xref: /openbmc/linux/drivers/nvmem/qfprom.c (revision 7a010c3c)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2015 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
4  */
5 
6 #include <linux/clk.h>
7 #include <linux/device.h>
8 #include <linux/io.h>
9 #include <linux/iopoll.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/mod_devicetable.h>
13 #include <linux/nvmem-provider.h>
14 #include <linux/platform_device.h>
15 #include <linux/pm_domain.h>
16 #include <linux/pm_runtime.h>
17 #include <linux/property.h>
18 #include <linux/regulator/consumer.h>
19 
20 /* Blow timer clock frequency in Mhz */
21 #define QFPROM_BLOW_TIMER_OFFSET 0x03c
22 
23 /* Amount of time required to hold charge to blow fuse in micro-seconds */
24 #define QFPROM_FUSE_BLOW_POLL_US	100
25 #define QFPROM_FUSE_BLOW_TIMEOUT_US	1000
26 
27 #define QFPROM_BLOW_STATUS_OFFSET	0x048
28 #define QFPROM_BLOW_STATUS_BUSY		0x1
29 #define QFPROM_BLOW_STATUS_READY	0x0
30 
31 #define QFPROM_ACCEL_OFFSET		0x044
32 
33 #define QFPROM_VERSION_OFFSET		0x0
34 #define QFPROM_MAJOR_VERSION_SHIFT	28
35 #define QFPROM_MAJOR_VERSION_MASK	GENMASK(31, QFPROM_MAJOR_VERSION_SHIFT)
36 #define QFPROM_MINOR_VERSION_SHIFT	16
37 #define QFPROM_MINOR_VERSION_MASK	GENMASK(27, QFPROM_MINOR_VERSION_SHIFT)
38 
39 static bool read_raw_data;
40 module_param(read_raw_data, bool, 0644);
41 MODULE_PARM_DESC(read_raw_data, "Read raw instead of corrected data");
42 
43 /**
44  * struct qfprom_soc_data - config that varies from SoC to SoC.
45  *
46  * @accel_value:             Should contain qfprom accel value.
47  * @qfprom_blow_timer_value: The timer value of qfprom when doing efuse blow.
48  * @qfprom_blow_set_freq:    The frequency required to set when we start the
49  *                           fuse blowing.
50  * @qfprom_blow_uV:          LDO voltage to be set when doing efuse blow
51  */
52 struct qfprom_soc_data {
53 	u32 accel_value;
54 	u32 qfprom_blow_timer_value;
55 	u32 qfprom_blow_set_freq;
56 	int qfprom_blow_uV;
57 };
58 
59 /**
60  * struct qfprom_priv - structure holding qfprom attributes
61  *
62  * @qfpraw:       iomapped memory space for qfprom-efuse raw address space.
63  * @qfpconf:      iomapped memory space for qfprom-efuse configuration address
64  *                space.
65  * @qfpcorrected: iomapped memory space for qfprom corrected address space.
66  * @qfpsecurity:  iomapped memory space for qfprom security control space.
67  * @dev:          qfprom device structure.
68  * @secclk:       Clock supply.
69  * @vcc:          Regulator supply.
70  * @soc_data:     Data that for things that varies from SoC to SoC.
71  */
72 struct qfprom_priv {
73 	void __iomem *qfpraw;
74 	void __iomem *qfpconf;
75 	void __iomem *qfpcorrected;
76 	void __iomem *qfpsecurity;
77 	struct device *dev;
78 	struct clk *secclk;
79 	struct regulator *vcc;
80 	const struct qfprom_soc_data *soc_data;
81 };
82 
83 /**
84  * struct qfprom_touched_values - saved values to restore after blowing
85  *
86  * @clk_rate: The rate the clock was at before blowing.
87  * @accel_val: The value of the accel reg before blowing.
88  * @timer_val: The value of the timer before blowing.
89  */
90 struct qfprom_touched_values {
91 	unsigned long clk_rate;
92 	u32 accel_val;
93 	u32 timer_val;
94 };
95 
96 /**
97  * struct qfprom_soc_compatible_data - Data matched against the SoC
98  * compatible string.
99  *
100  * @keepout: Array of keepout regions for this SoC.
101  * @nkeepout: Number of elements in the keepout array.
102  */
103 struct qfprom_soc_compatible_data {
104 	const struct nvmem_keepout *keepout;
105 	unsigned int nkeepout;
106 };
107 
108 static const struct nvmem_keepout sc7180_qfprom_keepout[] = {
109 	{.start = 0x128, .end = 0x148},
110 	{.start = 0x220, .end = 0x228}
111 };
112 
113 static const struct qfprom_soc_compatible_data sc7180_qfprom = {
114 	.keepout = sc7180_qfprom_keepout,
115 	.nkeepout = ARRAY_SIZE(sc7180_qfprom_keepout)
116 };
117 
118 static const struct nvmem_keepout sc7280_qfprom_keepout[] = {
119 	{.start = 0x128, .end = 0x148},
120 	{.start = 0x238, .end = 0x248}
121 };
122 
123 static const struct qfprom_soc_compatible_data sc7280_qfprom = {
124 	.keepout = sc7280_qfprom_keepout,
125 	.nkeepout = ARRAY_SIZE(sc7280_qfprom_keepout)
126 };
127 
128 /**
129  * qfprom_disable_fuse_blowing() - Undo enabling of fuse blowing.
130  * @priv: Our driver data.
131  * @old:  The data that was stashed from before fuse blowing.
132  *
133  * Resets the value of the blow timer, accel register and the clock
134  * and voltage settings.
135  *
136  * Prints messages if there are errors but doesn't return an error code
137  * since there's not much we can do upon failure.
138  */
139 static void qfprom_disable_fuse_blowing(const struct qfprom_priv *priv,
140 					const struct qfprom_touched_values *old)
141 {
142 	int ret;
143 
144 	writel(old->timer_val, priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
145 	writel(old->accel_val, priv->qfpconf + QFPROM_ACCEL_OFFSET);
146 
147 	dev_pm_genpd_set_performance_state(priv->dev, 0);
148 	pm_runtime_put(priv->dev);
149 
150 	/*
151 	 * This may be a shared rail and may be able to run at a lower rate
152 	 * when we're not blowing fuses.  At the moment, the regulator framework
153 	 * applies voltage constraints even on disabled rails, so remove our
154 	 * constraints and allow the rail to be adjusted by other users.
155 	 */
156 	ret = regulator_set_voltage(priv->vcc, 0, INT_MAX);
157 	if (ret)
158 		dev_warn(priv->dev, "Failed to set 0 voltage (ignoring)\n");
159 
160 	ret = regulator_disable(priv->vcc);
161 	if (ret)
162 		dev_warn(priv->dev, "Failed to disable regulator (ignoring)\n");
163 
164 	ret = clk_set_rate(priv->secclk, old->clk_rate);
165 	if (ret)
166 		dev_warn(priv->dev,
167 			 "Failed to set clock rate for disable (ignoring)\n");
168 
169 	clk_disable_unprepare(priv->secclk);
170 }
171 
172 /**
173  * qfprom_enable_fuse_blowing() - Enable fuse blowing.
174  * @priv: Our driver data.
175  * @old:  We'll stash stuff here to use when disabling.
176  *
177  * Sets the value of the blow timer, accel register and the clock
178  * and voltage settings.
179  *
180  * Prints messages if there are errors so caller doesn't need to.
181  *
182  * Return: 0 or -err.
183  */
184 static int qfprom_enable_fuse_blowing(const struct qfprom_priv *priv,
185 				      struct qfprom_touched_values *old)
186 {
187 	int ret;
188 	int qfprom_blow_uV = priv->soc_data->qfprom_blow_uV;
189 
190 	ret = clk_prepare_enable(priv->secclk);
191 	if (ret) {
192 		dev_err(priv->dev, "Failed to enable clock\n");
193 		return ret;
194 	}
195 
196 	old->clk_rate = clk_get_rate(priv->secclk);
197 	ret = clk_set_rate(priv->secclk, priv->soc_data->qfprom_blow_set_freq);
198 	if (ret) {
199 		dev_err(priv->dev, "Failed to set clock rate for enable\n");
200 		goto err_clk_prepared;
201 	}
202 
203 	/*
204 	 * Hardware requires a minimum voltage for fuse blowing.
205 	 * This may be a shared rail so don't specify a maximum.
206 	 * Regulator constraints will cap to the actual maximum.
207 	 */
208 	ret = regulator_set_voltage(priv->vcc, qfprom_blow_uV, INT_MAX);
209 	if (ret) {
210 		dev_err(priv->dev, "Failed to set %duV\n", qfprom_blow_uV);
211 		goto err_clk_rate_set;
212 	}
213 
214 	ret = regulator_enable(priv->vcc);
215 	if (ret) {
216 		dev_err(priv->dev, "Failed to enable regulator\n");
217 		goto err_clk_rate_set;
218 	}
219 
220 	ret = pm_runtime_get_sync(priv->dev);
221 	if (ret < 0) {
222 		pm_runtime_put_noidle(priv->dev);
223 		dev_err(priv->dev, "Failed to enable power-domain\n");
224 		goto err_reg_enable;
225 	}
226 	dev_pm_genpd_set_performance_state(priv->dev, INT_MAX);
227 
228 	old->timer_val = readl(priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
229 	old->accel_val = readl(priv->qfpconf + QFPROM_ACCEL_OFFSET);
230 	writel(priv->soc_data->qfprom_blow_timer_value,
231 	       priv->qfpconf + QFPROM_BLOW_TIMER_OFFSET);
232 	writel(priv->soc_data->accel_value,
233 	       priv->qfpconf + QFPROM_ACCEL_OFFSET);
234 
235 	return 0;
236 
237 err_reg_enable:
238 	regulator_disable(priv->vcc);
239 err_clk_rate_set:
240 	clk_set_rate(priv->secclk, old->clk_rate);
241 err_clk_prepared:
242 	clk_disable_unprepare(priv->secclk);
243 	return ret;
244 }
245 
246 /**
247  * qfprom_efuse_reg_write() - Write to fuses.
248  * @context: Our driver data.
249  * @reg:     The offset to write at.
250  * @_val:    Pointer to data to write.
251  * @bytes:   The number of bytes to write.
252  *
253  * Writes to fuses.  WARNING: THIS IS PERMANENT.
254  *
255  * Return: 0 or -err.
256  */
257 static int qfprom_reg_write(void *context, unsigned int reg, void *_val,
258 			    size_t bytes)
259 {
260 	struct qfprom_priv *priv = context;
261 	struct qfprom_touched_values old;
262 	int words = bytes / 4;
263 	u32 *value = _val;
264 	u32 blow_status;
265 	int ret;
266 	int i;
267 
268 	dev_dbg(priv->dev,
269 		"Writing to raw qfprom region : %#010x of size: %zu\n",
270 		reg, bytes);
271 
272 	/*
273 	 * The hardware only allows us to write word at a time, but we can
274 	 * read byte at a time.  Until the nvmem framework allows a separate
275 	 * word_size and stride for reading vs. writing, we'll enforce here.
276 	 */
277 	if (bytes % 4) {
278 		dev_err(priv->dev,
279 			"%zu is not an integral number of words\n", bytes);
280 		return -EINVAL;
281 	}
282 	if (reg % 4) {
283 		dev_err(priv->dev,
284 			"Invalid offset: %#x.  Must be word aligned\n", reg);
285 		return -EINVAL;
286 	}
287 
288 	ret = qfprom_enable_fuse_blowing(priv, &old);
289 	if (ret)
290 		return ret;
291 
292 	ret = readl_relaxed_poll_timeout(
293 		priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
294 		blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
295 		QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);
296 
297 	if (ret) {
298 		dev_err(priv->dev,
299 			"Timeout waiting for initial ready; aborting.\n");
300 		goto exit_enabled_fuse_blowing;
301 	}
302 
303 	for (i = 0; i < words; i++)
304 		writel(value[i], priv->qfpraw + reg + (i * 4));
305 
306 	ret = readl_relaxed_poll_timeout(
307 		priv->qfpconf + QFPROM_BLOW_STATUS_OFFSET,
308 		blow_status, blow_status == QFPROM_BLOW_STATUS_READY,
309 		QFPROM_FUSE_BLOW_POLL_US, QFPROM_FUSE_BLOW_TIMEOUT_US);
310 
311 	/* Give an error, but not much we can do in this case */
312 	if (ret)
313 		dev_err(priv->dev, "Timeout waiting for finish.\n");
314 
315 exit_enabled_fuse_blowing:
316 	qfprom_disable_fuse_blowing(priv, &old);
317 
318 	return ret;
319 }
320 
321 static int qfprom_reg_read(void *context,
322 			unsigned int reg, void *_val, size_t bytes)
323 {
324 	struct qfprom_priv *priv = context;
325 	u8 *val = _val;
326 	int i = 0, words = bytes;
327 	void __iomem *base = priv->qfpcorrected;
328 
329 	if (read_raw_data && priv->qfpraw)
330 		base = priv->qfpraw;
331 
332 	while (words--)
333 		*val++ = readb(base + reg + i++);
334 
335 	return 0;
336 }
337 
338 static void qfprom_runtime_disable(void *data)
339 {
340 	pm_runtime_disable(data);
341 }
342 
343 static const struct qfprom_soc_data qfprom_7_8_data = {
344 	.accel_value = 0xD10,
345 	.qfprom_blow_timer_value = 25,
346 	.qfprom_blow_set_freq = 4800000,
347 	.qfprom_blow_uV = 1800000,
348 };
349 
350 static const struct qfprom_soc_data qfprom_7_15_data = {
351 	.accel_value = 0xD08,
352 	.qfprom_blow_timer_value = 24,
353 	.qfprom_blow_set_freq = 4800000,
354 	.qfprom_blow_uV = 1900000,
355 };
356 
357 static int qfprom_probe(struct platform_device *pdev)
358 {
359 	struct nvmem_config econfig = {
360 		.name = "qfprom",
361 		.stride = 1,
362 		.word_size = 1,
363 		.id = NVMEM_DEVID_AUTO,
364 		.reg_read = qfprom_reg_read,
365 	};
366 	struct device *dev = &pdev->dev;
367 	struct resource *res;
368 	struct nvmem_device *nvmem;
369 	const struct qfprom_soc_compatible_data *soc_data;
370 	struct qfprom_priv *priv;
371 	int ret;
372 
373 	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
374 	if (!priv)
375 		return -ENOMEM;
376 
377 	/* The corrected section is always provided */
378 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
379 	priv->qfpcorrected = devm_ioremap_resource(dev, res);
380 	if (IS_ERR(priv->qfpcorrected))
381 		return PTR_ERR(priv->qfpcorrected);
382 
383 	econfig.size = resource_size(res);
384 	econfig.dev = dev;
385 	econfig.priv = priv;
386 
387 	priv->dev = dev;
388 	soc_data = device_get_match_data(dev);
389 	if (soc_data) {
390 		econfig.keepout = soc_data->keepout;
391 		econfig.nkeepout = soc_data->nkeepout;
392 	}
393 
394 	/*
395 	 * If more than one region is provided then the OS has the ability
396 	 * to write.
397 	 */
398 	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
399 	if (res) {
400 		u32 version;
401 		int major_version, minor_version;
402 
403 		priv->qfpraw = devm_ioremap_resource(dev, res);
404 		if (IS_ERR(priv->qfpraw))
405 			return PTR_ERR(priv->qfpraw);
406 		res = platform_get_resource(pdev, IORESOURCE_MEM, 2);
407 		priv->qfpconf = devm_ioremap_resource(dev, res);
408 		if (IS_ERR(priv->qfpconf))
409 			return PTR_ERR(priv->qfpconf);
410 		res = platform_get_resource(pdev, IORESOURCE_MEM, 3);
411 		priv->qfpsecurity = devm_ioremap_resource(dev, res);
412 		if (IS_ERR(priv->qfpsecurity))
413 			return PTR_ERR(priv->qfpsecurity);
414 
415 		version = readl(priv->qfpsecurity + QFPROM_VERSION_OFFSET);
416 		major_version = (version & QFPROM_MAJOR_VERSION_MASK) >>
417 				QFPROM_MAJOR_VERSION_SHIFT;
418 		minor_version = (version & QFPROM_MINOR_VERSION_MASK) >>
419 				QFPROM_MINOR_VERSION_SHIFT;
420 
421 		if (major_version == 7 && minor_version == 8)
422 			priv->soc_data = &qfprom_7_8_data;
423 		else if (major_version == 7 && minor_version == 15)
424 			priv->soc_data = &qfprom_7_15_data;
425 
426 		priv->vcc = devm_regulator_get(&pdev->dev, "vcc");
427 		if (IS_ERR(priv->vcc))
428 			return PTR_ERR(priv->vcc);
429 
430 		priv->secclk = devm_clk_get(dev, "core");
431 		if (IS_ERR(priv->secclk)) {
432 			ret = PTR_ERR(priv->secclk);
433 			if (ret != -EPROBE_DEFER)
434 				dev_err(dev, "Error getting clock: %d\n", ret);
435 			return ret;
436 		}
437 
438 		/* Only enable writing if we have SoC data. */
439 		if (priv->soc_data)
440 			econfig.reg_write = qfprom_reg_write;
441 	}
442 
443 	pm_runtime_enable(dev);
444 	ret = devm_add_action_or_reset(dev, qfprom_runtime_disable, dev);
445 	if (ret)
446 		return ret;
447 
448 	nvmem = devm_nvmem_register(dev, &econfig);
449 
450 	return PTR_ERR_OR_ZERO(nvmem);
451 }
452 
453 static const struct of_device_id qfprom_of_match[] = {
454 	{ .compatible = "qcom,qfprom",},
455 	{ .compatible = "qcom,sc7180-qfprom", .data = &sc7180_qfprom},
456 	{ .compatible = "qcom,sc7280-qfprom", .data = &sc7280_qfprom},
457 	{/* sentinel */},
458 };
459 MODULE_DEVICE_TABLE(of, qfprom_of_match);
460 
461 static struct platform_driver qfprom_driver = {
462 	.probe = qfprom_probe,
463 	.driver = {
464 		.name = "qcom,qfprom",
465 		.of_match_table = qfprom_of_match,
466 	},
467 };
468 module_platform_driver(qfprom_driver);
469 MODULE_AUTHOR("Srinivas Kandagatla <srinivas.kandagatla@linaro.org>");
470 MODULE_DESCRIPTION("Qualcomm QFPROM driver");
471 MODULE_LICENSE("GPL v2");
472