remoteproc: remove the single rpmsg vdev limitation

Now that the resource table supports publishing a virtio device
in a single resource entry, firmware images can start supporting
more than a single vdev.

This patch removes the single vdev limitation of the remoteproc
framework so multi-vdev firmwares can be leveraged: VDEV resource
entries are parsed when the rproc is registered, and as a result
their vrings are set up and the virtio devices are registered
(and they go away when the rproc goes away).

Moreover, we no longer only support VIRTIO_ID_RPMSG vdevs; any
virtio device type goes now. As a result, there's no more any
rpmsg-specific APIs or code in remoteproc: it all becomes generic
virtio handling.
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>

Documentation/remoteproc.txt

@@ -20,6 +20,11 @@ platform-specific remoteproc drivers only need to provide a few low-level
 handlers, and then all rpmsg drivers will then just work
 (for more information about the virtio-based rpmsg bus and its drivers,
 please read Documentation/rpmsg.txt).
+Registration of other types of virtio devices is now also possible. Firmwares
+just need to publish what kind of virtio devices do they support, and then
+remoteproc will add those devices. This makes it possible to reuse the
+existing virtio drivers with remote processor backends at a minimal development
+cost.
 
 2. User API
 
@@ -136,8 +141,6 @@ int dummy_rproc_example(struct rproc *my_rproc)
       If found, those virtio devices will be created and added, so as a result
       of registering this remote processor, additional virtio drivers might get
       probed.
-      Currently, though, we only support a single RPMSG virtio vdev per remote
-      processor.
 
   int rproc_unregister(struct rproc *rproc)
     - Unregister a remote processor, and decrement its refcount.
@@ -174,7 +177,7 @@ struct rproc_ops {
 };
 
 Every remoteproc implementation should at least provide the ->start and ->stop
-handlers. If rpmsg functionality is also desired, then the ->kick handler
+handlers. If rpmsg/virtio functionality is also desired, then the ->kick handler
 should be provided as well.
 
 The ->start() handler takes an rproc handle and should then power on the

drivers/remoteproc/remoteproc_internal.h

@@ -28,9 +28,9 @@ struct rproc;
 void rproc_release(struct kref *kref);
 irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id);
 
-/* from remoteproc_rpmsg.c */
-int rproc_add_rpmsg_vdev(struct rproc *);
-void rproc_remove_rpmsg_vdev(struct rproc *rproc);
+/* from remoteproc_virtio.c */
+int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id);
+void rproc_remove_virtio_dev(struct rproc_vdev *rvdev);
 
 /* from remoteproc_debugfs.c */
 void rproc_remove_trace_file(struct dentry *tfile);

drivers/remoteproc/remoteproc_virtio.c

@@ -19,7 +19,6 @@
 
 #include <linux/export.h>
 #include <linux/remoteproc.h>
-#include <linux/rpmsg.h>
 #include <linux/virtio.h>
 #include <linux/virtio_config.h>
 #include <linux/virtio_ids.h>
@@ -30,45 +29,41 @@
 
 #include "remoteproc_internal.h"
 
-/**
- * struct rproc_virtio_vq_info - virtqueue state
- * @vq_id: a unique index of this virtqueue (unique for this @rproc)
- * @rproc: handle to the remote processor
- *
- * Such a struct will be maintained for every virtqueue we're
- * using to communicate with the remote processor
- */
-struct rproc_virtio_vq_info {
-	__u16 vq_id;
-	struct rproc *rproc;
-};
-
 /* kick the remote processor, and let it know which virtqueue to poke at */
 static void rproc_virtio_notify(struct virtqueue *vq)
 {
-	struct rproc_virtio_vq_info *rpvq = vq->priv;
-	struct rproc *rproc = rpvq->rproc;
+	struct rproc_vring *rvring = vq->priv;
+	struct rproc *rproc = rvring->rvdev->rproc;
+	int notifyid = rvring->notifyid;
 
-	dev_dbg(rproc->dev, "kicking vq id: %d\n", rpvq->vq_id);
+	dev_dbg(rproc->dev, "kicking vq index: %d\n", notifyid);
 
-	rproc->ops->kick(rproc, rpvq->vq_id);
+	rproc->ops->kick(rproc, notifyid);
 }
 
 /**
  * rproc_vq_interrupt() - tell remoteproc that a virtqueue is interrupted
  * @rproc: handle to the remote processor
- * @vq_id: index of the signalled virtqueue
+ * @notifyid: index of the signalled virtqueue (unique per this @rproc)
  *
  * This function should be called by the platform-specific rproc driver,
  * when the remote processor signals that a specific virtqueue has pending
  * messages available.
  *
- * Returns IRQ_NONE if no message was found in the @vq_id virtqueue,
+ * Returns IRQ_NONE if no message was found in the @notifyid virtqueue,
  * and otherwise returns IRQ_HANDLED.
  */
-irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int vq_id)
+irqreturn_t rproc_vq_interrupt(struct rproc *rproc, int notifyid)
 {
-	return vring_interrupt(0, rproc->rvdev->vq[vq_id]);
+	struct rproc_vring *rvring;
+
+	dev_dbg(rproc->dev, "vq index %d is interrupted\n", notifyid);
+
+	rvring = idr_find(&rproc->notifyids, notifyid);
+	if (!rvring || !rvring->vq)
+		return IRQ_NONE;
+
+	return vring_interrupt(0, rvring->vq);
 }
 EXPORT_SYMBOL(rproc_vq_interrupt);
 
@@ -77,24 +72,28 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
 				    void (*callback)(struct virtqueue *vq),
 				    const char *name)
 {
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 	struct rproc *rproc = vdev_to_rproc(vdev);
-	struct rproc_vdev *rvdev = rproc->rvdev;
-	struct rproc_virtio_vq_info *rpvq;
+	struct rproc_vring *rvring;
 	struct virtqueue *vq;
 	void *addr;
-	int ret, len;
+	int len, size;
 
-	rpvq = kmalloc(sizeof(*rpvq), GFP_KERNEL);
-	if (!rpvq)
-		return ERR_PTR(-ENOMEM);
+	/* we're temporarily limited to two virtqueues per rvdev */
+	if (id >= ARRAY_SIZE(rvdev->vring))
+		return ERR_PTR(-EINVAL);
+
+	rvring = &rvdev->vring[id];
 
-	rpvq->rproc = rproc;
-	rpvq->vq_id = id;
+	addr = rvring->va;
+	len = rvring->len;
 
-	addr = rvdev->vring[id].va;
-	len = rvdev->vring[id].len;
+	/* zero vring */
+	size = vring_size(len, rvring->align);
+	memset(addr, 0, size);
 
-	dev_dbg(rproc->dev, "vring%d: va %p qsz %d\n", id, addr, len);
+	dev_dbg(rproc->dev, "vring%d: va %p qsz %d notifyid %d\n",
+					id, addr, len, rvring->notifyid);
 
 	/*
 	 * Create the new vq, and tell virtio we're not interested in
@@ -104,32 +103,28 @@ static struct virtqueue *rp_find_vq(struct virtio_device *vdev,
 					rproc_virtio_notify, callback, name);
 	if (!vq) {
 		dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);
-		ret = -ENOMEM;
-		goto free_rpvq;
+		return ERR_PTR(-ENOMEM);
 	}
 
-	rvdev->vq[id] = vq;
-	vq->priv = rpvq;
+	rvring->vq = vq;
+	vq->priv = rvring;
 
 	return vq;
-
-free_rpvq:
-	kfree(rpvq);
-	return ERR_PTR(ret);
 }
 
 static void rproc_virtio_del_vqs(struct virtio_device *vdev)
 {
 	struct virtqueue *vq, *n;
 	struct rproc *rproc = vdev_to_rproc(vdev);
+	struct rproc_vring *rvring;
 
 	/* power down the remote processor before deleting vqs */
 	rproc_shutdown(rproc);
 
 	list_for_each_entry_safe(vq, n, &vdev->vqs, list) {
-		struct rproc_virtio_vq_info *rpvq = vq->priv;
+		rvring = vq->priv;
+		rvring->vq = NULL;
 		vring_del_virtqueue(vq);
-		kfree(rpvq);
 	}
 }
 
@@ -141,10 +136,6 @@ static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	struct rproc *rproc = vdev_to_rproc(vdev);
 	int i, ret;
 
-	/* we maintain two virtqueues per remote processor (for RX and TX) */
-	if (nvqs != 2)
-		return -EINVAL;
-
 	for (i = 0; i < nvqs; ++i) {
 		vqs[i] = rp_find_vq(vdev, i, callbacks[i], names[i]);
 		if (IS_ERR(vqs[i])) {
@@ -170,7 +161,7 @@ static int rproc_virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 /*
  * We don't support yet real virtio status semantics.
  *
- * The plan is to provide this via the VIRTIO HDR resource entry
+ * The plan is to provide this via the VDEV resource entry
  * which is part of the firmware: this way the remote processor
  * will be able to access the status values as set by us.
  */
@@ -181,7 +172,7 @@ static u8 rproc_virtio_get_status(struct virtio_device *vdev)
 
 static void rproc_virtio_set_status(struct virtio_device *vdev, u8 status)
 {
-	dev_dbg(&vdev->dev, "new status: %d\n", status);
+	dev_dbg(&vdev->dev, "status: %d\n", status);
 }
 
 static void rproc_virtio_reset(struct virtio_device *vdev)
@@ -192,15 +183,14 @@ static void rproc_virtio_reset(struct virtio_device *vdev)
 /* provide the vdev features as retrieved from the firmware */
 static u32 rproc_virtio_get_features(struct virtio_device *vdev)
 {
-	struct rproc *rproc = vdev_to_rproc(vdev);
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 
-	/* we only support a single vdev device for now */
-	return rproc->rvdev->dfeatures;
+	return rvdev->dfeatures;
 }
 
 static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 {
-	struct rproc *rproc = vdev_to_rproc(vdev);
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 
 	/* Give virtio_ring a chance to accept features */
 	vring_transport_features(vdev);
@@ -214,7 +204,7 @@ static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 	 * fixed as part of a small resource table overhaul and then an
 	 * extension of the virtio resource entries.
 	 */
-	rproc->rvdev->gfeatures = vdev->features[0];
+	rvdev->gfeatures = vdev->features[0];
 }
 
 static struct virtio_config_ops rproc_virtio_config_ops = {
@@ -244,26 +234,25 @@ static void rproc_vdev_release(struct device *dev)
 }
 
 /**
- * rproc_add_rpmsg_vdev() - create an rpmsg virtio device
- * @rproc: the rproc handle
+ * rproc_add_virtio_dev() - register an rproc-induced virtio device
+ * @rvdev: the remote vdev
  *
- * This function is called if virtio rpmsg support was found in the
- * firmware of the remote processor.
+ * This function registers a virtio device. This vdev's partent is
+ * the rproc device.
  *
- * Today we only support creating a single rpmsg vdev (virtio device),
- * but the plan is to remove this limitation. At that point this interface
- * will be revised/extended.
+ * Returns 0 on success or an appropriate error value otherwise.
  */
-int rproc_add_rpmsg_vdev(struct rproc *rproc)
+int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 {
+	struct rproc *rproc = rvdev->rproc;
 	struct device *dev = rproc->dev;
-	struct rproc_vdev *rvdev = rproc->rvdev;
+	struct virtio_device *vdev = &rvdev->vdev;
 	int ret;
 
-	rvdev->vdev.id.device	= VIRTIO_ID_RPMSG,
-	rvdev->vdev.config	= &rproc_virtio_config_ops,
-	rvdev->vdev.dev.parent	= dev;
-	rvdev->vdev.dev.release	= rproc_vdev_release;
+	vdev->id.device	= id,
+	vdev->config = &rproc_virtio_config_ops,
+	vdev->dev.parent = dev;
+	vdev->dev.release = rproc_vdev_release;
 
 	/*
 	 * We're indirectly making a non-temporary copy of the rproc pointer
@@ -275,25 +264,26 @@ int rproc_add_rpmsg_vdev(struct rproc *rproc)
 	 */
 	kref_get(&rproc->refcount);
 
-	ret = register_virtio_device(&rvdev->vdev);
+	ret = register_virtio_device(vdev);
 	if (ret) {
 		kref_put(&rproc->refcount, rproc_release);
 		dev_err(dev, "failed to register vdev: %d\n", ret);
+		goto out;
 	}
 
+	dev_info(dev, "registered %s (type %d)\n", dev_name(&vdev->dev), id);
+
+out:
 	return ret;
 }
 
 /**
- * rproc_remove_rpmsg_vdev() - remove an rpmsg vdev device
- * @rproc: the rproc handle
+ * rproc_remove_virtio_dev() - remove an rproc-induced virtio device
+ * @rvdev: the remote vdev
  *
- * This function is called whenever @rproc is removed _iff_ an rpmsg
- * vdev was created beforehand.
+ * This function unregisters an existing virtio device.
  */
-void rproc_remove_rpmsg_vdev(struct rproc *rproc)
+void rproc_remove_virtio_dev(struct rproc_vdev *rvdev)
 {
-	struct rproc_vdev *rvdev = rproc->rvdev;
-
 	unregister_virtio_device(&rvdev->vdev);
 }

include/linux/remoteproc.h

@@ -41,6 +41,7 @@
 #include <linux/mutex.h>
 #include <linux/virtio.h>
 #include <linux/completion.h>
+#include <linux/idr.h>
 
 /*
  * The alignment between the consumer and producer parts of the vring.
@@ -387,7 +388,8 @@ enum rproc_state {
  * @mappings: list of iommu mappings we initiated, needed on shutdown
  * @firmware_loading_complete: marks e/o asynchronous firmware loading
  * @bootaddr: address of first instruction to boot rproc with (optional)
- * @rvdev: virtio device (we only support a single rpmsg virtio device for now)
+ * @rvdevs: list of remote virtio devices
+ * @notifyids: idr for dynamically assigning rproc-wide unique notify ids
  */
 struct rproc {
 	struct klist_node node;
@@ -408,23 +410,47 @@ struct rproc {
 	struct list_head mappings;
 	struct completion firmware_loading_complete;
 	u32 bootaddr;
+	struct list_head rvdevs;
+	struct idr notifyids;
+};
+
+/* we currently support only two vrings per rvdev */
+#define RVDEV_NUM_VRINGS 2
+
+/**
+ * struct rproc_vring - remoteproc vring state
+ * @va:	virtual address
+ * @dma: dma address
+ * @len: length, in bytes
+ * @da: device address
+ * @notifyid: rproc-specific unique vring index
+ * @rvdev: remote vdev
+ * @vq: the virtqueue of this vring
+ */
+struct rproc_vring {
+	void *va;
+	dma_addr_t dma;
+	int len;
+	u32 da;
+	int notifyid;
 	struct rproc_vdev *rvdev;
+	struct virtqueue *vq;
 };
 
 /**
  * struct rproc_vdev - remoteproc state for a supported virtio device
+ * @node: list node
  * @rproc: the rproc handle
  * @vdev: the virio device
- * @vq: the virtqueues for this vdev
  * @vring: the vrings for this vdev
  * @dfeatures: virtio device features
  * @gfeatures: virtio guest features
  */
 struct rproc_vdev {
+	struct list_head node;
 	struct rproc *rproc;
 	struct virtio_device vdev;
-	struct virtqueue *vq[2];
-	struct rproc_mem_entry vring[2];
+	struct rproc_vring vring[RVDEV_NUM_VRINGS];
 	unsigned long dfeatures;
 	unsigned long gfeatures;
 };
@@ -442,9 +468,14 @@ int rproc_unregister(struct rproc *rproc);
 int rproc_boot(struct rproc *rproc);
 void rproc_shutdown(struct rproc *rproc);
 
+static inline struct rproc_vdev *vdev_to_rvdev(struct virtio_device *vdev)
+{
+	return container_of(vdev, struct rproc_vdev, vdev);
+}
+
 static inline struct rproc *vdev_to_rproc(struct virtio_device *vdev)
 {
-	struct rproc_vdev *rvdev = container_of(vdev, struct rproc_vdev, vdev);
+	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 
 	return rvdev->rproc;
 }