staging: rtl8188eu: rename HalSetBrateCfg() - style
[linux/fpc-iii.git] / drivers / crypto / qcom-rng.c
blobe54249ccc009202973fcbaf4635ac563ab174cbf
1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2017-18 Linaro Limited
3 //
4 // Based on msm-rng.c and downstream driver
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>
14 /* Device specific register offsets */
15 #define PRNG_DATA_OUT 0x0000
16 #define PRNG_STATUS 0x0004
17 #define PRNG_LFSR_CFG 0x0100
18 #define PRNG_CONFIG 0x0104
20 /* Device specific register masks and config values */
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)
26 #define WORD_SZ 4
28 struct qcom_rng {
29 struct mutex lock;
30 void __iomem *base;
31 struct clk *clk;
32 unsigned int skip_init;
35 struct qcom_rng_ctx {
36 struct qcom_rng *rng;
39 static struct qcom_rng *qcom_rng_dev;
41 static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
43 unsigned int currsize = 0;
44 u32 val;
46 /* read random data from hardware */
47 do {
48 val = readl_relaxed(rng->base + PRNG_STATUS);
49 if (!(val & PRNG_STATUS_DATA_AVAIL))
50 break;
52 val = readl_relaxed(rng->base + PRNG_DATA_OUT);
53 if (!val)
54 break;
56 if ((max - currsize) >= WORD_SZ) {
57 memcpy(data, &val, WORD_SZ);
58 data += WORD_SZ;
59 currsize += WORD_SZ;
60 } else {
61 /* copy only remaining bytes */
62 memcpy(data, &val, max - currsize);
63 break;
65 } while (currsize < max);
67 return currsize;
70 static int qcom_rng_generate(struct crypto_rng *tfm,
71 const u8 *src, unsigned int slen,
72 u8 *dstn, unsigned int dlen)
74 struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm);
75 struct qcom_rng *rng = ctx->rng;
76 int ret;
78 ret = clk_prepare_enable(rng->clk);
79 if (ret)
80 return ret;
82 mutex_lock(&rng->lock);
84 ret = qcom_rng_read(rng, dstn, dlen);
86 mutex_unlock(&rng->lock);
87 clk_disable_unprepare(rng->clk);
89 return 0;
92 static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
93 unsigned int slen)
95 return 0;
98 static int qcom_rng_enable(struct qcom_rng *rng)
100 u32 val;
101 int ret;
103 ret = clk_prepare_enable(rng->clk);
104 if (ret)
105 return ret;
107 /* Enable PRNG only if it is not already enabled */
108 val = readl_relaxed(rng->base + PRNG_CONFIG);
109 if (val & PRNG_CONFIG_HW_ENABLE)
110 goto already_enabled;
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);
117 val = readl_relaxed(rng->base + PRNG_CONFIG);
118 val |= PRNG_CONFIG_HW_ENABLE;
119 writel(val, rng->base + PRNG_CONFIG);
121 already_enabled:
122 clk_disable_unprepare(rng->clk);
124 return 0;
127 static int qcom_rng_init(struct crypto_tfm *tfm)
129 struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm);
131 ctx->rng = qcom_rng_dev;
133 if (!ctx->rng->skip_init)
134 return qcom_rng_enable(ctx->rng);
136 return 0;
139 static 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,
154 static int qcom_rng_probe(struct platform_device *pdev)
156 struct resource *res;
157 struct qcom_rng *rng;
158 int ret;
160 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
161 if (!rng)
162 return -ENOMEM;
164 platform_set_drvdata(pdev, rng);
165 mutex_init(&rng->lock);
167 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
168 rng->base = devm_ioremap_resource(&pdev->dev, res);
169 if (IS_ERR(rng->base))
170 return PTR_ERR(rng->base);
172 /* ACPI systems have clk already on, so skip clk_get */
173 if (!has_acpi_companion(&pdev->dev)) {
174 rng->clk = devm_clk_get(&pdev->dev, "core");
175 if (IS_ERR(rng->clk))
176 return PTR_ERR(rng->clk);
180 rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev);
182 qcom_rng_dev = rng;
183 ret = crypto_register_rng(&qcom_rng_alg);
184 if (ret) {
185 dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);
186 qcom_rng_dev = NULL;
189 return ret;
192 static int qcom_rng_remove(struct platform_device *pdev)
194 crypto_unregister_rng(&qcom_rng_alg);
196 qcom_rng_dev = NULL;
198 return 0;
201 #if IS_ENABLED(CONFIG_ACPI)
202 static const struct acpi_device_id qcom_rng_acpi_match[] = {
203 { .id = "QCOM8160", .driver_data = 1 },
206 MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match);
207 #endif
209 static const struct of_device_id qcom_rng_of_match[] = {
210 { .compatible = "qcom,prng", .data = (void *)0},
211 { .compatible = "qcom,prng-ee", .data = (void *)1},
214 MODULE_DEVICE_TABLE(of, qcom_rng_of_match);
216 static struct platform_driver qcom_rng_driver = {
217 .probe = qcom_rng_probe,
218 .remove = qcom_rng_remove,
219 .driver = {
220 .name = KBUILD_MODNAME,
221 .of_match_table = of_match_ptr(qcom_rng_of_match),
222 .acpi_match_table = ACPI_PTR(qcom_rng_acpi_match),
225 module_platform_driver(qcom_rng_driver);
227 MODULE_ALIAS("platform:" KBUILD_MODNAME);
228 MODULE_DESCRIPTION("Qualcomm random number generator driver");
229 MODULE_LICENSE("GPL v2");