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1 | // SPDX-License-Identifier: GPL-2.0 |
2 | // Copyright (c) 2017-18 Linaro Limited | |
3 | // | |
4 | // Based on msm-rng.c and downstream driver | |
5 | ||
6 | #include <crypto/internal/rng.h> | |
d96542ac | 7 | #include <linux/acpi.h> |
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8 | #include <linux/clk.h> |
9 | #include <linux/crypto.h> | |
0c3dc787 | 10 | #include <linux/io.h> |
a680b183 | 11 | #include <linux/iopoll.h> |
882aa652 | 12 | #include <linux/kernel.h> |
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13 | #include <linux/module.h> |
14 | #include <linux/of.h> | |
15 | #include <linux/platform_device.h> | |
16 | ||
17 | /* Device specific register offsets */ | |
18 | #define PRNG_DATA_OUT 0x0000 | |
19 | #define PRNG_STATUS 0x0004 | |
20 | #define PRNG_LFSR_CFG 0x0100 | |
21 | #define PRNG_CONFIG 0x0104 | |
22 | ||
23 | /* Device specific register masks and config values */ | |
24 | #define PRNG_LFSR_CFG_MASK 0x0000ffff | |
25 | #define PRNG_LFSR_CFG_CLOCKS 0x0000dddd | |
26 | #define PRNG_CONFIG_HW_ENABLE BIT(1) | |
27 | #define PRNG_STATUS_DATA_AVAIL BIT(0) | |
28 | ||
29 | #define WORD_SZ 4 | |
30 | ||
31 | struct qcom_rng { | |
32 | struct mutex lock; | |
33 | void __iomem *base; | |
34 | struct clk *clk; | |
ba3ab637 | 35 | unsigned int skip_init; |
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36 | }; |
37 | ||
38 | struct qcom_rng_ctx { | |
39 | struct qcom_rng *rng; | |
40 | }; | |
41 | ||
42 | static struct qcom_rng *qcom_rng_dev; | |
43 | ||
44 | static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max) | |
45 | { | |
46 | unsigned int currsize = 0; | |
47 | u32 val; | |
a680b183 | 48 | int ret; |
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49 | |
50 | /* read random data from hardware */ | |
51 | do { | |
a680b183 BM |
52 | ret = readl_poll_timeout(rng->base + PRNG_STATUS, val, |
53 | val & PRNG_STATUS_DATA_AVAIL, | |
54 | 200, 10000); | |
55 | if (ret) | |
56 | return ret; | |
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57 | |
58 | val = readl_relaxed(rng->base + PRNG_DATA_OUT); | |
59 | if (!val) | |
a680b183 | 60 | return -EINVAL; |
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61 | |
62 | if ((max - currsize) >= WORD_SZ) { | |
63 | memcpy(data, &val, WORD_SZ); | |
64 | data += WORD_SZ; | |
65 | currsize += WORD_SZ; | |
66 | } else { | |
67 | /* copy only remaining bytes */ | |
68 | memcpy(data, &val, max - currsize); | |
16287397 | 69 | break; |
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70 | } |
71 | } while (currsize < max); | |
72 | ||
a680b183 | 73 | return 0; |
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74 | } |
75 | ||
76 | static int qcom_rng_generate(struct crypto_rng *tfm, | |
77 | const u8 *src, unsigned int slen, | |
78 | u8 *dstn, unsigned int dlen) | |
79 | { | |
80 | struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm); | |
81 | struct qcom_rng *rng = ctx->rng; | |
82 | int ret; | |
83 | ||
84 | ret = clk_prepare_enable(rng->clk); | |
85 | if (ret) | |
86 | return ret; | |
87 | ||
88 | mutex_lock(&rng->lock); | |
89 | ||
90 | ret = qcom_rng_read(rng, dstn, dlen); | |
91 | ||
92 | mutex_unlock(&rng->lock); | |
93 | clk_disable_unprepare(rng->clk); | |
94 | ||
a680b183 | 95 | return ret; |
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96 | } |
97 | ||
98 | static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed, | |
99 | unsigned int slen) | |
100 | { | |
101 | return 0; | |
102 | } | |
103 | ||
104 | static int qcom_rng_enable(struct qcom_rng *rng) | |
105 | { | |
106 | u32 val; | |
107 | int ret; | |
108 | ||
109 | ret = clk_prepare_enable(rng->clk); | |
110 | if (ret) | |
111 | return ret; | |
112 | ||
113 | /* Enable PRNG only if it is not already enabled */ | |
114 | val = readl_relaxed(rng->base + PRNG_CONFIG); | |
115 | if (val & PRNG_CONFIG_HW_ENABLE) | |
116 | goto already_enabled; | |
117 | ||
118 | val = readl_relaxed(rng->base + PRNG_LFSR_CFG); | |
119 | val &= ~PRNG_LFSR_CFG_MASK; | |
120 | val |= PRNG_LFSR_CFG_CLOCKS; | |
121 | writel(val, rng->base + PRNG_LFSR_CFG); | |
122 | ||
123 | val = readl_relaxed(rng->base + PRNG_CONFIG); | |
124 | val |= PRNG_CONFIG_HW_ENABLE; | |
125 | writel(val, rng->base + PRNG_CONFIG); | |
126 | ||
127 | already_enabled: | |
128 | clk_disable_unprepare(rng->clk); | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static int qcom_rng_init(struct crypto_tfm *tfm) | |
134 | { | |
135 | struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm); | |
136 | ||
137 | ctx->rng = qcom_rng_dev; | |
138 | ||
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139 | if (!ctx->rng->skip_init) |
140 | return qcom_rng_enable(ctx->rng); | |
141 | ||
142 | return 0; | |
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143 | } |
144 | ||
145 | static struct rng_alg qcom_rng_alg = { | |
146 | .generate = qcom_rng_generate, | |
147 | .seed = qcom_rng_seed, | |
148 | .seedsize = 0, | |
149 | .base = { | |
150 | .cra_name = "stdrng", | |
151 | .cra_driver_name = "qcom-rng", | |
152 | .cra_flags = CRYPTO_ALG_TYPE_RNG, | |
153 | .cra_priority = 300, | |
154 | .cra_ctxsize = sizeof(struct qcom_rng_ctx), | |
155 | .cra_module = THIS_MODULE, | |
156 | .cra_init = qcom_rng_init, | |
157 | } | |
158 | }; | |
159 | ||
160 | static int qcom_rng_probe(struct platform_device *pdev) | |
161 | { | |
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162 | struct qcom_rng *rng; |
163 | int ret; | |
164 | ||
165 | rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL); | |
166 | if (!rng) | |
167 | return -ENOMEM; | |
168 | ||
169 | platform_set_drvdata(pdev, rng); | |
170 | mutex_init(&rng->lock); | |
171 | ||
2229c740 | 172 | rng->base = devm_platform_ioremap_resource(pdev, 0); |
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173 | if (IS_ERR(rng->base)) |
174 | return PTR_ERR(rng->base); | |
175 | ||
d96542ac TT |
176 | /* ACPI systems have clk already on, so skip clk_get */ |
177 | if (!has_acpi_companion(&pdev->dev)) { | |
178 | rng->clk = devm_clk_get(&pdev->dev, "core"); | |
179 | if (IS_ERR(rng->clk)) | |
180 | return PTR_ERR(rng->clk); | |
181 | } | |
182 | ||
ceec5f5b | 183 | |
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184 | rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev); |
185 | ||
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186 | qcom_rng_dev = rng; |
187 | ret = crypto_register_rng(&qcom_rng_alg); | |
188 | if (ret) { | |
189 | dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret); | |
190 | qcom_rng_dev = NULL; | |
191 | } | |
192 | ||
193 | return ret; | |
194 | } | |
195 | ||
196 | static int qcom_rng_remove(struct platform_device *pdev) | |
197 | { | |
198 | crypto_unregister_rng(&qcom_rng_alg); | |
199 | ||
200 | qcom_rng_dev = NULL; | |
201 | ||
202 | return 0; | |
203 | } | |
204 | ||
882aa652 | 205 | static const struct acpi_device_id __maybe_unused qcom_rng_acpi_match[] = { |
d96542ac TT |
206 | { .id = "QCOM8160", .driver_data = 1 }, |
207 | {} | |
208 | }; | |
209 | MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match); | |
d96542ac | 210 | |
882aa652 | 211 | static const struct of_device_id __maybe_unused qcom_rng_of_match[] = { |
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212 | { .compatible = "qcom,prng", .data = (void *)0}, |
213 | { .compatible = "qcom,prng-ee", .data = (void *)1}, | |
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214 | {} |
215 | }; | |
216 | MODULE_DEVICE_TABLE(of, qcom_rng_of_match); | |
217 | ||
218 | static struct platform_driver qcom_rng_driver = { | |
219 | .probe = qcom_rng_probe, | |
220 | .remove = qcom_rng_remove, | |
221 | .driver = { | |
222 | .name = KBUILD_MODNAME, | |
223 | .of_match_table = of_match_ptr(qcom_rng_of_match), | |
d96542ac | 224 | .acpi_match_table = ACPI_PTR(qcom_rng_acpi_match), |
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225 | } |
226 | }; | |
227 | module_platform_driver(qcom_rng_driver); | |
228 | ||
229 | MODULE_ALIAS("platform:" KBUILD_MODNAME); | |
230 | MODULE_DESCRIPTION("Qualcomm random number generator driver"); | |
231 | MODULE_LICENSE("GPL v2"); |