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From: Grant Likely <grant.likely@arm.com>
To: Andrew Lunn <andrew@lunn.ch>,
	Calvin Johnson <calvin.johnson@oss.nxp.com>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
	Jeremy Linton <jeremy.linton@arm.com>,
	Russell King - ARM Linux admin <linux@armlinux.org.uk>,
	Jon <jon@solid-run.com>,
	Cristi Sovaiala <cristian.sovaiala@nxp.com>,
	Ioana Ciornei <ioana.ciornei@nxp.com>,
	Andy Shevchenko <andy.shevchenko@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Madalin Bucur <madalin.bucur@oss.nxp.com>,
	netdev@vger.kernel.org, linux.cj@gmail.com,
	linux-acpi@vger.kernel.org, nd <nd@arm.com>
Subject: Re: [net-next PATCH v7 1/6] Documentation: ACPI: DSD: Document MDIO PHY
Date: Tue, 29 Sep 2020 16:53:47 +0100
Message-ID: <8dff0439-100c-cdee-915f-e793b55f9007@arm.com> (raw)
In-Reply-To: <20200929134302.GF3950513@lunn.ch>



On 29/09/2020 14:43, Andrew Lunn wrote:
> On Tue, Sep 29, 2020 at 10:47:03AM +0530, Calvin Johnson wrote:
>> Hi Grant,
>>
>> On Fri, Sep 25, 2020 at 02:34:21PM +0100, Grant Likely wrote:
>>>> +DSDT entry for MDIO node
>>>> +------------------------
>>>> +a) Silicon Component
>>>> +--------------------
>>>> +	Scope(_SB)
>>>> +	{
>>>> +	  Device(MDI0) {
>>>> +	    Name(_HID, "NXP0006")
>>>> +	    Name(_CCA, 1)
>>>> +	    Name(_UID, 0)
>>>> +	    Name(_CRS, ResourceTemplate() {
>>>> +	      Memory32Fixed(ReadWrite, MDI0_BASE, MDI_LEN)
>>>> +	      Interrupt(ResourceConsumer, Level, ActiveHigh, Shared)
>>>> +	       {
>>>> +		 MDI0_IT
>>>> +	       }
>>>> +	    }) // end of _CRS for MDI0
>>>> +	    Name (_DSD, Package () {
>>>> +	      ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"),
>>>> +	      Package () {
>>>> +		 Package () {"little-endian", 1},
>>>> +	      }
>>>
>>> Adopting the 'little-endian' property here makes little sense. This looks
>>> like legacy from old PowerPC DT platforms that doesn't belong here. I would
>>> drop this bit.
>>
>> I'm unable to drop this as the xgmac_mdio driver relies on this variable to
>> change the io access to little-endian. Default is big-endian.
>> Please see:
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/net/ethernet/freescale/xgmac_mdio.c?h=v5.9-rc7#n55
> 
> Hi Calvin
> 
> Are we talking about the bus controller endiannes, or the CPU
> endianness?

This is orthogonal to the MDIO bus issue. This is a legacy of the xgmac 
IP block originating in PowerPC platforms with a big-endian bus wiring. 
The flag here tells the driver to use little endian when accessing MMIO 
registers.

> If we are talking about the CPU endiannes, are you plan on supporting
> any big endian platforms using ACPI? If not, just hard code it.
> Newbie ACPI question: Does ACPI even support big endian CPUs, given
> its x86 origins? >
> If this is the bus controller endianness, are all the SoCs you plan to
> support via ACPI the same endianness? If they are all the same, you
> can hard code it.

I would agree. The ACPI and DT probe paths are different. It would be 
easy to automatically set the little-endian flag by default when xgmac 
is described via ACPI.

g.

  parent reply index

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-15  9:03 [net-next PATCH v7 0/6] ACPI support for dpaa2 MAC driver Calvin Johnson
2020-07-15  9:03 ` [net-next PATCH v7 1/6] Documentation: ACPI: DSD: Document MDIO PHY Calvin Johnson
2020-07-16  3:04   ` Florian Fainelli
2020-07-16  3:11     ` Andrew Lunn
2020-07-23 23:26   ` Jeremy Linton
2020-07-24 13:39     ` Andrew Lunn
2020-07-24 17:26       ` Jeremy Linton
2020-07-24 17:39         ` Florian Fainelli
2020-07-24 19:20           ` Andrew Lunn
2020-07-24 20:12             ` Andy Shevchenko
2020-07-24 20:13               ` Florian Fainelli
2020-07-24 20:20                 ` Andy Shevchenko
2020-07-25  7:36                   ` Calvin Johnson
2020-07-25 10:48                     ` Andy Shevchenko
2020-07-24 21:06               ` Russell King - ARM Linux admin
2020-07-27 17:03             ` Sudeep Holla
2020-07-24 19:14         ` Andrew Lunn
2020-07-27 17:21           ` Sudeep Holla
2020-07-28 20:34             ` Andrew Lunn
2020-07-28 20:59               ` Russell King - ARM Linux admin
2020-07-28 21:26                 ` Andy Shevchenko
2020-07-29 16:00               ` Rafael J. Wysocki
2020-07-31 15:08                 ` Andrew Lunn
2020-07-27 17:32           ` Jon Nettleton
     [not found]           ` <1595922651-sup-5323@galangal.danc.bne.opengear.com>
2020-07-28 20:45             ` Andrew Lunn
2020-07-28 20:56               ` Florian Fainelli
2020-07-28 21:28                 ` Andy Shevchenko
2020-07-28 21:40                   ` Florian Fainelli
2020-07-31 15:14                   ` Andrew Lunn
2020-09-25 13:22                     ` Grant Likely
2020-07-28 22:30             ` Jeremy Linton
2020-07-29  0:39               ` Florian Fainelli
2020-07-29  2:53                 ` Jeremy Linton
2020-07-29  3:16                   ` Florian Fainelli
2020-07-29  8:43                   ` Jon Nettleton
2020-07-29  9:39                     ` Calvin Johnson
2020-09-25 13:34   ` Grant Likely
2020-09-26  4:30     ` Calvin Johnson
2020-09-29  5:17     ` Calvin Johnson
2020-09-29 13:43       ` Andrew Lunn
2020-09-29 13:55         ` Andy Shevchenko
2020-09-29 14:32           ` Andrew Lunn
2020-09-29 14:46             ` Andy Shevchenko
2020-09-29 15:06               ` Andrew Lunn
2020-09-29 15:29               ` Arnd Bergmann
2020-09-29 14:44         ` Arnd Bergmann
2020-09-29 14:59           ` Andrew Lunn
2020-09-29 15:59             ` Grant Likely
2020-09-29 15:53         ` Grant Likely [this message]
2020-09-29 16:04           ` Calvin Johnson
2020-07-15  9:03 ` [net-next PATCH v7 2/6] net: phy: introduce device_mdiobus_register() Calvin Johnson
2020-07-16  3:05   ` Florian Fainelli
2020-07-15  9:03 ` [net-next PATCH v7 3/6] net/fsl: use device_mdiobus_register() Calvin Johnson
2020-07-16  3:05   ` Florian Fainelli
2020-07-15  9:03 ` [net-next PATCH v7 4/6] net: phy: introduce phy_find_by_mdio_handle() Calvin Johnson
2020-07-16  3:06   ` Florian Fainelli
2020-07-15  9:03 ` [net-next PATCH v7 5/6] phylink: introduce phylink_fwnode_phy_connect() Calvin Johnson
2020-07-15  9:04 ` [net-next PATCH v7 6/6] net: dpaa2-mac: Add ACPI support for DPAA2 MAC driver Calvin Johnson
2020-09-25 13:39 ` [net-next PATCH v7 0/6] ACPI support for dpaa2 " Grant Likely
2020-09-26  4:34   ` Calvin Johnson
2020-07-25 14:23 Calvin Johnson
2020-07-25 14:23 ` [net-next PATCH v7 1/6] Documentation: ACPI: DSD: Document MDIO PHY Calvin Johnson

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