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    SubjectRe: [PATCH v16 8/9] PCI/DPC: Unify and plumb error handling into DPC
    On 2018-05-11 16:13, Oza Pawandeep wrote:
    > DPC driver implements link_reset callback, and calls
    > pci_do_fatal_recovery().
    >
    > Which follows standard path of ERR_FATAL recovery.
    >
    > Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
    >
    > diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
    > index 5e8857a..6af7595 100644
    > --- a/drivers/pci/pci.h
    > +++ b/drivers/pci/pci.h
    > @@ -354,7 +354,7 @@ static inline resource_size_t
    > pci_resource_alignment(struct pci_dev *dev,
    > void pci_enable_acs(struct pci_dev *dev);
    >
    > /* PCI error reporting and recovery */
    > -void pcie_do_fatal_recovery(struct pci_dev *dev);
    > +void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service);
    > void pcie_do_nonfatal_recovery(struct pci_dev *dev);
    >
    > bool pcie_wait_for_link(struct pci_dev *pdev, bool active);
    > diff --git a/drivers/pci/pcie/aer/aerdrv_core.c
    > b/drivers/pci/pcie/aer/aerdrv_core.c
    > index fdfc474..36e622d 100644
    > --- a/drivers/pci/pcie/aer/aerdrv_core.c
    > +++ b/drivers/pci/pcie/aer/aerdrv_core.c
    > @@ -254,7 +254,7 @@ static void handle_error_source(struct pcie_device
    > *aerdev,
    > } else if (info->severity == AER_NONFATAL)
    > pcie_do_nonfatal_recovery(dev);
    > else if (info->severity == AER_FATAL)
    > - pcie_do_fatal_recovery(dev);
    > + pcie_do_fatal_recovery(dev, PCIE_PORT_SERVICE_AER);
    > }
    >
    > #ifdef CONFIG_ACPI_APEI_PCIEAER
    > @@ -321,7 +321,7 @@ static void aer_recover_work_func(struct
    > work_struct *work)
    > if (entry.severity == AER_NONFATAL)
    > pcie_do_nonfatal_recovery(pdev);
    > else if (entry.severity == AER_FATAL)
    > - pcie_do_fatal_recovery(pdev);
    > + pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_AER);
    > pci_dev_put(pdev);
    > }
    > }
    > diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
    > index 80ec384..5680c13 100644
    > --- a/drivers/pci/pcie/dpc.c
    > +++ b/drivers/pci/pcie/dpc.c
    > @@ -73,29 +73,31 @@ static void dpc_wait_link_inactive(struct dpc_dev
    > *dpc)
    > pcie_wait_for_link(pdev, false);
    > }
    >
    > -static void dpc_work(struct work_struct *work)
    > +static pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
    > {
    > - struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
    > - struct pci_dev *dev, *temp, *pdev = dpc->dev->port;
    > - struct pci_bus *parent = pdev->subordinate;
    > - u16 cap = dpc->cap_pos, ctl;
    > -
    > - pci_lock_rescan_remove();
    > - list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
    > - bus_list) {
    > - pci_dev_get(dev);
    > - pci_dev_set_disconnected(dev, NULL);
    > - if (pci_has_subordinate(dev))
    > - pci_walk_bus(dev->subordinate,
    > - pci_dev_set_disconnected, NULL);
    > - pci_stop_and_remove_bus_device(dev);
    > - pci_dev_put(dev);
    > - }
    > - pci_unlock_rescan_remove();
    > -
    > + struct dpc_dev *dpc;
    > + struct pcie_device *pciedev;
    > + struct device *devdpc;
    > + u16 cap, ctl;
    > +
    > + /*
    > + * DPC disables the Link automatically in hardware, so it has
    > + * already been reset by the time we get here.
    > + */
    > +
    > + devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
    > + pciedev = to_pcie_device(devdpc);
    > + dpc = get_service_data(pciedev);
    > + cap = dpc->cap_pos;
    > +
    > + /*
    > + * Waiting until the link is inactive, then clearing DPC
    > + * trigger status to allow the port to leave DPC.
    > + */
    > dpc_wait_link_inactive(dpc);
    > +
    > if (dpc->rp_extensions && dpc_wait_rp_inactive(dpc))
    > - return;
    > + return PCI_ERS_RESULT_DISCONNECT;
    > if (dpc->rp_extensions && dpc->rp_pio_status) {
    > pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS,
    > dpc->rp_pio_status);
    > @@ -108,6 +110,17 @@ static void dpc_work(struct work_struct *work)
    > pci_read_config_word(pdev, cap + PCI_EXP_DPC_CTL, &ctl);
    > pci_write_config_word(pdev, cap + PCI_EXP_DPC_CTL,
    > ctl | PCI_EXP_DPC_CTL_INT_EN);
    > +
    > + return PCI_ERS_RESULT_RECOVERED;
    > +}
    > +
    > +static void dpc_work(struct work_struct *work)
    > +{
    > + struct dpc_dev *dpc = container_of(work, struct dpc_dev, work);
    > + struct pci_dev *pdev = dpc->dev->port;
    > +
    > + /* From DPC point of view error is always FATAL. */
    > + pcie_do_fatal_recovery(pdev, PCIE_PORT_SERVICE_DPC);
    > }
    >
    > static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
    > @@ -288,6 +301,7 @@ static struct pcie_port_service_driver dpcdriver =
    > {
    > .service = PCIE_PORT_SERVICE_DPC,
    > .probe = dpc_probe,
    > .remove = dpc_remove,
    > + .reset_link = dpc_reset_link,
    > };
    >
    > static int __init dpc_service_init(void)
    > diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
    > index 33a16b1..29ff148 100644
    > --- a/drivers/pci/pcie/err.c
    > +++ b/drivers/pci/pcie/err.c
    > @@ -185,7 +185,7 @@ static pci_ers_result_t default_reset_link(struct
    > pci_dev *dev)
    > return PCI_ERS_RESULT_RECOVERED;
    > }
    >
    > -static pci_ers_result_t reset_link(struct pci_dev *dev)
    > +static pci_ers_result_t reset_link(struct pci_dev *dev, u32 service)
    > {
    > struct pci_dev *udev;
    > pci_ers_result_t status;
    > @@ -200,7 +200,7 @@ static pci_ers_result_t reset_link(struct pci_dev
    > *dev)
    > }
    >
    > /* Use the aer driver of the component firstly */
    > - driver = pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
    > + driver = pcie_port_find_service(udev, service);
    >
    > if (driver && driver->reset_link) {
    > status = driver->reset_link(udev);
    > @@ -287,7 +287,7 @@ static pci_ers_result_t
    > broadcast_error_message(struct pci_dev *dev,
    > * followed by re-enumeration of devices.
    > */
    >
    > -void pcie_do_fatal_recovery(struct pci_dev *dev)
    > +void pcie_do_fatal_recovery(struct pci_dev *dev, u32 service)
    > {
    > struct pci_dev *udev;
    > struct pci_bus *parent;
    > @@ -313,7 +313,7 @@ void pcie_do_fatal_recovery(struct pci_dev *dev)
    > pci_dev_put(pdev);
    > }
    >
    > - result = reset_link(udev);
    > + result = reset_link(udev, service);
    >
    > if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
    > /*
    > diff --git a/include/linux/aer.h b/include/linux/aer.h
    > index 8f87bbe..0c506fe 100644
    > --- a/include/linux/aer.h
    > +++ b/include/linux/aer.h
    > @@ -14,6 +14,7 @@
    > #define AER_NONFATAL 0
    > #define AER_FATAL 1
    > #define AER_CORRECTABLE 2
    > +#define DPC_FATAL 4
    >
    > struct pci_dev;


    Hi Bjorn,


    I have addressed all the comments, and I hope we are heading towards
    closure.

    I just figure that pcie_do_fatal_recovery (which is getting executed
    for DPC as well)

    if (result == PCI_ERS_RESULT_RECOVERED) {
    if (pcie_wait_for_link(udev, true))
    pci_rescan_bus(udev->bus);
    pci_info(dev, "Device recovery successful\n");
    }

    I have to correct it to

    if (service==AER && result == PCI_ERS_RESULT_RECOVERED) {
    if (pcie_wait_for_link(udev, true))
    pci_rescan_bus(udev->bus);
    pci_info(dev, "Device recovery successful\n");
    }


    rest of the things look okay to me.
    If you have any more comments,
    I can fix them with this one and hopefully v17 will be the final one.


    PS: I am going though the code more, and we can have some follow up
    patches (probably some cleanup)
    for e.g. pcie_portdrv_slot_reset() checks
    if (dev->error_state == pci_channel_io_frozen) {
    dev->state_saved = true;
    pci_restore_state(dev);
    pcie_portdrv_restore_config(dev);
    pci_enable_pcie_error_reporting(dev);
    }


    but now since the ERR_FATAL path does not call pcie_portdrv_slot_reset
    the check is meaning less.

    besides driver's shut_down callbacks might want to handle
    pci_channel_io_frozen, but that something left to be discussed later.
    So, I am not touching dev->error_state anywhere as of now in ERR_FATAL
    case.

    Regards,
    Oza.








































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