Re: [PATCH v11 05/23] cxl: Move CXL driver RCH error handling into CONFIG_CXL_RCH_RAS conditional block

Bowman, Terry
2025-09-15T13:32:53Z

On 9/11/2025 2:41 PM, Dave Jiang wrote:
>
> On 9/11/25 10:48 AM, Bowman, Terry wrote:
>>
>> On 8/29/2025 10:33 AM, Jonathan Cameron wrote:
>>> On Tue, 26 Aug 2025 20:35:20 -0500
>>> Terry Bowman <terry.bowman@amd.com> wrote:
>>>
>>>> Restricted CXL Host (RCH) protocol error handling uses a procedure distinct
>>>> from the CXL Virtual Hierarchy (VH) handling. This is because of the
>>>> differences in the RCH and VH topologies. Improve the maintainability and
>>>> add ability to enable/disable RCH handling.
>>>>
>>>> Move and combine the RCH handling code into a single block conditionally
>>>> compiled with the CONFIG_CXL_RCH_RAS kernel config.
>>>>
>>>> Signed-off-by: Terry Bowman <terry.bowman@amd.com>
>>>>
>>> How painful to move this to a ras_rch.c file and conditionally compile that?
>>>
>>> Would want to do that is some merged thing with patch 1 though, rather than
>>> moving at least some of the code twice.
>>>
>> I don't see an issue and the effort would be a simple rework of patch1 as you
>> mentioned. But, it would drop the 'reviewed-by' sign-offs. Should we check with
>> others about this too?
> I would go ahead and do it.
>

Dan mentioned he prefers leaving it all together in drivers/cxl/ras.c.

https://lore.kernel.org/linux-cxl/68829db3d3e63_134cc710080@dwillia2-xfh.jf.intel.com.notmuch/

Terry

>> Terry
>>
>>>> ---
>>>> v10->v11:
>>>> - New patch
>>>> ---
>>>> drivers/cxl/core/ras.c | 175 +++++++++++++++++++++--------------------
>>>> 1 file changed, 90 insertions(+), 85 deletions(-)
>>>>
>>>> diff --git a/drivers/cxl/core/ras.c b/drivers/cxl/core/ras.c
>>>> index 0875ce8116ff..f42f9a255ef8 100644
>>>> --- a/drivers/cxl/core/ras.c
>>>> +++ b/drivers/cxl/core/ras.c
>>>> @@ -126,6 +126,7 @@ void cxl_ras_exit(void)
>>>> cancel_work_sync(&cxl_cper_prot_err_work);
>>>> }
>>>>
>>>> +#ifdef CONFIG_CXL_RCH_RAS
>>>> static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
>>>> {
>>>> resource_size_t aer_phys;
>>>> @@ -141,18 +142,6 @@ static void cxl_dport_map_rch_aer(struct cxl_dport *dport)
>>>> }
>>>> }
>>>>
>>>> -static void cxl_dport_map_ras(struct cxl_dport *dport)
>>>> -{
>>>> - struct cxl_register_map *map = &dport->reg_map;
>>>> - struct device *dev = dport->dport_dev;
>>>> -
>>>> - if (!map->component_map.ras.valid)
>>>> - dev_dbg(dev, "RAS registers not found\n");
>>>> - else if (cxl_map_component_regs(map, &dport->regs.component,
>>>> - BIT(CXL_CM_CAP_CAP_ID_RAS)))
>>>> - dev_dbg(dev, "Failed to map RAS capability.\n");
>>>> -}
>>>> -
>>>> static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
>>>> {
>>>> void __iomem *aer_base = dport->regs.dport_aer;
>>>> @@ -177,6 +166,95 @@ static void cxl_disable_rch_root_ints(struct cxl_dport *dport)
>>>> writel(aer_cmd, aer_base + PCI_ERR_ROOT_COMMAND);
>>>> }
>>>>
>>>> +/*
>>>> + * Copy the AER capability registers using 32 bit read accesses.
>>>> + * This is necessary because RCRB AER capability is MMIO mapped. Clear the
>>>> + * status after copying.
>>>> + *
>>>> + * @aer_base: base address of AER capability block in RCRB
>>>> + * @aer_regs: destination for copying AER capability
>>>> + */
>>>> +static bool cxl_rch_get_aer_info(void __iomem *aer_base,
>>>> + struct aer_capability_regs *aer_regs)
>>>> +{
>>>> + int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
>>>> + u32 *aer_regs_buf = (u32 *)aer_regs;
>>>> + int n;
>>>> +
>>>> + if (!aer_base)
>>>> + return false;
>>>> +
>>>> + /* Use readl() to guarantee 32-bit accesses */
>>>> + for (n = 0; n < read_cnt; n++)
>>>> + aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
>>>> +
>>>> + writel(aer_regs->uncor_status, aer_base + PCI_ERR_UNCOR_STATUS);
>>>> + writel(aer_regs->cor_status, aer_base + PCI_ERR_COR_STATUS);
>>>> +
>>>> + return true;
>>>> +}
>>>> +
>>>> +/* Get AER severity. Return false if there is no error. */
>>>> +static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
>>>> + int *severity)
>>>> +{
>>>> + if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
>>>> + if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
>>>> + *severity = AER_FATAL;
>>>> + else
>>>> + *severity = AER_NONFATAL;
>>>> + return true;
>>>> + }
>>>> +
>>>> + if (aer_regs->cor_status & ~aer_regs->cor_mask) {
>>>> + *severity = AER_CORRECTABLE;
>>>> + return true;
>>>> + }
>>>> +
>>>> + return false;
>>>> +}
>>>> +
>>>> +static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
>>>> +{
>>>> + struct pci_dev *pdev = to_pci_dev(cxlds->dev);
>>>> + struct aer_capability_regs aer_regs;
>>>> + struct cxl_dport *dport;
>>>> + int severity;
>>>> +
>>>> + struct cxl_port *port __free(put_cxl_port) =
>>>> + cxl_pci_find_port(pdev, &dport);
>>>> + if (!port)
>>>> + return;
>>>> +
>>>> + if (!cxl_rch_get_aer_info(dport->regs.dport_aer, &aer_regs))
>>>> + return;
>>>> +
>>>> + if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
>>>> + return;
>>>> +
>>>> + pci_print_aer(pdev, severity, &aer_regs);
>>>> + if (severity == AER_CORRECTABLE)
>>>> + cxl_handle_cor_ras(cxlds, dport->regs.ras);
>>>> + else
>>>> + cxl_handle_ras(cxlds, dport->regs.ras);
>>>> +}
>>>> +#else
>>>> +static inline void cxl_dport_map_rch_aer(struct cxl_dport *dport) { }
>>>> +static inline void cxl_disable_rch_root_ints(struct cxl_dport *dport) { }
>>>> +static inline void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds) { }
>>>> +#endif
>>>> +
>>>> +static void cxl_dport_map_ras(struct cxl_dport *dport)
>>>> +{
>>>> + struct cxl_register_map *map = &dport->reg_map;
>>>> + struct device *dev = dport->dport_dev;
>>>> +
>>>> + if (!map->component_map.ras.valid)
>>>> + dev_dbg(dev, "RAS registers not found\n");
>>>> + else if (cxl_map_component_regs(map, &dport->regs.component,
>>>> + BIT(CXL_CM_CAP_CAP_ID_RAS)))
>>>> + dev_dbg(dev, "Failed to map RAS capability.\n");
>>>> +}
>>>>
>>>> /**
>>>> * cxl_dport_init_ras_reporting - Setup CXL RAS report on this dport
>>>> @@ -270,79 +348,6 @@ static bool cxl_handle_ras(struct cxl_dev_state *cxlds, void __iomem *ras_base)
>>>> return true;
>>>> }
>>>>
>>>> -/*
>>>> - * Copy the AER capability registers using 32 bit read accesses.
>>>> - * This is necessary because RCRB AER capability is MMIO mapped. Clear the
>>>> - * status after copying.
>>>> - *
>>>> - * @aer_base: base address of AER capability block in RCRB
>>>> - * @aer_regs: destination for copying AER capability
>>>> - */
>>>> -static bool cxl_rch_get_aer_info(void __iomem *aer_base,
>>>> - struct aer_capability_regs *aer_regs)
>>>> -{
>>>> - int read_cnt = sizeof(struct aer_capability_regs) / sizeof(u32);
>>>> - u32 *aer_regs_buf = (u32 *)aer_regs;
>>>> - int n;
>>>> -
>>>> - if (!aer_base)
>>>> - return false;
>>>> -
>>>> - /* Use readl() to guarantee 32-bit accesses */
>>>> - for (n = 0; n < read_cnt; n++)
>>>> - aer_regs_buf[n] = readl(aer_base + n * sizeof(u32));
>>>> -
>>>> - writel(aer_regs->uncor_status, aer_base + PCI_ERR_UNCOR_STATUS);
>>>> - writel(aer_regs->cor_status, aer_base + PCI_ERR_COR_STATUS);
>>>> -
>>>> - return true;
>>>> -}
>>>> -
>>>> -/* Get AER severity. Return false if there is no error. */
>>>> -static bool cxl_rch_get_aer_severity(struct aer_capability_regs *aer_regs,
>>>> - int *severity)
>>>> -{
>>>> - if (aer_regs->uncor_status & ~aer_regs->uncor_mask) {
>>>> - if (aer_regs->uncor_status & PCI_ERR_ROOT_FATAL_RCV)
>>>> - *severity = AER_FATAL;
>>>> - else
>>>> - *severity = AER_NONFATAL;
>>>> - return true;
>>>> - }
>>>> -
>>>> - if (aer_regs->cor_status & ~aer_regs->cor_mask) {
>>>> - *severity = AER_CORRECTABLE;
>>>> - return true;
>>>> - }
>>>> -
>>>> - return false;
>>>> -}
>>>> -
>>>> -static void cxl_handle_rdport_errors(struct cxl_dev_state *cxlds)
>>>> -{
>>>> - struct pci_dev *pdev = to_pci_dev(cxlds->dev);
>>>> - struct aer_capability_regs aer_regs;
>>>> - struct cxl_dport *dport;
>>>> - int severity;
>>>> -
>>>> - struct cxl_port *port __free(put_cxl_port) =
>>>> - cxl_pci_find_port(pdev, &dport);
>>>> - if (!port)
>>>> - return;
>>>> -
>>>> - if (!cxl_rch_get_aer_info(dport->regs.dport_aer, &aer_regs))
>>>> - return;
>>>> -
>>>> - if (!cxl_rch_get_aer_severity(&aer_regs, &severity))
>>>> - return;
>>>> -
>>>> - pci_print_aer(pdev, severity, &aer_regs);
>>>> - if (severity == AER_CORRECTABLE)
>>>> - cxl_handle_cor_ras(cxlds, dport->regs.ras);
>>>> - else
>>>> - cxl_handle_ras(cxlds, dport->regs.ras);
>>>> -}
>>>> -
>>>> void cxl_cor_error_detected(struct pci_dev *pdev)
>>>> {
>>>> struct cxl_dev_state *cxlds = pci_get_drvdata(pdev);