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92 lines
2.2 KiB
92 lines
2.2 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2010 Michael Neuling IBM Corporation |
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* |
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* Driver for the pseries hardware RNG for POWER7+ and above |
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*/ |
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/hw_random.h> |
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#include <asm/vio.h> |
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static int pseries_rng_read(struct hwrng *rng, void *data, size_t max, bool wait) |
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{ |
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u64 buffer[PLPAR_HCALL_BUFSIZE]; |
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int rc; |
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rc = plpar_hcall(H_RANDOM, (unsigned long *)buffer); |
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if (rc != H_SUCCESS) { |
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pr_err_ratelimited("H_RANDOM call failed %d\n", rc); |
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return -EIO; |
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} |
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memcpy(data, buffer, 8); |
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/* The hypervisor interface returns 64 bits */ |
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return 8; |
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} |
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/* |
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* pseries_rng_get_desired_dma - Return desired DMA allocate for CMO operations |
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* |
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* This is a required function for a driver to operate in a CMO environment |
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* but this device does not make use of DMA allocations, return 0. |
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* |
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* Return value: |
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* Number of bytes of IO data the driver will need to perform well -> 0 |
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*/ |
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static unsigned long pseries_rng_get_desired_dma(struct vio_dev *vdev) |
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{ |
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return 0; |
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}; |
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static struct hwrng pseries_rng = { |
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.name = KBUILD_MODNAME, |
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.read = pseries_rng_read, |
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}; |
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static int pseries_rng_probe(struct vio_dev *dev, |
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const struct vio_device_id *id) |
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{ |
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return hwrng_register(&pseries_rng); |
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} |
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static void pseries_rng_remove(struct vio_dev *dev) |
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{ |
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hwrng_unregister(&pseries_rng); |
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} |
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static const struct vio_device_id pseries_rng_driver_ids[] = { |
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{ "ibm,random-v1", "ibm,random"}, |
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{ "", "" } |
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}; |
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MODULE_DEVICE_TABLE(vio, pseries_rng_driver_ids); |
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static struct vio_driver pseries_rng_driver = { |
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.name = KBUILD_MODNAME, |
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.probe = pseries_rng_probe, |
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.remove = pseries_rng_remove, |
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.get_desired_dma = pseries_rng_get_desired_dma, |
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.id_table = pseries_rng_driver_ids |
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}; |
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static int __init rng_init(void) |
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{ |
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pr_info("Registering IBM pSeries RNG driver\n"); |
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return vio_register_driver(&pseries_rng_driver); |
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} |
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module_init(rng_init); |
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static void __exit rng_exit(void) |
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{ |
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vio_unregister_driver(&pseries_rng_driver); |
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} |
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module_exit(rng_exit); |
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MODULE_LICENSE("GPL"); |
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MODULE_AUTHOR("Michael Neuling <[email protected]>"); |
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MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");
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