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Message-ID: <0d8f7d31-2356-4c9e-9f2e-4bd070edf1e4@intel.com>
Date: Fri, 18 Jul 2025 15:01:52 -0700
From: Dave Jiang <dave.jiang@...el.com>
To: "Bowman, Terry" <terry.bowman@....com>, dave@...olabs.net,
jonathan.cameron@...wei.com, alison.schofield@...el.com,
dan.j.williams@...el.com, bhelgaas@...gle.com, shiju.jose@...wei.com,
ming.li@...omail.com, Smita.KoralahalliChannabasappa@....com,
rrichter@....com, dan.carpenter@...aro.org,
PradeepVineshReddy.Kodamati@....com, lukas@...ner.de,
Benjamin.Cheatham@....com, sathyanarayanan.kuppuswamy@...ux.intel.com,
linux-cxl@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org
Subject: Re: [PATCH v10 09/17] cxl/pci: Map CXL Endpoint Port and CXL Switch
Port RAS registers
On 7/18/25 2:55 PM, Bowman, Terry wrote:
>
>
> On 7/18/2025 4:28 PM, Dave Jiang wrote:
>>
>> On 6/26/25 3:42 PM, Terry Bowman wrote:
>>> CXL Endpoint (EP) Ports may include Root Ports (RP) or Downstream Switch
>>> Ports (DSP). CXL RPs and DSPs contain RAS registers that require memory
>>> mapping to enable RAS logging. This initialization is currently missing and
>>> must be added for CXL RPs and DSPs.
>>>
>>> Update cxl_dport_init_ras_reporting() to support RP and DSP RAS mapping.
>>> Add alongside the existing Restricted CXL Host Downstream Port RAS mapping.
>>>
>>> Update cxl_endpoint_port_probe() to invoke cxl_dport_init_ras_reporting().
>>> This will initiate the RAS mapping for CXL RPs and DSPs when each CXL EP is
>>> created and added to the EP port.
>>>
>>> Signed-off-by: Terry Bowman <terry.bowman@....com>
>>> ---
>>> drivers/cxl/cxl.h | 2 ++
>>> drivers/cxl/mem.c | 3 ++-
>>> drivers/cxl/port.c | 58 +++++++++++++++++++++++++++++++++++++++++++++-
>>> 3 files changed, 61 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>>> index c57c160f3e5e..d696d419bd5a 100644
>>> --- a/drivers/cxl/cxl.h
>>> +++ b/drivers/cxl/cxl.h
>>> @@ -590,6 +590,7 @@ struct cxl_dax_region {
>>> * @parent_dport: dport that points to this port in the parent
>>> * @decoder_ida: allocator for decoder ids
>>> * @reg_map: component and ras register mapping parameters
>>> + * @uport_regs: mapped component registers
>>> * @nr_dports: number of entries in @dports
>>> * @hdm_end: track last allocated HDM decoder instance for allocation ordering
>>> * @commit_end: cursor to track highest committed decoder for commit ordering
>>> @@ -610,6 +611,7 @@ struct cxl_port {
>>> struct cxl_dport *parent_dport;
>>> struct ida decoder_ida;
>>> struct cxl_register_map reg_map;
>>> + struct cxl_component_regs uport_regs;
>>> int nr_dports;
>>> int hdm_end;
>>> int commit_end;
>>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
>>> index 6e6777b7bafb..d2155f45240d 100644
>>> --- a/drivers/cxl/mem.c
>>> +++ b/drivers/cxl/mem.c
>>> @@ -166,7 +166,8 @@ static int cxl_mem_probe(struct device *dev)
>>> else
>>> endpoint_parent = &parent_port->dev;
>>>
>>> - cxl_dport_init_ras_reporting(dport, dev);
>>> + if (dport->rch)
>>> + cxl_dport_init_ras_reporting(dport, dev);
>>>
>>> scoped_guard(device, endpoint_parent) {
>>> if (!endpoint_parent->driver) {
>>> diff --git a/drivers/cxl/port.c b/drivers/cxl/port.c
>>> index 021f35145c65..b52f82925891 100644
>>> --- a/drivers/cxl/port.c
>>> +++ b/drivers/cxl/port.c
>>> @@ -111,6 +111,17 @@ static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
>>> writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
>>> }
>>>
>>> +static void cxl_uport_init_ras_reporting(struct cxl_port *port,
>>> + struct device *host)
>>> +{
>>> + struct cxl_register_map *map = &port->reg_map;
>>> +
>>> + map->host = host;
>>> + if (cxl_map_component_regs(map, &port->uport_regs,
>>> + BIT(CXL_CM_CAP_CAP_ID_RAS)))
>>> + dev_dbg(&port->dev, "Failed to map RAS capability\n");
>>> +}
>>> +
>>> /**
>>> * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
>>> * @dport: the cxl_dport that needs to be initialized
>>> @@ -119,7 +130,6 @@ static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
>>> void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
>>> {
>>> dport->reg_map.host = host;
>>> - cxl_dport_map_ras(dport);
>>>
>>> if (dport->rch) {
>>> struct pci_host_bridge *host_bridge = to_pci_host_bridge(dport->dport_dev);
>>> @@ -127,12 +137,54 @@ void cxl_dport_init_ras_reporting(struct cxl_dport *dport, struct device *host)
>>> if (!host_bridge->native_aer)
>>> return;
>>>
>>> + cxl_dport_map_ras(dport);
>>> cxl_dport_map_rch_aer(dport);
>>> cxl_disable_rch_root_ints(dport);
>>> + return;
>>> }
>>> +
>>> + if (cxl_map_component_regs(&dport->reg_map, &dport->regs.component,
>>> + BIT(CXL_CM_CAP_CAP_ID_RAS)))
>>> + dev_dbg(dport->dport_dev, "Failed to map RAS capability\n");
>>> +
>>> }
>>> EXPORT_SYMBOL_NS_GPL(cxl_dport_init_ras_reporting, "CXL");
>>>
>>> +static void cxl_switch_port_init_ras(struct cxl_port *port)
>>> +{
>>> + if (is_cxl_root(to_cxl_port(port->dev.parent)))
>>> + return;
>>> +
>>> + /* May have upstream DSP or RP */
>>> + if (port->parent_dport && dev_is_pci(port->parent_dport->dport_dev)) {
>>> + struct pci_dev *pdev = to_pci_dev(port->parent_dport->dport_dev);
>>> +
>>> + if ((pci_pcie_type(pdev) == PCI_EXP_TYPE_ROOT_PORT) ||
>>> + (pci_pcie_type(pdev) == PCI_EXP_TYPE_DOWNSTREAM))
>>> + cxl_dport_init_ras_reporting(port->parent_dport, &port->dev);
>>> + }
>>> +
>>> + cxl_uport_init_ras_reporting(port, &port->dev);
>>> +}
>>> +
>>> +static void cxl_endpoint_port_init_ras(struct cxl_port *port)
>> Maybe rename 'port' to 'ep' to be explicit
> Ok
>>> +{
>>> + struct cxl_dport *dport;
>> parent_dport would be clearer. I was thinking why does the endpoint have a dport for a second there.
> Ok
>>> + struct cxl_memdev *cxlmd = to_cxl_memdev(port->uport_dev);
>>> + struct cxl_port *parent_port __free(put_cxl_port) =
>>> + cxl_mem_find_port(cxlmd, &dport);
>>> +
>>> + if (!dport || !dev_is_pci(dport->dport_dev)) {
>>> + dev_err(&port->dev, "CXL port topology not found\n");> + return;
>>> + }
>>> +
>>> + cxl_dport_init_ras_reporting(dport, cxlmd->cxlds->dev);
>>> +}
>>> +
>>> +#else
>>> +static void cxl_endpoint_port_init_ras(struct cxl_port *port) { }
>>> +static void cxl_switch_port_init_ras(struct cxl_port *port) { }
>>> #endif /* CONFIG_PCIEAER_CXL */
>> I cc'd you on the new patch to move all the AER stuff to core/pci_aer.c. That should take care of ifdef CONFIG_PCIEAER_CXL in pci.c and port.c.
>>
>> DJ
>
> Move to core/native_ras.c introduced in "Dequeue forwarded CXL error", right? I just want to be certain.
I just posted this [1] to clean up what's there. Do you prefer me to just rename the file to native_ras.c? Or maybe pci_ras.c?
[1]: https://lore.kernel.org/linux-cxl/20250718212452.2100663-1-dave.jiang@intel.com/
DJ
>
> Regards,
> Terry
>
>>> > static int cxl_switch_port_probe(struct cxl_port *port)
>>> @@ -149,6 +201,8 @@ static int cxl_switch_port_probe(struct cxl_port *port)
>>>
>>> cxl_switch_parse_cdat(port);
>>>
>>> + cxl_switch_port_init_ras(port);
>>> +
>>> cxlhdm = devm_cxl_setup_hdm(port, NULL);
>>> if (!IS_ERR(cxlhdm))
>>> return devm_cxl_enumerate_decoders(cxlhdm, NULL);
>>> @@ -203,6 +257,8 @@ static int cxl_endpoint_port_probe(struct cxl_port *port)
>>> if (rc)
>>> return rc;
>>>
>>> + cxl_endpoint_port_init_ras(port);
>>> +
>>> /*
>>> * Now that all endpoint decoders are successfully enumerated, try to
>>> * assemble regions from committed decoders
>
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