Re: [RFC PATCH 3/9] PCI/portdrv: Add pcie_walk_rcec() to walk RCiEPs associated with RCEC

Sean V Kelley
2020-07-27T15:21:17Z

Hi,

Comments below:

On 27 Jul 2020, at 3:49, Jonathan Cameron wrote:

> On Fri, 24 Jul 2020 10:22:17 -0700
> Sean V Kelley <sean.v.kelley@intel.com> wrote:
>
>> From: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
>>
>> When an RCEC device signals error(s) to a CPU core, the CPU core
>> needs to walk all the RCiEPs associated with that RCEC to check
>> errors. So add the function pcie_walk_rcec() to walk all RCiEPs
>> associated with the RCEC device.
>>
>> Co-developed-by: Sean V Kelley <sean.v.kelley@intel.com>
>> Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
>> Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
>
> A few trivial points inline. With those tidied up.
>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>
>> ---
>> drivers/pci/pcie/portdrv.h | 2 +
>> drivers/pci/pcie/portdrv_core.c | 82
>> +++++++++++++++++++++++++++++++++
>> 2 files changed, 84 insertions(+)
>>
>> diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
>> index af7cf237432a..c11d5ecbad76 100644
>> --- a/drivers/pci/pcie/portdrv.h
>> +++ b/drivers/pci/pcie/portdrv.h
>> @@ -116,6 +116,8 @@ void pcie_port_service_unregister(struct
>> pcie_port_service_driver *new);
>>
>> extern struct bus_type pcie_port_bus_type;
>> int pcie_port_device_register(struct pci_dev *dev);
>> +void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev
>> *, void *),
>> + void *userdata);
>> #ifdef CONFIG_PM
>> int pcie_port_device_suspend(struct device *dev);
>> int pcie_port_device_resume_noirq(struct device *dev);
>> diff --git a/drivers/pci/pcie/portdrv_core.c
>> b/drivers/pci/pcie/portdrv_core.c
>> index 50a9522ab07d..bdcbb34764c2 100644
>> --- a/drivers/pci/pcie/portdrv_core.c
>> +++ b/drivers/pci/pcie/portdrv_core.c
>> @@ -14,6 +14,7 @@
>> #include <linux/pm_runtime.h>
>> #include <linux/string.h>
>> #include <linux/slab.h>
>> +#include <linux/bitops.h>
>> #include <linux/aer.h>
>>
>> #include "../pci.h"
>> @@ -365,6 +366,87 @@ int pcie_port_device_register(struct pci_dev
>> *dev)
>> return status;
>> }
>>
>> +static int pcie_walk_rciep_devfn(struct pci_bus *pbus, int
>> (*cb)(struct pci_dev *, void *),
>> + void *userdata, unsigned long bitmap)
>> +{
>> + unsigned int dev, fn;
>> + struct pci_dev *pdev;
>> + int retval;
>> +
>> + for_each_set_bit(dev, &bitmap, 32) {
>> + for (fn = 0; fn < 8; fn++) {
>> + pdev = pci_get_slot(pbus, PCI_DEVFN(dev, fn));
>> +
>> + if (!pdev || pci_pcie_type(pdev) != PCI_EXP_TYPE_RC_END)
>> + continue;
>> +
>> + retval = cb(pdev, userdata);
>> + if (retval)
>> + return retval;
>> + }
>> + }
>> +
>> + return 0;
>> +}
>> +
>> +/** pcie_walk_rcec - Walk RCiEP devices associating with RCEC and
>> call callback.
>
> /**
> * pcie...

Will correct.

>
>> + * @rcec RCEC whose RCiEP devices should be walked.
>> + * @cb Callback to be called for each RCiEP device found.
>> + * @userdata Arbitrary pointer to be passed to callback.
>> + *
>> + * Walk the given RCEC. Call the provided callback on each RCiEP
>> device found.
>> + *
>> + * We check the return of @cb each time. If it returns anything
>> + * other than 0, we break out.
>> + *
>> + */
>> +void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev
>> *, void *),
>> + void *userdata)
>> +{
>> + u32 pos, bitmap, hdr, busn;
>> + u8 ver, nextbusn, lastbusn;
>> + struct pci_bus *pbus;
>> + unsigned int bnr;
>> +
>> + pos = pci_find_ext_capability(rcec, PCI_EXT_CAP_ID_RCEC);
>> + if (!pos)
>> + return;
>> +
>> + pbus = pci_find_bus(pci_domain_nr(rcec->bus), rcec->bus->number);
>> + if (!pbus)
>> + return;
>> +
>> + pci_read_config_dword(rcec, pos + PCI_RCEC_RCIEP_BITMAP, &bitmap);
>> +
>> + /* Find RCiEP devices on the same bus as the RCEC */
>> + if (pcie_walk_rciep_devfn(pbus, cb, userdata, (unsigned
>> long)bitmap))
>> + return;
>> +
>> + /* Check whether RCEC BUSN register is present */
>> + pci_read_config_dword(rcec, pos, &hdr);
>> + ver = PCI_EXT_CAP_VER(hdr);
>> + if (ver < PCI_RCEC_BUSN_REG_VER)
>> + return;
>> +
>> + pci_read_config_dword(rcec, pos + PCI_RCEC_BUSN, &busn);
>> + nextbusn = PCI_RCEC_BUSN_NEXT(busn);
>> + lastbusn = PCI_RCEC_BUSN_LAST(busn);
>> +
>> + /* All RCiEP devices are on the same bus as the RCEC */
>> + if (nextbusn == 0xff && lastbusn == 0x00)
>> + return;
>> +
>> + for (bnr = nextbusn; bnr < (lastbusn + 1); bnr++) {
>
> Why not bnr <= lastbusn? Seems more intuitive way of making it clear
> the
> range is inclusive.

Good suggestion. Will change.

Thanks,

Sean

>
>
>> + pbus = pci_find_bus(pci_domain_nr(rcec->bus), bnr);
>> + if (!pbus)
>> + continue;
>> +
>> + /* Find RCiEP devices on the given bus */
>> + if (pcie_walk_rciep_devfn(pbus, cb, userdata, 0xffffffff))
>> + return;
>> + }
>> +}
>> +
>> #ifdef CONFIG_PM
>> typedef int (*pcie_pm_callback_t)(struct pcie_device *);
>>