On Tue, Jan 13, 2015 at 3:25 PM, Suman Anna [off-list ref] wrote:

Hi Rob,

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

quoted

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")?

I believe that's the one.

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()?

IIRC, the problem is inserting a resource twice on add from 2
different nodes, not the removal path. Perhaps we could make a
collision non-fatal for in the DT case. Grant may have some ideas on
what's needed here.

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

Yes, I know.

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.

Missed this one. I'll reply to that patch.

Rob

regards
Suman

quoted

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