avr/qmk/ChibiOS - [no description]

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author	acirillo87 <acirillo87@35acf78f-673a-0410-8e92-d51de3d6d3f4>	2013-07-31 13:25:46 +0000
committer	acirillo87 <acirillo87@35acf78f-673a-0410-8e92-d51de3d6d3f4>	2013-07-31 13:25:46 +0000
commit	6acc48bc50785ef5d8eaf2fdf11ac229489edad9 (patch)
tree	41d196ee1d17d0a85b280a1a65e59206220612cb /docs
parent	16c83514ae6459e4ef2395ad22f32f1d8713a17b (diff)
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git-svn-id: svn://svn.code.sf.net/p/chibios/svn/trunk@6057 35acf78f-673a-0410-8e92-d51de3d6d3f4

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/* * Randomness driver for virtio * Copyright (C) 2007, 2008 Rusty Russell IBM Corporation * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA */ #include <linux/err.h> #include <linux/hw_random.h> #include <linux/scatterlist.h> #include <linux/spinlock.h> #include <linux/virtio.h> #include <linux/virtio_rng.h> static struct virtqueue *vq; static unsigned int data_avail; static DECLARE_COMPLETION(have_data); static bool busy; static void random_recv_done(struct virtqueue *vq) { /* We can get spurious callbacks, e.g. shared IRQs + virtio_pci. */ if (!virtqueue_get_buf(vq, &data_avail)) return; complete(&have_data); } /* The host will fill any buffer we give it with sweet, sweet randomness. */ static void register_buffer(u8 *buf, size_t size) { struct scatterlist sg; sg_init_one(&sg, buf, size); /* There should always be room for one buffer. */ if (virtqueue_add_buf(vq, &sg, 0, 1, buf) < 0) BUG(); virtqueue_kick(vq); } static int virtio_read(struct hwrng *rng, void *buf, size_t size, bool wait) { if (!busy) { busy = true; init_completion(&have_data); register_buffer(buf, size); } if (!wait) return 0; wait_for_completion(&have_data); busy = false; return data_avail; } static void virtio_cleanup(struct hwrng *rng) { if (busy) wait_for_completion(&have_data); } static struct hwrng virtio_hwrng = { .name = "virtio", .cleanup = virtio_cleanup, .read = virtio_read, }; static int virtrng_probe(struct virtio_device *vdev) { int err; /* We expect a single virtqueue. */ vq = virtio_find_single_vq(vdev, random_recv_done, "input"); if (IS_ERR(vq)) return PTR_ERR(vq); err = hwrng_register(&virtio_hwrng); if (err) { vdev->config->del_vqs(vdev); return err; } return 0; } static void __devexit virtrng_remove(struct virtio_device *vdev) { vdev->config->reset(vdev); hwrng_unregister(&virtio_hwrng); vdev->config->del_vqs(vdev); } static struct virtio_device_id id_table[] = { { VIRTIO_ID_RNG, VIRTIO_DEV_ANY_ID }, { 0 }, }; static struct virtio_driver virtio_rng_driver = { .driver.name = KBUILD_MODNAME, .driver.owner = THIS_MODULE, .id_table = id_table, .probe = virtrng_probe, .remove = __devexit_p(virtrng_remove), }; static int __init init(void) { return register_virtio_driver(&virtio_rng_driver); } static void __exit fini(void) { unregister_virtio_driver(&virtio_rng_driver); } module_init(init); module_exit(fini); MODULE_DEVICE_TABLE(virtio, id_table); MODULE_DESCRIPTION("Virtio random number driver"); MODULE_LICENSE("GPL");


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