[PATCH v5 7/9] PCI: PCI: Add pcie_link_is_active() to determine if the PCIe link is active

[Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>]

Introduce a common API to check if the PCIe link is active, replacing
duplicate code in multiple locations.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
---
 drivers/pci/hotplug/pciehp.h      |  1 -
 drivers/pci/hotplug/pciehp_ctrl.c |  7 ++++---
 drivers/pci/hotplug/pciehp_hpc.c  | 33 +++------------------------------
 drivers/pci/pci.c                 | 26 +++++++++++++++++++++++---
 include/linux/pci.h               |  4 ++++
 5 files changed, 34 insertions(+), 37 deletions(-)

diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index 273dd8c66f4eff8b62ab065cebf97db3c343977d..acef728530e36d6ea4d7db3afe97ed31b85be064 100644
--- a/drivers/pci/hotplug/pciehp.h
+++ b/drivers/pci/hotplug/pciehp.h
@@ -186,7 +186,6 @@ int pciehp_query_power_fault(struct controller *ctrl);
 int pciehp_card_present(struct controller *ctrl);
 int pciehp_card_present_or_link_active(struct controller *ctrl);
 int pciehp_check_link_status(struct controller *ctrl);
-int pciehp_check_link_active(struct controller *ctrl);
 void pciehp_release_ctrl(struct controller *ctrl);
 
 int pciehp_sysfs_enable_slot(struct hotplug_slot *hotplug_slot);
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index d603a7aa74838c748f6ac2d22ffb8b8cfe64e469..36468a9c31d669ec916e867ecfb7a8220cfab157 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -230,7 +230,8 @@ void pciehp_handle_disable_request(struct controller *ctrl)
 
 void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 {
-	int present, link_active;
+	bool link_active;
+	int present;
 
 	/*
 	 * If the slot is on and presence or link has changed, turn it off.
@@ -260,8 +261,8 @@ void pciehp_handle_presence_or_link_change(struct controller *ctrl, u32 events)
 	/* Turn the slot on if it's occupied or link is up */
 	mutex_lock(&ctrl->state_lock);
 	present = pciehp_card_present(ctrl);
-	link_active = pciehp_check_link_active(ctrl);
-	if (present <= 0 && link_active <= 0) {
+	link_active = pcie_link_is_active(ctrl->pcie->port);
+	if (present <= 0 && !link_active) {
 		if (ctrl->state == BLINKINGON_STATE) {
 			ctrl->state = OFF_STATE;
 			cancel_delayed_work(&ctrl->button_work);
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index 8a09fb6083e27669a12f1a3bb2a550369d471d16..278bc21d531dd20a38e06e5d33f5ccd18131c2c3 100644
--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -221,33 +221,6 @@ static void pcie_write_cmd_nowait(struct controller *ctrl, u16 cmd, u16 mask)
 	pcie_do_write_cmd(ctrl, cmd, mask, false);
 }
 
-/**
- * pciehp_check_link_active() - Is the link active
- * @ctrl: PCIe hotplug controller
- *
- * Check whether the downstream link is currently active. Note it is
- * possible that the card is removed immediately after this so the
- * caller may need to take it into account.
- *
- * If the hotplug controller itself is not available anymore returns
- * %-ENODEV.
- */
-int pciehp_check_link_active(struct controller *ctrl)
-{
-	struct pci_dev *pdev = ctrl_dev(ctrl);
-	u16 lnk_status;
-	int ret;
-
-	ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
-	if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status))
-		return -ENODEV;
-
-	ret = !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
-	ctrl_dbg(ctrl, "%s: lnk_status = %x\n", __func__, lnk_status);
-
-	return ret;
-}
-
 static bool pci_bus_check_dev(struct pci_bus *bus, int devfn)
 {
 	u32 l;
@@ -467,7 +440,7 @@ int pciehp_card_present_or_link_active(struct controller *ctrl)
 	if (ret)
 		return ret;
 
-	return pciehp_check_link_active(ctrl);
+	return pcie_link_is_active(ctrl_dev(ctrl));
 }
 
 int pciehp_query_power_fault(struct controller *ctrl)
@@ -584,7 +557,7 @@ static void pciehp_ignore_dpc_link_change(struct controller *ctrl,
 	 * Synthesize it to ensure that it is acted on.
 	 */
 	down_read_nested(&ctrl->reset_lock, ctrl->depth);
-	if (!pciehp_check_link_active(ctrl))
+	if (!pcie_link_is_active(ctrl_dev(ctrl)))
 		pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC);
 	up_read(&ctrl->reset_lock);
 }
@@ -884,7 +857,7 @@ int pciehp_slot_reset(struct pcie_device *dev)
 	pcie_capability_write_word(dev->port, PCI_EXP_SLTSTA,
 				   PCI_EXP_SLTSTA_DLLSC);
 
-	if (!pciehp_check_link_active(ctrl))
+	if (!pcie_link_is_active(ctrl_dev(ctrl)))
 		pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC);
 
 	return 0;
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 4d7c9f64ea24ec754a135a2585c99489cfa641a9..d14cd6843a020f2cec3e4cc36522526cf1faf0ba 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4926,7 +4926,6 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type)
 		return 0;
 
 	if (pcie_get_speed_cap(dev) <= PCIE_SPEED_5_0GT) {
-		u16 status;
 
 		pci_dbg(dev, "waiting %d ms for downstream link\n", delay);
 		msleep(delay);
@@ -4942,8 +4941,7 @@ int pci_bridge_wait_for_secondary_bus(struct pci_dev *dev, char *reset_type)
 		if (!dev->link_active_reporting)
 			return -ENOTTY;
 
-		pcie_capability_read_word(dev, PCI_EXP_LNKSTA, &status);
-		if (!(status & PCI_EXP_LNKSTA_DLLLA))
+		if (!pcie_link_is_active(dev))
 			return -ENOTTY;
 
 		return pci_dev_wait(child, reset_type,
@@ -6251,6 +6249,28 @@ void pcie_print_link_status(struct pci_dev *dev)
 }
 EXPORT_SYMBOL(pcie_print_link_status);
 
+/**
+ * pcie_link_is_active() - Checks if the link is active or not
+ * @pdev: PCI device to query
+ *
+ * Check whether the link is active or not.
+ *
+ * Return: true if link is active.
+ */
+bool pcie_link_is_active(struct pci_dev *pdev)
+{
+	u16 lnk_status;
+	int ret;
+
+	ret = pcie_capability_read_word(pdev, PCI_EXP_LNKSTA, &lnk_status);
+	if (ret == PCIBIOS_DEVICE_NOT_FOUND || PCI_POSSIBLE_ERROR(lnk_status))
+		return false;
+
+	pci_dbg(pdev, "lnk_status = %x\n", lnk_status);
+	return !!(lnk_status & PCI_EXP_LNKSTA_DLLLA);
+}
+EXPORT_SYMBOL(pcie_link_is_active);
+
 /**
  * pci_select_bars - Make BAR mask from the type of resource
  * @dev: the PCI device for which BAR mask is made
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 09cda518350c8ea86bf1c6bd64ed8d67e774c8df..2c34302dc5bb73aa2f9e3bd02c12684d8b6856d9 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1945,6 +1945,7 @@ pci_release_mem_regions(struct pci_dev *pdev)
 			    pci_select_bars(pdev, IORESOURCE_MEM));
 }
 
+bool pcie_link_is_active(struct pci_dev *dev);
 #else /* CONFIG_PCI is not enabled */
 
 static inline void pci_set_flags(int flags) { }
@@ -2093,6 +2094,9 @@ pci_alloc_irq_vectors(struct pci_dev *dev, unsigned int min_vecs,
 {
 	return -ENOSPC;
 }
+
+static inline bool pcie_link_is_active(struct pci_dev *dev)
+{ return false; }
 #endif /* CONFIG_PCI */
 
 /* Include architecture-dependent settings and functions */

-- 
2.34.1