On Thu, Dec 10, 2020 at 7:02 PM Peter Chen <peter.chen@xxxxxxx> wrote: > > On 20-12-10 09:38:49, Rob Herring wrote: > > On Thu, Dec 10, 2020 at 7:42 AM Peter Chen <peter.chen@xxxxxxxxxx> wrote: > > > > > > From: Peter Chen <peter.chen@xxxxxxx> > > > > > > When a platform device is released, it frees the device platform_data > > > memory region using kfree, if the memory is not allocated by kmalloc, > > > it may run into trouble. See the below comments from kfree API. > > > > > > * Don't free memory not originally allocated by kmalloc() > > > * or you will run into trouble. > > > > > > For the device which is created dynamically using of_platform_populate, > > > if the platform_data is existed at of_dev_auxdata structure, the OF code > > > simply assigns the platform_data pointer to newly created device, but > > > not using platform_device_add_data to allocate one. For most of platform > > > data region at device driver, which may not be allocated by kmalloc, they > > > are at global data region or at stack region at some situations. > > > > auxdata is a "temporary" thing for transitioning to DT which I want to > > remove. So I don't really want to see it expanded nor new users. We've > > got about a dozen arm32 platforms and 5 cases under drivers/. > > > > How to handle the below user case: > Parent device creates child device through device tree node (eg, usb/dwc3, > usb/cdns3), there are some platform quirks at parent device(vendor glue > layer) need child device (core IP device) driver to handle. The quirks > are not limited to the hardware quirk, may include the callbacks, software > flag (eg: XHCI_DEFAULT_PM_RUNTIME_ALLOW/XHCI_SKIP_PHY_INIT, at > drivers/usb/host/xhci.h) The split of these between a platform specific driver and the core IP driver was just wrong to begin with. There should only be 1 driver with common 'library' functions like we do for every other case of common, licensed IP. Perhaps the core driver should stop pretending it is generic and figure out the quirks for itself by looking at the parent node. Rob
