1 // SPDX-License-Identifier: GPL-2.0
2 //
3 // Copyright (c) 2015 Samsung Electronics Co., Ltd.
4 //	      http://www.samsung.com/
5 //
6 // EXYNOS - SROM Controller support
7 // Author: Pankaj Dubey <pankaj.dubey@samsung.com>
8 
9 #include <linux/io.h>
10 #include <linux/init.h>
11 #include <linux/of.h>
12 #include <linux/of_address.h>
13 #include <linux/of_platform.h>
14 #include <linux/platform_device.h>
15 #include <linux/slab.h>
16 
17 #include "exynos-srom.h"
18 
19 static const unsigned long exynos_srom_offsets[] = {
20 	/* SROM side */
21 	EXYNOS_SROM_BW,
22 	EXYNOS_SROM_BC0,
23 	EXYNOS_SROM_BC1,
24 	EXYNOS_SROM_BC2,
25 	EXYNOS_SROM_BC3,
26 };
27 
28 /**
29  * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
30  * @offset: srom register offset from the controller base address.
31  * @value: the value of register under the offset.
32  */
33 struct exynos_srom_reg_dump {
34 	u32     offset;
35 	u32     value;
36 };
37 
38 /**
39  * struct exynos_srom: platform data for exynos srom controller driver.
40  * @dev: platform device pointer
41  * @reg_base: srom base address
42  * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
43  */
44 struct exynos_srom {
45 	struct device *dev;
46 	void __iomem *reg_base;
47 	struct exynos_srom_reg_dump *reg_offset;
48 };
49 
50 static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
51 		const unsigned long *rdump,
52 		unsigned long nr_rdump)
53 {
54 	struct exynos_srom_reg_dump *rd;
55 	unsigned int i;
56 
57 	rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
58 	if (!rd)
59 		return NULL;
60 
61 	for (i = 0; i < nr_rdump; ++i)
62 		rd[i].offset = rdump[i];
63 
64 	return rd;
65 }
66 
67 static int exynos_srom_configure_bank(struct exynos_srom *srom,
68 				      struct device_node *np)
69 {
70 	u32 bank, width, pmc = 0;
71 	u32 timing[6];
72 	u32 cs, bw;
73 
74 	if (of_property_read_u32(np, "reg", &bank))
75 		return -EINVAL;
76 	if (of_property_read_u32(np, "reg-io-width", &width))
77 		width = 1;
78 	if (of_property_read_bool(np, "samsung,srom-page-mode"))
79 		pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT;
80 	if (of_property_read_u32_array(np, "samsung,srom-timing", timing,
81 				       ARRAY_SIZE(timing)))
82 		return -EINVAL;
83 
84 	bank *= 4; /* Convert bank into shift/offset */
85 
86 	cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
87 	if (width == 2)
88 		cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
89 
90 	bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW);
91 	bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank);
92 	writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW);
93 
94 	writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) |
95 		       (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
96 		       (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
97 		       (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) |
98 		       (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
99 		       (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT),
100 		       srom->reg_base + EXYNOS_SROM_BC0 + bank);
101 
102 	return 0;
103 }
104 
105 static int exynos_srom_probe(struct platform_device *pdev)
106 {
107 	struct device_node *np, *child;
108 	struct exynos_srom *srom;
109 	struct device *dev = &pdev->dev;
110 	bool bad_bank_config = false;
111 
112 	np = dev->of_node;
113 	if (!np) {
114 		dev_err(&pdev->dev, "could not find device info\n");
115 		return -EINVAL;
116 	}
117 
118 	srom = devm_kzalloc(&pdev->dev,
119 			sizeof(struct exynos_srom), GFP_KERNEL);
120 	if (!srom)
121 		return -ENOMEM;
122 
123 	srom->dev = dev;
124 	srom->reg_base = of_iomap(np, 0);
125 	if (!srom->reg_base) {
126 		dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
127 		return -ENOMEM;
128 	}
129 
130 	platform_set_drvdata(pdev, srom);
131 
132 	srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
133 			ARRAY_SIZE(exynos_srom_offsets));
134 	if (!srom->reg_offset) {
135 		iounmap(srom->reg_base);
136 		return -ENOMEM;
137 	}
138 
139 	for_each_child_of_node(np, child) {
140 		if (exynos_srom_configure_bank(srom, child)) {
141 			dev_err(dev,
142 				"Could not decode bank configuration for %pOFn\n",
143 				child);
144 			bad_bank_config = true;
145 		}
146 	}
147 
148 	/*
149 	 * If any bank failed to configure, we still provide suspend/resume,
150 	 * but do not probe child devices
151 	 */
152 	if (bad_bank_config)
153 		return 0;
154 
155 	return of_platform_populate(np, NULL, NULL, dev);
156 }
157 
158 #ifdef CONFIG_PM_SLEEP
159 static void exynos_srom_save(void __iomem *base,
160 				    struct exynos_srom_reg_dump *rd,
161 				    unsigned int num_regs)
162 {
163 	for (; num_regs > 0; --num_regs, ++rd)
164 		rd->value = readl(base + rd->offset);
165 }
166 
167 static void exynos_srom_restore(void __iomem *base,
168 				      const struct exynos_srom_reg_dump *rd,
169 				      unsigned int num_regs)
170 {
171 	for (; num_regs > 0; --num_regs, ++rd)
172 		writel(rd->value, base + rd->offset);
173 }
174 
175 static int exynos_srom_suspend(struct device *dev)
176 {
177 	struct exynos_srom *srom = dev_get_drvdata(dev);
178 
179 	exynos_srom_save(srom->reg_base, srom->reg_offset,
180 				ARRAY_SIZE(exynos_srom_offsets));
181 	return 0;
182 }
183 
184 static int exynos_srom_resume(struct device *dev)
185 {
186 	struct exynos_srom *srom = dev_get_drvdata(dev);
187 
188 	exynos_srom_restore(srom->reg_base, srom->reg_offset,
189 				ARRAY_SIZE(exynos_srom_offsets));
190 	return 0;
191 }
192 #endif
193 
194 static const struct of_device_id of_exynos_srom_ids[] = {
195 	{
196 		.compatible	= "samsung,exynos4210-srom",
197 	},
198 	{},
199 };
200 
201 static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
202 
203 static struct platform_driver exynos_srom_driver = {
204 	.probe = exynos_srom_probe,
205 	.driver = {
206 		.name = "exynos-srom",
207 		.of_match_table = of_exynos_srom_ids,
208 		.pm = &exynos_srom_pm_ops,
209 		.suppress_bind_attrs = true,
210 	},
211 };
212 builtin_platform_driver(exynos_srom_driver);
213