Re: [PATCH v5 0/3] Add logic to consolidate TRBs for Synopsys xHC

[Tejas Joglekar <Tejas.Joglekar@synopsys.com>]

Hi,
On 11/6/2020 9:36 PM, Tejas Joglekar wrote:
> Hi Felipe,
> On 10/28/2020 8:50 PM, Tejas Joglekar wrote:
>> Hi,
>> On 10/28/2020 8:12 PM, Mathias Nyman wrote:
>>> On 27.10.2020 20.28, Tejas Joglekar wrote:
>>>> Hi Mathias,
>>>> On 10/16/2020 6:34 PM, Tejas Joglekar wrote:
>>>>> The Synopsys xHC has an internal TRB cache of size TRB_CACHE_SIZE for
>>>>> each endpoint. The default value for TRB_CACHE_SIZE is 16 for SS and 8
>>>>> for HS. The controller loads and updates the TRB cache from the
>>>>> transfer ring in system memory whenever the driver issues a start
>>>>> transfer or update transfer command.
>>>>>
>>>>> For chained TRBs, the Synopsys xHC requires that the total amount of
>>>>> bytes for all TRBs loaded in the TRB cache be greater than or equal to
>>>>> 1 MPS. Or the chain ends within the TRB cache (with a last TRB).
>>>>>
>>>>> If this requirement is not met, the controller will not be able to
>>>>> send or receive a packet and it will hang causing a driver timeout and
>>>>> error.
>>>>>
>>>>> This patch set adds logic to the XHCI driver to detect and prevent this
>>>>> from happening along with the quirk to enable this logic for Synopsys
>>>>> HAPS platform.
>>>>>
>>>>> Based on Mathias's feedback on previous implementation where consolidation
>>>>> was done in TRB cache, with this patch series the implementation is done
>>>>> during mapping of the URB by consolidating the SG list into a temporary
>>>>> buffer if the SG list buffer sizes within TRB_CACHE_SIZE is less than MPS.
>>>>>
>>>>> Changes since v4:
>>>>>  - Updated [Patch 3/3] platform data structure initialization
>>>>>  - Trivial changes in commit wordings
>>>>>
>>>>> Changes since v3:
>>>>>  - Removed the dt-binding patch
>>>>>  - Added new patch to pass the quirk as platform data
>>>>>  - Modified the patch to set the quirk
>>>>>
>>>>> Changes since v2:
>>>>>  - Modified the xhci_unmap_temp_buffer function to unmap dma and c
>>>>>    the dma flag
>>>>>  - Removed RFC tag
>>>>>
>>>>> Changes since v1:
>>>>>  - Comments from Greg are addressed on [PATCH 4/4] and [PATCH 1/4]
>>>>>  - Renamed the property and quirk as in other patches based on [PATCH 1/4]
>>>>>
>>>>>
>>>>>
>>>>> Tejas Joglekar (3):
>>>>>   usb: xhci: Set quirk for XHCI_SG_TRB_CACHE_SIZE_QUIRK
>>>>>   usb: xhci: Use temporary buffer to consolidate SG
>>>>>   usb: dwc3: Pass quirk as platform data
>>>>>
>>>>>  drivers/usb/dwc3/host.c      |  10 +++
>>>>>  drivers/usb/host/xhci-plat.c |   3 +
>>>>>  drivers/usb/host/xhci-ring.c |   2 +-
>>>>>  drivers/usb/host/xhci.c      | 137 ++++++++++++++++++++++++++++++++++-
>>>>>  drivers/usb/host/xhci.h      |   5 ++
>>>>>  5 files changed, 155 insertions(+), 2 deletions(-)
>>>>>
>>>> I have removed the dependency on setting quirk through device tree binding
>>>> and added the quirk using platform data. Can you please review and if 
>>>> everything looks OK, can you please add this patch series to your tree?
>>> Sure, there aren't any functional changes to xhci since v3 of this series right?
>>> And if I remember correctly Felipe didn't have any objections to the dwc3 part either.
>>>
>> You are right, there are no functional changes to xhci since v3.
>>
>>> Felipe, do you want to take the 3/3 dwc3 patch separately after 1/3 and 2/3 are in, or should
>>> I take them all, or ask if Greg would like to pick up this series?
>>>
> How would you like Mathias to go about merging the patch series?
@Felipe: Any input on this ?


Thanks & Regards,

Tejas Joglekar