1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * i.MX8 OCOTP fusebox driver
4 *
5 * Copyright 2019 NXP
6 *
7 * Peng Fan <peng.fan@nxp.com>
8 */
9
10 #include <linux/arm-smccc.h>
11 #include <linux/firmware/imx/sci.h>
12 #include <linux/module.h>
13 #include <linux/nvmem-provider.h>
14 #include <linux/of.h>
15 #include <linux/platform_device.h>
16 #include <linux/slab.h>
17
18 #define IMX_SIP_OTP_WRITE 0xc200000B
19
20 enum ocotp_devtype {
21 IMX8QXP,
22 IMX8QM,
23 };
24
25 #define ECC_REGION BIT(0)
26 #define HOLE_REGION BIT(1)
27
28 struct ocotp_region {
29 u32 start;
30 u32 end;
31 u32 flag;
32 };
33
34 struct ocotp_devtype_data {
35 int devtype;
36 int nregs;
37 u32 num_region;
38 struct ocotp_region region[];
39 };
40
41 struct ocotp_priv {
42 struct device *dev;
43 const struct ocotp_devtype_data *data;
44 struct imx_sc_ipc *nvmem_ipc;
45 };
46
47 struct imx_sc_msg_misc_fuse_read {
48 struct imx_sc_rpc_msg hdr;
49 u32 word;
50 } __packed;
51
52 static DEFINE_MUTEX(scu_ocotp_mutex);
53
54 static struct ocotp_devtype_data imx8qxp_data = {
55 .devtype = IMX8QXP,
56 .nregs = 800,
57 .num_region = 3,
58 .region = {
59 {0x10, 0x10f, ECC_REGION},
60 {0x110, 0x21F, HOLE_REGION},
61 {0x220, 0x31F, ECC_REGION},
62 },
63 };
64
65 static struct ocotp_devtype_data imx8qm_data = {
66 .devtype = IMX8QM,
67 .nregs = 800,
68 .num_region = 2,
69 .region = {
70 {0x10, 0x10f, ECC_REGION},
71 {0x1a0, 0x1ff, ECC_REGION},
72 },
73 };
74
in_hole(void * context,u32 index)75 static bool in_hole(void *context, u32 index)
76 {
77 struct ocotp_priv *priv = context;
78 const struct ocotp_devtype_data *data = priv->data;
79 int i;
80
81 for (i = 0; i < data->num_region; i++) {
82 if (data->region[i].flag & HOLE_REGION) {
83 if ((index >= data->region[i].start) &&
84 (index <= data->region[i].end))
85 return true;
86 }
87 }
88
89 return false;
90 }
91
in_ecc(void * context,u32 index)92 static bool in_ecc(void *context, u32 index)
93 {
94 struct ocotp_priv *priv = context;
95 const struct ocotp_devtype_data *data = priv->data;
96 int i;
97
98 for (i = 0; i < data->num_region; i++) {
99 if (data->region[i].flag & ECC_REGION) {
100 if ((index >= data->region[i].start) &&
101 (index <= data->region[i].end))
102 return true;
103 }
104 }
105
106 return false;
107 }
108
imx_sc_misc_otp_fuse_read(struct imx_sc_ipc * ipc,u32 word,u32 * val)109 static int imx_sc_misc_otp_fuse_read(struct imx_sc_ipc *ipc, u32 word,
110 u32 *val)
111 {
112 struct imx_sc_msg_misc_fuse_read msg;
113 struct imx_sc_rpc_msg *hdr = &msg.hdr;
114 int ret;
115
116 hdr->ver = IMX_SC_RPC_VERSION;
117 hdr->svc = IMX_SC_RPC_SVC_MISC;
118 hdr->func = IMX_SC_MISC_FUNC_OTP_FUSE_READ;
119 hdr->size = 2;
120
121 msg.word = word;
122
123 ret = imx_scu_call_rpc(ipc, &msg, true);
124 if (ret)
125 return ret;
126
127 *val = msg.word;
128
129 return 0;
130 }
131
imx_scu_ocotp_read(void * context,unsigned int offset,void * val,size_t bytes)132 static int imx_scu_ocotp_read(void *context, unsigned int offset,
133 void *val, size_t bytes)
134 {
135 struct ocotp_priv *priv = context;
136 u32 count, index, num_bytes;
137 u32 *buf;
138 void *p;
139 int i, ret;
140
141 index = offset;
142 num_bytes = round_up(bytes, 4);
143 count = num_bytes >> 2;
144
145 if (count > (priv->data->nregs - index))
146 count = priv->data->nregs - index;
147
148 p = kzalloc(num_bytes, GFP_KERNEL);
149 if (!p)
150 return -ENOMEM;
151
152 mutex_lock(&scu_ocotp_mutex);
153
154 buf = p;
155
156 for (i = index; i < (index + count); i++) {
157 if (in_hole(context, i)) {
158 *buf++ = 0;
159 continue;
160 }
161
162 ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, i, buf);
163 if (ret) {
164 mutex_unlock(&scu_ocotp_mutex);
165 kfree(p);
166 return ret;
167 }
168 buf++;
169 }
170
171 memcpy(val, (u8 *)p, bytes);
172
173 mutex_unlock(&scu_ocotp_mutex);
174
175 kfree(p);
176
177 return 0;
178 }
179
imx_scu_ocotp_write(void * context,unsigned int offset,void * val,size_t bytes)180 static int imx_scu_ocotp_write(void *context, unsigned int offset,
181 void *val, size_t bytes)
182 {
183 struct ocotp_priv *priv = context;
184 struct arm_smccc_res res;
185 u32 *buf = val;
186 u32 tmp;
187 u32 index;
188 int ret;
189
190 /* allow only writing one complete OTP word at a time */
191 if (bytes != 4)
192 return -EINVAL;
193
194 index = offset;
195
196 if (in_hole(context, index))
197 return -EINVAL;
198
199 if (in_ecc(context, index)) {
200 pr_warn("ECC region, only program once\n");
201 mutex_lock(&scu_ocotp_mutex);
202 ret = imx_sc_misc_otp_fuse_read(priv->nvmem_ipc, index, &tmp);
203 mutex_unlock(&scu_ocotp_mutex);
204 if (ret)
205 return ret;
206 if (tmp) {
207 pr_warn("ECC region, already has value: %x\n", tmp);
208 return -EIO;
209 }
210 }
211
212 mutex_lock(&scu_ocotp_mutex);
213
214 arm_smccc_smc(IMX_SIP_OTP_WRITE, index, *buf, 0, 0, 0, 0, 0, &res);
215
216 mutex_unlock(&scu_ocotp_mutex);
217
218 return res.a0;
219 }
220
221 static struct nvmem_config imx_scu_ocotp_nvmem_config = {
222 .name = "imx-scu-ocotp",
223 .add_legacy_fixed_of_cells = true,
224 .read_only = false,
225 .word_size = 4,
226 .stride = 1,
227 .owner = THIS_MODULE,
228 .reg_read = imx_scu_ocotp_read,
229 .reg_write = imx_scu_ocotp_write,
230 };
231
232 static const struct of_device_id imx_scu_ocotp_dt_ids[] = {
233 { .compatible = "fsl,imx8qxp-scu-ocotp", (void *)&imx8qxp_data },
234 { .compatible = "fsl,imx8qm-scu-ocotp", (void *)&imx8qm_data },
235 { },
236 };
237 MODULE_DEVICE_TABLE(of, imx_scu_ocotp_dt_ids);
238
imx_scu_ocotp_probe(struct platform_device * pdev)239 static int imx_scu_ocotp_probe(struct platform_device *pdev)
240 {
241 struct device *dev = &pdev->dev;
242 struct ocotp_priv *priv;
243 struct nvmem_device *nvmem;
244 int ret;
245
246 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
247 if (!priv)
248 return -ENOMEM;
249
250 ret = imx_scu_get_handle(&priv->nvmem_ipc);
251 if (ret)
252 return ret;
253
254 priv->data = of_device_get_match_data(dev);
255 priv->dev = dev;
256 imx_scu_ocotp_nvmem_config.size = 4 * priv->data->nregs;
257 imx_scu_ocotp_nvmem_config.dev = dev;
258 imx_scu_ocotp_nvmem_config.priv = priv;
259 nvmem = devm_nvmem_register(dev, &imx_scu_ocotp_nvmem_config);
260
261 return PTR_ERR_OR_ZERO(nvmem);
262 }
263
264 static struct platform_driver imx_scu_ocotp_driver = {
265 .probe = imx_scu_ocotp_probe,
266 .driver = {
267 .name = "imx_scu_ocotp",
268 .of_match_table = imx_scu_ocotp_dt_ids,
269 },
270 };
271 module_platform_driver(imx_scu_ocotp_driver);
272
273 MODULE_AUTHOR("Peng Fan <peng.fan@nxp.com>");
274 MODULE_DESCRIPTION("i.MX8 SCU OCOTP fuse box driver");
275 MODULE_LICENSE("GPL v2");
276