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d319fe2a0a
We don't expect to get errors from the hypervisor when reading the rng, but if we do we should pass the error up to the hwrng driver. Otherwise the hwrng driver will continue calling us forever. Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
103 lines
2.7 KiB
C
103 lines
2.7 KiB
C
/*
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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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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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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_data_read(struct hwrng *rng, u32 *data)
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{
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int rc;
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rc = plpar_hcall(H_RANDOM, (unsigned long *)data);
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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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/* 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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.data_read = pseries_rng_data_read,
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};
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static int __init 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 int __exit pseries_rng_remove(struct vio_dev *dev)
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{
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hwrng_unregister(&pseries_rng);
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return 0;
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}
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static 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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printk(KERN_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 <mikey@neuling.org>");
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MODULE_DESCRIPTION("H/W RNG driver for IBM pSeries processors");
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