From: Valentine Barshak <vbarshak@ru•mvista.com>
To: Dale Farnsworth <dale@farnsworth•org>
Cc: Linuxppc-dev@ozlabs•org
Subject: Re: [PATCH] PowerPC 440EPx Sequoia USB OHCI DTS entry
Date: Wed, 24 Oct 2007 18:23:50 +0400 [thread overview]
Message-ID: <471F5576.4060603@ru.mvista.com> (raw)
In-Reply-To: <20071024141041.GA13586@xyzzy.farnsworth.org>
Dale Farnsworth wrote:
> On Wed, Oct 24, 2007 at 05:44:51PM +0400, Valentine Barshak wrote:
>> Dale Farnsworth wrote:
>>> On Wed, Oct 24, 2007 at 03:19:14PM +0400, Valentine Barshak wrote:
>>>> Dale Farnsworth wrote:
>>>>> Valentine wrote:
>>>>>> Actually I also don't see much reason for the
>>>>>> USB_OHCI_HCD_PPC_OF_BE/USB_OHCI_HCD_PPC_OF_LE stuff.
>>>>>> Is this really needed?
>>>>> I think so. The SOC host controllers are BE and the PCI
>>>>> host controllers are LE. Or, do you have an alternative
>>>>> method of handling both types?
>>>> Yes, PCI controllers are LE, but do we really need user-selectable
>>>> USB_OHCI_HCD_PPC_OF_LE option, since USB_OHCI_LITTLE_ENDIAN is selected
>>>> by default for USB_OHCI_HCD_PCI?
>>>> The USB_OHCI_HCD_PPC_OF_LE/BE stuff is related to PPC OF glue only.
>>>> I think it's useless. We should always enable
>>>> USB_OHCI_BIG_ENDIAN_DESC and USB_OHCI_BIG_ENDIAN_MMIO for PPC OF
>>>> and the real LE/BE implementation should be selected by the
>>>> corresponding properties in the device tree.
>>> I agree that they don't need to be user selectable. It is far preferable
>>> to deduce their values from existing information, if possible.
>>>
>>> -Dale
>> This is the original thread:
>> http://ozlabs.org/pipermail/linuxppc-embedded/2006-November/025054.html
>>
>> I think the USB_OHCI_HCD_PPC_OF_LE/BE should be removed.
>> We can't avoid the slight overhead even using these options, since
>> USB_OHCI_BIG_ENDIAN_MMIO/DESC should always be anabled for PPC OF and we
>> we still enable USB_OHCI_LITTLE_ENDIAN for USB_OHCI_HCD_PCI even if
>> USB_OHCI_HCD_PPC_OF_LE is not set.
>
> I believe you are saying that we can select any valid combination
> of USB_OHCI_BIG_ENDIAN_DESC, USB_OHCI_BIG_ENDIAN_MMIO, and
> USB_OHCI_LITTLE_ENDIAN, without using USB_OHCI_HCD_PPC_OF_BE and
> USB_OHCI_HCD_PPC_OF_LE. I agree. It looks like we can get rid of
> these last two with zero loss in performance or functionality.
>
> Do you have a patch?
No I don't have it yet :)
I planed to make, test and submit it a bit later.
Thanks,
Valentine.
>
> -Dale
prev parent reply other threads:[~2007-10-24 14:23 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-10-08 14:26 [PATCH] PowerPC 440EPx Sequoia USB OHCI DTS entry Valentine Barshak
2007-10-23 15:33 ` Josh Boyer
2007-10-23 15:35 ` Valentine Barshak
2007-10-23 15:50 ` Josh Boyer
2007-10-23 17:03 ` Segher Boessenkool
2007-10-23 17:18 ` Valentine Barshak
2007-10-23 21:40 ` Dale Farnsworth
2007-10-24 11:19 ` Valentine Barshak
2007-10-24 12:08 ` Dale Farnsworth
2007-10-24 13:44 ` Valentine Barshak
2007-10-24 14:10 ` Dale Farnsworth
2007-10-24 14:23 ` Valentine Barshak [this message]
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