GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / nvmem / vf610-ocotp.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2015 Toradex AG.
4  *
5  * Author: Sanchayan Maity <sanchayan.maity@toradex.com>
6  *
7  * Based on the barebox ocotp driver,
8  * Copyright (c) 2010 Baruch Siach <baruch@tkos.co.il>
9  *      Orex Computed Radiography
10  */
11
12 #include <linux/clk.h>
13 #include <linux/delay.h>
14 #include <linux/device.h>
15 #include <linux/io.h>
16 #include <linux/module.h>
17 #include <linux/nvmem-provider.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/slab.h>
21
22 /* OCOTP Register Offsets */
23 #define OCOTP_CTRL_REG                          0x00
24 #define OCOTP_CTRL_SET                          0x04
25 #define OCOTP_CTRL_CLR                          0x08
26 #define OCOTP_TIMING                            0x10
27 #define OCOTP_DATA                              0x20
28 #define OCOTP_READ_CTRL_REG                     0x30
29 #define OCOTP_READ_FUSE_DATA                    0x40
30
31 /* OCOTP Register bits and masks */
32 #define OCOTP_CTRL_WR_UNLOCK                    16
33 #define OCOTP_CTRL_WR_UNLOCK_KEY                0x3E77
34 #define OCOTP_CTRL_WR_UNLOCK_MASK               GENMASK(31, 16)
35 #define OCOTP_CTRL_ADDR                         0
36 #define OCOTP_CTRL_ADDR_MASK                    GENMASK(6, 0)
37 #define OCOTP_CTRL_RELOAD_SHADOWS               BIT(10)
38 #define OCOTP_CTRL_ERR                          BIT(9)
39 #define OCOTP_CTRL_BUSY                         BIT(8)
40
41 #define OCOTP_TIMING_STROBE_READ                16
42 #define OCOTP_TIMING_STROBE_READ_MASK           GENMASK(21, 16)
43 #define OCOTP_TIMING_RELAX                      12
44 #define OCOTP_TIMING_RELAX_MASK                 GENMASK(15, 12)
45 #define OCOTP_TIMING_STROBE_PROG                0
46 #define OCOTP_TIMING_STROBE_PROG_MASK           GENMASK(11, 0)
47
48 #define OCOTP_READ_CTRL_READ_FUSE               0x1
49
50 #define VF610_OCOTP_TIMEOUT                     100000
51
52 #define BF(value, field)                (((value) << field) & field##_MASK)
53
54 #define DEF_RELAX                               20
55
56 static const int base_to_fuse_addr_mappings[][2] = {
57         {0x400, 0x00},
58         {0x410, 0x01},
59         {0x420, 0x02},
60         {0x450, 0x05},
61         {0x4F0, 0x0F},
62         {0x600, 0x20},
63         {0x610, 0x21},
64         {0x620, 0x22},
65         {0x630, 0x23},
66         {0x640, 0x24},
67         {0x650, 0x25},
68         {0x660, 0x26},
69         {0x670, 0x27},
70         {0x6F0, 0x2F},
71         {0x880, 0x38},
72         {0x890, 0x39},
73         {0x8A0, 0x3A},
74         {0x8B0, 0x3B},
75         {0x8C0, 0x3C},
76         {0x8D0, 0x3D},
77         {0x8E0, 0x3E},
78         {0x8F0, 0x3F},
79         {0xC80, 0x78},
80         {0xC90, 0x79},
81         {0xCA0, 0x7A},
82         {0xCB0, 0x7B},
83         {0xCC0, 0x7C},
84         {0xCD0, 0x7D},
85         {0xCE0, 0x7E},
86         {0xCF0, 0x7F},
87 };
88
89 struct vf610_ocotp {
90         void __iomem *base;
91         struct clk *clk;
92         struct device *dev;
93         struct nvmem_device *nvmem;
94         int timing;
95 };
96
97 static int vf610_ocotp_wait_busy(void __iomem *base)
98 {
99         int timeout = VF610_OCOTP_TIMEOUT;
100
101         while ((readl(base) & OCOTP_CTRL_BUSY) && --timeout)
102                 udelay(10);
103
104         if (!timeout) {
105                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
106                 return -ETIMEDOUT;
107         }
108
109         udelay(10);
110
111         return 0;
112 }
113
114 static int vf610_ocotp_calculate_timing(struct vf610_ocotp *ocotp_dev)
115 {
116         u32 clk_rate;
117         u32 relax, strobe_read, strobe_prog;
118         u32 timing;
119
120         clk_rate = clk_get_rate(ocotp_dev->clk);
121
122         /* Refer section OTP read/write timing parameters in TRM */
123         relax = clk_rate / (1000000000 / DEF_RELAX) - 1;
124         strobe_prog = clk_rate / (1000000000 / 10000) + 2 * (DEF_RELAX + 1) - 1;
125         strobe_read = clk_rate / (1000000000 / 40) + 2 * (DEF_RELAX + 1) - 1;
126
127         timing = BF(relax, OCOTP_TIMING_RELAX);
128         timing |= BF(strobe_read, OCOTP_TIMING_STROBE_READ);
129         timing |= BF(strobe_prog, OCOTP_TIMING_STROBE_PROG);
130
131         return timing;
132 }
133
134 static int vf610_get_fuse_address(int base_addr_offset)
135 {
136         int i;
137
138         for (i = 0; i < ARRAY_SIZE(base_to_fuse_addr_mappings); i++) {
139                 if (base_to_fuse_addr_mappings[i][0] == base_addr_offset)
140                         return base_to_fuse_addr_mappings[i][1];
141         }
142
143         return -EINVAL;
144 }
145
146 static int vf610_ocotp_read(void *context, unsigned int offset,
147                         void *val, size_t bytes)
148 {
149         struct vf610_ocotp *ocotp = context;
150         void __iomem *base = ocotp->base;
151         u32 reg, *buf = val;
152         int fuse_addr;
153         int ret;
154
155         while (bytes > 0) {
156                 fuse_addr = vf610_get_fuse_address(offset);
157                 if (fuse_addr > 0) {
158                         writel(ocotp->timing, base + OCOTP_TIMING);
159                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
160                         if (ret)
161                                 return ret;
162
163                         reg = readl(base + OCOTP_CTRL_REG);
164                         reg &= ~OCOTP_CTRL_ADDR_MASK;
165                         reg &= ~OCOTP_CTRL_WR_UNLOCK_MASK;
166                         reg |= BF(fuse_addr, OCOTP_CTRL_ADDR);
167                         writel(reg, base + OCOTP_CTRL_REG);
168
169                         writel(OCOTP_READ_CTRL_READ_FUSE,
170                                 base + OCOTP_READ_CTRL_REG);
171                         ret = vf610_ocotp_wait_busy(base + OCOTP_CTRL_REG);
172                         if (ret)
173                                 return ret;
174
175                         if (readl(base) & OCOTP_CTRL_ERR) {
176                                 dev_dbg(ocotp->dev, "Error reading from fuse address %x\n",
177                                         fuse_addr);
178                                 writel(OCOTP_CTRL_ERR, base + OCOTP_CTRL_CLR);
179                         }
180
181                         /*
182                          * In case of error, we do not abort and expect to read
183                          * 0xBADABADA as mentioned by the TRM. We just read this
184                          * value and return.
185                          */
186                         *buf = readl(base + OCOTP_READ_FUSE_DATA);
187                 } else {
188                         *buf = 0;
189                 }
190
191                 buf++;
192                 bytes -= 4;
193                 offset += 4;
194         }
195
196         return 0;
197 }
198
199 static struct nvmem_config ocotp_config = {
200         .name = "ocotp",
201         .stride = 4,
202         .word_size = 4,
203         .reg_read = vf610_ocotp_read,
204 };
205
206 static const struct of_device_id ocotp_of_match[] = {
207         { .compatible = "fsl,vf610-ocotp", },
208         {/* sentinel */},
209 };
210 MODULE_DEVICE_TABLE(of, ocotp_of_match);
211
212 static int vf610_ocotp_probe(struct platform_device *pdev)
213 {
214         struct device *dev = &pdev->dev;
215         struct resource *res;
216         struct vf610_ocotp *ocotp_dev;
217
218         ocotp_dev = devm_kzalloc(dev, sizeof(struct vf610_ocotp), GFP_KERNEL);
219         if (!ocotp_dev)
220                 return -ENOMEM;
221
222         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
223         ocotp_dev->base = devm_ioremap_resource(dev, res);
224         if (IS_ERR(ocotp_dev->base))
225                 return PTR_ERR(ocotp_dev->base);
226
227         ocotp_dev->clk = devm_clk_get(dev, NULL);
228         if (IS_ERR(ocotp_dev->clk)) {
229                 dev_err(dev, "failed getting clock, err = %ld\n",
230                         PTR_ERR(ocotp_dev->clk));
231                 return PTR_ERR(ocotp_dev->clk);
232         }
233         ocotp_dev->dev = dev;
234         ocotp_dev->timing = vf610_ocotp_calculate_timing(ocotp_dev);
235
236         ocotp_config.size = resource_size(res);
237         ocotp_config.priv = ocotp_dev;
238         ocotp_config.dev = dev;
239
240         ocotp_dev->nvmem = devm_nvmem_register(dev, &ocotp_config);
241
242         return PTR_ERR_OR_ZERO(ocotp_dev->nvmem);
243 }
244
245 static struct platform_driver vf610_ocotp_driver = {
246         .probe = vf610_ocotp_probe,
247         .driver = {
248                 .name = "vf610-ocotp",
249                 .of_match_table = ocotp_of_match,
250         },
251 };
252 module_platform_driver(vf610_ocotp_driver);
253 MODULE_AUTHOR("Sanchayan Maity <sanchayan.maity@toradex.com>");
254 MODULE_DESCRIPTION("Vybrid OCOTP driver");
255 MODULE_LICENSE("GPL v2");