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70 lines
1.5 KiB
70 lines
1.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp. |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/module.h> |
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#include <linux/mod_devicetable.h> |
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#include <linux/kernel.h> |
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#include <linux/platform_device.h> |
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#include <linux/random.h> |
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#include <linux/hw_random.h> |
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static int powernv_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) |
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{ |
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unsigned long *buf; |
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int i, len; |
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/* We rely on rng_buffer_size() being >= sizeof(unsigned long) */ |
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len = max / sizeof(unsigned long); |
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buf = (unsigned long *)data; |
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for (i = 0; i < len; i++) |
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powernv_get_random_long(buf++); |
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return len * sizeof(unsigned long); |
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} |
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static struct hwrng powernv_hwrng = { |
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.name = "powernv-rng", |
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.read = powernv_rng_read, |
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}; |
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static int powernv_rng_probe(struct platform_device *pdev) |
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{ |
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int rc; |
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rc = devm_hwrng_register(&pdev->dev, &powernv_hwrng); |
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if (rc) { |
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/* We only register one device, ignore any others */ |
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if (rc == -EEXIST) |
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rc = -ENODEV; |
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return rc; |
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} |
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pr_info("Registered powernv hwrng.\n"); |
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return 0; |
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} |
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static const struct of_device_id powernv_rng_match[] = { |
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{ .compatible = "ibm,power-rng",}, |
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{}, |
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}; |
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MODULE_DEVICE_TABLE(of, powernv_rng_match); |
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static struct platform_driver powernv_rng_driver = { |
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.driver = { |
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.name = "powernv_rng", |
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.of_match_table = powernv_rng_match, |
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}, |
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.probe = powernv_rng_probe, |
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}; |
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module_platform_driver(powernv_rng_driver); |
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MODULE_LICENSE("GPL"); |
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MODULE_DESCRIPTION("Bare metal HWRNG driver for POWER7+ and above");
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