83 lines
1.8 KiB
C
83 lines
1.8 KiB
C
/*
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* Copyright 2013 Michael Ellerman, Guo Chao, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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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_remove(struct platform_device *pdev)
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{
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hwrng_unregister(&powernv_hwrng);
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return 0;
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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 = hwrng_register(&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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.remove = powernv_rng_remove,
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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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