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Subject[PATCH v6 7/7] PCI: Unify wait for link active into generic pci
Date
Clients such as pciehp, dpc are using pcie_wait_link_active, which waits
till the link becomes active or inactive.

Made generic function and moved it to drivers/pci/pci.c

Signed-off-by: Oza Pawandeep <poza@codeaurora.org>

diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 7bab060..26afeff 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -245,25 +245,12 @@ bool pciehp_check_link_active(struct controller *ctrl)
return ret;
}

-static void __pcie_wait_link_active(struct controller *ctrl, bool active)
+static bool pcie_wait_link_active(struct controller *ctrl)
{
- int timeout = 1000;
-
- if (pciehp_check_link_active(ctrl) == active)
- return;
- while (timeout > 0) {
- msleep(10);
- timeout -= 10;
- if (pciehp_check_link_active(ctrl) == active)
- return;
- }
- ctrl_dbg(ctrl, "Data Link Layer Link Active not %s in 1000 msec\n",
- active ? "set" : "cleared");
-}
+ struct pci_dev *pdev = ctrl_dev(ctrl);
+ bool active = true;

-static void pcie_wait_link_active(struct controller *ctrl)
-{
- __pcie_wait_link_active(ctrl, true);
+ return pci_wait_for_link(pdev, active);
}

static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4a7c686..0de83ea 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -2805,7 +2805,7 @@ static void pci_std_enable_acs(struct pci_dev *dev)
pci_read_config_word(dev, pos + PCI_ACS_CTRL, &ctrl);

/* Source Validation */
- ctrl |= (cap & PCI_ACS_SV);
+// ctrl |= (cap & PCI_ACS_SV);

/* P2P Request Redirect */
ctrl |= (cap & PCI_ACS_RR);
@@ -4079,6 +4079,43 @@ static int pci_pm_reset(struct pci_dev *dev, int probe)
return 0;
}

+/**
+ * pci__wait_for_link - Wait for link till its active/inactive
+ * @dev: Bridge device
+ * @active: waiting for active or inactive ?
+ *
+ * Use this to wait till link becomes active or inactive.
+ */
+
+bool pci_wait_for_link(struct pci_dev *pdev, bool active)
+{
+ int timeout = 1000;
+ bool ret;
+ u16 lnk_status;
+
+check_link:
+ pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+ ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+
+ if (ret == active) {
+ dev_printk(KERN_DEBUG, &pdev->dev,
+ "%s: lnk_status = %x\n", __func__, lnk_status);
+ return true;
+ }
+
+ while (timeout > 0) {
+ msleep(10);
+ timeout -= 10;
+ goto check_link;
+ }
+ dev_printk(KERN_DEBUG, &pdev->dev,
+ "Data Link Layer Link Active not %s in 1000 msec\n",
+ active ? "set" : "cleared");
+
+ return false;
+}
+EXPORT_SYMBOL(pci_wait_for_link);
+
void pci_reset_secondary_bus(struct pci_dev *dev)
{
u16 ctrl;
diff --git a/drivers/pci/pcie/pcie-dpc.c b/drivers/pci/pcie/pcie-dpc.c
index 1b06a8e..67502a5 100644
--- a/drivers/pci/pcie/pcie-dpc.c
+++ b/drivers/pci/pcie/pcie-dpc.c
@@ -150,37 +150,9 @@ static void dpc_wait_link_inactive(struct dpc_dev *dpc)
struct pci_dev *pdev = dpc->dev->port;
struct device *dev = &dpc->dev->device;
u16 lnk_status;
+ bool active = false;

- pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
- while (lnk_status & PCI_EXP_LNKSTA_DLLLA &&
- !time_after(jiffies, timeout)) {
- msleep(10);
- pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
- }
- if (lnk_status & PCI_EXP_LNKSTA_DLLLA)
- dev_warn(dev, "Link state not disabled for DPC event\n");
-}
-
-static bool dpc_wait_link_active(struct pci_dev *pdev)
-{
- unsigned long timeout = jiffies + HZ;
- u16 lnk_status;
- bool ret = true;
-
- pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
-
- while (!(lnk_status & PCI_EXP_LNKSTA_DLLLA) &&
- !time_after(jiffies, timeout)) {
- msleep(10);
- pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
- }
-
- if (!(lnk_status & PCI_EXP_LNKSTA_DLLLA)) {
- dev_warn(&pdev->dev, "Link state not enabled after DPC event\n");
- ret = false;
- }
-
- return ret;
+ pci_wait_for_link(pdev, active);
}

/**
@@ -191,7 +163,9 @@ static bool dpc_wait_link_active(struct pci_dev *pdev)
*/
static void dpc_error_resume(struct pci_dev *pdev)
{
- if (dpc_wait_link_active(pdev)) {
+ bool active = true;
+
+ if (pci_wait_for_link(pdev, active)) {
pci_lock_rescan_remove();
pci_rescan_bus(pdev->bus);
pci_unlock_rescan_remove();
diff --git a/include/linux/pci.h b/include/linux/pci.h
index c170c92..f9f6a3d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1201,6 +1201,7 @@ int pci_add_ext_cap_save_buffer(struct pci_dev *dev,
int pci_request_selected_regions(struct pci_dev *, int, const char *);
int pci_request_selected_regions_exclusive(struct pci_dev *, int, const char *);
void pci_release_selected_regions(struct pci_dev *, int);
+bool pci_wait_for_link(struct pci_dev *pdev, bool active);

/* drivers/pci/bus.c */
struct pci_bus *pci_bus_get(struct pci_bus *bus);
--
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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