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425640256a
The temperature calculation must be typecasted to keep the compiler from sign extending a negative value prior to division. This fixes an issue where if the CPU temperature is <0C it will get stuck in the busywait loop until the CPU heats up to 0C. Cc: Ye Li <b37916@freescale.com> Cc: Jason Liu <r64343@freescale.com> Signed-off-by: Tim Harvey <tharvey@gateworks.com>
183 lines
4.9 KiB
C
183 lines
4.9 KiB
C
/*
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* (C) Copyright 2014 Freescale Semiconductor, Inc.
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* Author: Nitin Garg <nitin.garg@freescale.com>
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* Ye Li <Ye.Li@freescale.com>
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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#include <config.h>
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#include <common.h>
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#include <div64.h>
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#include <fuse.h>
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#include <asm/io.h>
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#include <asm/arch/clock.h>
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#include <asm/arch/sys_proto.h>
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#include <dm.h>
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#include <errno.h>
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#include <malloc.h>
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#include <thermal.h>
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#include <imx_thermal.h>
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/* board will busyloop until this many degrees C below CPU max temperature */
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#define TEMPERATURE_HOT_DELTA 5 /* CPU maxT - 5C */
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#define FACTOR0 10000000
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#define FACTOR1 15976
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#define FACTOR2 4297157
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#define MEASURE_FREQ 327
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#define TEMPSENSE0_TEMP_CNT_SHIFT 8
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#define TEMPSENSE0_TEMP_CNT_MASK (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
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#define TEMPSENSE0_FINISHED (1 << 2)
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#define TEMPSENSE0_MEASURE_TEMP (1 << 1)
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#define TEMPSENSE0_POWER_DOWN (1 << 0)
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#define MISC0_REFTOP_SELBIASOFF (1 << 3)
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#define TEMPSENSE1_MEASURE_FREQ 0xffff
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struct thermal_data {
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unsigned int fuse;
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int critical;
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int minc;
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int maxc;
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};
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static int read_cpu_temperature(struct udevice *dev)
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{
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int temperature;
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unsigned int reg, n_meas;
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const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
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struct anatop_regs *anatop = (struct anatop_regs *)pdata->regs;
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struct thermal_data *priv = dev_get_priv(dev);
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u32 fuse = priv->fuse;
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int t1, n1;
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u32 c1, c2;
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u64 temp64;
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/*
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* Sensor data layout:
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* [31:20] - sensor value @ 25C
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* We use universal formula now and only need sensor value @ 25C
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* slope = 0.4297157 - (0.0015976 * 25C fuse)
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*/
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n1 = fuse >> 20;
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t1 = 25; /* t1 always 25C */
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/*
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* Derived from linear interpolation:
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* slope = 0.4297157 - (0.0015976 * 25C fuse)
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* slope = (FACTOR2 - FACTOR1 * n1) / FACTOR0
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* (Nmeas - n1) / (Tmeas - t1) = slope
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* We want to reduce this down to the minimum computation necessary
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* for each temperature read. Also, we want Tmeas in millicelsius
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* and we don't want to lose precision from integer division. So...
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* Tmeas = (Nmeas - n1) / slope + t1
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* milli_Tmeas = 1000 * (Nmeas - n1) / slope + 1000 * t1
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* milli_Tmeas = -1000 * (n1 - Nmeas) / slope + 1000 * t1
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* Let constant c1 = (-1000 / slope)
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* milli_Tmeas = (n1 - Nmeas) * c1 + 1000 * t1
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* Let constant c2 = n1 *c1 + 1000 * t1
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* milli_Tmeas = c2 - Nmeas * c1
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*/
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temp64 = FACTOR0;
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temp64 *= 1000;
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do_div(temp64, FACTOR1 * n1 - FACTOR2);
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c1 = temp64;
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c2 = n1 * c1 + 1000 * t1;
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/*
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* now we only use single measure, every time we read
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* the temperature, we will power on/down anadig thermal
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* module
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*/
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writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr);
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writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set);
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/* setup measure freq */
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reg = readl(&anatop->tempsense1);
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reg &= ~TEMPSENSE1_MEASURE_FREQ;
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reg |= MEASURE_FREQ;
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writel(reg, &anatop->tempsense1);
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/* start the measurement process */
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writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr);
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writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
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writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set);
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/* make sure that the latest temp is valid */
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while ((readl(&anatop->tempsense0) &
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TEMPSENSE0_FINISHED) == 0)
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udelay(10000);
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/* read temperature count */
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reg = readl(&anatop->tempsense0);
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n_meas = (reg & TEMPSENSE0_TEMP_CNT_MASK)
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>> TEMPSENSE0_TEMP_CNT_SHIFT;
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writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
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/* milli_Tmeas = c2 - Nmeas * c1 */
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temperature = (long)(c2 - n_meas * c1)/1000;
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/* power down anatop thermal sensor */
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writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set);
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writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr);
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return temperature;
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}
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int imx_thermal_get_temp(struct udevice *dev, int *temp)
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{
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struct thermal_data *priv = dev_get_priv(dev);
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int cpu_tmp = 0;
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cpu_tmp = read_cpu_temperature(dev);
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while (cpu_tmp >= priv->critical) {
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printf("CPU Temperature (%dC) too close to max (%dC)",
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cpu_tmp, priv->maxc);
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puts(" waiting...\n");
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udelay(5000000);
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cpu_tmp = read_cpu_temperature(dev);
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}
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*temp = cpu_tmp;
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return 0;
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}
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static const struct dm_thermal_ops imx_thermal_ops = {
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.get_temp = imx_thermal_get_temp,
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};
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static int imx_thermal_probe(struct udevice *dev)
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{
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unsigned int fuse = ~0;
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const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
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struct thermal_data *priv = dev_get_priv(dev);
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/* Read Temperature calibration data fuse */
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fuse_read(pdata->fuse_bank, pdata->fuse_word, &fuse);
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/* Check for valid fuse */
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if (fuse == 0 || fuse == ~0) {
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printf("CPU: Thermal invalid data, fuse: 0x%x\n", fuse);
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return -EPERM;
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}
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/* set critical cooling temp */
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get_cpu_temp_grade(&priv->minc, &priv->maxc);
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priv->critical = priv->maxc - TEMPERATURE_HOT_DELTA;
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priv->fuse = fuse;
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enable_thermal_clk();
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return 0;
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}
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U_BOOT_DRIVER(imx_thermal) = {
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.name = "imx_thermal",
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.id = UCLASS_THERMAL,
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.ops = &imx_thermal_ops,
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.probe = imx_thermal_probe,
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.priv_auto_alloc_size = sizeof(struct thermal_data),
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.flags = DM_FLAG_PRE_RELOC,
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};
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