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Date:   Tue, 22 Oct 2019 16:15:39 -0500
From:   Bjorn Helgaas <helgaas@kernel.org>
To:     George Cherian <gcherian@marvell.com>
Cc:     Robert Richter <rrichter@marvell.com>,
        Jayachandran Chandrasekharan Nair <jnair@marvell.com>,
        "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "shannon.zhao@linux.alibaba.com" <shannon.zhao@linux.alibaba.com>,
        Sunil Kovvuri Goutham <sgoutham@marvell.com>
Subject: Re: [EXT] Re: [PATCH] PCI: Enhance the ACS quirk for Cavium devices
Message-ID: <20191022211539.GA34867@google.com>
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On Wed, Oct 09, 2019 at 07:42:53AM -0500, Bjorn Helgaas wrote:
> On Wed, Oct 09, 2019 at 02:51:15AM +0000, George Cherian wrote:
> > Hi Bjorn,
> > 
> > Sorry for the late reply I was off for couple of days.
> > 
> > On 10/8/19 2:32 PM, Bjorn Helgaas wrote:
> > > External Email
> > >
> > > ----------------------------------------------------------------------
> > > On Tue, Oct 08, 2019 at 08:25:23AM +0000, Robert Richter wrote:
> > >> On 04.10.19 14:48:13, Bjorn Helgaas wrote:
> > >>> commit 37b22fbfec2d
> > >>> Author: George Cherian <george.cherian@marvell.com>
> > >>> Date:   Thu Sep 19 02:43:34 2019 +0000
> > >>>
> > >>>      PCI: Apply Cavium ACS quirk to CN99xx and CN11xxx Root Ports
> > >>>      
> > >>>      Add an array of Cavium Root Port device IDs and apply the quirk only to the
> > >>>      listed devices.
> > >>>      
> > >>>      Instead of applying the quirk to all Root Ports where
> > >>>      "(dev->device & 0xf800) == 0xa000", apply it only to CN88xx 0xa180 and
> > >>>      0xa170 Root Ports.
> > 
> > All the root ports of CN88xx series will have device id's 0xa180 and 0xa170.
> > 
> > This patch currently targets only CN88xx series and not all of the CN8xxx.
> > 
> > For eg:- 83xx devices don't wont the quirk to be applied as of today. 
> > The quirk
> > 
> > needs to be applied only for TX1 series and not oncteon-tx1 series.
> > 
> > >> No, this can't be removed. It is a match all for all CN8xxx variants
> > >> (note the 3 'x', all TX1 cores). So all device ids from 0xa000 to
> > >> 0xa7FF are affected here and need the quirk.
> > > OK, I'll drop the patch and wait for a new one.  Maybe what was needed
> > > was to keep the "(dev->device & 0xf800) == 0xa000" part and add the
> > > pci_quirk_cavium_acs_ids[] array in addition?
> > >
> > >>>      Also apply the quirk to CN99xx (0xaf84) and CN11xxx (0xb884) Root Ports.
> > 
> > The device id's for all variants of CN99xx is 0xaf84 and CN11xxx will be 
> > 0xb884.
> > 
> > So this patch holds good for TX2 as well as TX3 series of processors.
> 
> OK, can you and Robert get together and post something with Robert's
> Reviewed-by?  Please make the commit log a little more specific about
> which families/variants are supported (the vendor IDs are very
> specific, but not as user-friendly as CN99xx, etc).

Just to make sure this doesn't get lost, please post an update.  I
currently do not have this patch queued up for v5.5 because I haven't
seen a clear consensus on what it should look like.

> > >> I thought the quirk is CN8xxx specific, but I could be wrong here.
> > >>
> > >> -Robert
> > >>
> > >>>      
> > >>>      Link: https://urldefense.proofpoint.com/v2/url?u=https-3A__lore.kernel.org_r_20190919024319.GA8792-40dc5-2Deodlnx05.marvell.com&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=8vKOpC26NZGzQPAMiIlimxyEGCRSJiq-j8yyjPJ6VZ4&m=Vmml-rx3t63ZbbXZ0XaESAM9yAlexE29R-giTbcj4Qk&s=57jKIj8BAydbLpftLt5Ssva7vD6GuoCaIpjTi-sB5kU&e=
> > >>>      Fixes: f2ddaf8dfd4a ("PCI: Apply Cavium ThunderX ACS quirk to more Root Ports")
> > >>>      Fixes: b404bcfbf035 ("PCI: Add ACS quirk for all Cavium devices")
> > >>>      Signed-off-by: George Cherian <george.cherian@marvell.com>
> > >>>      Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
> > >>>      Cc: stable@vger.kernel.org      # v4.12+
> > >>>
> > >>> diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
> > >>> index 320255e5e8f8..4e5048cb5ec6 100644
> > >>> --- a/drivers/pci/quirks.c
> > >>> +++ b/drivers/pci/quirks.c
> > >>> @@ -4311,17 +4311,24 @@ static int pci_quirk_amd_sb_acs(struct pci_dev *dev, u16 acs_flags)
> > >>>   #endif
> > >>>   }
> > >>>   
> > >>> +static const u16 pci_quirk_cavium_acs_ids[] = {
> > >>> +	0xa180, 0xa170,		/* CN88xx family of devices */
> > >>> +	0xaf84,			/* CN99xx family of devices */
> > >>> +	0xb884,			/* CN11xxx family of devices */
> > >>> +};
> > >>> +
> > >>>   static bool pci_quirk_cavium_acs_match(struct pci_dev *dev)
> > >>>   {
> > >>> -	/*
> > >>> -	 * Effectively selects all downstream ports for whole ThunderX 1
> > >>> -	 * family by 0xf800 mask (which represents 8 SoCs), while the lower
> > >>> -	 * bits of device ID are used to indicate which subdevice is used
> > >>> -	 * within the SoC.
> > >>> -	 */
> > >>> -	return (pci_is_pcie(dev) &&
> > >>> -		(pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT) &&
> > >>> -		((dev->device & 0xf800) == 0xa000));
> > >>> +	int i;
> > >>> +
> > >>> +	if (!pci_is_pcie(dev) || pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
> > >>> +		return false;
> > >>> +
> > >>> +	for (i = 0; i < ARRAY_SIZE(pci_quirk_cavium_acs_ids); i++)
> > >>> +		if (pci_quirk_cavium_acs_ids[i] == dev->device)
> > >>> +			return true;
> > >>> +
> > >>> +	return false;
> > >>>   }
> > >>>   
> > >>>   static int pci_quirk_cavium_acs(struct pci_dev *dev, u16 acs_flags)