On Mon, Sep 13, 2021 at 07:19:17PM +1000, Alexey Kardashevskiy wrote:
> 
> 
> On 26/07/2021 14:51, Viresh Kumar wrote:
> > Bind the virtio devices with their of_node. This will help users of the
> > virtio devices to mention their dependencies on the device in the DT
> > itself. Like GPIO pin users can use the phandle of the device node, or
> > the node may contain more subnodes to add i2c or spi eeproms and other
> > users.
> > 
> > Reviewed-by: Arnd Bergmann <a...@arndb.de>
> > Signed-off-by: Viresh Kumar <viresh.ku...@linaro.org>
> > ---
> >  drivers/virtio/virtio.c | 57 ++++++++++++++++++++++++++++++++++++++---
> >  1 file changed, 54 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
> > index 4b15c00c0a0a..d001e84a5b23 100644
> > --- a/drivers/virtio/virtio.c
> > +++ b/drivers/virtio/virtio.c
> > @@ -4,6 +4,7 @@
> >  #include <linux/virtio_config.h>
> >  #include <linux/module.h>
> >  #include <linux/idr.h>
> > +#include <linux/of.h>
> >  #include <uapi/linux/virtio_ids.h>
> >  
> >  /* Unique numbering for virtio devices. */
> > @@ -292,6 +293,9 @@ static int virtio_dev_remove(struct device *_d)
> >  
> >     /* Acknowledge the device's existence again. */
> >     virtio_add_status(dev, VIRTIO_CONFIG_S_ACKNOWLEDGE);
> > +
> > +   of_node_put(dev->dev.of_node);
> > +
> >     return 0;
> >  }
> >  
> > @@ -319,6 +323,43 @@ void unregister_virtio_driver(struct virtio_driver 
> > *driver)
> >  }
> >  EXPORT_SYMBOL_GPL(unregister_virtio_driver);
> >  
> > +static int virtio_device_of_init(struct virtio_device *dev)
> > +{
> > +   struct device_node *np, *pnode = dev_of_node(dev->dev.parent);
> > +   char compat[] = "virtio,XXXXXXXX"; /* Reserve enough space 32-bit id */
> > +   int ret, count;
> > +
> > +   if (!pnode)
> > +           return 0;
> > +
> > +   count = of_get_available_child_count(pnode);
> > +   if (!count)
> > +           return 0;
> > +
> > +   /* There can be only 1 child node */
> > +   if (WARN_ON(count > 1))
> > +           return -EINVAL;
> > +
> > +   np = of_get_next_available_child(pnode, NULL);
> > +   if (WARN_ON(!np))
> > +           return -ENODEV;
> > +
> > +   BUG_ON(snprintf(compat, sizeof(compat), "virtio,%x", dev->id.device) >=
> > +          sizeof(compat));
> > +
> > +   if (!of_device_is_compatible(np, compat)) {
> 
> 
> This broke powerpc/pseries as there these virtio devices are PCI so
> there is no "compat" - PCI vendor id/device ids play role of "compat".
> Thanks,

Hmm now that you say this I wonder why do we bother
with this check, too. When can this be invoked for something
that is not a virtio device? And is it enough to just
skip of_node initialization then?


> 
> 
> 
> > +           ret = -EINVAL;


So basically ret = 0 above?


> > +           goto out;
> > +   }
> > +
> > +   dev->dev.of_node = np;
> > +   return 0;
> > +
> > +out:
> > +   of_node_put(np);
> > +   return ret;
> > +}
> > +
> >  /**
> >   * register_virtio_device - register virtio device
> >   * @dev        : virtio device to be registered
> > @@ -343,6 +384,10 @@ int register_virtio_device(struct virtio_device *dev)
> >     dev->index = err;
> >     dev_set_name(&dev->dev, "virtio%u", dev->index);
> >  
> > +   err = virtio_device_of_init(dev);
> > +   if (err)
> > +           goto out_ida_remove;
> > +
> >     spin_lock_init(&dev->config_lock);
> >     dev->config_enabled = false;
> >     dev->config_change_pending = false;
> > @@ -362,10 +407,16 @@ int register_virtio_device(struct virtio_device *dev)
> >      */
> >     err = device_add(&dev->dev);
> >     if (err)
> > -           ida_simple_remove(&virtio_index_ida, dev->index);
> > +           goto out_of_node_put;
> > +
> > +   return 0;
> > +
> > +out_of_node_put:
> > +   of_node_put(dev->dev.of_node);
> > +out_ida_remove:
> > +   ida_simple_remove(&virtio_index_ida, dev->index);
> >  out:
> > -   if (err)
> > -           virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> > +   virtio_add_status(dev, VIRTIO_CONFIG_S_FAILED);
> >     return err;
> >  }
> >  EXPORT_SYMBOL_GPL(register_virtio_device);
> > 
> 
> -- 
> Alexey

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