Re: [PATCH v2 1/1] cxl/test: Update mock dev array before calling platform_device_add()

[Li Ming <ming.li@zohomail.com>]

在 2026/5/21 20:25, Li Ming 写道:
>
> 在 2026/5/21 15:25, Alison Schofield 写道:
>> On Wed, May 20, 2026 at 08:14:57PM +0800, Li Ming wrote:
>>> CXL test environment hits the following error sometimes.
>>>
>>>   cxl_mem mem9: endpoint7 failed probe
>>>
>>> All mock memdevs are platform firmware devices added by cxl_test 
>>> module,
>>> and cxl_test module also provides a platform device driver for them to
>>> create a memdev device to CXL subsystem. cxl_test module uses
>>> cxl_rcd/mem_single/mem arrays to store different types of mock memdevs.
>>> CXL drivers calls registered mock functions for a mock memdev by
>>> checking if a given memdev is in these arrays.
>>>
>>> When cxl_test module adds these mock memdevs, it always calls
>>> platform_device_add() before adding them to a suitable mock memdev
>>> array. However, there is a small window where CXL drivers calls mock
>>> function for a added memdev before it added to a mock memdev array. In
>>> above case, cxl endpoint driver considers a added memdev was not a mock
>>> memdev, then calling devm_cxl_endpoint_decoders_setup() for it rather
>>> than mock_endpoint_decoders_setup().
>>>
>>> An appropriate solution is that adding a new mock device to a mock
>>> device array before calling platform_device_add() for it. It can
>>> guarantee the new mock device is visible to CXL subsystem.
>>>
>>> This patch introduces a new helped called 
>>> cxl_mock_platform_device_add()
>>> to handle the issue, and uses the function for all mock devices 
>>> addition.
>>>
>> Reviewed-by: Alison Schofield <alison.schofield@intel.com>
>
> Hi Alison,
>
>
> I missed that you mentioned putting platform_device_alloc() into the 
> helper. I will send out v3 for that.
>
>
After taking a look into the implementation, maybe keep current 
implementation would be better.

This helper is responsible for performing the platform_device_add() 
operation for all mock devices. However, each type of mock device has 
its own specific logic between platform_device_alloc() and 
platform_device_add().

If I move platform_device_alloc() into this helper,I will also have to 
incorporate all these device-specific implementations.

Ming

> Ming
>
>>
>>
>>> Fixes: 3a2b97b3210b ("cxl/test: Improve init-order fidelity relative 
>>> to real-world systems")
>>> Signed-off-by: Li Ming <ming.li@zohomail.com>
>>> ---
>>> Changes from v1:
>>> - Rebase to v7.1-rc4.
>>> - Introduce a new helper to handle the issue. (Alison)
>>> - Use new helper for all mock device addition.
>>> ---
>>>   tools/testing/cxl/test/cxl.c | 105 
>>> ++++++++++++++---------------------
>>>   1 file changed, 43 insertions(+), 62 deletions(-)
>>>