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>

3 files changed, 218 insertions, 220 deletions

diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
index 10348451c6c9..ca02f128b435 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -52,8 +52,8 @@ static void klist_rproc_put(struct klist_node *n);
  * We need this in order to support name-based lookups (needed by the
  * rproc_get_by_name()).
  *
- * That said, we don't use rproc_get_by_name() anymore within the rpmsg
- * framework. The use cases that do require its existence should be
+ * That said, we don't use rproc_get_by_name() at this point.
+ * The use cases that do require its existence should be
  * scrutinized, and hopefully migrated to rproc_boot() using device-based
  * binding.
  *
@@ -279,80 +279,112 @@ rproc_load_segments(struct rproc *rproc, const u8 *elf_data, size_t len)
         return ret;
 }
 
-/**
- * rproc_handle_early_vdev() - early handle a virtio header resource
- * @rproc: the remote processor
- * @rsc: the resource descriptor
- * @avail: size of available data (for sanity checking the image)
- *
- * The existence of this virtio hdr resource entry means that the firmware
- * of this @rproc supports this virtio device.
- *
- * Currently we support only a single virtio device of type VIRTIO_ID_RPMSG,
- * but the plan is to remove this limitation and support any number
- * of virtio devices (and of any type). We'll also add support for dynamically
- * adding (and removing) virtio devices over the rpmsg bus, but simple
- * firmwares that doesn't want to get involved with rpmsg will be able
- * to simply use the resource table for this.
- *
- * Returns 0 on success, or an appropriate error code otherwise
- */
-static int rproc_handle_early_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
-                                                                int avail)
+static int
+__rproc_handle_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
 {
-        struct rproc_vdev *rvdev;
+        struct rproc *rproc = rvdev->rproc;
+        struct device *dev = rproc->dev;
+        struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
+        dma_addr_t dma;
+        void *va;
+        int ret, size, notifyid;
 
-        /* make sure resource isn't truncated */
-        if (sizeof(*rsc) > avail) {
-                dev_err(rproc->dev, "vdev rsc is truncated\n");
+        dev_dbg(dev, "vdev rsc: vring%d: da %x, qsz %d, align %d\n",
+                                i, vring->da, vring->num, vring->align);
+
+        /* make sure reserved bytes are zeroes */
+        if (vring->reserved) {
+                dev_err(dev, "vring rsc has non zero reserved bytes\n");
                 return -EINVAL;
         }
 
-        /* we only support VIRTIO_ID_RPMSG devices for now */
-        if (rsc->id != VIRTIO_ID_RPMSG) {
-                dev_warn(rproc->dev, "unsupported vdev: %d\n", rsc->id);
+        /* the firmware must provide the expected queue size */
+        if (!vring->num) {
+                dev_err(dev, "invalid qsz (%d)\n", vring->num);
                 return -EINVAL;
         }
 
-        /* we only support a single vdev per rproc for now */
-        if (rproc->rvdev) {
-                dev_warn(rproc->dev, "redundant vdev entry\n");
+        /* actual size of vring (in bytes) */
+        size = PAGE_ALIGN(vring_size(vring->num, AMP_VRING_ALIGN));
+
+        if (!idr_pre_get(&rproc->notifyids, GFP_KERNEL)) {
+                dev_err(dev, "idr_pre_get failed\n");
+                return -ENOMEM;
+        }
+
+        /*
+         * Allocate non-cacheable memory for the vring. In the future
+         * this call will also configure the IOMMU for us
+         */
+        va = dma_alloc_coherent(dev, size, &dma, GFP_KERNEL);
+        if (!va) {
+                dev_err(dev, "dma_alloc_coherent failed\n");
                 return -EINVAL;
         }
 
-        rvdev = kzalloc(sizeof(struct rproc_vdev), GFP_KERNEL);
-        if (!rvdev)
-                return -ENOMEM;
+        /* assign an rproc-wide unique index for this vring */
+        /* TODO: assign a notifyid for rvdev updates as well */
+        ret = idr_get_new(&rproc->notifyids, &rvdev->vring[i], &notifyid);
+        if (ret) {
+                dev_err(dev, "idr_get_new failed: %d\n", ret);
+                dma_free_coherent(dev, size, va, dma);
+                return ret;
+        }
 
-        /* remember the device features */
-        rvdev->dfeatures = rsc->dfeatures;
+        /* let the rproc know the da and notifyid of this vring */
+        /* TODO: expose this to remote processor */
+        vring->da = dma;
+        vring->notifyid = notifyid;
 
-        rproc->rvdev = rvdev;
-        rvdev->rproc = rproc;
+        dev_dbg(dev, "vring%d: va %p dma %x size %x idr %d\n", i, va,
+                                        dma, size, notifyid);
+
+        rvdev->vring[i].len = vring->num;
+        rvdev->vring[i].va = va;
+        rvdev->vring[i].dma = dma;
+        rvdev->vring[i].notifyid = notifyid;
+        rvdev->vring[i].rvdev = rvdev;
 
         return 0;
 }
 
+static void __rproc_free_vrings(struct rproc_vdev *rvdev, int i)
+{
+        struct rproc *rproc = rvdev->rproc;
+
+        for (i--; i > 0; i--) {
+                struct rproc_vring *rvring = &rvdev->vring[i];
+                int size = PAGE_ALIGN(vring_size(rvring->len, AMP_VRING_ALIGN));
+
+                dma_free_coherent(rproc->dev, size, rvring->va, rvring->dma);
+                idr_remove(&rproc->notifyids, rvring->notifyid);
+        }
+}
+
 /**
  * rproc_handle_vdev() - handle a vdev fw resource
  * @rproc: the remote processor
  * @rsc: the vring resource descriptor
  * @avail: size of available data (for sanity checking the image)
  *
- * This resource entry requires allocation of non-cacheable memory
- * for a virtio vring. Currently we only support two vrings per remote
- * processor, required for the virtio rpmsg device.
- *
- * The 'len' member of @rsc should contain the number of buffers this vring
- * support and 'da' should either contain the device address where
- * the remote processor is expecting the vring, or indicate that
- * dynamically allocation of the vring's device address is supported.
- *
- * Note: 'da' is currently not handled. This will be revised when the generic
- * iommu-based DMA API will arrive, or a dynanic & non-iommu use case show
- * up. Meanwhile, statically-addressed iommu-based images should use
- * RSC_DEVMEM resource entries to map their require 'da' to the physical
- * address of their base CMA region.
+ * This resource entry requests the host to statically register a virtio
+ * device (vdev), and setup everything needed to support it. It contains
+ * everything needed to make it possible: the virtio device id, virtio
+ * device features, vrings information, virtio config space, etc...
+ *
+ * Before registering the vdev, the vrings are allocated from non-cacheable
+ * physically contiguous memory. Currently we only support two vrings per
+ * remote processor (temporary limitation). We might also want to consider
+ * doing the vring allocation only later when ->find_vqs() is invoked, and
+ * then release them upon ->del_vqs().
+ *
+ * Note: @da is currently not really handled correctly: we dynamically
+ * allocate it using the DMA API, ignoring requested hard coded addresses,
+ * and we don't take care of any required IOMMU programming. This is all
+ * going to be taken care of when the generic iommu-based DMA API will be
+ * merged. Meanwhile, statically-addressed iommu-based firmware images should
+ * use RSC_DEVMEM resource entries to map their required @da to the physical
+ * address of their base CMA region (ouch, hacky!).
  *
  * Returns 0 on success, or an appropriate error code otherwise
  */
@@ -360,8 +392,8 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
                                                                 int avail)
 {
         struct device *dev = rproc->dev;
-        struct rproc_vdev *rvdev = rproc->rvdev;
-        int i;
+        struct rproc_vdev *rvdev;
+        int i, ret;
 
         /* make sure resource isn't truncated */
         if (sizeof(*rsc) + rsc->num_of_vrings * sizeof(struct fw_rsc_vdev_vring)
@@ -379,61 +411,41 @@ static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
         dev_dbg(dev, "vdev rsc: id %d, dfeatures %x, cfg len %d, %d vrings\n",
                 rsc->id, rsc->dfeatures, rsc->config_len, rsc->num_of_vrings);
 
-        /* no vdev is in place ? */
-        if (!rvdev) {
-                dev_err(dev, "vring requested without a virtio dev entry\n");
-                return -EINVAL;
-        }
-
-        /* we currently support two vrings per rproc (for rx and tx) */
-        if (rsc->num_of_vrings != ARRAY_SIZE(rvdev->vring)) {
+        /* we currently support only two vrings per rvdev */
+        if (rsc->num_of_vrings > ARRAY_SIZE(rvdev->vring)) {
                 dev_err(dev, "too many vrings: %d\n", rsc->num_of_vrings);
                 return -EINVAL;
         }
 
-        /* initialize the vrings */
-        for (i = 0; i < rsc->num_of_vrings; i++) {
-                struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
-                dma_addr_t dma;
-                int size;
-                void *va;
-
-                /* make sure reserved bytes are zeroes */
-                if (vring->reserved) {
-                        dev_err(dev, "vring rsc has non zero reserved bytes\n");
-                        return -EINVAL;
-                }
+        rvdev = kzalloc(sizeof(struct rproc_vdev), GFP_KERNEL);
+        if (!rvdev)
+                return -ENOMEM;
 
-                /* the firmware must provide the expected queue size */
-                if (!vring->num) {
-                        dev_err(dev, "missing expected queue size\n");
-                        /* potential cleanups are taken care of later on */
-                        return -EINVAL;
-                }
+        rvdev->rproc = rproc;
 
-                /* actual size of vring (in bytes) */
-                size = PAGE_ALIGN(vring_size(vring->num, AMP_VRING_ALIGN));
+        /* allocate the vrings */
+        for (i = 0; i < rsc->num_of_vrings; i++) {
+                ret = __rproc_handle_vring(rvdev, rsc, i);
+                if (ret)
+                        goto free_vrings;
+        }
 
-                /*
-                 * Allocate non-cacheable memory for the vring. In the future
-                 * this call will also configure the IOMMU for us
-                 */
-                va = dma_alloc_coherent(dev, size, &dma, GFP_KERNEL);
-                if (!va) {
-                        dev_err(dev, "dma_alloc_coherent failed\n");
-                        /* potential cleanups are taken care of later on */
-                        return -EINVAL;
-                }
+        /* remember the device features */
+        rvdev->dfeatures = rsc->dfeatures;
 
-                dev_dbg(dev, "vring%d: va %p dma %x qsz %d ring size %x\n", i,
-                                                va, dma, vring->num, size);
+        list_add_tail(&rvdev->node, &rproc->rvdevs);
 
-                rvdev->vring[i].len = vring->num;
-                rvdev->vring[i].va = va;
-                rvdev->vring[i].dma = dma;
-        }
+        /* it is now safe to add the virtio device */
+        ret = rproc_add_virtio_dev(rvdev, rsc->id);
+        if (ret)
+                goto free_vrings;
 
         return 0;
+
+free_vrings:
+        __rproc_free_vrings(rvdev, i);
+        kfree(rvdev);
+        return ret;
 }
 
 /**
@@ -731,7 +743,7 @@ static rproc_handle_resource_t rproc_handle_rsc[] = {
         [RSC_CARVEOUT] = (rproc_handle_resource_t)rproc_handle_carveout,
         [RSC_DEVMEM] = (rproc_handle_resource_t)rproc_handle_devmem,
         [RSC_TRACE] = (rproc_handle_resource_t)rproc_handle_trace,
-        [RSC_VDEV] = (rproc_handle_resource_t)rproc_handle_vdev,
+        [RSC_VDEV] = NULL, /* VDEVs were handled upon registrarion */
 };
 
 /* handle firmware resource entries before booting the remote processor */
@@ -784,6 +796,7 @@ rproc_handle_virtio_rsc(struct rproc *rproc, struct resource_table *table, int l
                 int offset = table->offset[i];
                 struct fw_rsc_hdr *hdr = (void *)table + offset;
                 int avail = len - offset - sizeof(*hdr);
+                struct fw_rsc_vdev *vrsc;
 
                 /* make sure table isn't truncated */
                 if (avail < 0) {
@@ -793,12 +806,14 @@ rproc_handle_virtio_rsc(struct rproc *rproc, struct resource_table *table, int l
 
                 dev_dbg(dev, "%s: rsc type %d\n", __func__, hdr->type);
 
-                if (hdr->type == RSC_VDEV) {
-                        struct fw_rsc_vdev *vrsc =
-                                        (struct fw_rsc_vdev *)hdr->data;
-                        ret = rproc_handle_early_vdev(rproc, vrsc, avail);
+                if (hdr->type != RSC_VDEV)
+                        continue;
+
+                vrsc = (struct fw_rsc_vdev *)hdr->data;
+
+                ret = rproc_handle_vdev(rproc, vrsc, avail);
+                if (ret)
                         break;
-                }
         }
 
         return ret;
@@ -889,14 +904,12 @@ static int rproc_handle_resources(struct rproc *rproc, const u8 *elf_data,
  * @rproc: rproc handle
  *
  * This function will free all resources acquired for @rproc, and it
- * is called when @rproc shuts down, or just failed booting.
+ * is called whenever @rproc either shuts down or fails to boot.
  */
 static void rproc_resource_cleanup(struct rproc *rproc)
 {
         struct rproc_mem_entry *entry, *tmp;
         struct device *dev = rproc->dev;
-        struct rproc_vdev *rvdev = rproc->rvdev;
-        int i;
 
         /* clean up debugfs trace entries */
         list_for_each_entry_safe(entry, tmp, &rproc->traces, node) {
@@ -906,23 +919,6 @@ static void rproc_resource_cleanup(struct rproc *rproc)
                 kfree(entry);
         }
 
-        /* free the coherent memory allocated for the vrings */
-        for (i = 0; rvdev && i < ARRAY_SIZE(rvdev->vring); i++) {
-                int qsz = rvdev->vring[i].len;
-                void *va = rvdev->vring[i].va;
-                int dma = rvdev->vring[i].dma;
-
-                /* virtqueue size is expressed in number of buffers supported */
-                if (qsz) {
-                        /* how many bytes does this vring really occupy ? */
-                        int size = PAGE_ALIGN(vring_size(qsz, AMP_VRING_ALIGN));
-
-                        dma_free_coherent(rproc->dev, size, va, dma);
-
-                        rvdev->vring[i].len = 0;
-                }
-        }
-
         /* clean up carveout allocations */
         list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
                 dma_free_coherent(dev, entry->len, entry->va, entry->dma);
@@ -1100,11 +1096,6 @@ static void rproc_fw_config_virtio(const struct firmware *fw, void *context)
                 goto out;
         }
 
-        /* add the virtio device (currently only rpmsg vdevs are supported) */
-        ret = rproc_add_rpmsg_vdev(rproc);
-        if (ret)
-                goto out;
-
 out:
         if (fw)
                 release_firmware(fw);
@@ -1266,13 +1257,23 @@ EXPORT_SYMBOL(rproc_shutdown);
 void rproc_release(struct kref *kref)
 {
         struct rproc *rproc = container_of(kref, struct rproc, refcount);
+        struct rproc_vdev *rvdev, *rvtmp;
 
         dev_info(rproc->dev, "removing %s\n", rproc->name);
 
         rproc_delete_debug_dir(rproc);
 
-        /* at this point no one holds a reference to rproc anymore */
-        kfree(rproc);
+        /* clean up remote vdev entries */
+        list_for_each_entry_safe(rvdev, rvtmp, &rproc->rvdevs, node) {
+                __rproc_free_vrings(rvdev, RVDEV_NUM_VRINGS);
+                list_del(&rvdev->node);
+        }
+
+        /*
+         * At this point no one holds a reference to rproc anymore,
+         * so we can directly unroll rproc_alloc()
+         */
+        rproc_free(rproc);
 }
 
 /* will be called when an rproc is added to the rprocs klist */
@@ -1316,7 +1317,7 @@ static struct rproc *next_rproc(struct klist_iter *i)
  * use rproc_put() to decrement it back once rproc isn't needed anymore.
  *
  * Note: currently this function (and its counterpart rproc_put()) are not
- * used anymore by the rpmsg subsystem. We need to scrutinize the use cases
+ * being used. We need to scrutinize the use cases
  * that still need them, and see if we can migrate them to use the non
  * name-based boot/shutdown interface.
  */
@@ -1391,11 +1392,8 @@ EXPORT_SYMBOL(rproc_put);
  * firmware.
  *
  * If found, those virtio devices will be created and added, so as a result
- * of registering this remote processor, additional virtio drivers will be
+ * of registering this remote processor, additional virtio drivers might be
  * probed.
- *
- * Currently, though, we only support a single RPMSG virtio vdev per remote
- * processor.
  */
 int rproc_register(struct rproc *rproc)
 {
@@ -1418,7 +1416,7 @@ int rproc_register(struct rproc *rproc)
 
         /*
          * We must retrieve early virtio configuration info from
-         * the firmware (e.g. whether to register a virtio rpmsg device,
+         * the firmware (e.g. whether to register a virtio device,
          * what virtio features does it support, ...).
          *
          * We're initiating an asynchronous firmware loading, so we can
@@ -1487,9 +1485,12 @@ struct rproc *rproc_alloc(struct device *dev, const char *name,
 
         mutex_init(&rproc->lock);
 
+        idr_init(&rproc->notifyids);
+
         INIT_LIST_HEAD(&rproc->carveouts);
         INIT_LIST_HEAD(&rproc->mappings);
         INIT_LIST_HEAD(&rproc->traces);
+        INIT_LIST_HEAD(&rproc->rvdevs);
 
         rproc->state = RPROC_OFFLINE;
 
@@ -1509,6 +1510,9 @@ EXPORT_SYMBOL(rproc_alloc);
  */
 void rproc_free(struct rproc *rproc)
 {
+        idr_remove_all(&rproc->notifyids);
+        idr_destroy(&rproc->notifyids);
+
         kfree(rproc);
 }
 EXPORT_SYMBOL(rproc_free);
@@ -1535,18 +1539,22 @@ EXPORT_SYMBOL(rproc_free);
  */
 int rproc_unregister(struct rproc *rproc)
 {
+        struct rproc_vdev *rvdev;
+
         if (!rproc)
                 return -EINVAL;
 
         /* if rproc is just being registered, wait */
         wait_for_completion(&rproc->firmware_loading_complete);
 
-        /* was an rpmsg vdev created ? */
-        if (rproc->rvdev)
-                rproc_remove_rpmsg_vdev(rproc);
+        /* clean up remote vdev entries */
+        list_for_each_entry(rvdev, &rproc->rvdevs, node)
+                rproc_remove_virtio_dev(rvdev);
 
-        klist_remove(&rproc->node);
+        /* the rproc is downref'ed as soon as it's removed from the klist */
+        klist_del(&rproc->node);
 
+        /* the rproc will only be released after its refcount drops to zero */
         kref_put(&rproc->refcount, rproc_release);
 
         return 0;
diff --git a/drivers/remoteproc/remoteproc_internal.h b/drivers/remoteproc/remoteproc_internal.h
index 8b2fc40e92d0..9f336d6bdef3 100644
--- a/drivers/remoteproc/remoteproc_internal.h
+++ b/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);
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index 78d8527a8fec..07004106c954 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/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 @@ error:
 /*
  * 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);
 }