imx_thermal.c
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/*
* (C) Copyright 2014 Freescale Semiconductor, Inc.
* Author: Nitin Garg <nitin.garg@freescale.com>
* Ye Li <Ye.Li@freescale.com>
*
* SPDX-License-Identifier: GPL-2.0+
*/
#include <config.h>
#include <common.h>
#include <div64.h>
#include <fuse.h>
#include <asm/io.h>
#include <asm/arch/clock.h>
#include <dm.h>
#include <errno.h>
#include <malloc.h>
#include <thermal.h>
#include <imx_thermal.h>
#define TEMPERATURE_MIN -40
#define TEMPERATURE_HOT 80
#define TEMPERATURE_MAX 125
#define FACTOR0 10000000
#define FACTOR1 15976
#define FACTOR2 4297157
#define MEASURE_FREQ 327
#define TEMPSENSE0_TEMP_CNT_SHIFT 8
#define TEMPSENSE0_TEMP_CNT_MASK (0xfff << TEMPSENSE0_TEMP_CNT_SHIFT)
#define TEMPSENSE0_FINISHED (1 << 2)
#define TEMPSENSE0_MEASURE_TEMP (1 << 1)
#define TEMPSENSE0_POWER_DOWN (1 << 0)
#define MISC0_REFTOP_SELBIASOFF (1 << 3)
#define TEMPSENSE1_MEASURE_FREQ 0xffff
static int read_cpu_temperature(struct udevice *dev)
{
int temperature;
unsigned int reg, n_meas;
const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
struct anatop_regs *anatop = (struct anatop_regs *)pdata->regs;
unsigned int *priv = dev_get_priv(dev);
u32 fuse = *priv;
int t1, n1;
u32 c1, c2;
u64 temp64;
/*
* Sensor data layout:
* [31:20] - sensor value @ 25C
* We use universal formula now and only need sensor value @ 25C
* slope = 0.4297157 - (0.0015976 * 25C fuse)
*/
n1 = fuse >> 20;
t1 = 25; /* t1 always 25C */
/*
* 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 = FACTOR0;
temp64 *= 1000;
do_div(temp64, FACTOR1 * n1 - FACTOR2);
c1 = temp64;
c2 = n1 * c1 + 1000 * t1;
/*
* now we only use single measure, every time we read
* the temperature, we will power on/down anadig thermal
* module
*/
writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_clr);
writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_set);
/* setup measure freq */
reg = readl(&anatop->tempsense1);
reg &= ~TEMPSENSE1_MEASURE_FREQ;
reg |= MEASURE_FREQ;
writel(reg, &anatop->tempsense1);
/* start the measurement process */
writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_clr);
writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
writel(TEMPSENSE0_MEASURE_TEMP, &anatop->tempsense0_set);
/* make sure that the latest temp is valid */
while ((readl(&anatop->tempsense0) &
TEMPSENSE0_FINISHED) == 0)
udelay(10000);
/* read temperature count */
reg = readl(&anatop->tempsense0);
n_meas = (reg & TEMPSENSE0_TEMP_CNT_MASK)
>> TEMPSENSE0_TEMP_CNT_SHIFT;
writel(TEMPSENSE0_FINISHED, &anatop->tempsense0_clr);
/* milli_Tmeas = c2 - Nmeas * c1 */
temperature = (c2 - n_meas * c1)/1000;
/* power down anatop thermal sensor */
writel(TEMPSENSE0_POWER_DOWN, &anatop->tempsense0_set);
writel(MISC0_REFTOP_SELBIASOFF, &anatop->ana_misc0_clr);
return temperature;
}
int imx_thermal_get_temp(struct udevice *dev, int *temp)
{
int cpu_tmp = 0;
cpu_tmp = read_cpu_temperature(dev);
while (cpu_tmp > TEMPERATURE_MIN && cpu_tmp < TEMPERATURE_MAX) {
if (cpu_tmp >= TEMPERATURE_HOT) {
printf("CPU Temperature is %d C, too hot to boot, waiting...\n",
cpu_tmp);
udelay(5000000);
cpu_tmp = read_cpu_temperature(dev);
} else {
break;
}
}
*temp = cpu_tmp;
return 0;
}
static const struct dm_thermal_ops imx_thermal_ops = {
.get_temp = imx_thermal_get_temp,
};
static int imx_thermal_probe(struct udevice *dev)
{
unsigned int fuse = ~0;
const struct imx_thermal_plat *pdata = dev_get_platdata(dev);
unsigned int *priv = dev_get_priv(dev);
/* Read Temperature calibration data fuse */
fuse_read(pdata->fuse_bank, pdata->fuse_word, &fuse);
/* Check for valid fuse */
if (fuse == 0 || fuse == ~0) {
printf("CPU: Thermal invalid data, fuse: 0x%x\n", fuse);
return -EPERM;
} else {
printf("CPU: Thermal calibration data: 0x%x\n", fuse);
}
*priv = fuse;
enable_thermal_clk();
return 0;
}
U_BOOT_DRIVER(imx_thermal) = {
.name = "imx_thermal",
.id = UCLASS_THERMAL,
.ops = &imx_thermal_ops,
.probe = imx_thermal_probe,
.priv_auto_alloc_size = sizeof(unsigned int),
.flags = DM_FLAG_PRE_RELOC,
};