Re: [PATCH v11 10/20] cxl/pci: Introduce config option PCIEAER_CXL

Terry Bowman
2023-10-09T14:44:30Z

Hi Jonathan,

I added responses inline below.

On 10/2/23 09:46, Jonathan Cameron wrote:
> On Wed, 27 Sep 2023 17:43:29 +0200
> Robert Richter <rrichter@amd.com> wrote:
>
>> CXL error handling depends on AER.
>>
>> Introduce config option PCIEAER_CXL in preparation of the AER dport
>> error handling. Also, introduce the stub function
>> devm_cxl_setup_parent_dport() to setup dports.
>>
>> This is in preparation of follow on patches.
>>
>> Note the Kconfg part of the option is added in a later patch to enable
>> it once coding of the feature is complete.
>>
>> Signed-off-by: Robert Richter <rrichter@amd.com>
>
> Feels like it should just be combined with a later patch that fills
> some of this in as on it's own it's just a weird snippet of code :)
>

We will look to merge with the following patch.

> Still, one comment inline anyway.
>
>
>> ---
>> drivers/cxl/core/pci.c | 9 +++++++++
>> drivers/cxl/cxl.h | 7 +++++++
>> drivers/cxl/mem.c | 2 ++
>> 3 files changed, 18 insertions(+)
>>
>> diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c
>> index c7a7887ebdcf..6ba3b7370816 100644
>> --- a/drivers/cxl/core/pci.c
>> +++ b/drivers/cxl/core/pci.c
>> @@ -718,6 +718,15 @@ static bool cxl_report_and_clear(struct cxl_dev_state *cxlds)
>> return true;
>> }
>>
>> +#ifdef CONFIG_PCIEAER_CXL
>> +
>> +void devm_cxl_setup_parent_dport(struct device *host, struct cxl_dport *dport)
>> +{
>> +}
>> +EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_parent_dport, CXL);
>> +
>> +#endif
>> +
>> pci_ers_result_t cxl_error_detected(struct pci_dev *pdev,
>> pci_channel_state_t state)
>> {
>> diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h
>> index c07064e0c136..cfa2f6bede41 100644
>> --- a/drivers/cxl/cxl.h
>> +++ b/drivers/cxl/cxl.h
>> @@ -704,6 +704,13 @@ struct cxl_dport *devm_cxl_add_rch_dport(struct cxl_port *port,
>> struct device *dport_dev, int port_id,
>> resource_size_t rcrb);
>>
>> +#ifdef CONFIG_PCIEAER_CXL
>> +void devm_cxl_setup_parent_dport(struct device *host, struct cxl_dport *dport);
>> +#else
>> +static inline void devm_cxl_setup_parent_dport(struct device *host,
>> + struct cxl_dport *dport) { }
>> +#endif
>> +
>> struct cxl_decoder *to_cxl_decoder(struct device *dev);
>> struct cxl_root_decoder *to_cxl_root_decoder(struct device *dev);
>> struct cxl_switch_decoder *to_cxl_switch_decoder(struct device *dev);
>> diff --git a/drivers/cxl/mem.c b/drivers/cxl/mem.c
>> index 04107058739b..61ca21c020fa 100644
>> --- a/drivers/cxl/mem.c
>> +++ b/drivers/cxl/mem.c
>> @@ -157,6 +157,8 @@ static int cxl_mem_probe(struct device *dev)
>> else
>> endpoint_parent = &parent_port->dev;
>>
>> + devm_cxl_setup_parent_dport(dev, dport);
>
> devm calls can always fail (because if nothing else you have to register
> some cleanup and that involves an allocation. If you want to ignore
> that I'd expect a comment here.
>

We will add error handling here.

Regards,
Terry

>> +
>> device_lock(endpoint_parent);
>> if (!endpoint_parent->driver) {
>> dev_err(dev, "CXL port topology %s not enabled\n",
>