Re: [PATCH V4 5/6] usb: host: xhci-tegra: Add Tegra234 XHCI support

[Jon Hunter <jonathanh@nvidia.com>]

On 22/11/2022 16:07, Greg KH wrote:
> On Fri, Nov 18, 2022 at 03:40:05PM +0000, Jon Hunter wrote:
>> From: Sing-Han Chen <singhanc@nvidia.com>
>>
>> This change adds Tegra234 XUSB host mode controller support.
>>
>> In Tegra234, some of the registers have moved to bar2 space.
>> The new soc variable has_bar2 indicates the chip with bar2
>> area. This patch adds new reg helper to let the driver reuse
>> the same code for those chips with bar2 support.
>>
>> Signed-off-by: Sing-Han Chen <singhanc@nvidia.com>
>> Co-developed-by: Wayne Chang <waynec@nvidia.com>
>> Signed-off-by: Wayne Chang <waynec@nvidia.com>
>> Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
> 
> This is should be much slower with the additional redirection.  Is it
> noticable on this hardware platform with, and without this change?  Or
> is the hardware slow enough that it doesn't even show up as a speed
> decrease?
Wayne, do we have any inputs on this?

I know that we have been using this implementation now for some time on 
the kernels we ship and that would be tested on Tegra210, Tegar186, 
Tegra194 and Tegra234. So I assume that the performance there is good, 
but not sure about Tegra124.

Jon

-- 
nvpublic