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/mtd/map.h>
13#include <linux/mfd/syscon.h>
14#include <linux/platform_device.h>
15#include <linux/regmap.h>
16#include <linux/bitops.h>
17#include "physmap-versatile.h"
18
19static struct regmap *syscon_regmap;
20
21enum versatile_flashprot {
22	INTEGRATOR_AP_FLASHPROT,
23	INTEGRATOR_CP_FLASHPROT,
24	VERSATILE_FLASHPROT,
25	REALVIEW_FLASHPROT,
26};
27
28static 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
78static const struct of_device_id ebi_match[] = {
79	{ .compatible = "arm,external-bus-interface"},
80	{ },
81};
82
83static 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
122static 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
150static 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
177static 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
187int 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 = (uintptr_t)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