
+ BM_ANADIG_TEMPSENSE0_TEMP_VALUE) >>
+ BP_ANADIG_TEMPSENSE0_TEMP_VALUE;
+ if (i == 0)
+ tmp = reg;
+ else
+ tmp = (tmp * i + reg) / (i + 1);
+ writel(BM_ANADIG_TEMPSENSE0_FINISHED,
+ &anatop->tempsense0_clr);
+ }
+
+ temperature = raw_to_celsius(tmp, raw_25c, raw_hot, hot_temp);
+
+ /* power down anatop thermal sensor */
+ writel(BM_ANADIG_TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set);
+ writel(BM_ANADIG_ANA_MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr);
+
+ return temperature;
+}
+
+int check_cpu_temperature(int boot)
+{
+ static int __data max_temp;
+ int boot_limit = getenv_ulong("max_boot_temp", 10, TEMPERATURE_HOT);
+ int tmp = read_cpu_temperature();
+ bool first = true;
+
+ if (tmp < TEMPERATURE_MIN || tmp > TEMPERATURE_MAX) {
+ printf("Temperature: can't get valid data!\n");
+ return tmp;
+ }
+
+ if (!boot) {
+ if (tmp > boot_limit) {
+ printf("CPU is %d C, too hot, resetting...\n", tmp);
+ udelay(100000);
+ reset_cpu(0);
+ }
+ if (tmp > max_temp) {
+ if (tmp > boot_limit - TEMP_WARN_THRESHOLD)
+ printf("WARNING: CPU temperature %d C\n", tmp);
+ max_temp = tmp;
+ }
+ } else {
+ printf("Temperature: %d C, calibration data 0x%x\n",
+ tmp, thermal_calib);
+ while (tmp >= boot_limit) {
+ if (first) {
+ printf("CPU is %d C, too hot to boot, waiting...\n",
+ tmp);
+ first = false;
+ }
+ if (ctrlc())
+ break;
+ udelay(50000);
+ tmp = read_cpu_temperature();
+ if (tmp > boot_limit - TEMP_WARN_THRESHOLD && tmp != max_temp)
+ printf("WARNING: CPU temperature %d C\n", tmp);
+ max_temp = tmp;
+ }
+ }
+ return tmp;
+}
+