![Ohad Ben-Cohen](/assets/img/avatar_default.png)
Boot the remote processor only after setting up the virtqueues, and shut it down before deleting them. Remote processors should obey virtio status changes, and therefore not manipulate/trigger the virtqueues while the virtio driver isn't ready, but it's just safer not to rely on that (plus a vq access might already be inflight while a vdev status is changed). We also don't have yet status change notifications, but that's a temporary limitation. Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com> Cc: Brian Swetland <swetland@google.com> Cc: Iliyan Malchev <malchev@google.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Grant Likely <grant.likely@secretlab.ca> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Mark Grosen <mgrosen@ti.com> Cc: John Williams <john.williams@petalogix.com> Cc: Michal Simek <monstr@monstr.eu> Cc: Loic PALLARDY <loic.pallardy@stericsson.com> Cc: Ludovic BARRE <ludovic.barre@stericsson.com> Cc: Omar Ramirez Luna <omar.luna@linaro.org> Cc: Guzman Lugo Fernando <fernando.lugo@ti.com> Cc: Anna Suman <s-anna@ti.com> Cc: Clark Rob <rob@ti.com> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Saravana Kannan <skannan@codeaurora.org> Cc: David Brown <davidb@codeaurora.org> Cc: Kieran Bingham <kieranbingham@gmail.com> Cc: Tony Lindgren <tony@atomide.com>
300 lines
8 KiB
C
300 lines
8 KiB
C
/*
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* Remote processor messaging transport (OMAP platform-specific bits)
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*
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* Copyright (C) 2011 Texas Instruments, Inc.
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* Copyright (C) 2011 Google, Inc.
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*
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* Ohad Ben-Cohen <ohad@wizery.com>
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* Brian Swetland <swetland@google.com>
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*
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* This software is licensed under the terms of the GNU General Public
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* License version 2, as published by the Free Software Foundation, and
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* may be copied, distributed, and modified under those terms.
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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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#include <linux/export.h>
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#include <linux/remoteproc.h>
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#include <linux/rpmsg.h>
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#include <linux/virtio.h>
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#include <linux/virtio_config.h>
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#include <linux/virtio_ids.h>
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#include <linux/virtio_ring.h>
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#include <linux/err.h>
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#include <linux/kref.h>
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#include <linux/slab.h>
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#include "remoteproc_internal.h"
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/**
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* struct rproc_virtio_vq_info - virtqueue state
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* @vq_id: a unique index of this virtqueue (unique for this @rproc)
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* @rproc: handle to the remote processor
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*
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* Such a struct will be maintained for every virtqueue we're
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* using to communicate with the remote processor
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*/
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struct rproc_virtio_vq_info {
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__u16 vq_id;
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struct rproc *rproc;
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};
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/* kick the remote processor, and let it know which virtqueue to poke at */
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static void rproc_virtio_notify(struct virtqueue *vq)
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{
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struct rproc_virtio_vq_info *rpvq = vq->priv;
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struct rproc *rproc = rpvq->rproc;
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dev_dbg(rproc->dev, "kicking vq id: %d\n", rpvq->vq_id);
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rproc->ops->kick(rproc, rpvq->vq_id);
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}
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/**
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* rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
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* @rproc: handle to the remote processor
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* @vq_id: index of the signalled virtqueue
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*
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* This function should be called by the platform-specific rproc driver,
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* when the remote processor signals that a specific virtqueue has pending
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* messages available.
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*
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* Returns IRQ_NONE if no message was found in the @vq_id virtqueue,
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* and otherwise returns IRQ_HANDLED.
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*/
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irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id)
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{
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return vring_interrupt(0, rproc->rvdev->vq[vq_id]);
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}
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EXPORT_SYMBOL(rproc_vq_interrupt);
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static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
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unsigned id,
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void (*callback)(struct virtqueue *vq),
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const char *name)
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{
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struct rproc *rproc = vdev_to_rproc(vdev);
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struct rproc_vdev *rvdev = rproc->rvdev;
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struct rproc_virtio_vq_info *rpvq;
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struct virtqueue *vq;
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void *addr;
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int ret, len;
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rpvq = kmalloc(sizeof(*rpvq), GFP_KERNEL);
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if (!rpvq)
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return ERR_PTR(-ENOMEM);
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rpvq->rproc = rproc;
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rpvq->vq_id = id;
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addr = rvdev->vring[id].va;
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len = rvdev->vring[id].len;
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dev_dbg(rproc->dev, "vring%d: va %p qsz %d\n", id, addr, len);
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/*
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* Create the new vq, and tell virtio we're not interested in
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* the 'weak' smp barriers, since we're talking with a real device.
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*/
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vq = vring_new_virtqueue(len, AMP_VRING_ALIGN, vdev, false, addr,
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rproc_virtio_notify, callback, name);
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if (!vq) {
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dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);
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ret = -ENOMEM;
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goto free_rpvq;
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}
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rvdev->vq[id] = vq;
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vq->priv = rpvq;
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return vq;
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free_rpvq:
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kfree(rpvq);
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return ERR_PTR(ret);
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}
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static void rproc_virtio_del_vqs(struct virtio_device *vdev)
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{
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struct virtqueue *vq, *n;
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struct rproc *rproc = vdev_to_rproc(vdev);
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/* power down the remote processor before deleting vqs */
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rproc_shutdown(rproc);
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list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
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struct rproc_virtio_vq_info *rpvq = vq->priv;
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vring_del_virtqueue(vq);
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kfree(rpvq);
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}
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}
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static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
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struct virtqueue *vqs[],
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vq_callback_t *callbacks[],
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const char *names[])
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{
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struct rproc *rproc = vdev_to_rproc(vdev);
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int i, ret;
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/* we maintain two virtqueues per remote processor (for RX and TX) */
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if (nvqs != 2)
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return -EINVAL;
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for (i = 0; i < nvqs; ++i) {
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vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
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if (IS_ERR(vqs[i])) {
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ret = PTR_ERR(vqs[i]);
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goto error;
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}
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}
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/* now that the vqs are all set, boot the remote processor */
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ret = rproc_boot(rproc);
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if (ret) {
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dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
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goto error;
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}
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return 0;
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error:
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rproc_virtio_del_vqs(vdev);
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return ret;
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}
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/*
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* We don't support yet real virtio status semantics.
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*
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* The plan is to provide this via the VIRTIO HDR resource entry
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* which is part of the firmware: this way the remote processor
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* will be able to access the status values as set by us.
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*/
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static u8 rproc_virtio_get_status(struct virtio_device *vdev)
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{
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return 0;
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}
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static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
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{
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dev_dbg(&vdev->dev, "new status: %d\n", status);
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}
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static void rproc_virtio_reset(struct virtio_device *vdev)
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{
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dev_dbg(&vdev->dev, "reset !\n");
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}
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/* provide the vdev features as retrieved from the firmware */
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static u32 rproc_virtio_get_features(struct virtio_device *vdev)
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{
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struct rproc *rproc = vdev_to_rproc(vdev);
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/* we only support a single vdev device for now */
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return rproc->rvdev->dfeatures;
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}
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static void rproc_virtio_finalize_features(struct virtio_device *vdev)
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{
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struct rproc *rproc = vdev_to_rproc(vdev);
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/* Give virtio_ring a chance to accept features */
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vring_transport_features(vdev);
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/*
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* Remember the finalized features of our vdev, and provide it
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* to the remote processor once it is powered on.
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*
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* Similarly to the status field, we don't expose yet the negotiated
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* features to the remote processors at this point. This will be
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* fixed as part of a small resource table overhaul and then an
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* extension of the virtio resource entries.
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*/
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rproc->rvdev->gfeatures = vdev->features[0];
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}
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static struct virtio_config_ops rproc_virtio_config_ops = {
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.get_features = rproc_virtio_get_features,
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.finalize_features = rproc_virtio_finalize_features,
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.find_vqs = rproc_virtio_find_vqs,
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.del_vqs = rproc_virtio_del_vqs,
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.reset = rproc_virtio_reset,
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.set_status = rproc_virtio_set_status,
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.get_status = rproc_virtio_get_status,
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};
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/*
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* This function is called whenever vdev is released, and is responsible
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* to decrement the remote processor's refcount taken when vdev was
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* added.
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*
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* Never call this function directly; it will be called by the driver
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* core when needed.
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*/
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static void rproc_vdev_release(struct device *dev)
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{
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struct virtio_device *vdev = dev_to_virtio(dev);
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struct rproc *rproc = vdev_to_rproc(vdev);
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kref_put(&rproc->refcount, rproc_release);
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}
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/**
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* rproc_add_rpmsg_vdev() - create an rpmsg virtio device
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* @rproc: the rproc handle
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*
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* This function is called if virtio rpmsg support was found in the
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* firmware of the remote processor.
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*
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* Today we only support creating a single rpmsg vdev (virtio device),
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* but the plan is to remove this limitation. At that point this interface
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* will be revised/extended.
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*/
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int rproc_add_rpmsg_vdev(struct rproc *rproc)
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{
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struct device *dev = rproc->dev;
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struct rproc_vdev *rvdev = rproc->rvdev;
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int ret;
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rvdev->vdev.id.device = VIRTIO_ID_RPMSG,
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rvdev->vdev.config = &rproc_virtio_config_ops,
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rvdev->vdev.dev.parent = dev;
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rvdev->vdev.dev.release = rproc_vdev_release;
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/*
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* We're indirectly making a non-temporary copy of the rproc pointer
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* here, because drivers probed with this vdev will indirectly
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* access the wrapping rproc.
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*
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* Therefore we must increment the rproc refcount here, and decrement
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* it _only_ when the vdev is released.
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*/
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kref_get(&rproc->refcount);
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ret = register_virtio_device(&rvdev->vdev);
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if (ret) {
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kref_put(&rproc->refcount, rproc_release);
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dev_err(dev, "failed to register vdev: %d\n", ret);
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}
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return ret;
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}
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/**
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* rproc_remove_rpmsg_vdev() - remove an rpmsg vdev device
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* @rproc: the rproc handle
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*
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* This function is called whenever @rproc is removed _iff_ an rpmsg
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* vdev was created beforehand.
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*/
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void rproc_remove_rpmsg_vdev(struct rproc *rproc)
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{
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struct rproc_vdev *rvdev = rproc->rvdev;
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unregister_virtio_device(&rvdev->vdev);
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}
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