1 /*
2  * Copyright (c) 2012 The Chromium OS Authors.
3  * SPDX-License-Identifier:	GPL-2.0+
4  */
5 
6 /*
7  * This is a GPIO driver for Intel ICH6 and later. The x86 GPIOs are accessed
8  * through the PCI bus. Each PCI device has 256 bytes of configuration space,
9  * consisting of a standard header and a device-specific set of registers. PCI
10  * bus 0, device 31, function 0 gives us access to the chipset GPIOs (among
11  * other things). Within the PCI configuration space, the GPIOBASE register
12  * tells us where in the device's I/O region we can find more registers to
13  * actually access the GPIOs.
14  *
15  * PCI bus/device/function 0:1f:0  => PCI config registers
16  *   PCI config register "GPIOBASE"
17  *     PCI I/O space + [GPIOBASE]  => start of GPIO registers
18  *       GPIO registers => gpio pin function, direction, value
19  *
20  *
21  * Danger Will Robinson! Bank 0 (GPIOs 0-31) seems to be fairly stable. Most
22  * ICH versions have more, but the decoding the matrix that describes them is
23  * absurdly complex and constantly changing. We'll provide Bank 1 and Bank 2,
24  * but they will ONLY work for certain unspecified chipsets because the offset
25  * from GPIOBASE changes randomly. Even then, many GPIOs are unimplemented or
26  * reserved or subject to arcane restrictions.
27  */
28 
29 #include <common.h>
30 #include <dm.h>
31 #include <errno.h>
32 #include <fdtdec.h>
33 #include <pch.h>
34 #include <pci.h>
35 #include <asm/cpu.h>
36 #include <asm/gpio.h>
37 #include <asm/io.h>
38 #include <asm/pci.h>
39 
40 DECLARE_GLOBAL_DATA_PTR;
41 
42 #define GPIO_PER_BANK	32
43 
44 struct ich6_bank_priv {
45 	/* These are I/O addresses */
46 	uint16_t use_sel;
47 	uint16_t io_sel;
48 	uint16_t lvl;
49 	u32 lvl_write_cache;
50 	bool use_lvl_write_cache;
51 };
52 
53 #define GPIO_USESEL_OFFSET(x)	(x)
54 #define GPIO_IOSEL_OFFSET(x)	(x + 4)
55 #define GPIO_LVL_OFFSET(x)	(x + 8)
56 
57 static int _ich6_gpio_set_value(struct ich6_bank_priv *bank, unsigned offset,
58 				int value)
59 {
60 	u32 val;
61 
62 	if (bank->use_lvl_write_cache)
63 		val = bank->lvl_write_cache;
64 	else
65 		val = inl(bank->lvl);
66 
67 	if (value)
68 		val |= (1UL << offset);
69 	else
70 		val &= ~(1UL << offset);
71 	outl(val, bank->lvl);
72 	if (bank->use_lvl_write_cache)
73 		bank->lvl_write_cache = val;
74 
75 	return 0;
76 }
77 
78 static int _ich6_gpio_set_direction(uint16_t base, unsigned offset, int dir)
79 {
80 	u32 val;
81 
82 	if (!dir) {
83 		val = inl(base);
84 		val |= (1UL << offset);
85 		outl(val, base);
86 	} else {
87 		val = inl(base);
88 		val &= ~(1UL << offset);
89 		outl(val, base);
90 	}
91 
92 	return 0;
93 }
94 
95 static int gpio_ich6_ofdata_to_platdata(struct udevice *dev)
96 {
97 	struct ich6_bank_platdata *plat = dev_get_platdata(dev);
98 	u32 gpiobase;
99 	int offset;
100 	int ret;
101 
102 	ret = pch_get_gpio_base(dev->parent, &gpiobase);
103 	if (ret)
104 		return ret;
105 
106 	offset = fdtdec_get_int(gd->fdt_blob, dev_of_offset(dev), "reg", -1);
107 	if (offset == -1) {
108 		debug("%s: Invalid register offset %d\n", __func__, offset);
109 		return -EINVAL;
110 	}
111 	plat->offset = offset;
112 	plat->base_addr = gpiobase + offset;
113 	plat->bank_name = fdt_getprop(gd->fdt_blob, dev_of_offset(dev),
114 				      "bank-name", NULL);
115 
116 	return 0;
117 }
118 
119 static int ich6_gpio_probe(struct udevice *dev)
120 {
121 	struct ich6_bank_platdata *plat = dev_get_platdata(dev);
122 	struct gpio_dev_priv *uc_priv = dev_get_uclass_priv(dev);
123 	struct ich6_bank_priv *bank = dev_get_priv(dev);
124 	const void *prop;
125 
126 	uc_priv->gpio_count = GPIO_PER_BANK;
127 	uc_priv->bank_name = plat->bank_name;
128 	bank->use_sel = plat->base_addr;
129 	bank->io_sel = plat->base_addr + 4;
130 	bank->lvl = plat->base_addr + 8;
131 
132 	prop = fdt_getprop(gd->fdt_blob, dev_of_offset(dev),
133 			   "use-lvl-write-cache", NULL);
134 	if (prop)
135 		bank->use_lvl_write_cache = true;
136 	else
137 		bank->use_lvl_write_cache = false;
138 	bank->lvl_write_cache = 0;
139 
140 	return 0;
141 }
142 
143 static int ich6_gpio_request(struct udevice *dev, unsigned offset,
144 			     const char *label)
145 {
146 	struct ich6_bank_priv *bank = dev_get_priv(dev);
147 	u32 tmplong;
148 
149 	/*
150 	 * Make sure that the GPIO pin we want isn't already in use for some
151 	 * built-in hardware function. We have to check this for every
152 	 * requested pin.
153 	 */
154 	tmplong = inl(bank->use_sel);
155 	if (!(tmplong & (1UL << offset))) {
156 		debug("%s: gpio %d is reserved for internal use\n", __func__,
157 		      offset);
158 		return -EPERM;
159 	}
160 
161 	return 0;
162 }
163 
164 static int ich6_gpio_direction_input(struct udevice *dev, unsigned offset)
165 {
166 	struct ich6_bank_priv *bank = dev_get_priv(dev);
167 
168 	return _ich6_gpio_set_direction(bank->io_sel, offset, 0);
169 }
170 
171 static int ich6_gpio_direction_output(struct udevice *dev, unsigned offset,
172 				       int value)
173 {
174 	int ret;
175 	struct ich6_bank_priv *bank = dev_get_priv(dev);
176 
177 	ret = _ich6_gpio_set_direction(bank->io_sel, offset, 1);
178 	if (ret)
179 		return ret;
180 
181 	return _ich6_gpio_set_value(bank, offset, value);
182 }
183 
184 static int ich6_gpio_get_value(struct udevice *dev, unsigned offset)
185 {
186 	struct ich6_bank_priv *bank = dev_get_priv(dev);
187 	u32 tmplong;
188 	int r;
189 
190 	tmplong = inl(bank->lvl);
191 	if (bank->use_lvl_write_cache)
192 		tmplong |= bank->lvl_write_cache;
193 	r = (tmplong & (1UL << offset)) ? 1 : 0;
194 	return r;
195 }
196 
197 static int ich6_gpio_set_value(struct udevice *dev, unsigned offset,
198 			       int value)
199 {
200 	struct ich6_bank_priv *bank = dev_get_priv(dev);
201 	return _ich6_gpio_set_value(bank, offset, value);
202 }
203 
204 static int ich6_gpio_get_function(struct udevice *dev, unsigned offset)
205 {
206 	struct ich6_bank_priv *bank = dev_get_priv(dev);
207 	u32 mask = 1UL << offset;
208 
209 	if (!(inl(bank->use_sel) & mask))
210 		return GPIOF_FUNC;
211 	if (inl(bank->io_sel) & mask)
212 		return GPIOF_INPUT;
213 	else
214 		return GPIOF_OUTPUT;
215 }
216 
217 static const struct dm_gpio_ops gpio_ich6_ops = {
218 	.request		= ich6_gpio_request,
219 	.direction_input	= ich6_gpio_direction_input,
220 	.direction_output	= ich6_gpio_direction_output,
221 	.get_value		= ich6_gpio_get_value,
222 	.set_value		= ich6_gpio_set_value,
223 	.get_function		= ich6_gpio_get_function,
224 };
225 
226 static const struct udevice_id intel_ich6_gpio_ids[] = {
227 	{ .compatible = "intel,ich6-gpio" },
228 	{ }
229 };
230 
231 U_BOOT_DRIVER(gpio_ich6) = {
232 	.name	= "gpio_ich6",
233 	.id	= UCLASS_GPIO,
234 	.of_match = intel_ich6_gpio_ids,
235 	.ops	= &gpio_ich6_ops,
236 	.ofdata_to_platdata	= gpio_ich6_ofdata_to_platdata,
237 	.probe	= ich6_gpio_probe,
238 	.priv_auto_alloc_size = sizeof(struct ich6_bank_priv),
239 	.platdata_auto_alloc_size = sizeof(struct ich6_bank_platdata),
240 };
241