Re: [PATCH v12 6/9] usb: xhci: use bus->sysdev for DMA configuration

From: Roger Quadros <rogerq@ti.com>
To: Jack Pham <jackp@codeaurora.org>, Peter Chen <peter.chen@nxp.com>
Cc: <gregkh@linuxfoundation.org>, <stern@rowland.harvard.edu>,
	<ulf.hansson@linaro.org>, <broonie@kernel.org>, <sre@kernel.org>,
	<robh+dt@kernel.org>, <shawnguo@kernel.org>, <rjw@rjwysocki.net>,
	<dbaryshkov@gmail.com>, <heiko@sntech.de>,
	<linux-arm-kernel@lists.infradead.org>, <p.zabel@pengutronix.de>,
	<devicetree@vger.kernel.org>, <pawel.moll@arm.com>,
	<mark.rutland@arm.com>, <linux-usb@vger.kernel.org>,
	<arnd@arndb.de>, <s.hauer@pengutronix.de>,
	<mail@maciej.szmigiero.name>, <troy.kisky@boundarydevices.com>,
	<festevam@gmail.com>, <oscar@naiandei.net>,
	<stephen.boyd@linaro.org>, <linux-pm@vger.kernel.org>,
	<stillcompiling@gmail.com>, <linux-kernel@vger.kernel.org>,
	<mka@chromium.org>, <vaibhav.hiremath@linaro.org>,
	<gary.bisson@boundarydevices.com>, <hverkuil@xs4all.nl>,
	<krzk@kernel.org>, Sriram Dash <sriram.dash@nxp.com>,
	Mathias Nyman <mathias.nyman@linux.intel.com>
Subject: Re: [PATCH v12 6/9] usb: xhci: use bus->sysdev for DMA configuration
Date: Thu, 9 Feb 2017 13:53:25 +0200	[thread overview]
Message-ID: <85873d69-5664-0603-8cbd-a250d29ac335@ti.com> (raw)
In-Reply-To: <20170208204300.GC8068@usblab-sd-06.qualcomm.com>

On 08/02/17 22:43, Jack Pham wrote:
> Hi Peter, Sriram, Arnd,
> 
> On Mon, Feb 06, 2017 at 05:13:38PM +0800, Peter Chen wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>>
>> For xhci-hcd platform device, all the DMA parameters are not
>> configured properly, notably dma ops for dwc3 devices. So, set
>> the dma for xhci from sysdev. sysdev is pointing to device that
>> is known to the system firmware or hardware.
>>
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>> Signed-off-by: Sriram Dash <sriram.dash@nxp.com>
>> Tested-by: Baolin Wang <baolin.wang@linaro.org>
>> Tested-by: Vivek Gautam <vivek.gautam@codeaurora.org>
>> Tested-by: Alexander Sverdlin <alexander.sverdlin@nokia.com>
>> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
>> ---
>> diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
>> index 6d33b42..7a9c860 100644
>> --- a/drivers/usb/host/xhci-plat.c
>> +++ b/drivers/usb/host/xhci-plat.c
> 
>> -	hcd = usb_create_hcd(driver, &pdev->dev, dev_name(&pdev->dev));
>> +	hcd = __usb_create_hcd(driver, sysdev, &pdev->dev,
>> +			       dev_name(&pdev->dev), NULL);
> 
> As mentioned already in [1], usb_create_shared_hcd() is called to create
> the second bus, however it also needs to be converted.
> 
> Not exactly as Roger's suggestion but this worked for me:
> 
> -       xhci->shared_hcd = usb_create_shared_hcd(driver, &pdev->dev,
> +       xhci->shared_hcd = __usb_create_hcd(driver, sysdev, &pdev->dev,
>                         dev_name(&pdev->dev), hcd);

But we're creating a shared_hcd and there is an API for that so why not use it
instead of calling __usb_create_hcd()?

>         if (!xhci->shared_hcd) {
>                 ret = -ENOMEM;
> 
> Without this, SuperSpeed devices fail to enumerate:
> 
>  usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
>  usb 2-1: device descriptor read/8, error -11
>  usb 2-1: new SuperSpeed USB device number 2 using xhci-hcd
>  usb 2-1: device descriptor read/8, error -11
>  usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
>  usb 2-1: device descriptor read/8, error -11
>  usb 2-1: new SuperSpeed USB device number 3 using xhci-hcd
>  usb 2-1: device descriptor read/8, error -11
>  <and continues...>
> 
> Thanks,
> Jack
> 
> [1] https://lkml.org/lkml/2016/12/9/240
> 

-- 
cheers,
-roger