100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2019 HiSilicon Limited. */
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#include <linux/acpi.h>
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#include <linux/err.h>
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#include <linux/hw_random.h>
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#include <linux/io.h>
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#include <linux/iopoll.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/platform_device.h>
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#include <linux/random.h>
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#define HISI_TRNG_REG 0x00F0
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#define HISI_TRNG_BYTES 4
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#define HISI_TRNG_QUALITY 512
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#define SLEEP_US 10
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#define TIMEOUT_US 10000
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struct hisi_trng {
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void __iomem *base;
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struct hwrng rng;
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};
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static int hisi_trng_read(struct hwrng *rng, void *buf, size_t max, bool wait)
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{
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struct hisi_trng *trng;
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int currsize = 0;
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u32 val = 0;
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u32 ret;
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trng = container_of(rng, struct hisi_trng, rng);
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do {
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ret = readl_poll_timeout(trng->base + HISI_TRNG_REG, val,
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val, SLEEP_US, TIMEOUT_US);
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if (ret)
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return currsize;
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if (max - currsize >= HISI_TRNG_BYTES) {
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memcpy(buf + currsize, &val, HISI_TRNG_BYTES);
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currsize += HISI_TRNG_BYTES;
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if (currsize == max)
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return currsize;
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continue;
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}
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/* copy remaining bytes */
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memcpy(buf + currsize, &val, max - currsize);
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currsize = max;
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} while (currsize < max);
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return currsize;
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}
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static int hisi_trng_probe(struct platform_device *pdev)
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{
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struct hisi_trng *trng;
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int ret;
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trng = devm_kzalloc(&pdev->dev, sizeof(*trng), GFP_KERNEL);
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if (!trng)
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return -ENOMEM;
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trng->base = devm_platform_ioremap_resource(pdev, 0);
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if (IS_ERR(trng->base))
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return PTR_ERR(trng->base);
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trng->rng.name = pdev->name;
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trng->rng.read = hisi_trng_read;
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trng->rng.quality = HISI_TRNG_QUALITY;
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ret = devm_hwrng_register(&pdev->dev, &trng->rng);
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if (ret)
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dev_err(&pdev->dev, "failed to register hwrng!\n");
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return ret;
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}
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static const struct acpi_device_id hisi_trng_acpi_match[] = {
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{ "HISI02B3", 0 },
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{ }
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};
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MODULE_DEVICE_TABLE(acpi, hisi_trng_acpi_match);
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static struct platform_driver hisi_trng_driver = {
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.probe = hisi_trng_probe,
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.driver = {
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.name = "hisi-trng-v2",
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.acpi_match_table = ACPI_PTR(hisi_trng_acpi_match),
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},
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};
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module_platform_driver(hisi_trng_driver);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR("Weili Qian <qianweili@huawei.com>");
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MODULE_AUTHOR("Zaibo Xu <xuzaibo@huawei.com>");
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MODULE_DESCRIPTION("HiSilicon true random number generator V2 driver");
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