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Subject[PATCH] of: use platform_device_add
Date
This allows platform_device_add a chance to call insert_resource on all
of the resources from OF. At a minimum this fills in proc/iomem and
presumably makes resource tracking and conflict detection work better.
However, it has the side effect of moving all OF generated platform
devices from /sys/devices to /sys/devices/platform/. It /shouldn't/
break userspace because userspace is not supposed to depend on the full
path (because userspace always does what it is supposed to, right?).

It also has a backup call to of_device_add() when running on PowerPC to
catch any devices that have overlapping regions. It will complain about
them, but it will not fail to register the device.

Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---

Greg, do you mind taking a look at this? The reason the OF code hasn't been
calling platform_device_add() directly to this point is:
a) there are some trees with resource overlays
b) I want the devices in /sys/devices not /sys/devices/platform.

I could easily add exceptions to platform_device_add() for both those cases, but
I don't like adding DT exceptions to the common code. However, I still need to
support the platforms that unfortunately have overlapping resources. This patch
does that by still calling the old path if platform_device_add() fails, but it
isn't nice either because of_device_add() has to duplicate
platform_device_add(). Blech. Plus the exception only applies for PowerPC.

So, how do you feel about having a 'relaxed' mode for platform_device_add()
which means it won't fail if resources overlap and maybe won't do the silly
platform_bus parent thing. Thoughts?

g.

drivers/of/platform.c | 28 ++++++++++++++++++++++++++--
1 file changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index b80891b..3d7ba40 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -203,6 +203,7 @@ struct platform_device *of_platform_device_create_pdata(
struct device *parent)
{
struct platform_device *dev;
+ int rc;

if (!of_device_is_available(np))
return NULL;
@@ -214,16 +215,39 @@ struct platform_device *of_platform_device_create_pdata(
#if defined(CONFIG_MICROBLAZE)
dev->archdata.dma_mask = 0xffffffffUL;
#endif
+ dev->name = dev_name(&dev->dev);
dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
- dev->dev.bus = &platform_bus_type;
dev->dev.platform_data = platform_data;
+ dev->dev.id = PLATFORM_DEVID_NONE;
+ /* device_add will assume that this device is on the same node as
+ * the parent. If there is no parent defined, set the node
+ * explicitly */
+ if (!parent)
+ set_dev_node(&dev->dev, of_node_to_nid(np));

/* We do not fill the DMA ops for platform devices by default.
* This is currently the responsibility of the platform code
* to do such, possibly using a device notifier
*/

- if (of_device_add(dev) != 0) {
+ rc = platform_device_add(dev);
+#ifdef CONFIG_POWERPC
+ /*
+ * This POWERPC block isn't pretty, but the commit that adds it is a
+ * little risky. There are possibly some powerpc platforms that have
+ * overlapping resources in the device tree. If so, then I want to find
+ * them, but I don't want to break support in the process. So, if
+ * platform_device_add() fails, then register the device anyway, but
+ * complain about it. Hopefully we can find and fix and problem
+ * platforms before removing this code.
+ */
+ if (rc == -EBUSY) {
+ dev_warn(&dev->dev, "WARNING: resource overlap in DT node %s\n",
+ np->full_name);
+ rc = of_device_add(dev);
+ }
+#endif
+ if (rc) {
platform_device_put(dev);
return NULL;
}
--
1.7.10.4


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