projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 3e90efd1 ZX |
1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* Copyright (c) 2019 HiSilicon Limited. */ | |
| 3 | ||
| 4 | #include <linux/acpi.h> | |
| 5 | #include <linux/err.h> | |
| 6 | #include <linux/hw_random.h> | |
| 7 | #include <linux/io.h> | |
| 8 | #include <linux/iopoll.h> | |
| 9 | #include <linux/kernel.h> | |
| 10 | #include <linux/module.h> | |
| 11 | #include <linux/platform_device.h> | |
| 12 | #include <linux/random.h> | |
| 13 | ||
| 14 | #define HISI_TRNG_REG 0x00F0 | |
| 15 | #define HISI_TRNG_BYTES 4 | |
| 16 | #define HISI_TRNG_QUALITY 512 | |
| 17 | #define SLEEP_US 10 | |
| 18 | #define TIMEOUT_US 10000 | |
| 19 | ||
| 20 | struct hisi_trng { | |
| 21 | void __iomem *base; | |
| 22 | struct hwrng rng; | |
| 23 | }; | |
| 24 | ||
| 25 | static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait) | |
| 26 | { | |
| 27 | struct hisi_trng *trng; | |
| 28 | int currsize = 0; | |
| 29 | u32 val = 0; | |
| 30 | u32 ret; | |
| 31 | ||
| 32 | trng = container_of(rng, struct hisi_trng, rng); | |
| 33 | ||
| 34 | do { | |
| 35 | ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val, | |
| 36 | val, SLEEP_US, TIMEOUT_US); | |
| 37 | if (ret) | |
| 38 | return currsize; | |
| 39 | ||
| 40 | if (max - currsize >= HISI_TRNG_BYTES) { | |
| 41 | memcpy(buf + currsize, &val, HISI_TRNG_BYTES); | |
| 42 | currsize += HISI_TRNG_BYTES; | |
| 43 | if (currsize == max) | |
| 44 | return currsize; | |
| 45 | continue; | |
| 46 | } | |
| 47 | ||
| 48 | /* copy remaining bytes */ | |
| 49 | memcpy(buf + currsize, &val, max - currsize); | |
| 50 | currsize = max; | |
| 51 | } while (currsize < max); | |
| 52 | ||
| 53 | return currsize; | |
| 54 | } | |
| 55 | ||
| 56 | static int hisi_trng_probe(struct platform_device *pdev) | |
| 57 | { | |
| 58 | struct hisi_trng *trng; | |
| 59 | int ret; | |
| 60 | ||
| 61 | trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL); | |
| 62 | if (!trng) | |
| 63 | return -ENOMEM; | |
| 64 | ||
| 65 | trng->base = devm_platform_ioremap_resource(pdev, 0); | |
| 66 | if (IS_ERR(trng->base)) | |
| 67 | return PTR_ERR(trng->base); | |
| 68 | ||
| 69 | trng->rng.name = pdev->name; | |
| 70 | trng->rng.read = hisi_trng_read; | |
| 71 | trng->rng.quality = HISI_TRNG_QUALITY; | |
| 72 | ||
| 73 | ret = devm_hwrng_register(&pdev->dev, &trng->rng); | |
| 74 | if (ret) | |
| 75 | dev_err(&pdev->dev, "failed to register hwrng!\n"); | |
| 76 | ||
| 77 | return ret; | |
| 78 | } | |
| 79 | ||
| 80 | static const struct acpi_device_id hisi_trng_acpi_match[] = { | |
| 81 | { "HISI02B3", 0 }, | |
| 82 | { } | |
| 83 | }; | |
| 84 | MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match); | |
| 85 | ||
| 86 | static struct platform_driver hisi_trng_driver = { | |
| 87 | .probe = hisi_trng_probe, | |
| 88 | .driver = { | |
| 89 | .name = "hisi-trng-v2", | |
| 90 | .acpi_match_table = ACPI_PTR(hisi_trng_acpi_match), | |
| 91 | }, | |
| 92 | }; | |
| 93 | ||
| 94 | module_platform_driver(hisi_trng_driver); | |
| 95 | ||
| 96 | MODULE_LICENSE("GPL v2"); | |
| 97 | MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>"); | |
| 98 | MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>"); | |
| 99 | MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver"); |