Re: [PATCH v15 8/9] PCI/DPC: Unify and plumb error handling into DPC
From: poza
Date: Thu May 10 2018 - 10:26:08 EST
On 2018-05-10 18:52, Bjorn Helgaas wrote:
On Thu, May 03, 2018 at 01:03:57AM -0400, 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
pci_do_recovery().
Signed-off-by: Oza Pawandeep <poza@xxxxxxxxxxxxxx>
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 80ec384..aed7c9f 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -73,29 +73,21 @@ 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();
I think it would be good to have a comment here about why this
"reset_link"
function doesn't actually reset the link, e.g.,
/*
* DPC disables the Link automatically in hardware, so it has
* already been reset by the time we get here.
*/
+ struct dpc_dev *dpc;
+ struct pcie_device *pciedev;
+ struct device *devdpc;
+ u16 cap, ctl;
+
+ devdpc = pcie_port_find_device(pdev, PCIE_PORT_SERVICE_DPC);
+ pciedev = to_pcie_device(devdpc);
+ dpc = get_service_data(pciedev);
+ cap = dpc->cap_pos;
And maybe one about 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 +100,17 @@ 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_recovery(pdev, DPC_FATAL);
}
static void dpc_process_rp_pio_error(struct dpc_dev *dpc)
@@ -288,6 +291,7 @@ 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 877785d..526aba8 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -181,11 +181,12 @@ 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;
struct pcie_port_service_driver *driver;
+ u32 service;
if (dev->hdr_type == PCI_HEADER_TYPE_BRIDGE) {
/* Reset this port for all subordinates */
@@ -196,7 +197,12 @@ 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);
+ if (severity == DPC_FATAL)
+ service = PCIE_PORT_SERVICE_DPC;
+ else
+ service = PCIE_PORT_SERVICE_AER;
+
+ driver = pcie_port_find_service(udev, service);
This is where I was wondering about passing in "service" directly
instead
of "severity".
I will take care of all your comments made on all the patches.
but this one I do not understand.
passing service directly instead of severity ? (I do not think you meant
to write severity there)
perhaps do you mean following ?
if (severity == DPC_FATAL)
pcie_port_find_service(udev, PCIE_PORT_SERVICE_DPC);
else
pcie_port_find_service(udev, PCIE_PORT_SERVICE_AER);
if (driver && driver->reset_link) {
status = driver->reset_link(udev);
@@ -302,7 +308,7 @@ static pci_ers_result_t do_fatal_recovery(struct
pci_dev *dev, int severity)
pci_dev_put(pdev);
}
- result = reset_link(udev);
+ result = reset_link(udev, severity);
if (result == PCI_ERS_RESULT_RECOVERED)
if (pcie_wait_for_link(udev, true))
pci_rescan_bus(udev->bus);
@@ -326,7 +332,8 @@ void pcie_do_recovery(struct pci_dev *dev, int
severity)
pci_ers_result_t status;
enum pci_channel_state state;
- if (severity == AER_FATAL) {
+ if ((severity == AER_FATAL) ||
+ (severity == DPC_FATAL)) {
status = do_fatal_recovery(dev, severity);
if (status != PCI_ERS_RESULT_RECOVERED)
goto failed;
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;
--
2.7.4