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