1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2017-18 Linaro Limited
4 // Based on msm-rng.c and downstream driver
6 #include <crypto/internal/rng.h>
7 #include <linux/acpi.h>
9 #include <linux/crypto.h>
10 #include <linux/iopoll.h>
11 #include <linux/module.h>
13 #include <linux/platform_device.h>
15 /* Device specific register offsets */
16 #define PRNG_DATA_OUT 0x0000
17 #define PRNG_STATUS 0x0004
18 #define PRNG_LFSR_CFG 0x0100
19 #define PRNG_CONFIG 0x0104
21 /* Device specific register masks and config values */
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)
33 unsigned int skip_init;
40 static struct qcom_rng *qcom_rng_dev;
42 static int qcom_rng_read(struct qcom_rng *rng, u8 *data, unsigned int max)
44 unsigned int currsize = 0;
48 /* read random data from hardware */
50 ret = readl_poll_timeout(rng->base + PRNG_STATUS, val,
51 val & PRNG_STATUS_DATA_AVAIL,
56 val = readl_relaxed(rng->base + PRNG_DATA_OUT);
60 if ((max - currsize) >= WORD_SZ) {
61 memcpy(data, &val, WORD_SZ);
65 /* copy only remaining bytes */
66 memcpy(data, &val, max - currsize);
68 } while (currsize < max);
73 static int qcom_rng_generate(struct crypto_rng *tfm,
74 const u8 *src, unsigned int slen,
75 u8 *dstn, unsigned int dlen)
77 struct qcom_rng_ctx *ctx = crypto_rng_ctx(tfm);
78 struct qcom_rng *rng = ctx->rng;
81 ret = clk_prepare_enable(rng->clk);
85 mutex_lock(&rng->lock);
87 ret = qcom_rng_read(rng, dstn, dlen);
89 mutex_unlock(&rng->lock);
90 clk_disable_unprepare(rng->clk);
95 static int qcom_rng_seed(struct crypto_rng *tfm, const u8 *seed,
101 static int qcom_rng_enable(struct qcom_rng *rng)
106 ret = clk_prepare_enable(rng->clk);
110 /* Enable PRNG only if it is not already enabled */
111 val = readl_relaxed(rng->base + PRNG_CONFIG);
112 if (val & PRNG_CONFIG_HW_ENABLE)
113 goto already_enabled;
115 val = readl_relaxed(rng->base + PRNG_LFSR_CFG);
116 val &= ~PRNG_LFSR_CFG_MASK;
117 val |= PRNG_LFSR_CFG_CLOCKS;
118 writel(val, rng->base + PRNG_LFSR_CFG);
120 val = readl_relaxed(rng->base + PRNG_CONFIG);
121 val |= PRNG_CONFIG_HW_ENABLE;
122 writel(val, rng->base + PRNG_CONFIG);
125 clk_disable_unprepare(rng->clk);
130 static int qcom_rng_init(struct crypto_tfm *tfm)
132 struct qcom_rng_ctx *ctx = crypto_tfm_ctx(tfm);
134 ctx->rng = qcom_rng_dev;
136 if (!ctx->rng->skip_init)
137 return qcom_rng_enable(ctx->rng);
142 static struct rng_alg qcom_rng_alg = {
143 .generate = qcom_rng_generate,
144 .seed = qcom_rng_seed,
147 .cra_name = "stdrng",
148 .cra_driver_name = "qcom-rng",
149 .cra_flags = CRYPTO_ALG_TYPE_RNG,
151 .cra_ctxsize = sizeof(struct qcom_rng_ctx),
152 .cra_module = THIS_MODULE,
153 .cra_init = qcom_rng_init,
157 static int qcom_rng_probe(struct platform_device *pdev)
159 struct resource *res;
160 struct qcom_rng *rng;
163 rng = devm_kzalloc(&pdev->dev, sizeof(*rng), GFP_KERNEL);
167 platform_set_drvdata(pdev, rng);
168 mutex_init(&rng->lock);
170 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
171 rng->base = devm_ioremap_resource(&pdev->dev, res);
172 if (IS_ERR(rng->base))
173 return PTR_ERR(rng->base);
175 /* ACPI systems have clk already on, so skip clk_get */
176 if (!has_acpi_companion(&pdev->dev)) {
177 rng->clk = devm_clk_get(&pdev->dev, "core");
178 if (IS_ERR(rng->clk))
179 return PTR_ERR(rng->clk);
183 rng->skip_init = (unsigned long)device_get_match_data(&pdev->dev);
186 ret = crypto_register_rng(&qcom_rng_alg);
188 dev_err(&pdev->dev, "Register crypto rng failed: %d\n", ret);
195 static int qcom_rng_remove(struct platform_device *pdev)
197 crypto_unregister_rng(&qcom_rng_alg);
204 #if IS_ENABLED(CONFIG_ACPI)
205 static const struct acpi_device_id qcom_rng_acpi_match[] = {
206 { .id = "QCOM8160", .driver_data = 1 },
209 MODULE_DEVICE_TABLE(acpi, qcom_rng_acpi_match);
212 static const struct of_device_id qcom_rng_of_match[] = {
213 { .compatible = "qcom,prng", .data = (void *)0},
214 { .compatible = "qcom,prng-ee", .data = (void *)1},
217 MODULE_DEVICE_TABLE(of, qcom_rng_of_match);
219 static struct platform_driver qcom_rng_driver = {
220 .probe = qcom_rng_probe,
221 .remove = qcom_rng_remove,
223 .name = KBUILD_MODNAME,
224 .of_match_table = of_match_ptr(qcom_rng_of_match),
225 .acpi_match_table = ACPI_PTR(qcom_rng_acpi_match),
228 module_platform_driver(qcom_rng_driver);
230 MODULE_ALIAS("platform:" KBUILD_MODNAME);
231 MODULE_DESCRIPTION("Qualcomm random number generator driver");
232 MODULE_LICENSE("GPL v2");