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