Date:	Fri, 28 Oct 2011 15:03:36 +0300
From:	Tero Kristo <t-kristo@...com>
To:	"Munegowda, Keshava" <keshava_mgowda@...com>
CC:	Paul Walmsley <paul@...an.com>,
	"Cousson, Benoit" <b-cousson@...com>,
	"Basak, Partha" <p-basak2@...com>, "Balbi, Felipe" <balbi@...com>,
	<parthab@...ia.ti.com>, <linux-usb@...r.kernel.org>,
	<linux-omap@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	"Gadiyar, Anand" <gadiyar@...com>, <sameo@...ux.intel.com>,
	<tony@...mide.com>, "Hilman, Kevin" <khilman@...com>,
	<johnstul@...ibm.com>,
	"Sripathy, Vishwanath" <vishwanath.bs@...com>
Subject: Re: [PATCH 2/5 v11] arm: omap: usb: ehci and ohci hwmod structures for omap3

Hi Again,

I created a new version of the patch which should be better than this
hack, I'll send it as an RFC to the l-o list in a bit.

On Thu, 2011-10-13 at 13:49 +0200, Munegowda, Keshava wrote:
> On Thu, Oct 13, 2011 at 4:58 PM, Tero Kristo <t-kristo@...com> wrote:
> > On Thu, 2011-10-13 at 09:12 +0200, Munegowda, Keshava wrote:
> >> On Tue, Sep 27, 2011 at 6:48 PM, Munegowda, Keshava
> >> <keshava_mgowda@...com> wrote:
> >> > On Tue, Sep 27, 2011 at 6:12 PM, Tero Kristo <t-kristo@...com> wrote:
> >> >> On Tue, 2011-09-27 at 08:04 +0200, Basak, Partha wrote:
> >> >>> >
> >> >> Texas Instruments Oy, Tekniikantie 12, 02150 Espoo. Y-tunnus: 0115040-6. Kotipaikka: Helsinki
> >> >>
> >> >>
> > Texas Instruments Oy, Porkkalankatu 22, 00180 Helsinki, Finland. Business ID: 0115040-6. Domicile: Helsinki
> >
> > 
Texas Instruments Oy, Porkkalankatu 22, 00180 Helsinki, Finland. Business ID: 0115040-6. Domicile: Helsinki
 
-----Original Message-----

> >
> >> >>
> >> >>> >From: Munegowda, Keshava [mailto:keshava_mgowda@...com]
> >> >>> >Sent: Monday, September 26, 2011 7:49 PM
> >> >>> >To: Paul Walmsley; Tero Kristo; b-cousson@...com; balbi@...com;
> >> >>> >parthab@...ia.ti.com
> >> >>> >Cc: linux-usb@...r.kernel.org; linux-omap@...r.kernel.org; linux-
> >> >>> >kernel@...r.kernel.org; gadiyar@...com; sameo@...ux.intel.com;
> >> >>> >tony@...mide.com; khilman@...com; johnstul@...ibm.com;
> >> >>> >vishwanath.bs@...com
> >> >>> >Subject: Re: [PATCH 2/5 v11] arm: omap: usb: ehci and ohci hwmod
> >> >>> >structures for omap3
> >> >>> >
> >> >>> >On Sat, Sep 24, 2011 at 12:00 PM, Paul Walmsley <paul@...an.com> wrote:
> >> >>> >> On Fri, 23 Sep 2011, Munegowda, Keshava wrote:
> >> >>> >>
> >> >>> >>> On Thu, Sep 22, 2011 at 11:31 PM, Paul Walmsley <paul@...an.com>
> >> >>> >wrote:
> >> >>> >>>
> >> >>> >>> But the question arises here , why do we need these ehci and ohci as
> >> >>> >two
> >> >>> >>> different hwmods containing only irq and base address? It is required
> >> >>> >>> for future - to implement remote wakeup feature for ehci and ohci
> >> >>> >ports
> >> >>> >>> depending on irq-chain handler patches by Tero. Separate hwmods for
> >> >>> >ehci
> >> >>> >>> and ohci are needed to enable prcm chain-handler to uniquely identify
> >> >>> >>> the wakeup source as ehci or ohci and call only the corresponding
> >> >>> >>> interrupt handler. We will be using omap_hwmod_mux_init for ehci and
> >> >>> >>> ohci hwmods to enable I/O wakeup capability for respective IO-pads.
> >> >>> >>> Depending on the particular wakeup source(ehci/ohci), the
> >> >>> >corresponding
> >> >>> >>> ehci or ohci irq handler will be called.
> >> >>> >>>
> >> >>> >>> If ehci and ohci are combined with usbhs hwmod as a single hwmod ,
> >> >>> >then
> >> >>> >>> for every wakeup (either ehci or ohci port wakeup) only the first
> >> >>> >>> interrupt handler will be called (please look at the function
> >> >>> >>> omap_hwmod_mux_handle_irq of
> >> >>> >>>
> >> >>> >>> /arch/arm/mach-omap2/mux.c file ; in tero's latest patch:
> >> >>> >>> http://www.mail-archive.com/linux-omap@vger.kernel.org/msg53139.html)
> >> >>> >>> , so in this
> >> >>> >>> case, if ehci interrupt is the first interrupt , then even for ohci
> >> >>> >wakeup
> >> >>> >>> , only ehci interrupt will get called; which will break the
> >> >>> >functionality.
> >> >>> >>
> >> >>> >> Any reason why this couldn't be handled either by:
> >> >>> >>
> >> >>> >> 1. adding an IRQ number field to struct omap_hwmod_mux_info, and
> >> >>> >changing
> >> >>> >> _omap_hwmod_mux_handle_irq() to raise that IRQ number?
> >> >>> >
> >> >>> >
> >> >>> >yes, it is possible by changing the existing irq-chain handler by tero
> >> >>> >Kristo
> >> >>> >
> >> >>> >I am looping tero too.
> >> >>> >
> >> >>> >So here are new requirements for the irq-chain handler
> >> >>> >
> >> >>> >1. The hwmod should have have option to have multiple mux structures
> >> >>> >
> >> >>> >This is something like:
> >> >>> >
> >> >>> >The existing mux structure definition in omap_hwmod [file:
> >> >>> >/arch/arm/plat-omap/include/plat/omap_hwmod.h ] structure
> >> >>> >
> >> >>> >     struct omap_hwmod_mux_info      *mux;
> >> >>> >
> >> >>> >it should changed to
> >> >>> >
> >> >>> >     struct omap_hwmod_mux_info      **pmux;
> >> >>> >         U32                                            mux_cnt;
> >> >>> >
> >> >>> >
> >> >>> >pmux - pointers to mux ; array of mux structures.
> >> >>> >mux_cnt - number of mux per hwmod.
> >> >>> >
> >> >>> >
> >> >>> >2. The mux  omap_hwmod_mux_info  structure should have new member
> >> >>> >called irq, like as follows:
> >> >>> >
> >> >>> >struct omap_hwmod_mux_info {
> >> >>> >     int                             nr_pads;
> >> >>> >     ...
> >> >>> >        ....
> >> >>> >        u32                           irq;
> >> >>> >
> >> >>> >};
> >> >>> >
> >> >>> >Upon wakeup of the I/O pad of the mux , the irq-chain handler should
> >> >>> >invoke the irq handler of the irq numbered <map_hwmod_mux_info.irq>
> >> >>> >
> >> >>> >3.  There should be "SOME WAY" to supply the irqs  from hwmod
> >> >>> >structure (omap_hwmod) to mux structure (omap_hwmod_mux_info)
> >> >>> >
> >> >>> >
> >> >>> >if you , tero and other opensource people are aligned on the proposed
> >> >>> >changes on the irq-handler ;
> >> >>> >then it is possible to have two hwmods ( usbhs and tll) for usbhost
> >> >>> >driver.
> >> >>> >please let me know you comments on the above approach.
> >> >>> >
> >> >>>
> >> >>> Hello Tero,
> >> >>>
> >> >>> I would like to draw your attention to the following thread:
> >> >>>
> >> >>> We need to support the following:
> >> >>> 1. Ability to associate multiple mux info to a hwmod.
> >> >>> 2. Able to associate a particular irq handler to a mux info.
> >> >>> 3. PRCM Chain handler should loop through all mux-info arrays
> >> >>>    for a particular hwmod to identify the possible wakeup source(s)
> >> >>>    and call the appropriate irq handler for that mux-info.
> >> >>>    (It is possible that both mux-info are woken up in which case both
> >> >>> handlers should be called).
> >> >>>
> >> >>> To give you a little more perspective, EHCI & OHCI are co-controllers
> >> >>> under UHH/TLL.
> >> >>> They do not get presented separately to the OCP bus, hence do not qualify
> >> >>> as separate hwmods
> >> >>> (Paul had objected to the design approach representing EHCI & OHCI as
> >> >>> different hwmods).
> >> >>>
> >> >>> However, we need a mechanism to efficiently identify/distinguish
> >> >>> remote-wakeup, connect/disconnect
> >> >>> On to an EHCI port vs an OHCI port & call only the correct interrupt
> >> >>> handler(EHCI or OHCI).
> >> >>>
> >> >>>  To incorporate this, chain handler implementation would need some
> >> >>> enhancements.
> >> >>>  We can look into the details in the next merge window cycle in
> >> >>> conjunction with aggressive clock management support for EHCI/OHCI.
> >> >>>  But fundamentally, if you are aligned to the approach, we can go ahead
> >> >>> collapsing the EHCI & OHCI hwmods into one.
> >> >>
> >> >> Hi,
> >> >>
> >> >> So, you would need a mechanism to do something like this:
> >> >>
> >> >> pad a or b wakeup detected -> irq0
> >> >> pad c or d wakeup detected -> irq1?
> >> >
> >> > yes, if get something like this , its perfect.
> >>
> >> Hi Tero
> >>            Are you posting the patches with these changes?
> >> please let me know when you will be able to post the patches.
> >> so that I start the design of usb host remote wakeup using your changes.
> >>
> >> regards
> >> keshava
> >>
> >
> > Sorry for the delay, but I am still not quite sure how this should be
> > handled for upstream. Attached is a proposal hack patch that should
> > work, you can at least try it out to see what happens. It applies on top
> > of my latest PRCM chain handler set (version 9.) Patch desc contains a
> > guide how to use it.
> >
> > -Tero
> 
> 
> Thanks tero,
>           we are still in the internal design discussion of usbhs remote wakeup.
> but, we are looking for the upstreamable code.
> I request please send it as formal patch so that we will align with
> Paul, benoit, kevin
> Felipe and all other USB and PM experts.
> 
> regards
> keshava


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