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 = (long)(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->critical) { 134 printf("CPU Temperature (%dC) too close to max (%dC)", 135 cpu_tmp, priv->maxc); 136 puts(" waiting...\n"); 137 udelay(5000000); 138 cpu_tmp = read_cpu_temperature(dev); 139 } 140 141 *temp = cpu_tmp; 142 143 return 0; 144 } 145 146 static const struct dm_thermal_ops imx_thermal_ops = { 147 .get_temp = imx_thermal_get_temp, 148 }; 149 150 static int imx_thermal_probe(struct udevice *dev) 151 { 152 unsigned int fuse = ~0; 153 154 const struct imx_thermal_plat *pdata = dev_get_platdata(dev); 155 struct thermal_data *priv = dev_get_priv(dev); 156 157 /* Read Temperature calibration data fuse */ 158 fuse_read(pdata->fuse_bank, pdata->fuse_word, &fuse); 159 160 /* Check for valid fuse */ 161 if (fuse == 0 || fuse == ~0) { 162 printf("CPU: Thermal invalid data, fuse: 0x%x\n", fuse); 163 return -EPERM; 164 } 165 166 /* set critical cooling temp */ 167 get_cpu_temp_grade(&priv->minc, &priv->maxc); 168 priv->critical = priv->maxc - TEMPERATURE_HOT_DELTA; 169 priv->fuse = fuse; 170 171 enable_thermal_clk(); 172 173 return 0; 174 } 175 176 U_BOOT_DRIVER(imx_thermal) = { 177 .name = "imx_thermal", 178 .id = UCLASS_THERMAL, 179 .ops = &imx_thermal_ops, 180 .probe = imx_thermal_probe, 181 .priv_auto_alloc_size = sizeof(struct thermal_data), 182 .flags = DM_FLAG_PRE_RELOC, 183 }; 184