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5
6#include <crypto/internal/rng.h>
7#include <linux/acpi.h>
8#include <linux/clk.h>
9#include <linux/crypto.h>
10#include <linux/io.h>
11#include <linux/module.h>
12#include <linux/of.h>
13#include <linux/platform_device.h>
14
15
16#define PRNG_DATA_OUT 0x0000
17#define PRNG_STATUS 0x0004
18#define PRNG_LFSR_CFG 0x0100
19#define PRNG_CONFIG 0x0104
20
21
22#define PRNG_LFSR_CFG_MASK 0x0000ffff
23#define PRNG_LFSR_CFG_CLOCKS 0x0000dddd
24#define PRNG_CONFIG_HW_ENABLE BIT(1)
25#define PRNG_STATUS_DATA_AVAIL BIT(0)
26
27#define WORD_SZ 4
28
29struct qcom_rng {
30 struct mutex lock;
31 void __iomem *base;
32 struct clk *clk;
33 unsigned int skip_init;
34};
35
36struct qcom_rng_ctx {
37 struct qcom_rng *rng;
38};
39
40static struct qcom_rng *qcom_rng_dev;
41
42static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
43{
44 unsigned int currsize = 0;
45 u32 val;
46
47
48 do {
49 val = readl_relaxed(rng->base + PRNG_STATUS);
50 if (!(val & PRNG_STATUS_DATA_AVAIL))
51 break;
52
53 val = readl_relaxed(rng->base + PRNG_DATA_OUT);
54 if (!val)
55 break;
56
57 if ((max - currsize) >= WORD_SZ) {
58 memcpy(data, &val, WORD_SZ);
59 data += WORD_SZ;
60 currsize += WORD_SZ;
61 } else {
62
63 memcpy(data, &val, max - currsize);
64 break;
65 }
66 } while (currsize < max);
67
68 return currsize;
69}
70
71static int qcom_rng_generate(struct crypto_rng *tfm,
72 const u8 *src, unsigned int slen,
73 u8 *dstn, unsigned int dlen)
74{
75 struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm);
76 struct qcom_rng *rng = ctx->rng;
77 int ret;
78
79 ret = clk_prepare_enable(rng->clk);
80 if (ret)
81 return ret;
82
83 mutex_lock(&rng->lock);
84
85 ret = qcom_rng_read(rng, dstn, dlen);
86
87 mutex_unlock(&rng->lock);
88 clk_disable_unprepare(rng->clk);
89
90 return 0;
91}
92
93static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
94 unsigned int slen)
95{
96 return 0;
97}
98
99static int qcom_rng_enable(struct qcom_rng *rng)
100{
101 u32 val;
102 int ret;
103
104 ret = clk_prepare_enable(rng->clk);
105 if (ret)
106 return ret;
107
108
109 val = readl_relaxed(rng->base + PRNG_CONFIG);
110 if (val & PRNG_CONFIG_HW_ENABLE)
111 goto already_enabled;
112
113 val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
114 val &= ~PRNG_LFSR_CFG_MASK;
115 val |= PRNG_LFSR_CFG_CLOCKS;
116 writel(val, rng->base + PRNG_LFSR_CFG);
117
118 val = readl_relaxed(rng->base + PRNG_CONFIG);
119 val |= PRNG_CONFIG_HW_ENABLE;
120 writel(val, rng->base + PRNG_CONFIG);
121
122already_enabled:
123 clk_disable_unprepare(rng->clk);
124
125 return 0;
126}
127
128static int qcom_rng_init(struct crypto_tfm *tfm)
129{
130 struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm);
131
132 ctx->rng = qcom_rng_dev;
133
134 if (!ctx->rng->skip_init)
135 return qcom_rng_enable(ctx->rng);
136
137 return 0;
138}
139
140static struct rng_alg qcom_rng_alg = {
141 .generate = qcom_rng_generate,
142 .seed = qcom_rng_seed,
143 .seedsize = 0,
144 .base = {
145 .cra_name = "stdrng",
146 .cra_driver_name = "qcom-rng",
147 .cra_flags = CRYPTO_ALG_TYPE_RNG,
148 .cra_priority = 300,
149 .cra_ctxsize = sizeof(struct qcom_rng_ctx),
150 .cra_module = THIS_MODULE,
151 .cra_init = qcom_rng_init,
152 }
153};
154
155static int qcom_rng_probe(struct platform_device *pdev)
156{
157 struct qcom_rng *rng;
158 int ret;
159
160 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
161 if (!rng)
162 return -ENOMEM;
163
164 platform_set_drvdata(pdev, rng);
165 mutex_init(&rng->lock);
166
167 rng->base = devm_platform_ioremap_resource(pdev, 0);
168 if (IS_ERR(rng->base))
169 return PTR_ERR(rng->base);
170
171
172 if (!has_acpi_companion(&pdev->dev)) {
173 rng->clk = devm_clk_get(&pdev->dev, "core");
174 if (IS_ERR(rng->clk))
175 return PTR_ERR(rng->clk);
176 }
177
178
179 rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev);
180
181 qcom_rng_dev = rng;
182 ret = crypto_register_rng(&qcom_rng_alg);
183 if (ret) {
184 dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);
185 qcom_rng_dev = NULL;
186 }
187
188 return ret;
189}
190
191static int qcom_rng_remove(struct platform_device *pdev)
192{
193 crypto_unregister_rng(&qcom_rng_alg);
194
195 qcom_rng_dev = NULL;
196
197 return 0;
198}
199
200#if IS_ENABLED(CONFIG_ACPI)
201static const struct acpi_device_id qcom_rng_acpi_match[] = {
202 { .id = "QCOM8160", .driver_data = 1 },
203 {}
204};
205MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match);
206#endif
207
208static const struct of_device_id qcom_rng_of_match[] = {
209 { .compatible = "qcom,prng", .data = (void *)0},
210 { .compatible = "qcom,prng-ee", .data = (void *)1},
211 {}
212};
213MODULE_DEVICE_TABLE(of, qcom_rng_of_match);
214
215static struct platform_driver qcom_rng_driver = {
216 .probe = qcom_rng_probe,
217 .remove = qcom_rng_remove,
218 .driver = {
219 .name = KBUILD_MODNAME,
220 .of_match_table = of_match_ptr(qcom_rng_of_match),
221 .acpi_match_table = ACPI_PTR(qcom_rng_acpi_match),
222 }
223};
224module_platform_driver(qcom_rng_driver);
225
226MODULE_ALIAS("platform:" KBUILD_MODNAME);
227MODULE_DESCRIPTION("Qualcomm random number generator driver");
228MODULE_LICENSE("GPL v2");
229
