Hi Rob,

On 01/13/2015 02:38 PM, Rob Herring wrote:

On Wed, Jan 7, 2015 at 11:30 AM, Suman Anna [off-list ref] wrote:

quoted

Drivers can use of_platform_populate() to create platform devices
for children of the device main node, and a complementary API
of_platform_depopulate() is provided to delete these child platform
devices. The of_platform_depopulate() leverages the platform API
for performing the cleanup of these devices.

The platform device resources are managed differently between
of_device_add and platform_device_add, and this asymmetry causes
a kernel oops in platform_device_del during removal of the resources.
Manage the platform device resources similar to platform_device_add
to fix this kernel oops.

This is a known issue and has been attempted to be fixed before (I
believe there is a revert in mainline). The problem is there are known
devicetrees which have overlapping resources and they will break with
your change.

Are you referring to 02bbde7849e6 (Revert "of: use
platform_device_add")? That one seems to be in registration path, and
this crash is in the unregistration path. If so, to fix the crash,
should we be skipping the release_resource() for now in
platform_device_del for DT nodes, or replace platform_device_unregister
with of_device_unregister in of_platform_device_destroy()?

This is a common crash and we cannot use of_platform_depopulate() today
in drivers to complement of_platform_populate().

Also, the platform_data crash is independent of this, I could reproduce
that one even with using of_device_unregister in a loop in driver remove.

regards
Suman

Rob

quoted

Signed-off-by: Suman Anna <redacted>
---
 drivers/of/device.c | 38 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 37 insertions(+), 1 deletion(-)

diff --git a/drivers/of/device.c b/drivers/of/device.c
index 46d6c75c1404..fa27c1c71f29 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c

@@ -50,6 +50,8 @@ EXPORT_SYMBOL(of_dev_put);

 int of_device_add(struct platform_device *ofdev)
 {
+       int i, ret;
+
        BUG_ON(ofdev->dev.of_node == NULL);

        /* name and id have to be set so that the platform bus doesn't get

@@ -63,7 +65,41 @@ int of_device_add(struct platform_device *ofdev)
        if (!ofdev->dev.parent)
                set_dev_node(&ofdev->dev, of_node_to_nid(ofdev->dev.of_node));

-       return device_add(&ofdev->dev);
+       for (i = 0; i < ofdev->num_resources; i++) {
+               struct resource *p, *r = &ofdev->resource[i];
+
+               if (!r->name)
+                       r->name = dev_name(&ofdev->dev);
+
+               p = r->parent;
+               if (!p) {
+                       if (resource_type(r) == IORESOURCE_MEM)
+                               p = &iomem_resource;
+                       else if (resource_type(r) == IORESOURCE_IO)
+                               p = &ioport_resource;
+               }
+
+               if (p && insert_resource(p, r)) {
+                       dev_err(&ofdev->dev, "failed to claim resource %d\n",
+                               i);
+                       ret = -EBUSY;
+                       goto failed;
+               }
+       }
+
+       ret = device_add(&ofdev->dev);
+       if (ret == 0)
+               return ret;
+
+failed:
+       while (--i >= 0) {
+               struct resource *r = &ofdev->resource[i];
+               unsigned long type = resource_type(r);
+
+               if (type == IORESOURCE_MEM || type == IORESOURCE_IO)
+                       release_resource(r);
+       }
+       return ret;
 }

 int of_device_register(struct platform_device *pdev)
--

2.2.1