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1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2019 Nuvoton Technology corporation.
3
4#include <linux/delay.h>
5#include <linux/err.h>
6#include <linux/io.h>
7#include <linux/init.h>
8#include <linux/of.h>
9#include <linux/of_device.h>
10#include <linux/platform_device.h>
11#include <linux/reboot.h>
12#include <linux/reset-controller.h>
13#include <linux/spinlock.h>
14#include <linux/mfd/syscon.h>
15#include <linux/regmap.h>
16#include <linux/of_address.h>
17
18/* NPCM7xx GCR registers */
19#define NPCM_MDLR_OFFSET 0x7C
20#define NPCM_MDLR_USBD0 BIT(9)
21#define NPCM_MDLR_USBD1 BIT(8)
22#define NPCM_MDLR_USBD2_4 BIT(21)
23#define NPCM_MDLR_USBD5_9 BIT(22)
24
25#define NPCM_USB1PHYCTL_OFFSET 0x140
26#define NPCM_USB2PHYCTL_OFFSET 0x144
27#define NPCM_USBXPHYCTL_RS BIT(28)
28
29/* NPCM7xx Reset registers */
30#define NPCM_SWRSTR 0x14
31#define NPCM_SWRST BIT(2)
32
33#define NPCM_IPSRST1 0x20
34#define NPCM_IPSRST1_USBD1 BIT(5)
35#define NPCM_IPSRST1_USBD2 BIT(8)
36#define NPCM_IPSRST1_USBD3 BIT(25)
37#define NPCM_IPSRST1_USBD4 BIT(22)
38#define NPCM_IPSRST1_USBD5 BIT(23)
39#define NPCM_IPSRST1_USBD6 BIT(24)
40
41#define NPCM_IPSRST2 0x24
42#define NPCM_IPSRST2_USB_HOST BIT(26)
43
44#define NPCM_IPSRST3 0x34
45#define NPCM_IPSRST3_USBD0 BIT(4)
46#define NPCM_IPSRST3_USBD7 BIT(5)
47#define NPCM_IPSRST3_USBD8 BIT(6)
48#define NPCM_IPSRST3_USBD9 BIT(7)
49#define NPCM_IPSRST3_USBPHY1 BIT(24)
50#define NPCM_IPSRST3_USBPHY2 BIT(25)
51
52#define NPCM_RC_RESETS_PER_REG 32
53#define NPCM_MASK_RESETS GENMASK(4, 0)
54
55struct npcm_rc_data {
56 struct reset_controller_dev rcdev;
57 struct notifier_block restart_nb;
58 u32 sw_reset_number;
59 void __iomem *base;
60 spinlock_t lock;
61};
62
63#define to_rc_data(p) container_of(p, struct npcm_rc_data, rcdev)
64
65static int npcm_rc_restart(struct notifier_block *nb, unsigned long mode,
66 void *cmd)
67{
68 struct npcm_rc_data *rc = container_of(nb, struct npcm_rc_data,
69 restart_nb);
70
71 writel(NPCM_SWRST << rc->sw_reset_number, rc->base + NPCM_SWRSTR);
72 mdelay(1000);
73
74 pr_emerg("%s: unable to restart system\n", __func__);
75
76 return NOTIFY_DONE;
77}
78
79static int npcm_rc_setclear_reset(struct reset_controller_dev *rcdev,
80 unsigned long id, bool set)
81{
82 struct npcm_rc_data *rc = to_rc_data(rcdev);
83 unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
84 unsigned int ctrl_offset = id >> 8;
85 unsigned long flags;
86 u32 stat;
87
88 spin_lock_irqsave(&rc->lock, flags);
89 stat = readl(rc->base + ctrl_offset);
90 if (set)
91 writel(stat | rst_bit, rc->base + ctrl_offset);
92 else
93 writel(stat & ~rst_bit, rc->base + ctrl_offset);
94 spin_unlock_irqrestore(&rc->lock, flags);
95
96 return 0;
97}
98
99static int npcm_rc_assert(struct reset_controller_dev *rcdev, unsigned long id)
100{
101 return npcm_rc_setclear_reset(rcdev, id, true);
102}
103
104static int npcm_rc_deassert(struct reset_controller_dev *rcdev,
105 unsigned long id)
106{
107 return npcm_rc_setclear_reset(rcdev, id, false);
108}
109
110static int npcm_rc_status(struct reset_controller_dev *rcdev,
111 unsigned long id)
112{
113 struct npcm_rc_data *rc = to_rc_data(rcdev);
114 unsigned int rst_bit = BIT(id & NPCM_MASK_RESETS);
115 unsigned int ctrl_offset = id >> 8;
116
117 return (readl(rc->base + ctrl_offset) & rst_bit);
118}
119
120static int npcm_reset_xlate(struct reset_controller_dev *rcdev,
121 const struct of_phandle_args *reset_spec)
122{
123 unsigned int offset, bit;
124
125 offset = reset_spec->args[0];
126 if (offset != NPCM_IPSRST1 && offset != NPCM_IPSRST2 &&
127 offset != NPCM_IPSRST3) {
128 dev_err(rcdev->dev, "Error reset register (0x%x)\n", offset);
129 return -EINVAL;
130 }
131 bit = reset_spec->args[1];
132 if (bit >= NPCM_RC_RESETS_PER_REG) {
133 dev_err(rcdev->dev, "Error reset number (%d)\n", bit);
134 return -EINVAL;
135 }
136
137 return (offset << 8) | bit;
138}
139
140static const struct of_device_id npcm_rc_match[] = {
141 { .compatible = "nuvoton,npcm750-reset",
142 .data = (void *)"nuvoton,npcm750-gcr" },
143 { }
144};
145
146/*
147 * The following procedure should be observed in USB PHY, USB device and
148 * USB host initialization at BMC boot
149 */
150static int npcm_usb_reset(struct platform_device *pdev, struct npcm_rc_data *rc)
151{
152 u32 mdlr, iprst1, iprst2, iprst3;
153 struct device *dev = &pdev->dev;
154 struct regmap *gcr_regmap;
155 u32 ipsrst1_bits = 0;
156 u32 ipsrst2_bits = NPCM_IPSRST2_USB_HOST;
157 u32 ipsrst3_bits = 0;
158 const char *gcr_dt;
159
160 gcr_dt = (const char *)
161 of_match_device(dev->driver->of_match_table, dev)->data;
162
163 gcr_regmap = syscon_regmap_lookup_by_compatible(gcr_dt);
164 if (IS_ERR(gcr_regmap)) {
165 dev_err(&pdev->dev, "Failed to find %s\n", gcr_dt);
166 return PTR_ERR(gcr_regmap);
167 }
168
169 /* checking which USB device is enabled */
170 regmap_read(gcr_regmap, NPCM_MDLR_OFFSET, &mdlr);
171 if (!(mdlr & NPCM_MDLR_USBD0))
172 ipsrst3_bits |= NPCM_IPSRST3_USBD0;
173 if (!(mdlr & NPCM_MDLR_USBD1))
174 ipsrst1_bits |= NPCM_IPSRST1_USBD1;
175 if (!(mdlr & NPCM_MDLR_USBD2_4))
176 ipsrst1_bits |= (NPCM_IPSRST1_USBD2 |
177 NPCM_IPSRST1_USBD3 |
178 NPCM_IPSRST1_USBD4);
179 if (!(mdlr & NPCM_MDLR_USBD0)) {
180 ipsrst1_bits |= (NPCM_IPSRST1_USBD5 |
181 NPCM_IPSRST1_USBD6);
182 ipsrst3_bits |= (NPCM_IPSRST3_USBD7 |
183 NPCM_IPSRST3_USBD8 |
184 NPCM_IPSRST3_USBD9);
185 }
186
187 /* assert reset USB PHY and USB devices */
188 iprst1 = readl(rc->base + NPCM_IPSRST1);
189 iprst2 = readl(rc->base + NPCM_IPSRST2);
190 iprst3 = readl(rc->base + NPCM_IPSRST3);
191
192 iprst1 |= ipsrst1_bits;
193 iprst2 |= ipsrst2_bits;
194 iprst3 |= (ipsrst3_bits | NPCM_IPSRST3_USBPHY1 |
195 NPCM_IPSRST3_USBPHY2);
196
197 writel(iprst1, rc->base + NPCM_IPSRST1);
198 writel(iprst2, rc->base + NPCM_IPSRST2);
199 writel(iprst3, rc->base + NPCM_IPSRST3);
200
201 /* clear USB PHY RS bit */
202 regmap_update_bits(gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
203 NPCM_USBXPHYCTL_RS, 0);
204 regmap_update_bits(gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
205 NPCM_USBXPHYCTL_RS, 0);
206
207 /* deassert reset USB PHY */
208 iprst3 &= ~(NPCM_IPSRST3_USBPHY1 | NPCM_IPSRST3_USBPHY2);
209 writel(iprst3, rc->base + NPCM_IPSRST3);
210
211 udelay(50);
212
213 /* set USB PHY RS bit */
214 regmap_update_bits(gcr_regmap, NPCM_USB1PHYCTL_OFFSET,
215 NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
216 regmap_update_bits(gcr_regmap, NPCM_USB2PHYCTL_OFFSET,
217 NPCM_USBXPHYCTL_RS, NPCM_USBXPHYCTL_RS);
218
219 /* deassert reset USB devices*/
220 iprst1 &= ~ipsrst1_bits;
221 iprst2 &= ~ipsrst2_bits;
222 iprst3 &= ~ipsrst3_bits;
223
224 writel(iprst1, rc->base + NPCM_IPSRST1);
225 writel(iprst2, rc->base + NPCM_IPSRST2);
226 writel(iprst3, rc->base + NPCM_IPSRST3);
227
228 return 0;
229}
230
231static const struct reset_control_ops npcm_rc_ops = {
232 .assert = npcm_rc_assert,
233 .deassert = npcm_rc_deassert,
234 .status = npcm_rc_status,
235};
236
237static int npcm_rc_probe(struct platform_device *pdev)
238{
239 struct npcm_rc_data *rc;
240 int ret;
241
242 rc = devm_kzalloc(&pdev->dev, sizeof(*rc), GFP_KERNEL);
243 if (!rc)
244 return -ENOMEM;
245
246 rc->base = devm_platform_ioremap_resource(pdev, 0);
247 if (IS_ERR(rc->base))
248 return PTR_ERR(rc->base);
249
250 spin_lock_init(&rc->lock);
251
252 rc->rcdev.owner = THIS_MODULE;
253 rc->rcdev.ops = &npcm_rc_ops;
254 rc->rcdev.of_node = pdev->dev.of_node;
255 rc->rcdev.of_reset_n_cells = 2;
256 rc->rcdev.of_xlate = npcm_reset_xlate;
257
258 platform_set_drvdata(pdev, rc);
259
260 ret = devm_reset_controller_register(&pdev->dev, &rc->rcdev);
261 if (ret) {
262 dev_err(&pdev->dev, "unable to register device\n");
263 return ret;
264 }
265
266 if (npcm_usb_reset(pdev, rc))
267 dev_warn(&pdev->dev, "NPCM USB reset failed, can cause issues with UDC and USB host\n");
268
269 if (!of_property_read_u32(pdev->dev.of_node, "nuvoton,sw-reset-number",
270 &rc->sw_reset_number)) {
271 if (rc->sw_reset_number && rc->sw_reset_number < 5) {
272 rc->restart_nb.priority = 192,
273 rc->restart_nb.notifier_call = npcm_rc_restart,
274 ret = register_restart_handler(&rc->restart_nb);
275 if (ret)
276 dev_warn(&pdev->dev, "failed to register restart handler\n");
277 }
278 }
279
280 return ret;
281}
282
283static struct platform_driver npcm_rc_driver = {
284 .probe = npcm_rc_probe,
285 .driver = {
286 .name = "npcm-reset",
287 .of_match_table = npcm_rc_match,
288 .suppress_bind_attrs = true,
289 },
290};
291builtin_platform_driver(npcm_rc_driver);