From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Darren Hart <dvhart@linux.intel.com>
Cc: Linux Net Dev <netdev@vger.kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"H. Peter Anvin" <hpa@zytor.com>,
Peter Waskiewicz <peter.p.waskiewicz.jr@intel.com>,
Joe Perches <joe@perches.com>
Subject: Re: [PATCH net-next 2/2] pch_gbe: Add MinnowBoard support
Date: Fri, 19 Jul 2013 11:48:32 +0300 [thread overview]
Message-ID: <1374223712.31118.33.camel@smile> (raw)
In-Reply-To: <1374167552.4900.13.camel@envy.home>
On Thu, 2013-07-18 at 10:12 -0700, Darren Hart wrote:
> On Thu, 2013-07-18 at 11:14 +0300, Andy Shevchenko wrote:
> > On Wed, 2013-07-17 at 13:10 -0700, Darren Hart wrote:
[]
> > > --- a/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> > > +++ b/drivers/net/ethernet/oki-semi/pch_gbe/pch_gbe_main.c
> > > +static int pch_gbe_minnow_platform_init(struct pci_dev *pdev)
[]
> > Here perhaps you check pdata and GPIO line number (let's say != -1)
> > and call GPIO request helper.
>
> I was doing exactly this in local previous version, but I decided
> against it for a few reasons:
>
> o If I specify GPIO, I must also specify GPIO flags, GPIO label,
> GPIO assertion level, GPIO reset and rest timings (and that is
> assuming it's just a set, release, wait cycle).
Why so complicated? Just keep them as defaults inside function like you
did until we will have the actual board which requires those to be
altered.
> o Setting all this in pdata makes very specific to resetting this
> specific PHY, while others may have any number of other methods or
> procedures. It also excludes other sorts of platform initialization
> which might necessary. Specifying GPIO here makes the interface overly
> specific in my opinion.
>
> > Next is the name of the function, since you are resetting PHY, what if
> > you call it like pch_gbe_reset_by_gpio ?
>
> We would need to include PHY in here as we are not resetting the MAC,
> we are resetting the PHY. I think specifying it as being by gpio is
> also overly restrictive. If you look at my two new functions (for tx
> clock delay and hibernate) you can see an example of how we might go
> about such a function (which indeed I had in a previous version as
> pch_gbe_phy_physical_reset()). I dropped this as I felt it required too
> many fields to be added to the pdata and I was better off with platform
> specific init routines.
>
> You've presented an alternative approach, but it isn't clear to me what
> your reservations are with the one I took here. What are the problems
> with it?
My point is there should be no callback function like
pch_gbe_minnow_platform_init. It may be transformed to a more generic
helper which could be reused by an ACPI case as well.
But okay, it might be I missed the point. Are you going to provide an
ACPI tables for this IP or you just rely on PCI forever?
> > And most important one is the ACPI case. As far as I understand Minnow
> > board supports / will support ACPI5 variant of device enumeration. In
> > such case the GPIO line will come in the ACPI resources. Moreover, you
> > will have no struct pci_dev. I highly recommend to rewrite this as a
> > generic helper, which takes GPIO line number as an input parameter and
> > does the job.
>
> While the MinnowBoard will be expanding its use of ACPI, we do not
> intend to rewrite existing drivers (such as this one)
Again, what is wrong with ACPI, if ACPI could manage by itself that
stuff like specific GPIO lines. I assume ACPI will help a lot to avoid
this legacy approach with driver_data / callbacks and such things.
What did I miss?
> > > static DEFINE_PCI_DEVICE_TABLE(pch_gbe_pcidev_id) = {
> > > {.vendor = PCI_VENDOR_ID_INTEL,
> > > .device = PCI_DEVICE_ID_INTEL_IOH1_GBE,
> > > + .subvendor = PCI_VENDOR_ID_CIRCUITCO,
> > > + .subdevice = PCI_SUBSYSTEM_ID_CIRCUITCO_MINNOWBOARD,
> > > + .class = (PCI_CLASS_NETWORK_ETHERNET << 8),
> > > + .class_mask = (0xFFFF00),
> > > + .driver_data = (unsigned long) &pch_gbe_minnow_privdata
> >
> > No need space before &.
>
> Indeed. Fixed. I'll include when I resubmit after netdev opens.
And you perhaps have to use kernel_ulong_t instead of unsigned long.
--
Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Intel Finland Oy
next prev parent reply other threads:[~2013-07-19 8:48 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-17 20:10 [PATCH net-next 0/2] pch_gbe: Minow fix and MinnowBoard support Darren Hart
2013-07-17 20:10 ` [PATCH net-next 1/2] pch_gbe: Use PCH_GBE_PHY_REGS_LEN instead of 32 Darren Hart
2013-07-17 20:10 ` [PATCH net-next 2/2] pch_gbe: Add MinnowBoard support Darren Hart
2013-07-18 8:14 ` Andy Shevchenko
2013-07-18 17:12 ` Darren Hart
2013-07-19 8:48 ` Andy Shevchenko [this message]
2013-07-22 20:54 ` Darren Hart
2013-07-18 0:58 ` [PATCH net-next 0/2] pch_gbe: Minow fix and " David Miller
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