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2024-05-13 9d77db3c730780c8ef5ccd4b66403ff5675cfe4e 
 kernel/drivers/char/hw_random/imx-rngc.c
....@@ -1,15 +1,9 @@
1
+// SPDX-License-Identifier: GPL-2.0-or-later
12 /*
23  * RNG driver for Freescale RNGC
34  *
45  * Copyright (C) 2008-2012 Freescale Semiconductor, Inc.
56  * Copyright (C) 2017 Martin Kaiser <martin@kaiser.cx>
6
- *
7
- * The code contained herein is licensed under the GNU General Public
8
- * License. You may obtain a copy of the GNU General Public License
9
- * Version 2 or later at the following locations:
10
- *
11
- * http://www.opensource.org/licenses/gpl-license.html
12
- * http://www.gnu.org/copyleft/gpl.html
137  */
148 
159 #include <linux/module.h>
....@@ -24,11 +18,21 @@
2418 #include <linux/completion.h>
2519 #include <linux/io.h>
2620 
21
+#define RNGC_VER_ID			0x0000
2722 #define RNGC_COMMAND			0x0004
2823 #define RNGC_CONTROL			0x0008
2924 #define RNGC_STATUS			0x000C
3025 #define RNGC_ERROR			0x0010
3126 #define RNGC_FIFO			0x0014
27
+
28
+/* the fields in the ver id register */
29
+#define RNGC_TYPE_SHIFT		28
30
+#define RNGC_VER_MAJ_SHIFT		8
31
+
32
+/* the rng_type field */
33
+#define RNGC_TYPE_RNGB			0x1
34
+#define RNGC_TYPE_RNGC			0x2
35
+
3236 
3337 #define RNGC_CMD_CLR_ERR		0x00000020
3438 #define RNGC_CMD_CLR_INT		0x00000010
....@@ -37,6 +41,7 @@
3741 
3842 #define RNGC_CTRL_MASK_ERROR		0x00000040
3943 #define RNGC_CTRL_MASK_DONE		0x00000020
44
+#define RNGC_CTRL_AUTO_SEED		0x00000010
4045 
4146 #define RNGC_STATUS_ERROR		0x00010000
4247 #define RNGC_STATUS_FIFO_LEVEL_MASK	0x00000f00
....@@ -105,18 +110,12 @@
105110 	cmd = readl(rngc->base + RNGC_COMMAND);
106111 	writel(cmd | RNGC_CMD_SELF_TEST, rngc->base + RNGC_COMMAND);
107112 
108
-	ret = wait_for_completion_timeout(&rngc->rng_op_done, RNGC_TIMEOUT);
109
-	if (!ret) {
110
-		imx_rngc_irq_mask_clear(rngc);
113
+	ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
114
+	imx_rngc_irq_mask_clear(rngc);
115
+	if (!ret)
111116 		return -ETIMEDOUT;
112
-	}
113117 
114
-	if (rngc->err_reg != 0) {
115
-		imx_rngc_irq_mask_clear(rngc);
116
-		return -EIO;
117
-	}
118
-
119
-	return 0;
118
+	return rngc->err_reg ? -EIO : 0;
120119 }
121120 
122121 static int imx_rngc_read(struct hwrng *rng, void *data, size_t max, bool wait)
....@@ -173,47 +172,74 @@
173172 static int imx_rngc_init(struct hwrng *rng)
174173 {
175174 	struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng);
176
-	u32 cmd;
175
+	u32 cmd, ctrl;
177176 	int ret;
178177 
179178 	/* clear error */
180179 	cmd = readl(rngc->base + RNGC_COMMAND);
181180 	writel(cmd | RNGC_CMD_CLR_ERR, rngc->base + RNGC_COMMAND);
182181 
182
+	imx_rngc_irq_unmask(rngc);
183
+
183184 	/* create seed, repeat while there is some statistical error */
184185 	do {
185
-		imx_rngc_irq_unmask(rngc);
186
-
187186 		/* seed creation */
188187 		cmd = readl(rngc->base + RNGC_COMMAND);
189188 		writel(cmd | RNGC_CMD_SEED, rngc->base + RNGC_COMMAND);
190189 
191
-		ret = wait_for_completion_timeout(&rngc->rng_op_done,
192
-				RNGC_TIMEOUT);
193
-
190
+		ret = wait_for_completion_timeout(&rngc->rng_op_done, msecs_to_jiffies(RNGC_TIMEOUT));
194191 		if (!ret) {
195
-			imx_rngc_irq_mask_clear(rngc);
196
-			return -ETIMEDOUT;
192
+			ret = -ETIMEDOUT;
193
+			goto err;
197194 		}
198195 
199196 	} while (rngc->err_reg == RNGC_ERROR_STATUS_STAT_ERR);
200197 
201
-	return rngc->err_reg ? -EIO : 0;
198
+	if (rngc->err_reg) {
199
+		ret = -EIO;
200
+		goto err;
201
+	}
202
+
203
+	/*
204
+	 * enable automatic seeding, the rngc creates a new seed automatically
205
+	 * after serving 2^20 random 160-bit words
206
+	 */
207
+	ctrl = readl(rngc->base + RNGC_CONTROL);
208
+	ctrl |= RNGC_CTRL_AUTO_SEED;
209
+	writel(ctrl, rngc->base + RNGC_CONTROL);
210
+
211
+	/*
212
+	 * if initialisation was successful, we keep the interrupt
213
+	 * unmasked until imx_rngc_cleanup is called
214
+	 * we mask the interrupt ourselves if we return an error
215
+	 */
216
+	return 0;
217
+
218
+err:
219
+	imx_rngc_irq_mask_clear(rngc);
220
+	return ret;
221
+}
222
+
223
+static void imx_rngc_cleanup(struct hwrng *rng)
224
+{
225
+	struct imx_rngc *rngc = container_of(rng, struct imx_rngc, rng);
226
+
227
+	imx_rngc_irq_mask_clear(rngc);
202228 }
203229 
204230 static int imx_rngc_probe(struct platform_device *pdev)
205231 {
206232 	struct imx_rngc *rngc;
207
-	struct resource *res;
208233 	int ret;
209234 	int irq;
235
+	u32 ver_id;
236
+	u8  rng_type;
210237 
211238 	rngc = devm_kzalloc(&pdev->dev, sizeof(*rngc), GFP_KERNEL);
212239 	if (!rngc)
213240 		return -ENOMEM;
214241 
215
-	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
216
-	rngc->base = devm_ioremap_resource(&pdev->dev, res);
242
+	rngc->base = devm_platform_ioremap_resource(pdev, 0);
217243 	if (IS_ERR(rngc->base))
218244 		return PTR_ERR(rngc->base);
219245 
....@@ -233,10 +259,14 @@
233259 	if (ret)
234260 		return ret;
235261 
236
-	ret = devm_request_irq(&pdev->dev,
237
-			irq, imx_rngc_irq, 0, pdev->name, (void *)rngc);
238
-	if (ret) {
239
-		dev_err(rngc->dev, "Can't get interrupt working.\n");
262
+	ver_id = readl(rngc->base + RNGC_VER_ID);
263
+	rng_type = ver_id >> RNGC_TYPE_SHIFT;
264
+	/*
265
+	 * This driver supports only RNGC and RNGB. (There's a different
266
+	 * driver for RNGA.)
267
+	 */
268
+	if (rng_type != RNGC_TYPE_RNGC && rng_type != RNGC_TYPE_RNGB) {
269
+		ret = -ENODEV;
240270 		goto err;
241271 	}
242272 
....@@ -245,27 +275,39 @@
245275 	rngc->rng.name = pdev->name;
246276 	rngc->rng.init = imx_rngc_init;
247277 	rngc->rng.read = imx_rngc_read;
278
+	rngc->rng.cleanup = imx_rngc_cleanup;
279
+	rngc->rng.quality = 19;
248280 
249281 	rngc->dev = &pdev->dev;
250282 	platform_set_drvdata(pdev, rngc);
251283 
252284 	imx_rngc_irq_mask_clear(rngc);
253285 
286
+	ret = devm_request_irq(&pdev->dev,
287
+			irq, imx_rngc_irq, 0, pdev->name, (void *)rngc);
288
+	if (ret) {
289
+		dev_err(rngc->dev, "Can't get interrupt working.\n");
290
+		return ret;
291
+	}
292
+
254293 	if (self_test) {
255294 		ret = imx_rngc_self_test(rngc);
256295 		if (ret) {
257
-			dev_err(rngc->dev, "FSL RNGC self test failed.\n");
296
+			dev_err(rngc->dev, "self test failed\n");
258297 			goto err;
259298 		}
260299 	}
261300 
262301 	ret = hwrng_register(&rngc->rng);
263302 	if (ret) {
264
-		dev_err(&pdev->dev, "FSL RNGC registering failed (%d)\n", ret);
303
+		dev_err(&pdev->dev, "hwrng registration failed\n");
265304 		goto err;
266305 	}
267306 
268
-	dev_info(&pdev->dev, "Freescale RNGC registered.\n");
307
+	dev_info(&pdev->dev,
308
+		"Freescale RNG%c registered (HW revision %d.%02d)\n",
309
+		rng_type == RNGC_TYPE_RNGB ? 'B' : 'C',
310
+		(ver_id >> RNGC_VER_MAJ_SHIFT) & 0xff, ver_id & 0xff);
269311 	return 0;
270312 
271313 err: