From: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> To: Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org> Cc: Tony Prisk <linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org>, Greg KH <gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>, devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Florian Fainelli <florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>, Grant Likely <grant.likely-s3s/WqlpOiPyB63q8FvJNQ@public.gmane.org> Subject: Re: [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver Date: Mon, 22 Oct 2012 11:48:29 -0600 [thread overview] Message-ID: <508586ED.1010106@wwwdotorg.org> (raw) In-Reply-To: <Pine.LNX.4.44L0.1210221324580.1724-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> On 10/22/2012 11:34 AM, Alan Stern wrote: > On Mon, 22 Oct 2012, Stephen Warren wrote: > >> On 10/20/2012 04:10 PM, Tony Prisk wrote: >>> Add a binding document for ehci-platform driver. > >>> +Optional properties: >>> +- caps-offset : offset to the capabilities register (default = 0) >>> +- has-tt : controller has transaction translator(s). >>> +- has-synopsys-hc-bug : controller has the synopsys hc bug >> >> That would normally be determined by the driver based on the particular >> compatible value that is in device tree. > > I don't understand this comment. Isn't "has-synopsys-hc-bug" the > compatible value in question? "compatible value" in this context means that value of the property named "compatible". >>> +- big-endian : descriptors and registers are both big endian. This >>> + is the equivalent of specifying big-endian-desc and big-endian-regs. >>> +OR >>> +- big-endian-desc : descriptors are in big-endian format >>> +- big-endian-regs : mmio is in big-endian format >> >> Hmmm. That looks odd. Presumably if those properties aren't specified, >> the default is little-endian? Shouldn't this be a tri-state: big, >> little, native, with default native? I don't know what the EHCI >> specification mandates here (and if it does mandate something, the >> default should match the specification). Isn't this something that >> readl/writel would take care of, or are there cases where the register >> endianness of just this one HW block mismatches all other HW blocks? > > The EHCI spec assumes a PCI implementation; it doesn't consider other > sorts. And it doesn't say anything about the endianness of multi-byte > descriptors in memory. OK, so does this binding default to assuming little-endian (which I assume matches PCI), unless the big-endian properties are given? Is the case of little-endian EHCI registers on a big-endian CPU a common enough thing that adding a third state native-endian wouldn't be useful? -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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From: swarren@wwwdotorg.org (Stephen Warren) To: linux-arm-kernel@lists.infradead.org Subject: [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver Date: Mon, 22 Oct 2012 11:48:29 -0600 [thread overview] Message-ID: <508586ED.1010106@wwwdotorg.org> (raw) In-Reply-To: <Pine.LNX.4.44L0.1210221324580.1724-100000@iolanthe.rowland.org> On 10/22/2012 11:34 AM, Alan Stern wrote: > On Mon, 22 Oct 2012, Stephen Warren wrote: > >> On 10/20/2012 04:10 PM, Tony Prisk wrote: >>> Add a binding document for ehci-platform driver. > >>> +Optional properties: >>> +- caps-offset : offset to the capabilities register (default = 0) >>> +- has-tt : controller has transaction translator(s). >>> +- has-synopsys-hc-bug : controller has the synopsys hc bug >> >> That would normally be determined by the driver based on the particular >> compatible value that is in device tree. > > I don't understand this comment. Isn't "has-synopsys-hc-bug" the > compatible value in question? "compatible value" in this context means that value of the property named "compatible". >>> +- big-endian : descriptors and registers are both big endian. This >>> + is the equivalent of specifying big-endian-desc and big-endian-regs. >>> +OR >>> +- big-endian-desc : descriptors are in big-endian format >>> +- big-endian-regs : mmio is in big-endian format >> >> Hmmm. That looks odd. Presumably if those properties aren't specified, >> the default is little-endian? Shouldn't this be a tri-state: big, >> little, native, with default native? I don't know what the EHCI >> specification mandates here (and if it does mandate something, the >> default should match the specification). Isn't this something that >> readl/writel would take care of, or are there cases where the register >> endianness of just this one HW block mismatches all other HW blocks? > > The EHCI spec assumes a PCI implementation; it doesn't consider other > sorts. And it doesn't say anything about the endianness of multi-byte > descriptors in memory. OK, so does this binding default to assuming little-endian (which I assume matches PCI), unless the big-endian properties are given? Is the case of little-endian EHCI registers on a big-endian CPU a common enough thing that adding a third state native-endian wouldn't be useful?
next prev parent reply other threads:[~2012-10-22 17:48 UTC|newest] Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-10-20 22:10 [PATCH v2 0/2] Update ehci-platform driver to support devicetree Tony Prisk 2012-10-20 22:10 ` Tony Prisk [not found] ` <1350771032-11527-1-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org> 2012-10-20 22:10 ` [PATCH v2 1/2] USB: Update EHCI-platform driver to devicetree Tony Prisk 2012-10-20 22:10 ` Tony Prisk [not found] ` <1350771032-11527-2-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org> 2012-10-21 2:02 ` Alan Stern 2012-10-21 2:02 ` Alan Stern 2012-10-22 14:51 ` Alan Stern 2012-10-20 22:10 ` [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver Tony Prisk 2012-10-20 22:10 ` Tony Prisk [not found] ` <1350771032-11527-3-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org> 2012-10-21 17:34 ` Florian Fainelli 2012-10-21 17:34 ` Florian Fainelli 2012-10-22 16:07 ` Stephen Warren 2012-10-22 16:07 ` Stephen Warren [not found] ` <50856F41.7000205-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-22 17:34 ` Alan Stern 2012-10-22 17:34 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210221324580.1724-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-22 17:48 ` Stephen Warren [this message] 2012-10-22 17:48 ` Stephen Warren [not found] ` <508586ED.1010106-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-22 19:00 ` Alan Stern 2012-10-22 19:00 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210221443580.1724-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-22 22:10 ` Stephen Warren 2012-10-22 22:10 ` Stephen Warren [not found] ` <5085C470.4040707-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-23 14:10 ` Alan Stern 2012-10-23 14:10 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210231004310.1635-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-23 16:15 ` Stephen Warren 2012-10-23 16:15 ` Stephen Warren [not found] ` <5086C2B0.6070006-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-23 17:59 ` Alan Stern 2012-10-23 17:59 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210231340340.1635-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-23 18:47 ` Stephen Warren 2012-10-23 18:47 ` Stephen Warren [not found] ` <5086E62D.8040407-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-23 19:33 ` Alan Stern 2012-10-23 19:33 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210231522230.1635-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-23 20:06 ` Rob Herring 2012-10-23 20:06 ` Rob Herring [not found] ` <5086F8D6.5050605-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2012-10-24 14:57 ` Alan Stern 2012-10-24 14:57 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241013310.1481-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 15:26 ` Sebastian Andrzej Siewior 2012-10-24 15:26 ` Sebastian Andrzej Siewior [not found] ` <20121024152652.GG4368-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org> 2012-10-24 16:16 ` Stephen Warren 2012-10-24 16:16 ` Stephen Warren [not found] ` <5088145F.1040504-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-24 16:36 ` Florian Fainelli 2012-10-24 16:36 ` Florian Fainelli 2012-10-24 16:38 ` Alan Stern 2012-10-24 16:38 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241233040.1282-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 16:44 ` Florian Fainelli 2012-10-24 16:44 ` Florian Fainelli 2012-10-24 18:04 ` Alan Stern 2012-10-24 18:04 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241358090.1282-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 18:18 ` Florian Fainelli 2012-10-24 18:18 ` Florian Fainelli 2012-10-24 16:45 ` Stephen Warren 2012-10-24 16:45 ` Stephen Warren [not found] ` <50881B19.3080609-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-24 17:46 ` Alan Stern 2012-10-24 17:46 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241329230.1282-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 18:09 ` Stephen Warren 2012-10-24 18:09 ` Stephen Warren [not found] ` <50882EED.9020200-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-24 18:55 ` Mitch Bradley 2012-10-24 18:55 ` Mitch Bradley [not found] ` <5088399F.2000102-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org> 2012-10-24 19:30 ` Alan Stern 2012-10-24 19:30 ` Alan Stern 2012-10-25 10:23 ` Sebastian Andrzej Siewior 2012-10-25 10:23 ` Sebastian Andrzej Siewior [not found] ` <20121025102301.GA3469-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org> 2012-10-25 14:36 ` Alan Stern 2012-10-25 14:36 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210251035270.1278-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-26 8:02 ` Sebastian Andrzej Siewior 2012-10-26 8:02 ` Sebastian Andrzej Siewior [not found] ` <20121026080254.GD3009-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org> 2012-10-26 14:54 ` Alan Stern 2012-10-26 14:54 ` Alan Stern 2012-10-25 15:53 ` Stephen Warren 2012-10-25 15:53 ` Stephen Warren 2012-10-24 19:41 ` Alan Stern 2012-10-24 19:41 ` Alan Stern 2012-10-24 16:44 ` Alan Stern 2012-10-24 16:44 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241238570.1282-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 16:48 ` Stephen Warren 2012-10-24 16:48 ` Stephen Warren 2012-10-24 17:42 ` Rob Herring 2012-10-24 17:42 ` Rob Herring [not found] ` <50882882.1090806-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> 2012-10-24 17:57 ` Alan Stern 2012-10-24 17:57 ` Alan Stern 2012-10-24 16:28 ` Stephen Warren 2012-10-24 16:28 ` Stephen Warren [not found] ` <50881727.10601-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org> 2012-10-24 16:54 ` Alan Stern 2012-10-24 16:54 ` Alan Stern [not found] ` <Pine.LNX.4.44L0.1210241249010.1282-100000-IYeN2dnnYyZXsRXLowluHWD2FQJk+8+b@public.gmane.org> 2012-10-24 17:37 ` Florian Fainelli 2012-10-24 17:37 ` Florian Fainelli
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