summaryrefslogtreecommitdiff
path: root/src/soc/amd/picasso/i2c.c
blob: fa59b994a270cbc6bd52b9caec111fcf411d2100 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
/* SPDX-License-Identifier: GPL-2.0-only */

#include <device/mmio.h>
#include <acpi/acpi.h>
#include <console/console.h>
#include <delay.h>
#include <device/device.h>
#include <drivers/i2c/designware/dw_i2c.h>
#include <amdblocks/acpimmio.h>
#include <soc/i2c.h>
#include <soc/iomap.h>
#include <soc/pci_devs.h>
#include <soc/southbridge.h>
#include "chip.h"

/*
 * We don't have addresses for I2C0-1.
 */
static const uintptr_t i2c_bus_address[I2C_MASTER_DEV_COUNT + I2C_SLAVE_DEV_COUNT] = {
	0,
	0,
	APU_I2C2_BASE,
	APU_I2C3_BASE,
	APU_I2C4_BASE, /* Can only be used in slave mode */
};

uintptr_t dw_i2c_base_address(unsigned int bus)
{
	if (bus >= ARRAY_SIZE(i2c_bus_address))
		return 0;

	return i2c_bus_address[bus];
}

const struct dw_i2c_bus_config *dw_i2c_get_soc_cfg(unsigned int bus)
{
	const struct soc_amd_picasso_config *config;

	if (bus >= ARRAY_SIZE(config->i2c))
		return NULL;

	/* config is not NULL; if it was, config_of_soc calls die() internally */
	config = config_of_soc();

	return &config->i2c[bus];
}

static const char *i2c_acpi_name(const struct device *dev)
{
	switch (dev->path.mmio.addr) {
	case APU_I2C2_BASE:
		return "I2C2";
	case APU_I2C3_BASE:
		return "I2C3";
	case APU_I2C4_BASE:
		return "I2C4";
	default:
		return NULL;
	}
}

int dw_i2c_soc_dev_to_bus(const struct device *dev)
{
	switch (dev->path.mmio.addr) {
	case APU_I2C2_BASE:
		return 2;
	case APU_I2C3_BASE:
		return 3;
	case APU_I2C4_BASE:
		return 4;
	}
	return -1;
}

__weak void mainboard_i2c_override(int bus, uint32_t *pad_settings) { }

static void dw_i2c_soc_init(bool is_early_init)
{
	size_t i;
	const struct soc_amd_picasso_config *config;
	uint32_t pad_ctrl;
	int misc_reg;

	/* config is not NULL; if it was, config_of_soc calls die() internally */
	config = config_of_soc();

	for (i = I2C_MASTER_START_INDEX; i < ARRAY_SIZE(config->i2c); i++) {
		const struct dw_i2c_bus_config *cfg  = &config->i2c[i];

		if (cfg->early_init != is_early_init)
			continue;

		if (dw_i2c_init(i, cfg)) {
			printk(BIOS_ERR, "Failed to init i2c bus %zd\n", i);
			continue;
		}

		misc_reg = MISC_I2C0_PAD_CTRL + sizeof(uint32_t) * i;
		pad_ctrl = misc_read32(misc_reg);

		pad_ctrl &= ~I2C_PAD_CTRL_NG_MASK;
		pad_ctrl |= I2C_PAD_CTRL_NG_NORMAL;

		pad_ctrl &= ~I2C_PAD_CTRL_RX_SEL_MASK;
		pad_ctrl |= I2C_PAD_CTRL_RX_SEL_3_3V;

		pad_ctrl &= ~I2C_PAD_CTRL_FALLSLEW_MASK;
		pad_ctrl |= cfg->speed == I2C_SPEED_STANDARD
				? I2C_PAD_CTRL_FALLSLEW_STD
				: I2C_PAD_CTRL_FALLSLEW_LOW;
		pad_ctrl |= I2C_PAD_CTRL_FALLSLEW_EN;

		mainboard_i2c_override(i, &pad_ctrl);
		misc_write32(misc_reg, pad_ctrl);
	}
}

void i2c_soc_early_init(void)
{
	dw_i2c_soc_init(true);
}

void i2c_soc_init(void)
{
	dw_i2c_soc_init(false);
}

struct device_operations picasso_i2c_mmio_ops = {
	/* TODO(teravest): Move I2C resource info here. */
	.read_resources = noop_read_resources,
	.set_resources = noop_set_resources,
	.scan_bus = scan_smbus,
	.acpi_name = i2c_acpi_name,
	.acpi_fill_ssdt = dw_i2c_acpi_fill_ssdt,
};

/*
 * I2C pins are open drain with external pull up, so in order to bit bang them
 * all, SCL pins must become GPIO inputs with no pull, then they need to be
 * toggled between input-no-pull and output-low. This table is for the initial
 * conversion of all SCL pins to input with no pull.
 */
static const struct soc_amd_gpio i2c_2_gpi[] = {
	PAD_GPI(I2C2_SCL_PIN, PULL_NONE),
	PAD_GPI(I2C3_SCL_PIN, PULL_NONE),
	/* I2C4 is a slave device only */
};
#define saved_pins_count ARRAY_SIZE(i2c_2_gpi)

/*
 * To program I2C pins without destroying their programming, the registers
 * that will be changed need to be saved first.
 */
static void save_i2c_pin_registers(uint8_t gpio,
					struct soc_amd_i2c_save *save_table)
{
	uint32_t *gpio_ptr;

	gpio_ptr = (uint32_t *)gpio_get_address(gpio);
	save_table->mux_value = iomux_read8(gpio);
	save_table->control_value = read32(gpio_ptr);
}

static void restore_i2c_pin_registers(uint8_t gpio,
					struct soc_amd_i2c_save *save_table)
{
	uint32_t *gpio_ptr;

	gpio_ptr = (uint32_t *)gpio_get_address(gpio);
	iomux_write8(gpio, save_table->mux_value);
	iomux_read8(gpio);
	write32(gpio_ptr, save_table->control_value);
	read32(gpio_ptr);
}

/* Slaves to be reset are controlled by devicetree register i2c_scl_reset */
void sb_reset_i2c_slaves(void)
{
	const struct soc_amd_picasso_config *cfg;
	const struct device *dev = pcidev_path_on_root(GNB_DEVFN);
	struct soc_amd_i2c_save save_table[saved_pins_count];
	uint8_t i, j, control;

	if (!dev || !dev->chip_info)
		return;
	cfg = dev->chip_info;
	control = cfg->i2c_scl_reset & GPIO_I2C_MASK;
	if (control == 0)
		return;

	/* Save and reprogram I2C SCL pins */
	for (i = 0; i < saved_pins_count; i++)
		save_i2c_pin_registers(i2c_2_gpi[i].gpio, &save_table[i]);
	program_gpios(i2c_2_gpi, saved_pins_count);

	/*
	 * Toggle SCL back and forth 9 times under 100KHz. A single read is
	 * needed after the writes to force the posted write to complete.
	 */
	for (j = 0; j < 9; j++) {
		if (control & GPIO_I2C2_SCL)
			write32((uint32_t *)GPIO_I2C2_ADDRESS, GPIO_SCL_LOW);
		if (control & GPIO_I2C3_SCL)
			write32((uint32_t *)GPIO_I2C3_ADDRESS, GPIO_SCL_LOW);

		read32((uint32_t *)GPIO_I2C3_ADDRESS); /* Flush posted write */
		udelay(4); /* 4usec gets 85KHz for 1 pin, 70KHz for 4 pins */

		if (control & GPIO_I2C2_SCL)
			write32((uint32_t *)GPIO_I2C2_ADDRESS, GPIO_SCL_HIGH);
		if (control & GPIO_I2C3_SCL)
			write32((uint32_t *)GPIO_I2C3_ADDRESS, GPIO_SCL_HIGH);

		read32((uint32_t *)GPIO_I2C3_ADDRESS); /* Flush posted write */
		udelay(4);
	}

	/* Restore I2C pins. */
	for (i = 0; i < saved_pins_count; i++)
		restore_i2c_pin_registers(i2c_2_gpi[i].gpio, &save_table[i]);
}