From: Michael Ellerman <mpe@ellerman•id.au>
To: "Bjorn Helgaas" <helgaas@kernel•org>, "Pali Rohár" <pali@kernel•org>
Cc: linux-kernel@vger•kernel.org, Paul Mackerras <paulus@samba•org>,
linux-pci@vger•kernel.org, Bjorn Helgaas <bhelgaas@google•com>,
linuxppc-dev@lists•ozlabs.org
Subject: Re: [PATCH] powerpc/fsl-pci: Fix Class Code of PCIe Root Port
Date: Mon, 25 Jul 2022 22:24:39 +1000 [thread overview]
Message-ID: <87r129bcs8.fsf@mpe.ellerman.id.au> (raw)
In-Reply-To: <20220722194226.GA1927257@bhelgaas>
Bjorn Helgaas <helgaas@kernel•org> writes:
> On Wed, Jul 06, 2022 at 12:10:43PM +0200, Pali Rohár wrote:
>> By default old pre-3.0 Freescale PCIe controllers reports invalid PCI Class
>> Code 0x0b20 for PCIe Root Port. It can be seen by lspci -b output on P2020
>> board which has this pre-3.0 controller:
>>
>> $ lspci -bvnn
>> 00:00.0 Power PC [0b20]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21)
>> !!! Invalid class 0b20 for header type 01
>> Capabilities: [4c] Express Root Port (Slot-), MSI 00
>>
>> Fix this issue by programming correct PCI Class Code 0x0604 for PCIe Root
>> Port to the Freescale specific PCIe register 0x474.
>>
>> With this change lspci -b output is:
>>
>> $ lspci -bvnn
>> 00:00.0 PCI bridge [0604]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21) (prog-if 00 [Normal decode])
>> Capabilities: [4c] Express Root Port (Slot-), MSI 00
>>
>> Without any "Invalid class" error. So class code was properly reflected
>> into standard (read-only) PCI register 0x08.
>>
>> Same fix is already implemented in U-Boot pcie_fsl.c driver in commit:
>> http://source.denx.de/u-boot/u-boot/-/commit/d18d06ac35229345a0af80977a408cfbe1d1015b
>>
>> Fix activated by U-Boot stay active also after booting Linux kernel.
>> But boards which use older U-Boot version without that fix are affected and
>> still require this fix.
>>
>> So implement this class code fix also in kernel fsl_pci.c driver.
>>
>> Cc: stable@vger•kernel.org
>> Signed-off-by: Pali Rohár <pali@kernel•org>
>
> I assume the powerpc folks will take care of this.
Will do.
cheers
next prev parent reply other threads:[~2022-07-25 12:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-06 10:10 [PATCH] powerpc/fsl-pci: Fix Class Code of PCIe Root Port Pali Rohár
2022-07-21 22:18 ` Pali Rohár
2022-07-22 19:42 ` Bjorn Helgaas
2022-07-25 12:24 ` Michael Ellerman [this message]
2022-07-29 13:02 ` Michael Ellerman
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