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SubjectRe: [PATCH v11 4/7] PCI/DPC: Unify and plumb error handling into DPC
On Fri, Feb 23, 2018 at 01:54:01PM +0530, Oza Pawandeep wrote:
> Current DPC driver does not do recovery, e.g. calling end-point's driver's
> callbacks, which sanitize the sw.
>
> DPC driver implements link_reset callback, and calls pcie_do_recovery.

s/pcie_do_recovery/pcie_do_recovery()/

> Signed-off-by: Oza Pawandeep <poza@codeaurora.org>
>
> diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
> index abc514e..f8575da 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -343,6 +343,8 @@ 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 */
> +#define DPC_FATAL 4

This needs to go next to the AER_FATAL, etc., definitions because
DPC_FATAL shares the namespace and they all need to have distinct
values. I can't tell from this patch whether they do or not.

> void pcie_do_recovery(struct pci_dev *dev, int severity);
>
> #ifdef CONFIG_PCIEASPM
> diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
> index 38e40c6..5c01c63 100644
> --- a/drivers/pci/pcie/pcie-dpc.c
> +++ b/drivers/pci/pcie/pcie-dpc.c
> @@ -13,6 +13,7 @@
> #include <linux/pcieport_if.h>
> #include "../pci.h"
> #include "aer/aerdrv.h"
> +#include "portdrv.h"
>
> struct dpc_dev {
> struct pcie_device *dev;
> @@ -45,6 +46,58 @@ struct dpc_dev {
> "Memory Request Completion Timeout", /* Bit Position 18 */
> };
>
> +static int find_dpc_dev_iter(struct device *device, void *data)
> +{
> + struct pcie_port_service_driver *service_driver;
> + struct device **dev = (struct device **) data;;
> +
> + if (device->bus == &pcie_port_bus_type && device->driver) {
> + service_driver = to_service_driver(device->driver);
> + if (service_driver->service == PCIE_PORT_SERVICE_DPC) {
> + *dev = device;
> + return 1;
> + }
> + }
> +
> + return 0;
> +}
> +
> +static struct device *pci_find_dpc_dev(struct pci_dev *pdev)
> +{
> + struct device *dev = NULL;
> +
> + device_for_each_child(&pdev->dev, &dev, find_dpc_dev_iter);
> +
> + return dev;
> +}

Ugh. You're not responsible for this and you don't need to do
anything, but hanging the struct dpc_dev off the struct pcie_device
and then having to grub around like this to locate it from the pci_dev
is just ... clunky. OK, rant over, sorry :)

> +static int find_dpc_service_iter(struct device *device, void *data)
> +{
> + struct pcie_port_service_driver *service_driver;
> + struct pcie_port_service_driver **drv =
> + (struct pcie_port_service_driver **) data;
> +
> + if (device->bus == &pcie_port_bus_type && device->driver) {
> + service_driver = to_service_driver(device->driver);
> + if (service_driver->service == PCIE_PORT_SERVICE_DPC) {
> + *drv = service_driver;
> + return 1;
> + }
> + }
> +
> + return 0;
> +}
> +
> +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev *dev)
> +{
> + struct pcie_port_service_driver *drv = NULL;
> +
> + device_for_each_child(&dev->dev, &drv, find_dpc_service_iter);
> +
> + return drv;
> +}
> +EXPORT_SYMBOL_GPL(pci_find_dpc_service);

No module uses this, so it doesn't need to be exported.

This is a clone of find_aer_service(). Can you add a preliminary patch to
make a generic "find service" interface that accepts the service type
(PCIE_PORT_SERVICE_AER, PCIE_PORT_SERVICE_DPC) as a parameter?

This whole "find service" thing is ugly as sin. You're not responsible for
cleaning it up, but maybe we can at least limit the proliferation of it.

> static int dpc_wait_rp_inactive(struct dpc_dev *dpc)
> {
> unsigned long timeout = jiffies + HZ;
> @@ -82,12 +135,25 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
> dev_warn(dev, "Link state not disabled for DPC event\n");
> }
>
> -static void dpc_work(struct work_struct *work)
> +/**
> + * dpc_reset_link - reset link DPC routine

s/ / / (remove extra space)

> + * @dev: pointer to Root Port's pci_dev data structure
> + *
> + * Invoked by Port Bus driver when performing link reset at Root Port.
> + */
> +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;
> + struct pci_dev *dev, *temp;
> + struct dpc_dev *dpc;
> + struct pcie_device *pciedev;
> + struct device *devdpc;
> + u16 cap, ctl;
> +
> + devdpc = pci_find_dpc_dev(pdev);
> + pciedev = to_pcie_device(devdpc);
> + dpc = get_service_data(pciedev);
> + cap = dpc->cap_pos;
>
> pci_lock_rescan_remove();
> list_for_each_entry_safe_reverse(dev, temp, &parent->devices,
> @@ -104,21 +170,31 @@ static void dpc_work(struct work_struct *work)
>
> 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);
> dpc->rp_pio_status = 0;
> }
>
> - pci_write_config_word(pdev, cap + PCI_EXP_DPC_STATUS,
> + pci_write_config_word(pdev, dpc->cap_pos + PCI_EXP_DPC_STATUS,
> PCI_EXP_DPC_STATUS_TRIGGER | PCI_EXP_DPC_STATUS_INTERRUPT);
>
> 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);
> + ctl | PCI_EXP_DPC_CTL_INT_EN);

Align "ctl" with "pdev".

> + 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_recovery(pdev, DPC_FATAL);
> +}
> static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
> {
> struct device *dev = &dpc->dev->device;
> @@ -297,6 +373,7 @@ static void dpc_remove(struct pcie_device *dev)
> .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/pcie-err.c b/drivers/pci/pcie/pcie-err.c
> index f830975..1ea4b9a 100644
> --- a/drivers/pci/pcie/pcie-err.c
> +++ b/drivers/pci/pcie/pcie-err.c
> @@ -19,6 +19,7 @@
> #include <linux/aer.h>
> #include <linux/pcieport_if.h>
> #include "portdrv.h"
> +#include "./../pci.h"
>
> static DEFINE_MUTEX(pci_err_recovery_lock);
>
> @@ -181,7 +182,7 @@ 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, int severity)
> {
> struct pci_dev *udev;
> pci_ers_result_t status;
> @@ -195,9 +196,17 @@ static pci_ers_result_t reset_link(struct pci_dev *dev)
> udev = dev->bus->self;
> }
>
> +
> + /* Use the service driver of the component firstly */
> +#if IS_ENABLED(CONFIG_PCIE_DPC)

#ifdef CONFIG_PCIE_DPC

> + if (severity == DPC_FATAL)
> + driver = pci_find_dpc_service(udev);
> +#endif
> #if IS_ENABLED(CONFIG_PCIEAER)
> - /* Use the aer driver of the component firstly */
> - driver = pci_find_aer_service(udev);
> + if (severity == AER_FATAL ||
> + severity == AER_NONFATAL ||
> + severity == AER_CORRECTABLE)

This change (to check for AER_FATAL, etc) looks like it belongs in a
different patch. This patch doesn't change any places that set the
severity.

> + driver = pci_find_aer_service(udev);
> #endif
>
> if (driver && driver->reset_link) {
> @@ -287,7 +296,8 @@ void pcie_do_recovery(struct pci_dev *dev, int severity)
>
> mutex_lock(&pci_err_recovery_lock);
>
> - if (severity == AER_FATAL)
> + if (severity == AER_FATAL ||
> + severity == DPC_FATAL)
> state = pci_channel_io_frozen;
> else
> state = pci_channel_io_normal;
> @@ -297,10 +307,14 @@ void pcie_do_recovery(struct pci_dev *dev, int severity)
> "error_detected",
> report_error_detected);
>
> - if (severity == AER_FATAL) {
> - result = reset_link(dev);
> + if (severity == AER_FATAL ||
> + severity == DPC_FATAL) {
> + result = reset_link(dev, severity);
> if (result != PCI_ERS_RESULT_RECOVERED)
> goto failed;
> + else if (severity == DPC_FATAL)
> + goto resume;
> +
> }
>
> if (status == PCI_ERS_RESULT_CAN_RECOVER)
> @@ -324,6 +338,7 @@ void pcie_do_recovery(struct pci_dev *dev, int severity)
> if (status != PCI_ERS_RESULT_RECOVERED)
> goto failed;
>
> +resume:
> broadcast_error_message(dev,
> state,
> "resume",
> diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
> index 4f1992d..b013e24 100644
> --- a/drivers/pci/pcie/portdrv.h
> +++ b/drivers/pci/pcie/portdrv.h
> @@ -80,4 +80,5 @@ static inline void pcie_port_platform_notify(struct pci_dev *port, int *mask){}
> #endif /* !CONFIG_ACPI */
>
> struct pcie_port_service_driver *pci_find_aer_service(struct pci_dev *dev);
> +struct pcie_port_service_driver *pci_find_dpc_service(struct pci_dev *dev);
> #endif /* _PORTDRV_H_ */
> --
> Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.,
> a Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
>

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