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From: Amit Virdi <amit.virdi@st.com>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 4/4] USB:gadget:designware Fix memory nonalignment issue
Date: Wed, 7 Mar 2012 12:44:48 +0530	[thread overview]
Message-ID: <4F570AE8.5070601@st.com> (raw)
In-Reply-To: <201203061108.12155.vapier@gentoo.org>

Dear Marek,

>>>>>    }
>>>>
>>>> This addresses EHCI cache problem, that's why you need bounce buffer,
>>>> right?
>>>
>>> No. The problem was we were copying data word-by-word to a non-word
>>> aligned memory in the USB gadget. So, this is different from the USB
>>> host controller issue.
>>
>> I see ... why isn't buffer aligned by the usb stack then?
>
> because it might not be a requirement higher up.  i.e. it's dealing with a
> data byte stream.  forcing all higher layers to use 32bit alignment because
> this host controller requires 32bit alignment in its FIFOs is incorrect.

The usb gadget is used by the usbtty so we can receive any number of 
bytes and, as Mike explains, we cannot force 32-bit alignment.

Thanks
Amit Virdi

  reply	other threads:[~2012-03-07  7:14 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-16 12:03 [U-Boot] [PATCH 0/4] USB: Add support for designware UDC Amit Virdi
2012-02-16 12:03 ` [U-Boot] [PATCH 1/4] USB:gadget:designware USB device controller (UDC) implementation Amit Virdi
2012-03-05 18:12   ` Marek Vasut
2012-03-06  4:32     ` Amit Virdi
2012-02-16 12:03 ` [U-Boot] [PATCH 2/4] USB:gadget:designware Device controller bugfixes Amit Virdi
2012-03-05 18:13   ` Marek Vasut
2012-03-06  4:34     ` Amit Virdi
2012-02-16 12:03 ` [U-Boot] [PATCH 3/4] USB:gadget:designware Support high speed Amit Virdi
2012-03-05 18:15   ` Marek Vasut
2012-03-06  5:44     ` Amit Virdi
2012-02-16 12:03 ` [U-Boot] [PATCH 4/4] USB:gadget:designware Fix memory nonalignment issue Amit Virdi
2012-03-05 18:21   ` Marek Vasut
2012-03-06  9:36     ` Amit Virdi
2012-03-06  9:51       ` Marek Vasut
2012-03-06 16:08         ` Mike Frysinger
2012-03-07  7:14           ` Amit Virdi [this message]
2012-03-06 16:09   ` Mike Frysinger
2012-03-07  7:04     ` Amit Virdi
2012-02-24 11:56 ` [U-Boot] [PATCH 0/4] USB: Add support for designware UDC Amit Virdi
2012-03-05 18:06   ` Marek Vasut

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