1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Versatile OF physmap driver add-on
4  *
5  * Copyright (c) 2016, Linaro Limited
6  * Author: Linus Walleij <linus.walleij@linaro.org>
7  */
8 #include <linux/export.h>
9 #include <linux/io.h>
10 #include <linux/of.h>
11 #include <linux/of_address.h>
12 #include <linux/of_device.h>
13 #include <linux/mtd/map.h>
14 #include <linux/mfd/syscon.h>
15 #include <linux/regmap.h>
16 #include <linux/bitops.h>
17 #include "physmap-versatile.h"
18 
19 static struct regmap *syscon_regmap;
20 
21 enum versatile_flashprot {
22 	INTEGRATOR_AP_FLASHPROT,
23 	INTEGRATOR_CP_FLASHPROT,
24 	VERSATILE_FLASHPROT,
25 	REALVIEW_FLASHPROT,
26 };
27 
28 static const struct of_device_id syscon_match[] = {
29 	{
30 		.compatible = "arm,integrator-ap-syscon",
31 		.data = (void *)INTEGRATOR_AP_FLASHPROT,
32 	},
33 	{
34 		.compatible = "arm,integrator-cp-syscon",
35 		.data = (void *)INTEGRATOR_CP_FLASHPROT,
36 	},
37 	{
38 		.compatible = "arm,core-module-versatile",
39 		.data = (void *)VERSATILE_FLASHPROT,
40 	},
41 	{
42 		.compatible = "arm,realview-eb-syscon",
43 		.data = (void *)REALVIEW_FLASHPROT,
44 	},
45 	{
46 		.compatible = "arm,realview-pb1176-syscon",
47 		.data = (void *)REALVIEW_FLASHPROT,
48 	},
49 	{
50 		.compatible = "arm,realview-pb11mp-syscon",
51 		.data = (void *)REALVIEW_FLASHPROT,
52 	},
53 	{
54 		.compatible = "arm,realview-pba8-syscon",
55 		.data = (void *)REALVIEW_FLASHPROT,
56 	},
57 	{
58 		.compatible = "arm,realview-pbx-syscon",
59 		.data = (void *)REALVIEW_FLASHPROT,
60 	},
61 	{},
62 };
63 
64 /*
65  * Flash protection handling for the Integrator/AP
66  */
67 #define INTEGRATOR_SC_CTRLS_OFFSET	0x08
68 #define INTEGRATOR_SC_CTRLC_OFFSET	0x0C
69 #define INTEGRATOR_SC_CTRL_FLVPPEN	BIT(1)
70 #define INTEGRATOR_SC_CTRL_FLWP		BIT(2)
71 
72 #define INTEGRATOR_EBI_CSR1_OFFSET	0x04
73 /* The manual says bit 2, the code says bit 3, trust the code */
74 #define INTEGRATOR_EBI_WRITE_ENABLE	BIT(3)
75 #define INTEGRATOR_EBI_LOCK_OFFSET	0x20
76 #define INTEGRATOR_EBI_LOCK_VAL		0xA05F
77 
78 static const struct of_device_id ebi_match[] = {
79 	{ .compatible = "arm,external-bus-interface"},
80 	{ },
81 };
82 
83 static int ap_flash_init(struct platform_device *pdev)
84 {
85 	struct device_node *ebi;
86 	void __iomem *ebi_base;
87 	u32 val;
88 	int ret;
89 
90 	/* Look up the EBI */
91 	ebi = of_find_matching_node(NULL, ebi_match);
92 	if (!ebi) {
93 		return -ENODEV;
94 	}
95 	ebi_base = of_iomap(ebi, 0);
96 	of_node_put(ebi);
97 	if (!ebi_base)
98 		return -ENODEV;
99 
100 	/* Clear VPP and write protection bits */
101 	ret = regmap_write(syscon_regmap,
102 		INTEGRATOR_SC_CTRLC_OFFSET,
103 		INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
104 	if (ret)
105 		dev_err(&pdev->dev, "error clearing Integrator VPP/WP\n");
106 
107 	/* Unlock the EBI */
108 	writel(INTEGRATOR_EBI_LOCK_VAL, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
109 
110 	/* Enable write cycles on the EBI, CSR1 (flash) */
111 	val = readl(ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
112 	val |= INTEGRATOR_EBI_WRITE_ENABLE;
113 	writel(val, ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
114 
115 	/* Lock the EBI again */
116 	writel(0, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
117 	iounmap(ebi_base);
118 
119 	return 0;
120 }
121 
122 static void ap_flash_set_vpp(struct map_info *map, int on)
123 {
124 	int ret;
125 
126 	if (on) {
127 		ret = regmap_write(syscon_regmap,
128 			INTEGRATOR_SC_CTRLS_OFFSET,
129 			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
130 		if (ret)
131 			pr_err("error enabling AP VPP\n");
132 	} else {
133 		ret = regmap_write(syscon_regmap,
134 			INTEGRATOR_SC_CTRLC_OFFSET,
135 			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
136 		if (ret)
137 			pr_err("error disabling AP VPP\n");
138 	}
139 }
140 
141 /*
142  * Flash protection handling for the Integrator/CP
143  */
144 
145 #define INTCP_FLASHPROG_OFFSET		0x04
146 #define CINTEGRATOR_FLVPPEN		BIT(0)
147 #define CINTEGRATOR_FLWREN		BIT(1)
148 #define CINTEGRATOR_FLMASK		BIT(0)|BIT(1)
149 
150 static void cp_flash_set_vpp(struct map_info *map, int on)
151 {
152 	int ret;
153 
154 	if (on) {
155 		ret = regmap_update_bits(syscon_regmap,
156 				INTCP_FLASHPROG_OFFSET,
157 				CINTEGRATOR_FLMASK,
158 				CINTEGRATOR_FLVPPEN | CINTEGRATOR_FLWREN);
159 		if (ret)
160 			pr_err("error setting CP VPP\n");
161 	} else {
162 		ret = regmap_update_bits(syscon_regmap,
163 				INTCP_FLASHPROG_OFFSET,
164 				CINTEGRATOR_FLMASK,
165 				0);
166 		if (ret)
167 			pr_err("error setting CP VPP\n");
168 	}
169 }
170 
171 /*
172  * Flash protection handling for the Versatiles and RealViews
173  */
174 
175 #define VERSATILE_SYS_FLASH_OFFSET            0x4C
176 
177 static void versatile_flash_set_vpp(struct map_info *map, int on)
178 {
179 	int ret;
180 
181 	ret = regmap_update_bits(syscon_regmap, VERSATILE_SYS_FLASH_OFFSET,
182 				 0x01, !!on);
183 	if (ret)
184 		pr_err("error setting Versatile VPP\n");
185 }
186 
187 int of_flash_probe_versatile(struct platform_device *pdev,
188 			     struct device_node *np,
189 			     struct map_info *map)
190 {
191 	struct device_node *sysnp;
192 	const struct of_device_id *devid;
193 	struct regmap *rmap;
194 	static enum versatile_flashprot versatile_flashprot;
195 	int ret;
196 
197 	/* Not all flash chips use this protection line */
198 	if (!of_device_is_compatible(np, "arm,versatile-flash"))
199 		return 0;
200 
201 	/* For first chip probed, look up the syscon regmap */
202 	if (!syscon_regmap) {
203 		sysnp = of_find_matching_node_and_match(NULL,
204 							syscon_match,
205 							&devid);
206 		if (!sysnp)
207 			return -ENODEV;
208 
209 		versatile_flashprot = (enum versatile_flashprot)devid->data;
210 		rmap = syscon_node_to_regmap(sysnp);
211 		of_node_put(sysnp);
212 		if (IS_ERR(rmap))
213 			return PTR_ERR(rmap);
214 
215 		syscon_regmap = rmap;
216 	}
217 
218 	switch (versatile_flashprot) {
219 	case INTEGRATOR_AP_FLASHPROT:
220 		ret = ap_flash_init(pdev);
221 		if (ret)
222 			return ret;
223 		map->set_vpp = ap_flash_set_vpp;
224 		dev_info(&pdev->dev, "Integrator/AP flash protection\n");
225 		break;
226 	case INTEGRATOR_CP_FLASHPROT:
227 		map->set_vpp = cp_flash_set_vpp;
228 		dev_info(&pdev->dev, "Integrator/CP flash protection\n");
229 		break;
230 	case VERSATILE_FLASHPROT:
231 	case REALVIEW_FLASHPROT:
232 		map->set_vpp = versatile_flash_set_vpp;
233 		dev_info(&pdev->dev, "versatile/realview flash protection\n");
234 		break;
235 	default:
236 		dev_info(&pdev->dev, "device marked as Versatile flash "
237 			 "but no system controller was found\n");
238 		break;
239 	}
240 
241 	return 0;
242 }
243