From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: "Dale Farnsworth" Date: Wed, 24 Oct 2007 07:10:41 -0700 To: Valentine Barshak Subject: Re: [PATCH] PowerPC 440EPx Sequoia USB OHCI DTS entry Message-ID: <20071024141041.GA13586@xyzzy.farnsworth.org> References: <20071008142658.GA15197@ru.mvista.com> <20071023214000.424.qmail@farnsworth.org> <471F2A32.8030202@ru.mvista.com> <20071024120804.GA1180@xyzzy.farnsworth.org> <471F4C53.1070506@ru.mvista.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <471F4C53.1070506@ru.mvista.com> Cc: Linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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? -Dale