drivers/thermal/imx_thermal.c

   1 /*
   2  * (C) Copyright 2014 Freescale Semiconductor, Inc.
   3  * Author: Nitin Garg <nitin.garg@freescale.com>
   4  *             Ye Li <Ye.Li@freescale.com>
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <config.h>
  10 #include <common.h>
  11 #include <div64.h>
  12 #include <fuse.h>
  13 #include <asm/io.h>
  14 #include <asm/arch/clock.h>
  15 #include <asm/arch/sys_proto.h>
  16 #include <dm.h>
  17 #include <errno.h>
  18 #include <malloc.h>
  19 #include <thermal.h>
  20 #include <imx_thermal.h>
  21
  22 /* board will busyloop until this many degrees C below CPU max temperature */
  23 #define TEMPERATURE_HOT_DELTA   5 /* CPU maxT - 5C */
  24 #define FACTOR0                 10000000
  25 #define FACTOR1                 15976
  26 #define FACTOR2                 4297157
  27 #define MEASURE_FREQ            327
  28
  29 #define TEMPSENSE0_TEMP_CNT_SHIFT       8
  30 #define TEMPSENSE0_TEMP_CNT_MASK        (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
  31 #define TEMPSENSE0_FINISHED             (1 << 2)
  32 #define TEMPSENSE0_MEASURE_TEMP         (1 << 1)
  33 #define TEMPSENSE0_POWER_DOWN           (1 << 0)
  34 #define MISC0_REFTOP_SELBIASOFF         (1 << 3)
  35 #define TEMPSENSE1_MEASURE_FREQ         0xffff
  36
  37 struct thermal_data {
  38         unsigned int fuse;
  39         int critical;
  40         int minc;
  41         int maxc;
  42 };
  43
  44 static int read_cpu_temperature(struct udevice *dev)
  45 {
  46         int temperature;
  47         unsigned int reg, n_meas;
  48         const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
  49         struct anatop_regs *anatop = (struct anatop_regs *)pdata->regs;
  50         struct thermal_data *priv = dev_get_priv(dev);
  51         u32 fuse = priv->fuse;
  52         int t1, n1;
  53         u32 c1, c2;
  54         u64 temp64;
  55
  56         /*
  57          * Sensor data layout:
  58          *   [31:20] - sensor value @ 25C
  59          * We use universal formula now and only need sensor value @ 25C
  60          * slope = 0.4297157 - (0.0015976 * 25C fuse)
  61          */
  62         n1 = fuse >> 20;
  63         t1 = 25; /* t1 always 25C */
  64
  65         /*
  66          * Derived from linear interpolation:
  67          * slope = 0.4297157 - (0.0015976 * 25C fuse)
  68          * slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
  69          * (Nmeas - n1) / (Tmeas - t1) = slope
  70          * We want to reduce this down to the minimum computation necessary
  71          * for each temperature read.  Also, we want Tmeas in millicelsius
  72          * and we don't want to lose precision from integer division. So...
  73          * Tmeas = (Nmeas - n1) / slope + t1
  74          * milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
  75          * milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
  76          * Let constant c1 = (-1000 / slope)
  77          * milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
  78          * Let constant c2 = n1 *c1 + 1000 * t1
  79          * milli_Tmeas = c2 - Nmeas * c1
  80          */
  81         temp64 = FACTOR0;
  82         temp64 *= 1000;
  83         do_div(temp64, FACTOR1 * n1 - FACTOR2);
  84         c1 = temp64;
  85         c2 = n1 * c1 + 1000 * t1;
  86
  87         /*
  88          * now we only use single measure, every time we read
  89          * the temperature, we will power on/down anadig thermal
  90          * module
  91          */
  92         writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr);
  93         writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set);
  94
  95         /* setup measure freq */
  96         reg = readl(&anatop->tempsense1);
  97         reg &= ~TEMPSENSE1_MEASURE_FREQ;
  98         reg |= MEASURE_FREQ;
  99         writel(reg, &anatop->tempsense1);
 100
 101         /* start the measurement process */
 102         writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr);
 103         writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
 104         writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set);
 105
 106         /* make sure that the latest temp is valid */
 107         while ((readl(&anatop->tempsense0) &
 108                 TEMPSENSE0_FINISHED) == 0)
 109                 udelay(10000);
 110
 111         /* read temperature count */
 112         reg = readl(&anatop->tempsense0);
 113         n_meas = (reg & TEMPSENSE0_TEMP_CNT_MASK)
 114                 >> TEMPSENSE0_TEMP_CNT_SHIFT;
 115         writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
 116
 117         /* milli_Tmeas = c2 - Nmeas * c1 */
 118         temperature = (c2 - n_meas * c1)/1000;
 119
 120         /* power down anatop thermal sensor */
 121         writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set);
 122         writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr);
 123
 124         return temperature;
 125 }
 126
 127 int imx_thermal_get_temp(struct udevice *dev, int *temp)
 128 {
 129         struct thermal_data *priv = dev_get_priv(dev);
 130         int cpu_tmp = 0;
 131
 132         cpu_tmp = read_cpu_temperature(dev);
 133         while (cpu_tmp > priv->minc && cpu_tmp < priv->maxc) {
 134                 if (cpu_tmp >= priv->critical) {
 135                         printf("CPU Temperature (%dC) too close to max (%dC)",
 136                                cpu_tmp, priv->maxc);
 137                         puts(" waiting...\n");
 138                         udelay(5000000);
 139                         cpu_tmp = read_cpu_temperature(dev);
 140                 } else {
 141                         break;
 142                 }
 143         }
 144
 145         *temp = cpu_tmp;
 146
 147         return 0;
 148 }
 149
 150 static const struct dm_thermal_ops imx_thermal_ops = {
 151         .get_temp       = imx_thermal_get_temp,
 152 };
 153
 154 static int imx_thermal_probe(struct udevice *dev)
 155 {
 156         unsigned int fuse = ~0;
 157
 158         const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
 159         struct thermal_data *priv = dev_get_priv(dev);
 160
 161         /* Read Temperature calibration data fuse */
 162         fuse_read(pdata->fuse_bank, pdata->fuse_word, &fuse);
 163
 164         /* Check for valid fuse */
 165         if (fuse == 0 || fuse == ~0) {
 166                 printf("CPU:   Thermal invalid data, fuse: 0x%x\n", fuse);
 167                 return -EPERM;
 168         }
 169
 170         /* set critical cooling temp */
 171         get_cpu_temp_grade(&priv->minc, &priv->maxc);
 172         priv->critical = priv->maxc - TEMPERATURE_HOT_DELTA;
 173         priv->fuse = fuse;
 174
 175         enable_thermal_clk();
 176
 177         return 0;
 178 }
 179
 180 U_BOOT_DRIVER(imx_thermal) = {
 181         .name   = "imx_thermal",
 182         .id     = UCLASS_THERMAL,
 183         .ops    = &imx_thermal_ops,
 184         .probe  = imx_thermal_probe,
 185         .priv_auto_alloc_size = sizeof(struct thermal_data),
 186         .flags  = DM_FLAG_PRE_RELOC,
 187 };