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(const unsigned long * rdump,unsigned long nr_rdump)51 exynos_srom_alloc_reg_dump(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
exynos_srom_configure_bank(struct exynos_srom * srom,struct device_node * np)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
exynos_srom_probe(struct platform_device * pdev)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
exynos_srom_save(void __iomem * base,struct exynos_srom_reg_dump * rd,unsigned int num_regs)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
exynos_srom_restore(void __iomem * base,const struct exynos_srom_reg_dump * rd,unsigned int num_regs)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
exynos_srom_suspend(struct device * dev)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
exynos_srom_resume(struct device * dev)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