1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2022 Sean Anderson <sean.anderson@seco.com>
4  *
5  * This driver supports the Security Fuse Processor device found on some
6  * Layerscape processors. At the moment, we only support a few processors.
7  * This driver was written with reference to the Layerscape SDK User
8  * Guide [1] and the ATF SFP driver [2].
9  *
10  * [1] https://docs.nxp.com/bundle/GUID-487B2E69-BB19-42CB-AC38-7EF18C0FE3AE/page/GUID-27FC40AD-3321-4A82-B29E-7BB49EE94F23.html
11  * [2] https://source.codeaurora.org/external/qoriq/qoriq-components/atf/tree/drivers/nxp/sfp?h=github.com/master
12  */
13 
14 #define LOG_CATEGORY UCLASS_MISC
15 #include <clk.h>
16 #include <fuse.h>
17 #include <misc.h>
18 #include <asm/io.h>
19 #include <dm/device_compat.h>
20 #include <dm/read.h>
21 #include <linux/bitfield.h>
22 #include <power/regulator.h>
23 
24 DECLARE_GLOBAL_DATA_PTR;
25 
26 #define SFP_INGR	0x20
27 #define SFP_SVHESR	0x24
28 #define SFP_SFPCR	0x28
29 
30 #define SFP_START	0x200
31 #define SFP_END		0x284
32 #define SFP_SIZE	(SFP_END - SFP_START + 4)
33 
34 #define SFP_INGR_ERR	BIT(8)
35 #define SFP_INGR_INST	GENMASK(7, 0)
36 
37 #define SFP_INGR_READFB	0x01
38 #define SFP_INGR_PROGFB	0x02
39 
40 #define SFP_SFPCR_PPW	GENMASK(15, 0)
41 
42 enum ls2_sfp_ioctl {
43 	LS2_SFP_IOCTL_READ,
44 	LS2_SFP_IOCTL_PROG,
45 };
46 
47 /**
48  * struct ls2_sfp_priv - private data for LS2 SFP
49  * @base: Base address of SFP
50  * @supply: The (optional) supply for TA_PROG_SFP
51  * @programmed: Whether we've already programmed the fuses since the last
52  *              reset. The SFP has a *very* limited amount of programming
53  *              cycles (two to six, depending on the model), so we try and
54  *              prevent accidentally performing additional programming
55  *              cycles.
56  * @dirty: Whether the mirror registers have been written to (overridden)
57  *         since we've last read the fuses (either as part of the reset
58  *         process or using a READFB instruction). There is a much larger,
59  *         but still finite, limit on the number of SFP read cycles (around
60  *         300,000), so we try and minimize reads as well.
61  */
62 struct ls2_sfp_priv {
63 	void __iomem *base;
64 	struct udevice *supply;
65 	bool programmed, dirty;
66 };
67 
ls2_sfp_readl(struct ls2_sfp_priv * priv,ulong off)68 static u32 ls2_sfp_readl(struct ls2_sfp_priv *priv, ulong off)
69 {
70 	u32 val = be32_to_cpu(readl(priv->base + off));
71 
72 	log_debug("%08x = readl(%p)\n", val, priv->base + off);
73 	return val;
74 }
75 
ls2_sfp_writel(struct ls2_sfp_priv * priv,ulong val,ulong off)76 static void ls2_sfp_writel(struct ls2_sfp_priv *priv, ulong val, ulong off)
77 {
78 	log_debug("writel(%08lx, %p)\n", val, priv->base + off);
79 	writel(cpu_to_be32(val), priv->base + off);
80 }
81 
ls2_sfp_validate(struct udevice * dev,int offset,int size)82 static bool ls2_sfp_validate(struct udevice *dev, int offset, int size)
83 {
84 	if (offset < 0 || size < 0) {
85 		dev_notice(dev, "size and offset must be positive\n");
86 		return false;
87 	}
88 
89 	if (offset & 3 || size & 3) {
90 		dev_notice(dev, "size and offset must be multiples of 4\n");
91 		return false;
92 	}
93 
94 	if (offset + size > SFP_SIZE) {
95 		dev_notice(dev, "size + offset must be <= %#x\n", SFP_SIZE);
96 		return false;
97 	}
98 
99 	return true;
100 }
101 
ls2_sfp_read(struct udevice * dev,int offset,void * buf_bytes,int size)102 static int ls2_sfp_read(struct udevice *dev, int offset, void *buf_bytes,
103 			int size)
104 {
105 	int i;
106 	struct ls2_sfp_priv *priv = dev_get_priv(dev);
107 	u32 *buf = buf_bytes;
108 
109 	if (!ls2_sfp_validate(dev, offset, size))
110 		return -EINVAL;
111 
112 	for (i = 0; i < size; i += 4)
113 		buf[i >> 2] = ls2_sfp_readl(priv, SFP_START + offset + i);
114 
115 	return size;
116 }
117 
ls2_sfp_write(struct udevice * dev,int offset,const void * buf_bytes,int size)118 static int ls2_sfp_write(struct udevice *dev, int offset,
119 			 const void *buf_bytes, int size)
120 {
121 	int i;
122 	struct ls2_sfp_priv *priv = dev_get_priv(dev);
123 	const u32 *buf = buf_bytes;
124 
125 	if (!ls2_sfp_validate(dev, offset, size))
126 		return -EINVAL;
127 
128 	for (i = 0; i < size; i += 4)
129 		ls2_sfp_writel(priv, buf[i >> 2], SFP_START + offset + i);
130 
131 	priv->dirty = true;
132 	return size;
133 }
134 
ls2_sfp_check_secret(struct udevice * dev)135 static int ls2_sfp_check_secret(struct udevice *dev)
136 {
137 	struct ls2_sfp_priv *priv = dev_get_priv(dev);
138 	u32 svhesr = ls2_sfp_readl(priv, SFP_SVHESR);
139 
140 	if (svhesr) {
141 		dev_warn(dev, "secret value hamming error not zero: %08x\n",
142 			 svhesr);
143 		return -EIO;
144 	}
145 	return 0;
146 }
147 
ls2_sfp_transaction(struct ls2_sfp_priv * priv,ulong inst)148 static int ls2_sfp_transaction(struct ls2_sfp_priv *priv, ulong inst)
149 {
150 	u32 ingr;
151 
152 	ls2_sfp_writel(priv, inst, SFP_INGR);
153 
154 	do {
155 		ingr = ls2_sfp_readl(priv, SFP_INGR);
156 	} while (FIELD_GET(SFP_INGR_INST, ingr));
157 
158 	return FIELD_GET(SFP_INGR_ERR, ingr) ? -EIO : 0;
159 }
160 
ls2_sfp_ioctl(struct udevice * dev,unsigned long request,void * buf)161 static int ls2_sfp_ioctl(struct udevice *dev, unsigned long request, void *buf)
162 {
163 	int ret;
164 	struct ls2_sfp_priv *priv = dev_get_priv(dev);
165 
166 	switch (request) {
167 	case LS2_SFP_IOCTL_READ:
168 		if (!priv->dirty) {
169 			dev_dbg(dev, "ignoring read request, since fuses are not dirty\n");
170 			return 0;
171 		}
172 
173 		ret = ls2_sfp_transaction(priv, SFP_INGR_READFB);
174 		if (ret) {
175 			dev_err(dev, "error reading fuses\n");
176 			return ret;
177 		}
178 
179 		ls2_sfp_check_secret(dev);
180 		priv->dirty = false;
181 		return 0;
182 	case LS2_SFP_IOCTL_PROG:
183 		if (priv->programmed) {
184 			dev_warn(dev, "fuses already programmed\n");
185 			return -EPERM;
186 		}
187 
188 		ret = ls2_sfp_check_secret(dev);
189 		if (ret)
190 			return ret;
191 
192 		if (priv->supply) {
193 			ret = regulator_set_enable(priv->supply, true);
194 			if (ret)
195 				return ret;
196 		}
197 
198 		ret = ls2_sfp_transaction(priv, SFP_INGR_PROGFB);
199 		priv->programmed = true;
200 		if (priv->supply)
201 			regulator_set_enable(priv->supply, false);
202 
203 		if (ret)
204 			dev_err(dev, "error programming fuses\n");
205 		return ret;
206 	default:
207 		dev_dbg(dev, "unknown ioctl %lu\n", request);
208 		return -EINVAL;
209 	}
210 }
211 
212 static const struct misc_ops ls2_sfp_ops = {
213 	.read = ls2_sfp_read,
214 	.write = ls2_sfp_write,
215 	.ioctl = ls2_sfp_ioctl,
216 };
217 
ls2_sfp_probe(struct udevice * dev)218 static int ls2_sfp_probe(struct udevice *dev)
219 {
220 	int ret;
221 	struct clk clk;
222 	struct ls2_sfp_priv *priv = dev_get_priv(dev);
223 	ulong rate;
224 
225 	priv->base = dev_read_addr_ptr(dev);
226 	if (!priv->base) {
227 		dev_dbg(dev, "could not read register base\n");
228 		return -EINVAL;
229 	}
230 
231 	ret = device_get_supply_regulator(dev, "ta-sfp-prog-supply", &priv->supply);
232 	if (ret && ret != -ENODEV && ret != -ENOSYS) {
233 		dev_dbg(dev, "problem getting supply (err %d)\n", ret);
234 		return ret;
235 	}
236 
237 	ret = clk_get_by_name(dev, "sfp", &clk);
238 	if (ret == -ENOSYS) {
239 		rate = gd->bus_clk / 4;
240 	} else if (ret) {
241 		dev_dbg(dev, "could not get clock (err %d)\n", ret);
242 		return ret;
243 	} else {
244 		ret = clk_enable(&clk);
245 		if (ret) {
246 			dev_dbg(dev, "could not enable clock (err %d)\n", ret);
247 			return ret;
248 		}
249 
250 		rate = clk_get_rate(&clk);
251 		if (!rate || IS_ERR_VALUE(rate)) {
252 			ret = rate ? rate : -ENOENT;
253 			dev_dbg(dev, "could not get clock rate (err %d)\n",
254 				ret);
255 			return ret;
256 		}
257 	}
258 
259 	/* sfp clock in MHz * 12 */
260 	ls2_sfp_writel(priv, FIELD_PREP(SFP_SFPCR_PPW, rate * 12 / 1000000),
261 		       SFP_SFPCR);
262 
263 	ls2_sfp_check_secret(dev);
264 	return 0;
265 }
266 
267 static const struct udevice_id ls2_sfp_ids[] = {
268 	{ .compatible = "fsl,ls1021a-sfp" },
269 	{ }
270 };
271 
272 U_BOOT_DRIVER(ls2_sfp) = {
273 	.name		= "ls2_sfp",
274 	.id		= UCLASS_MISC,
275 	.of_match	= ls2_sfp_ids,
276 	.probe		= ls2_sfp_probe,
277 	.ops		= &ls2_sfp_ops,
278 	.priv_auto	= sizeof(struct ls2_sfp_priv),
279 };
280 
ls2_sfp_device(struct udevice ** dev)281 static int ls2_sfp_device(struct udevice **dev)
282 {
283 	int ret = uclass_get_device_by_driver(UCLASS_MISC,
284 					      DM_DRIVER_GET(ls2_sfp), dev);
285 
286 	if (ret)
287 		log_debug("device not found (err %d)\n", ret);
288 	return ret;
289 }
290 
fuse_read(u32 bank,u32 word,u32 * val)291 int fuse_read(u32 bank, u32 word, u32 *val)
292 {
293 	int ret;
294 	struct udevice *dev;
295 
296 	ret = ls2_sfp_device(&dev);
297 	if (ret)
298 		return ret;
299 
300 	ret = misc_ioctl(dev, LS2_SFP_IOCTL_READ, NULL);
301 	if (ret)
302 		return ret;
303 
304 	ret = misc_read(dev, word << 2, val, sizeof(*val));
305 	return ret < 0 ? ret : 0;
306 }
307 
fuse_sense(u32 bank,u32 word,u32 * val)308 int fuse_sense(u32 bank, u32 word, u32 *val)
309 {
310 	int ret;
311 	struct udevice *dev;
312 
313 	ret = ls2_sfp_device(&dev);
314 	if (ret)
315 		return ret;
316 
317 	ret = misc_read(dev, word << 2, val, sizeof(*val));
318 	return ret < 0 ? ret : 0;
319 }
320 
fuse_prog(u32 bank,u32 word,u32 val)321 int fuse_prog(u32 bank, u32 word, u32 val)
322 {
323 	int ret;
324 	struct udevice *dev;
325 
326 	ret = ls2_sfp_device(&dev);
327 	if (ret)
328 		return ret;
329 
330 	ret = misc_write(dev, word << 2, &val, sizeof(val));
331 	if (ret < 0)
332 		return ret;
333 
334 	return misc_ioctl(dev, LS2_SFP_IOCTL_PROG, NULL);
335 }
336 
fuse_override(u32 bank,u32 word,u32 val)337 int fuse_override(u32 bank, u32 word, u32 val)
338 {
339 	int ret;
340 	struct udevice *dev;
341 
342 	ret = ls2_sfp_device(&dev);
343 	if (ret)
344 		return ret;
345 
346 	ret = misc_write(dev, word << 2, &val, sizeof(val));
347 	return ret < 0 ? ret : 0;
348 }
349