[1/2] remoteproc: maintain a generic child device for each rproc

Commit Message

Ohad Ben Cohen June 29, 2012, 8:13 a.m. UTC

On Wed, May 30, 2012 at 3:16 PM, Ohad Ben-Cohen <[e-mail]> wrote:
> In this case, I was more wondering between using a class to a device type.
>
>> I recall seeing a thread where
>> someone said classes were on the way out and shouldn't be used but I
>> can't find it anymore.
>
> I also remembered a similar discussion at a plumbers mini-conf about
> 2-3 years ago too, so I looked at device_type as an alternative to
> class. The former looks somewhat simpler, but I couldn't find any
> major advantage for using one over the other, and both seem to be in
> use by many subsystems.

Moving to device_type is so trivial that I gave it a spin (and moved
to IDA too while at it):

From caf8db2945ffe445e6b2b9e42b7afa14bae87d2c Mon Sep 17 00:00:00 2001
From: Ohad Ben-Cohen <[e-mail]>
Date: Wed, 30 May 2012 22:01:25 +0300
Subject: [PATCH 1/2] remoteproc: maintain a generic child device for each
 rproc

For each registered rproc, maintain a generic remoteproc device whose
parent is the low level platform-specific device (commonly a pdev, but
it may certainly be any other type of device too).

With this in hand, the resulting device hierarchy might then look like:

omap-rproc.0
 |
 - remoteproc0  <---- new !
    |
    - virtio0
    |
    - virtio1
       |
       - rpmsg0
       |
       - rpmsg1
       |
       - rpmsg2

Where:
- omap-rproc.0 is the low level device that's bound to the
  driver which invokes rproc_register()
- remoteproc0 is the result of this patch, and will be added by the
  remoteproc framework when rproc_register() is invoked
- virtio0 and virtio1 are vdevs that are registered by remoteproc
  when it realizes that they are supported by the firmware
  of the physical remote processor represented by omap-rproc.0
- rpmsg0, rpmsg1 and rpmsg2 are rpmsg devices that represent rpmsg
  channels, and are registerd by the rpmsg bus when it gets notified
  about their existence

Technically, this patch:
- changes 'struct rproc' to contain this generic remoteproc.x device
- creates a new "remoteproc" type, to which this new generic remoteproc.x
  device belong to.
- adds a super simple enumeration method for the indices of the
  remoteproc.x devices
- updates all dev_* messaging to use the generic remoteproc.x device
  instead of the low level platform-specific device
- updates all dma_* allocations to use the parent of remoteproc.x (where
  the platform-specific memory pools, most commonly CMA, are to be found)

Adding this generic device has several merits:
- we can now add remoteproc runtime PM support simply by hooking onto the
  new "remoteproc" type
- all remoteproc log messages will now carry a common name prefix
  instead of having a platform-specific one
- having a device as part of the rproc struct makes it possible to simplify
  refcounting (see subsequent patch)

Thanks to Stephen Boyd <[e-mail]> for suggesting and
discussing these ideas in one of the remoteproc review threads and
to Fernando Guzman Lugo <[e-mail]> for trying them out
with the (upcoming) runtime PM support for remoteproc.

Cc: Stephen Boyd <[e-mail]>
Cc: Fernando Guzman Lugo <[e-mail]>
Signed-off-by: Ohad Ben-Cohen <[e-mail]>
---
 drivers/remoteproc/omap_remoteproc.c    |  17 ++--
 drivers/remoteproc/remoteproc_core.c    | 135 ++++++++++++++++++++++----------
 drivers/remoteproc/remoteproc_debugfs.c |   4 +-
 drivers/remoteproc/remoteproc_virtio.c  |  13 +--
 drivers/rpmsg/virtio_rpmsg_bus.c        |   3 +-
 include/linux/remoteproc.h              |   6 +-
 6 files changed, 117 insertions(+), 61 deletions(-)

Comments

Stephen Boyd July 2, 2012, 7:06 p.m. UTC | #1

On 06/29/12 01:13, Ohad Ben-Cohen wrote:
> On Wed, May 30, 2012 at 3:16 PM, Ohad Ben-Cohen <[e-mail]> wrote:
>> In this case, I was more wondering between using a class to a device type.
>>
>>> I recall seeing a thread where
>>> someone said classes were on the way out and shouldn't be used but I
>>> can't find it anymore.
>> I also remembered a similar discussion at a plumbers mini-conf about
>> 2-3 years ago too, so I looked at device_type as an alternative to
>> class. The former looks somewhat simpler, but I couldn't find any
>> major advantage for using one over the other, and both seem to be in
>> use by many subsystems.
> Moving to device_type is so trivial that I gave it a spin (and moved
> to IDA too while at it):

Great! It looks like device_type doesn't have any list iteration support
though. Is that requirement gone? If that requirement is still there I
would think we need something like a class or bus still.

Will you resend this as part of a series? It will be easier to review then.

Ohad Ben Cohen July 2, 2012, 7:54 p.m. UTC | #2

On Mon, Jul 2, 2012 at 10:06 PM, Stephen Boyd <[e-mail]> wrote:
> Great! It looks like device_type doesn't have any list iteration support
> though. Is that requirement gone?

Pretty much, yeah. I'll soon post a separate patch which removes the
get_by_name functionality (together with its related klist).

> Will you resend this as part of a series? It will be easier to review then.

Not sure. There's a collection of discrete patches that I've been
posting, but they really aren't an organic series: as long as the
dependencies are met, each and every one of them is applicable even if
applied alone.

So I'd prefer (when possible) to treat patches in a discrete fashion
so we can start applying them and unblock others who depend on them
(e.g. Fernando's runtime PM work depends on this one).

But if you prefer me to send this one patch differently to make it
easier to review, let me know!

Thanks,
Ohad.
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Stephen Boyd July 5, 2012, 8:35 p.m. UTC | #3

On 07/02/12 12:54, Ohad Ben-Cohen wrote:
> On Mon, Jul 2, 2012 at 10:06 PM, Stephen Boyd <[e-mail]> wrote:
>> Great! It looks like device_type doesn't have any list iteration support
>> though. Is that requirement gone?
> Pretty much, yeah. I'll soon post a separate patch which removes the
> get_by_name functionality (together with its related klist).
>
>> Will you resend this as part of a series? It will be easier to review then.
> Not sure. There's a collection of discrete patches that I've been
> posting, but they really aren't an organic series: as long as the
> dependencies are met, each and every one of them is applicable even if
> applied alone.
>
> So I'd prefer (when possible) to treat patches in a discrete fashion
> so we can start applying them and unblock others who depend on them
> (e.g. Fernando's runtime PM work depends on this one).
>
> But if you prefer me to send this one patch differently to make it
> easier to review, let me know!
>

Ok then. Please add

Reviewed-by: Stephen Boyd <[e-mail]>

It would be nice if you got an ack from Greg or Kay on the device_type
usage too.

Ohad Ben Cohen July 15, 2012, 9:12 a.m. UTC | #4

On Thu, Jul 5, 2012 at 11:35 PM, Stephen Boyd <[e-mail]> wrote:
> Ok then. Please add
>
> Reviewed-by: Stephen Boyd <[e-mail]>

Added, and applied patch. thanks!

> It would be nice if you got an ack from Greg or Kay on the device_type
> usage too.

I agree, I'd just hate bothering them on this now. Probably a topic
for a conference chat :)
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Patch

diff --git a/drivers/remoteproc/omap_remoteproc.c
b/drivers/remoteproc/omap_remoteproc.c
index de138e30..f45230c 100644
--- a/drivers/remoteproc/omap_remoteproc.c
+++ b/drivers/remoteproc/omap_remoteproc.c
@@ -66,7 +66,7 @@  static int omap_rproc_mbox_callback(struct
notifier_block *this,
 {
 	mbox_msg_t msg = (mbox_msg_t) data;
 	struct omap_rproc *oproc = container_of(this, struct omap_rproc, nb);
-	struct device *dev = oproc->rproc->dev;
+	struct device *dev = oproc->rproc->dev.parent;
 	const char *name = oproc->rproc->name;

 	dev_dbg(dev, "mbox msg: 0x%x\n", msg);
@@ -92,12 +92,13 @@  static int omap_rproc_mbox_callback(struct
notifier_block *this,
 static void omap_rproc_kick(struct rproc *rproc, int vqid)
 {
 	struct omap_rproc *oproc = rproc->priv;
+	struct device *dev = rproc->dev.parent;
 	int ret;

 	/* send the index of the triggered virtqueue in the mailbox payload */
 	ret = omap_mbox_msg_send(oproc->mbox, vqid);
 	if (ret)
-		dev_err(rproc->dev, "omap_mbox_msg_send failed: %d\n", ret);
+		dev_err(dev, "omap_mbox_msg_send failed: %d\n", ret);
 }

 /*
@@ -110,7 +111,8 @@  static void omap_rproc_kick(struct rproc *rproc, int vqid)
 static int omap_rproc_start(struct rproc *rproc)
 {
 	struct omap_rproc *oproc = rproc->priv;
-	struct platform_device *pdev = to_platform_device(rproc->dev);
+	struct device *dev = rproc->dev.parent;
+	struct platform_device *pdev = to_platform_device(dev);
 	struct omap_rproc_pdata *pdata = pdev->dev.platform_data;
 	int ret;

@@ -120,7 +122,7 @@  static int omap_rproc_start(struct rproc *rproc)
 	oproc->mbox = omap_mbox_get(pdata->mbox_name, &oproc->nb);
 	if (IS_ERR(oproc->mbox)) {
 		ret = PTR_ERR(oproc->mbox);
-		dev_err(rproc->dev, "omap_mbox_get failed: %d\n", ret);
+		dev_err(dev, "omap_mbox_get failed: %d\n", ret);
 		return ret;
 	}

@@ -133,13 +135,13 @@  static int omap_rproc_start(struct rproc *rproc)
 	 */
 	ret = omap_mbox_msg_send(oproc->mbox, RP_MBOX_ECHO_REQUEST);
 	if (ret) {
-		dev_err(rproc->dev, "omap_mbox_get failed: %d\n", ret);
+		dev_err(dev, "omap_mbox_get failed: %d\n", ret);
 		goto put_mbox;
 	}

 	ret = pdata->device_enable(pdev);
 	if (ret) {
-		dev_err(rproc->dev, "omap_device_enable failed: %d\n", ret);
+		dev_err(dev, "omap_device_enable failed: %d\n", ret);
 		goto put_mbox;
 	}

@@ -153,7 +155,8 @@  put_mbox:
 /* power off the remote processor */
 static int omap_rproc_stop(struct rproc *rproc)
 {
-	struct platform_device *pdev = to_platform_device(rproc->dev);
+	struct device *dev = rproc->dev.parent;
+	struct platform_device *pdev = to_platform_device(dev);
 	struct omap_rproc_pdata *pdata = pdev->dev.platform_data;
 	struct omap_rproc *oproc = rproc->priv;
 	int ret;
diff --git a/drivers/remoteproc/remoteproc_core.c
b/drivers/remoteproc/remoteproc_core.c
index 464ea4f..46469b2 100644
--- a/drivers/remoteproc/remoteproc_core.c
+++ b/drivers/remoteproc/remoteproc_core.c
@@ -35,6 +35,7 @@ 
 #include <linux/debugfs.h>
 #include <linux/remoteproc.h>
 #include <linux/iommu.h>
+#include <linux/idr.h>
 #include <linux/klist.h>
 #include <linux/elf.h>
 #include <linux/virtio_ids.h>
@@ -66,6 +67,9 @@  typedef int (*rproc_handle_resources_t)(struct rproc *rproc,
 				struct resource_table *table, int len);
 typedef int (*rproc_handle_resource_t)(struct rproc *rproc, void *, int avail);

+/* Unique indices for remoteproc devices */
+static DEFINE_IDA(rproc_dev_index);
+
 /*
  * This is the IOMMU fault handler we register with the IOMMU API
  * (when relevant; not all remote processors access memory through
@@ -92,7 +96,7 @@  static int rproc_iommu_fault(struct iommu_domain
*domain, struct device *dev,
 static int rproc_enable_iommu(struct rproc *rproc)
 {
 	struct iommu_domain *domain;
-	struct device *dev = rproc->dev;
+	struct device *dev = rproc->dev.parent;
 	int ret;

 	/*
@@ -137,7 +141,7 @@  free_domain:
 static void rproc_disable_iommu(struct rproc *rproc)
 {
 	struct iommu_domain *domain = rproc->domain;
-	struct device *dev = rproc->dev;
+	struct device *dev = rproc->dev.parent;

 	if (!domain)
 		return;
@@ -217,7 +221,7 @@  static void *rproc_da_to_va(struct rproc *rproc,
u64 da, int len)
 static int
 rproc_load_segments(struct rproc *rproc, const u8 *elf_data, size_t len)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct elf32_hdr *ehdr;
 	struct elf32_phdr *phdr;
 	int i, ret = 0;
@@ -282,7 +286,7 @@  rproc_load_segments(struct rproc *rproc, const u8
*elf_data, size_t len)
 int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
 {
 	struct rproc *rproc = rvdev->rproc;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct rproc_vring *rvring = &rvdev->vring[i];
 	dma_addr_t dma;
 	void *va;
@@ -301,9 +305,9 @@  int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
 	 * this call will also configure the IOMMU for us
 	 * TODO: let the rproc know the da of this vring
 	 */
-	va = dma_alloc_coherent(dev, size, &dma, GFP_KERNEL);
+	va = dma_alloc_coherent(dev->parent, size, &dma, GFP_KERNEL);
 	if (!va) {
-		dev_err(dev, "dma_alloc_coherent failed\n");
+		dev_err(dev->parent, "dma_alloc_coherent failed\n");
 		return -EINVAL;
 	}

@@ -316,7 +320,7 @@  int rproc_alloc_vring(struct rproc_vdev *rvdev, int i)
 	ret = idr_get_new(&rproc->notifyids, rvring, &notifyid);
 	if (ret) {
 		dev_err(dev, "idr_get_new failed: %d\n", ret);
-		dma_free_coherent(dev, size, va, dma);
+		dma_free_coherent(dev->parent, size, va, dma);
 		return ret;
 	}

@@ -334,7 +338,7 @@  static int
 rproc_parse_vring(struct rproc_vdev *rvdev, struct fw_rsc_vdev *rsc, int i)
 {
 	struct rproc *rproc = rvdev->rproc;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct fw_rsc_vdev_vring *vring = &rsc->vring[i];
 	struct rproc_vring *rvring = &rvdev->vring[i];

@@ -366,7 +370,7 @@  void rproc_free_vring(struct rproc_vring *rvring)
 	int size = PAGE_ALIGN(vring_size(rvring->len, rvring->align));
 	struct rproc *rproc = rvring->rvdev->rproc;

-	dma_free_coherent(rproc->dev, size, rvring->va, rvring->dma);
+	dma_free_coherent(rproc->dev.parent, size, rvring->va, rvring->dma);
 	idr_remove(&rproc->notifyids, rvring->notifyid);
 }

@@ -400,14 +404,14 @@  void rproc_free_vring(struct rproc_vring *rvring)
 static int rproc_handle_vdev(struct rproc *rproc, struct fw_rsc_vdev *rsc,
 								int avail)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	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)
 			+ rsc->config_len > avail) {
-		dev_err(rproc->dev, "vdev rsc is truncated\n");
+		dev_err(dev, "vdev rsc is truncated\n");
 		return -EINVAL;
 	}

@@ -476,12 +480,12 @@  static int rproc_handle_trace(struct rproc
*rproc, struct fw_rsc_trace *rsc,
 								int avail)
 {
 	struct rproc_mem_entry *trace;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	void *ptr;
 	char name[15];

 	if (sizeof(*rsc) > avail) {
-		dev_err(rproc->dev, "trace rsc is truncated\n");
+		dev_err(dev, "trace rsc is truncated\n");
 		return -EINVAL;
 	}

@@ -558,6 +562,7 @@  static int rproc_handle_devmem(struct rproc
*rproc, struct fw_rsc_devmem *rsc,
 								int avail)
 {
 	struct rproc_mem_entry *mapping;
+	struct device *dev = &rproc->dev;
 	int ret;

 	/* no point in handling this resource without a valid iommu domain */
@@ -565,25 +570,25 @@  static int rproc_handle_devmem(struct rproc
*rproc, struct fw_rsc_devmem *rsc,
 		return -EINVAL;

 	if (sizeof(*rsc) > avail) {
-		dev_err(rproc->dev, "devmem rsc is truncated\n");
+		dev_err(dev, "devmem rsc is truncated\n");
 		return -EINVAL;
 	}

 	/* make sure reserved bytes are zeroes */
 	if (rsc->reserved) {
-		dev_err(rproc->dev, "devmem rsc has non zero reserved bytes\n");
+		dev_err(dev, "devmem rsc has non zero reserved bytes\n");
 		return -EINVAL;
 	}

 	mapping = kzalloc(sizeof(*mapping), GFP_KERNEL);
 	if (!mapping) {
-		dev_err(rproc->dev, "kzalloc mapping failed\n");
+		dev_err(dev, "kzalloc mapping failed\n");
 		return -ENOMEM;
 	}

 	ret = iommu_map(rproc->domain, rsc->da, rsc->pa, rsc->len, rsc->flags);
 	if (ret) {
-		dev_err(rproc->dev, "failed to map devmem: %d\n", ret);
+		dev_err(dev, "failed to map devmem: %d\n", ret);
 		goto out;
 	}

@@ -598,7 +603,7 @@  static int rproc_handle_devmem(struct rproc
*rproc, struct fw_rsc_devmem *rsc,
 	mapping->len = rsc->len;
 	list_add_tail(&mapping->node, &rproc->mappings);

-	dev_dbg(rproc->dev, "mapped devmem pa 0x%x, da 0x%x, len 0x%x\n",
+	dev_dbg(dev, "mapped devmem pa 0x%x, da 0x%x, len 0x%x\n",
 					rsc->pa, rsc->da, rsc->len);

 	return 0;
@@ -630,13 +635,13 @@  static int rproc_handle_carveout(struct rproc *rproc,
 				struct fw_rsc_carveout *rsc, int avail)
 {
 	struct rproc_mem_entry *carveout, *mapping;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	dma_addr_t dma;
 	void *va;
 	int ret;

 	if (sizeof(*rsc) > avail) {
-		dev_err(rproc->dev, "carveout rsc is truncated\n");
+		dev_err(dev, "carveout rsc is truncated\n");
 		return -EINVAL;
 	}

@@ -662,9 +667,9 @@  static int rproc_handle_carveout(struct rproc *rproc,
 		goto free_mapping;
 	}

-	va = dma_alloc_coherent(dev, rsc->len, &dma, GFP_KERNEL);
+	va = dma_alloc_coherent(dev->parent, rsc->len, &dma, GFP_KERNEL);
 	if (!va) {
-		dev_err(dev, "failed to dma alloc carveout: %d\n", rsc->len);
+		dev_err(dev->parent, "dma_alloc_coherent err: %d\n", rsc->len);
 		ret = -ENOMEM;
 		goto free_carv;
 	}
@@ -735,7 +740,7 @@  static int rproc_handle_carveout(struct rproc *rproc,
 	return 0;

 dma_free:
-	dma_free_coherent(dev, rsc->len, va, dma);
+	dma_free_coherent(dev->parent, rsc->len, va, dma);
 free_carv:
 	kfree(carveout);
 free_mapping:
@@ -758,7 +763,7 @@  static rproc_handle_resource_t rproc_handle_rsc[] = {
 static int
 rproc_handle_boot_rsc(struct rproc *rproc, struct resource_table
*table, int len)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	rproc_handle_resource_t handler;
 	int ret = 0, i;

@@ -797,7 +802,7 @@  rproc_handle_boot_rsc(struct rproc *rproc, struct
resource_table *table, int len
 static int
 rproc_handle_virtio_rsc(struct rproc *rproc, struct resource_table
*table, int len)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	int ret = 0, i;

 	for (i = 0; i < table->num; i++) {
@@ -850,7 +855,7 @@  rproc_find_rsc_table(struct rproc *rproc, const u8
*elf_data, size_t len,
 	struct elf32_hdr *ehdr;
 	struct elf32_shdr *shdr;
 	const char *name_table;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct resource_table *table = NULL;
 	int i;

@@ -916,7 +921,7 @@  rproc_find_rsc_table(struct rproc *rproc, const u8
*elf_data, size_t len,
 static void rproc_resource_cleanup(struct rproc *rproc)
 {
 	struct rproc_mem_entry *entry, *tmp;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;

 	/* clean up debugfs trace entries */
 	list_for_each_entry_safe(entry, tmp, &rproc->traces, node) {
@@ -928,7 +933,7 @@  static void rproc_resource_cleanup(struct rproc *rproc)

 	/* clean up carveout allocations */
 	list_for_each_entry_safe(entry, tmp, &rproc->carveouts, node) {
-		dma_free_coherent(dev, entry->len, entry->va, entry->dma);
+		dma_free_coherent(dev->parent, entry->len, entry->va, entry->dma);
 		list_del(&entry->node);
 		kfree(entry);
 	}
@@ -953,7 +958,7 @@  static void rproc_resource_cleanup(struct rproc *rproc)
 static int rproc_fw_sanity_check(struct rproc *rproc, const struct
firmware *fw)
 {
 	const char *name = rproc->firmware;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct elf32_hdr *ehdr;
 	char class;

@@ -1014,7 +1019,7 @@  static int rproc_fw_sanity_check(struct rproc
*rproc, const struct firmware *fw)
  */
 static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	const char *name = rproc->firmware;
 	struct elf32_hdr *ehdr;
 	struct resource_table *table;
@@ -1139,7 +1144,7 @@  int rproc_boot(struct rproc *rproc)
 		return -EINVAL;
 	}

-	dev = rproc->dev;
+	dev = &rproc->dev;

 	/*
 	 * if asynchronoush fw loading is underway, wait up to 65 secs
@@ -1167,7 +1172,7 @@  int rproc_boot(struct rproc *rproc)
 	}

 	/* prevent underlying implementation from being removed */
-	if (!try_module_get(dev->driver->owner)) {
+	if (!try_module_get(dev->parent->driver->owner)) {
 		dev_err(dev, "%s: can't get owner\n", __func__);
 		ret = -EINVAL;
 		goto unlock_mutex;
@@ -1194,7 +1199,7 @@  int rproc_boot(struct rproc *rproc)

 downref_rproc:
 	if (ret) {
-		module_put(dev->driver->owner);
+		module_put(dev->parent->driver->owner);
 		atomic_dec(&rproc->power);
 	}
 unlock_mutex:
@@ -1228,7 +1233,7 @@  EXPORT_SYMBOL(rproc_boot);
  */
 void rproc_shutdown(struct rproc *rproc)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	int ret;

 	ret = mutex_lock_interruptible(&rproc->lock);
@@ -1261,7 +1266,7 @@  void rproc_shutdown(struct rproc *rproc)
 out:
 	mutex_unlock(&rproc->lock);
 	if (!ret)
-		module_put(dev->driver->owner);
+		module_put(dev->parent->driver->owner);
 }
 EXPORT_SYMBOL(rproc_shutdown);

@@ -1284,7 +1289,7 @@  void rproc_release(struct kref *kref)
 {
 	struct rproc *rproc = container_of(kref, struct rproc, refcount);

-	dev_info(rproc->dev, "removing %s\n", rproc->name);
+	dev_info(&rproc->dev, "removing %s\n", rproc->name);

 	rproc_delete_debug_dir(rproc);

@@ -1416,13 +1421,17 @@  EXPORT_SYMBOL(rproc_put);
  */
 int rproc_register(struct rproc *rproc)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	int ret = 0;

+	ret = device_add(dev);
+	if (ret < 0)
+		return ret;
+
 	/* expose to rproc_get_by_name users */
 	klist_add_tail(&rproc->node, &rprocs);

-	dev_info(rproc->dev, "%s is available\n", rproc->name);
+	dev_info(dev, "%s is available\n", rproc->name);

 	dev_info(dev, "Note: remoteproc is still under development and
considered experimental.\n");
 	dev_info(dev, "THE BINARY FORMAT IS NOT YET FINALIZED, and backward
compatibility isn't yet guaranteed.\n");
@@ -1455,6 +1464,33 @@  int rproc_register(struct rproc *rproc)
 EXPORT_SYMBOL(rproc_register);

 /**
+ * rproc_type_release() - release a remote processor instance
+ * @dev: the rproc's device
+ *
+ * This function should _never_ be called directly.
+ *
+ * It will be called by the driver core when no one holds a valid pointer
+ * to @dev anymore.
+ */
+static void rproc_type_release(struct device *dev)
+{
+	struct rproc *rproc = container_of(dev, struct rproc, dev);
+
+	idr_remove_all(&rproc->notifyids);
+	idr_destroy(&rproc->notifyids);
+
+	if (rproc->index >= 0)
+		ida_simple_remove(&rproc_dev_index, rproc->index);
+
+	kfree(rproc);
+}
+
+static struct device_type rproc_type = {
+	.name		= "remoteproc",
+	.release	= rproc_type_release,
+};
+
+/**
  * rproc_alloc() - allocate a remote processor handle
  * @dev: the underlying device
  * @name: name of this remote processor
@@ -1492,12 +1528,25 @@  struct rproc *rproc_alloc(struct device *dev,
const char *name,
 		return NULL;
 	}

-	rproc->dev = dev;
 	rproc->name = name;
 	rproc->ops = ops;
 	rproc->firmware = firmware;
 	rproc->priv = &rproc[1];

+	device_initialize(&rproc->dev);
+	rproc->dev.parent = dev;
+	rproc->dev.type = &rproc_type;
+
+	/* Assign a unique device index and name */
+	rproc->index = ida_simple_get(&rproc_dev_index, 0, 0, GFP_KERNEL);
+	if (rproc->index < 0) {
+		dev_err(dev, "ida_simple_get failed: %d\n", rproc->index);
+		put_device(&rproc->dev);
+		return NULL;
+	}
+
+	dev_set_name(&rproc->dev, "remoteproc%d", rproc->index);
+
 	atomic_set(&rproc->power, 0);

 	kref_init(&rproc->refcount);
@@ -1529,10 +1578,7 @@  EXPORT_SYMBOL(rproc_alloc);
  */
 void rproc_free(struct rproc *rproc)
 {
-	idr_remove_all(&rproc->notifyids);
-	idr_destroy(&rproc->notifyids);
-
-	kfree(rproc);
+	put_device(&rproc->dev);
 }
 EXPORT_SYMBOL(rproc_free);

@@ -1573,6 +1619,8 @@  int rproc_unregister(struct rproc *rproc)
 	/* the rproc is downref'ed as soon as it's removed from the klist */
 	klist_del(&rproc->node);

+	device_del(&rproc->dev);
+
 	/* the rproc will only be released after its refcount drops to zero */
 	kref_put(&rproc->refcount, rproc_release);

@@ -1583,6 +1631,7 @@  EXPORT_SYMBOL(rproc_unregister);
 static int __init remoteproc_init(void)
 {
 	rproc_init_debugfs();
+
 	return 0;
 }
 module_init(remoteproc_init);
diff --git a/drivers/remoteproc/remoteproc_debugfs.c
b/drivers/remoteproc/remoteproc_debugfs.c
index 85d31a6..0383385 100644
--- a/drivers/remoteproc/remoteproc_debugfs.c
+++ b/drivers/remoteproc/remoteproc_debugfs.c
@@ -124,7 +124,7 @@  struct dentry *rproc_create_trace_file(const char
*name, struct rproc *rproc,
 	tfile = debugfs_create_file(name, 0400, rproc->dbg_dir,
 						trace, &trace_rproc_ops);
 	if (!tfile) {
-		dev_err(rproc->dev, "failed to create debugfs trace entry\n");
+		dev_err(&rproc->dev, "failed to create debugfs trace entry\n");
 		return NULL;
 	}

@@ -141,7 +141,7 @@  void rproc_delete_debug_dir(struct rproc *rproc)

 void rproc_create_debug_dir(struct rproc *rproc)
 {
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;

 	if (!rproc_dbg)
 		return;
diff --git a/drivers/remoteproc/remoteproc_virtio.c
b/drivers/remoteproc/remoteproc_virtio.c
index 26a7144..b662183 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -36,7 +36,7 @@  static void rproc_virtio_notify(struct virtqueue *vq)
 	struct rproc *rproc = rvring->rvdev->rproc;
 	int notifyid = rvring->notifyid;

-	dev_dbg(rproc->dev, "kicking vq index: %d\n", notifyid);
+	dev_dbg(&rproc->dev, "kicking vq index: %d\n", notifyid);

 	rproc->ops->kick(rproc, notifyid);
 }
@@ -57,7 +57,7 @@  irqreturn_t rproc_vq_interrupt(struct rproc *rproc,
int notifyid)
 {
 	struct rproc_vring *rvring;

-	dev_dbg(rproc->dev, "vq index %d is interrupted\n", notifyid);
+	dev_dbg(&rproc->dev, "vq index %d is interrupted\n", notifyid);

 	rvring = idr_find(&rproc->notifyids, notifyid);
 	if (!rvring || !rvring->vq)
@@ -74,6 +74,7 @@  static struct virtqueue *rp_find_vq(struct
virtio_device *vdev,
 {
 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 	struct rproc *rproc = vdev_to_rproc(vdev);
+	struct device *dev = &rproc->dev;
 	struct rproc_vring *rvring;
 	struct virtqueue *vq;
 	void *addr;
@@ -95,7 +96,7 @@  static struct virtqueue *rp_find_vq(struct
virtio_device *vdev,
 	size = vring_size(len, rvring->align);
 	memset(addr, 0, size);

-	dev_dbg(rproc->dev, "vring%d: va %p qsz %d notifyid %d\n",
+	dev_dbg(dev, "vring%d: va %p qsz %d notifyid %d\n",
 					id, addr, len, rvring->notifyid);

 	/*
@@ -105,7 +106,7 @@  static struct virtqueue *rp_find_vq(struct
virtio_device *vdev,
 	vq = vring_new_virtqueue(len, rvring->align, vdev, false, addr,
 					rproc_virtio_notify, callback, name);
 	if (!vq) {
-		dev_err(rproc->dev, "vring_new_virtqueue %s failed\n", name);
+		dev_err(dev, "vring_new_virtqueue %s failed\n", name);
 		rproc_free_vring(rvring);
 		return ERR_PTR(-ENOMEM);
 	}
@@ -152,7 +153,7 @@  static int rproc_virtio_find_vqs(struct
virtio_device *vdev, unsigned nvqs,
 	/* now that the vqs are all set, boot the remote processor */
 	ret = rproc_boot(rproc);
 	if (ret) {
-		dev_err(rproc->dev, "rproc_boot() failed %d\n", ret);
+		dev_err(&rproc->dev, "rproc_boot() failed %d\n", ret);
 		goto error;
 	}

@@ -254,7 +255,7 @@  static void rproc_vdev_release(struct device *dev)
 int rproc_add_virtio_dev(struct rproc_vdev *rvdev, int id)
 {
 	struct rproc *rproc = rvdev->rproc;
-	struct device *dev = rproc->dev;
+	struct device *dev = &rproc->dev;
 	struct virtio_device *vdev = &rvdev->vdev;
 	int ret;

diff --git a/drivers/rpmsg/virtio_rpmsg_bus.c b/drivers/rpmsg/virtio_rpmsg_bus.c
index d5572e8..0af7fd3 100644
--- a/drivers/rpmsg/virtio_rpmsg_bus.c
+++ b/drivers/rpmsg/virtio_rpmsg_bus.c
@@ -964,7 +964,8 @@  static int rpmsg_probe(struct virtio_device *vdev)
 	vrp->svq = vqs[1];

 	/* allocate coherent memory for the buffers */
-	bufs_va = dma_alloc_coherent(vdev->dev.parent, RPMSG_TOTAL_BUF_SPACE,
+	bufs_va = dma_alloc_coherent(vdev->dev.parent->parent,
+				RPMSG_TOTAL_BUF_SPACE,
 				&vrp->bufs_dma, GFP_KERNEL);
 	if (!bufs_va)
 		goto vqs_del;
diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
index f1ffabb..7f806dc 100644
--- a/include/linux/remoteproc.h
+++ b/include/linux/remoteproc.h
@@ -369,7 +369,7 @@  enum rproc_state {
  * @firmware: name of firmware file to be loaded
  * @priv: private data which belongs to the platform-specific rproc module
  * @ops: platform-specific start/stop rproc handlers
- * @dev: underlying device
+ * @dev: virtual device for refcounting and common remoteproc behavior
  * @refcount: refcount of users that have a valid pointer to this rproc
  * @power: refcount of users who need this rproc powered up
  * @state: state of the device
@@ -383,6 +383,7 @@  enum rproc_state {
  * @bootaddr: address of first instruction to boot rproc with (optional)
  * @rvdevs: list of remote virtio devices
  * @notifyids: idr for dynamically assigning rproc-wide unique notify ids
+ * @index: index of this rproc device
  */
 struct rproc {
 	struct klist_node node;
@@ -391,7 +392,7 @@  struct rproc {
 	const char *firmware;
 	void *priv;
 	const struct rproc_ops *ops;
-	struct device *dev;
+	struct device dev;
 	struct kref refcount;
 	atomic_t power;
 	unsigned int state;
@@ -405,6 +406,7 @@  struct rproc {
 	u32 bootaddr;
 	struct list_head rvdevs;
 	struct idr notifyids;
+	int index;
 };

 /* we currently support only two vrings per rvdev */