linux-kernel - Re: [PATCH V2 2/9] PCI: Extend Root Port Driver to support RCEC

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Message-ID: <7261b75710e55a10f08e04b4ff8de7158cebb0ed.camel@intel.com>
Date:   Wed, 26 Aug 2020 11:29:50 -0700
From:   sean.v.kelley@...el.com
To:     "Kuppuswamy, Sathyanarayanan" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>, bhelgaas@...gle.com,
        Jonathan.Cameron@...wei.com, rjw@...ysocki.net,
        ashok.raj@...el.com, tony.luck@...el.com
Cc:     linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        Qiuxu Zhuo <qiuxu.zhuo@...el.com>
Subject: Re: [PATCH V2 2/9] PCI: Extend Root Port Driver to support RCEC

Hi Sathya,

Thanks for reviewing.

If you haven't see it already there are newer patches under v3 here:

https://lore.kernel.org/linux-pci/20200812164659.1118946-1-sean.v.kelley@intel.com/

Comments below:

On Wed, 2020-08-26 at 09:16 -0700, Kuppuswamy, Sathyanarayanan wrote:
> 
> On 8/4/20 12:40 PM, Sean V Kelley wrote:
> > From: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> > 
> > If a Root Complex Integrated Endpoint (RCiEP) is implemented,
> > errors may
> > optionally be sent to a corresponding Root Complex Event Collector
> > (RCEC).
> > Each RCiEP must be associated with no more than one RCEC. Interface
> > errors
> > are reported to the OS by RCECs.
> > 
> > For an RCEC (technically not a Bridge), error messages "received"
> > from
> > associated RCiEPs must be enabled for "transmission" in order to
> > cause a
> > System Error via the Root Control register or (when the Advanced
> > Error
> > Reporting Capability is present) reporting via the Root Error
> > Command
> > register and logging in the Root Error Status register and Error
> > Source
> > Identification register.
> > 
> > Given the commonality with Root Ports and the need to also support
> > AER
> > and PME services for RCECs, extend the Root Port driver to support
> > RCEC
> > devices through the addition of the RCEC Class ID to the driver
> > structure.
> > 
> > Co-developed-by: Sean V Kelley <sean.v.kelley@...el.com>
> > Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@...el.com>
> > Signed-off-by: Sean V Kelley <sean.v.kelley@...el.com>
> > ---
> >   drivers/pci/pcie/portdrv_core.c | 8 ++++----
> >   drivers/pci/pcie/portdrv_pci.c  | 5 ++++-
> >   2 files changed, 8 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/pci/pcie/portdrv_core.c
> > b/drivers/pci/pcie/portdrv_core.c
> > index 50a9522ab07d..5d4a400094fc 100644
> > --- a/drivers/pci/pcie/portdrv_core.c
> > +++ b/drivers/pci/pcie/portdrv_core.c
> > @@ -234,11 +234,11 @@ static int get_port_device_capability(struct
> > pci_dev *dev)
> >   #endif
> >   
> >   	/*
> > -	 * Root ports are capable of generating PME too.  Root Complex
> > -	 * Event Collectors can also generate PMEs, but we don't handle
> > -	 * those yet.
> > +	 * Root ports and Root Complex Event Collectors are capable
> > +	 * of generating PME too.
> >   	 */
> > -	if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT &&
> > +	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
> > +	     pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC) &&
> >   	    (pcie_ports_native || host->native_pme)) {
> >   		services |= PCIE_PORT_SERVICE_PME;
> What about AER service? Don't you need to enable it for RCEC

It is enabled via set_device_error_reporting() in aer.c and in not seen
in this patch but in the lines above the code section you are
commenting on is:

#ifdef CONFIG_PCIEAER
        if (dev->aer_cap && pci_aer_available() &&
            (pcie_ports_native || host->native_aer)) {
                services |= PCIE_PORT_SERVICE_AER;

                /*
                 * Disable AER on this port in case it's been enabled
by the
                 * BIOS (the AER service driver will enable it when
necessary).
                 */
                pci_disable_pcie_error_reporting(dev);
        }
#endif

Let me know if I'm missing something here.


Thanks!

Sean


> >   
> > diff --git a/drivers/pci/pcie/portdrv_pci.c
> > b/drivers/pci/pcie/portdrv_pci.c
> > index 3a3ce40ae1ab..4d880679b9b1 100644
> > --- a/drivers/pci/pcie/portdrv_pci.c
> > +++ b/drivers/pci/pcie/portdrv_pci.c
> > @@ -106,7 +106,8 @@ static int pcie_portdrv_probe(struct pci_dev
> > *dev,
> >   	if (!pci_is_pcie(dev) ||
> >   	    ((pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT) &&
> >   	     (pci_pcie_type(dev) != PCI_EXP_TYPE_UPSTREAM) &&
> > -	     (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM)))
> > +	     (pci_pcie_type(dev) != PCI_EXP_TYPE_DOWNSTREAM) &&
> > +	     (pci_pcie_type(dev) != PCI_EXP_TYPE_RC_EC)))
> >   		return -ENODEV;
> >   
> >   	status = pcie_port_device_register(dev);
> > @@ -195,6 +196,8 @@ static const struct pci_device_id
> > port_pci_ids[] = {
> >   	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x00), ~0) },
> >   	/* subtractive decode PCI-to-PCI bridge, class type is 060401h
> > */
> >   	{ PCI_DEVICE_CLASS(((PCI_CLASS_BRIDGE_PCI << 8) | 0x01), ~0) },
> > +	/* handle any Root Complex Event Collector */
> > +	{ PCI_DEVICE_CLASS(((PCI_CLASS_SYSTEM_RCEC << 8) | 0x00), ~0)
> > },
> >   	{ },
> >   };
> >   
> >