1/*
  2 * Versatile OF physmap driver add-on
  3 *
  4 * Copyright (c) 2016, Linaro Limited
  5 * Author: Linus Walleij <linus.walleij@linaro.org>
  6 *
  7 * This program is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public License as
  9 * published by the Free Software Foundation; either version 2 of
 10 * the License, or (at your option) any later version.
 11 *
 12 * This program is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 15 * GNU General Public License for more details.
 16 *
 17 * You should have received a copy of the GNU General Public License
 18 * along with this program; if not, write to the Free Software
 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
 20 * MA 02111-1307 USA
 21 */
 22#include <linux/export.h>
 23#include <linux/io.h>
 24#include <linux/of.h>
 25#include <linux/of_address.h>
 26#include <linux/of_device.h>
 27#include <linux/mtd/map.h>
 28#include <linux/mfd/syscon.h>
 29#include <linux/regmap.h>
 30#include <linux/bitops.h>
 31#include "physmap_of_versatile.h"
 32
 33static struct regmap *syscon_regmap;
 34
 35enum versatile_flashprot {
 36	INTEGRATOR_AP_FLASHPROT,
 37	INTEGRATOR_CP_FLASHPROT,
 38	VERSATILE_FLASHPROT,
 39	REALVIEW_FLASHPROT,
 40};
 41
 42static const struct of_device_id syscon_match[] = {
 43	{
 44		.compatible = "arm,integrator-ap-syscon",
 45		.data = (void *)INTEGRATOR_AP_FLASHPROT,
 46	},
 47	{
 48		.compatible = "arm,integrator-cp-syscon",
 49		.data = (void *)INTEGRATOR_CP_FLASHPROT,
 50	},
 51	{
 52		.compatible = "arm,core-module-versatile",
 53		.data = (void *)VERSATILE_FLASHPROT,
 54	},
 55	{
 56		.compatible = "arm,realview-eb-syscon",
 57		.data = (void *)REALVIEW_FLASHPROT,
 58	},
 59	{
 60		.compatible = "arm,realview-pb1176-syscon",
 61		.data = (void *)REALVIEW_FLASHPROT,
 62	},
 63	{
 64		.compatible = "arm,realview-pb11mp-syscon",
 65		.data = (void *)REALVIEW_FLASHPROT,
 66	},
 67	{
 68		.compatible = "arm,realview-pba8-syscon",
 69		.data = (void *)REALVIEW_FLASHPROT,
 70	},
 71	{
 72		.compatible = "arm,realview-pbx-syscon",
 73		.data = (void *)REALVIEW_FLASHPROT,
 74	},
 75	{},
 76};
 77
 78/*
 79 * Flash protection handling for the Integrator/AP
 80 */
 81#define INTEGRATOR_SC_CTRLS_OFFSET	0x08
 82#define INTEGRATOR_SC_CTRLC_OFFSET	0x0C
 83#define INTEGRATOR_SC_CTRL_FLVPPEN	BIT(1)
 84#define INTEGRATOR_SC_CTRL_FLWP		BIT(2)
 85
 86#define INTEGRATOR_EBI_CSR1_OFFSET	0x04
 87/* The manual says bit 2, the code says bit 3, trust the code */
 88#define INTEGRATOR_EBI_WRITE_ENABLE	BIT(3)
 89#define INTEGRATOR_EBI_LOCK_OFFSET	0x20
 90#define INTEGRATOR_EBI_LOCK_VAL		0xA05F
 91
 92static const struct of_device_id ebi_match[] = {
 93	{ .compatible = "arm,external-bus-interface"},
 94	{ },
 95};
 96
 97static int ap_flash_init(struct platform_device *pdev)
 98{
 99	struct device_node *ebi;
100	static void __iomem *ebi_base;
101	u32 val;
102	int ret;
103
104	/* Look up the EBI */
105	ebi = of_find_matching_node(NULL, ebi_match);
106	if (!ebi) {
107		return -ENODEV;
108	}
109	ebi_base = of_iomap(ebi, 0);
110	if (!ebi_base)
111		return -ENODEV;
112
113	/* Clear VPP and write protection bits */
114	ret = regmap_write(syscon_regmap,
115		INTEGRATOR_SC_CTRLC_OFFSET,
116		INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
117	if (ret)
118		dev_err(&pdev->dev, "error clearing Integrator VPP/WP\n");
119
120	/* Unlock the EBI */
121	writel(INTEGRATOR_EBI_LOCK_VAL, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
122
123	/* Enable write cycles on the EBI, CSR1 (flash) */
124	val = readl(ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
125	val |= INTEGRATOR_EBI_WRITE_ENABLE;
126	writel(val, ebi_base + INTEGRATOR_EBI_CSR1_OFFSET);
127
128	/* Lock the EBI again */
129	writel(0, ebi_base + INTEGRATOR_EBI_LOCK_OFFSET);
130	iounmap(ebi_base);
131
132	return 0;
133}
134
135static void ap_flash_set_vpp(struct map_info *map, int on)
136{
137	int ret;
138
139	if (on) {
140		ret = regmap_write(syscon_regmap,
141			INTEGRATOR_SC_CTRLS_OFFSET,
142			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
143		if (ret)
144			pr_err("error enabling AP VPP\n");
145	} else {
146		ret = regmap_write(syscon_regmap,
147			INTEGRATOR_SC_CTRLC_OFFSET,
148			INTEGRATOR_SC_CTRL_FLVPPEN | INTEGRATOR_SC_CTRL_FLWP);
149		if (ret)
150			pr_err("error disabling AP VPP\n");
151	}
152}
153
154/*
155 * Flash protection handling for the Integrator/CP
156 */
157
158#define INTCP_FLASHPROG_OFFSET		0x04
159#define CINTEGRATOR_FLVPPEN		BIT(0)
160#define CINTEGRATOR_FLWREN		BIT(1)
161#define CINTEGRATOR_FLMASK		BIT(0)|BIT(1)
162
163static void cp_flash_set_vpp(struct map_info *map, int on)
164{
165	int ret;
166
167	if (on) {
168		ret = regmap_update_bits(syscon_regmap,
169				INTCP_FLASHPROG_OFFSET,
170				CINTEGRATOR_FLMASK,
171				CINTEGRATOR_FLVPPEN | CINTEGRATOR_FLWREN);
172		if (ret)
173			pr_err("error setting CP VPP\n");
174	} else {
175		ret = regmap_update_bits(syscon_regmap,
176				INTCP_FLASHPROG_OFFSET,
177				CINTEGRATOR_FLMASK,
178				0);
179		if (ret)
180			pr_err("error setting CP VPP\n");
181	}
182}
183
184/*
185 * Flash protection handling for the Versatiles and RealViews
186 */
187
188#define VERSATILE_SYS_FLASH_OFFSET            0x4C
189
190static void versatile_flash_set_vpp(struct map_info *map, int on)
191{
192	int ret;
193
194	ret = regmap_update_bits(syscon_regmap, VERSATILE_SYS_FLASH_OFFSET,
195				 0x01, !!on);
196	if (ret)
197		pr_err("error setting Versatile VPP\n");
198}
199
200int of_flash_probe_versatile(struct platform_device *pdev,
201			     struct device_node *np,
202			     struct map_info *map)
203{
204	struct device_node *sysnp;
205	const struct of_device_id *devid;
206	struct regmap *rmap;
207	static enum versatile_flashprot versatile_flashprot;
208	int ret;
209
210	/* Not all flash chips use this protection line */
211	if (!of_device_is_compatible(np, "arm,versatile-flash"))
212		return 0;
213
214	/* For first chip probed, look up the syscon regmap */
215	if (!syscon_regmap) {
216		sysnp = of_find_matching_node_and_match(NULL,
217							syscon_match,
218							&devid);
219		if (!sysnp)
220			return -ENODEV;
221
222		versatile_flashprot = (enum versatile_flashprot)devid->data;
223		rmap = syscon_node_to_regmap(sysnp);
224		if (IS_ERR(rmap))
225			return PTR_ERR(rmap);
226
227		syscon_regmap = rmap;
228	}
229
230	switch (versatile_flashprot) {
231	case INTEGRATOR_AP_FLASHPROT:
232		ret = ap_flash_init(pdev);
233		if (ret)
234			return ret;
235		map->set_vpp = ap_flash_set_vpp;
236		dev_info(&pdev->dev, "Integrator/AP flash protection\n");
237		break;
238	case INTEGRATOR_CP_FLASHPROT:
239		map->set_vpp = cp_flash_set_vpp;
240		dev_info(&pdev->dev, "Integrator/CP flash protection\n");
241		break;
242	case VERSATILE_FLASHPROT:
243	case REALVIEW_FLASHPROT:
244		map->set_vpp = versatile_flash_set_vpp;
245		dev_info(&pdev->dev, "versatile/realview flash protection\n");
246		break;
247	default:
248		dev_info(&pdev->dev, "device marked as Versatile flash "
249			 "but no system controller was found\n");
250		break;
251	}
252
253	return 0;
254}
255EXPORT_SYMBOL_GPL(of_flash_probe_versatile);