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Message-Id: <20250828-qps615_v4_1-v6-7-985f90a7dd03@oss.qualcomm.com>
Date: Thu, 28 Aug 2025 17:39:04 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Rob Herring <robh@...nel.org>,
Krzysztof Kozlowski <krzk+dt@...nel.org>,
Conor Dooley <conor+dt@...nel.org>,
chaitanya chundru <quic_krichai@...cinc.com>,
Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio <konradybcio@...nel.org>,
cros-qcom-dts-watchers@...omium.org, Jingoo Han <jingoohan1@...il.com>,
Bartosz Golaszewski <brgl@...ev.pl>,
Krzysztof Wilczyński <kwilczynski@...nel.org>,
Manivannan Sadhasivam <mani@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will@...nel.org>,
Krzysztof Wilczyński <kwilczynski@...nel.org>,
Manivannan Sadhasivam <mani@...nel.org>
Cc: quic_vbadigan@...cnic.com, amitk@...nel.org, linux-pci@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-msm@...r.kernel.org, jorge.ramirez@....qualcomm.com,
linux-arm-kernel@...ts.infradead.org,
Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>,
Dmitry Baryshkov <lumag@...nel.org>,
Shawn Anastasio <sanastasio@...torengineering.com>,
Timothy Pearson <tpearson@...torengineering.com>
Subject: [PATCH v6 7/9] PCI: Add pcie_link_is_active() to determine if the
link is active
Add pcie_link_is_active() 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@....qualcomm.com>
Signed-off-by: Shawn Anastasio <sanastasio@...torengineering.com>
Signed-off-by: Timothy Pearson <tpearson@...torengineering.com>
---
Posting this patch again as part of my series as I have dependency with
this patch.
---
drivers/pci/hotplug/pciehp.h | 1 -
drivers/pci/hotplug/pciehp_ctrl.c | 2 +-
drivers/pci/hotplug/pciehp_hpc.c | 35 ++++-------------------------------
drivers/pci/pci.c | 28 +++++++++++++++++++++++++---
drivers/pci/pci.h | 1 +
5 files changed, 31 insertions(+), 36 deletions(-)
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index debc79b0adfb2c8e06aabb765e1741572685100b..79df49cc99463829f563db1dc8014a51ccfac0af 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);
bool pciehp_device_replaced(struct controller *ctrl);
void pciehp_release_ctrl(struct controller *ctrl);
diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pciehp_ctrl.c
index bcc938d4420f3ddb301c1ec6b0bce0d7f9541658..6cc1b27b3b11a77678c24e464fbc61541a0bfa38 100644
--- a/drivers/pci/hotplug/pciehp_ctrl.c
+++ b/drivers/pci/hotplug/pciehp_ctrl.c
@@ -260,7 +260,7 @@ 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);
+ link_active = pcie_link_is_active(ctrl->pcie->port);
if (present <= 0 && link_active <= 0) {
if (ctrl->state == BLINKINGON_STATE) {
ctrl->state = OFF_STATE;
diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c
index bcc51b26d03d53ef7cb22b8e5868aa25b5ceedaa..2905ae7c9bbf7f9f656ec21ecd2e6bf9f7b5be47 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)
@@ -614,8 +587,8 @@ static void pciehp_ignore_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) || pciehp_device_replaced(ctrl))
- pciehp_request(ctrl, ignored_events);
+ if (!pcie_link_is_active(ctrl_dev(ctrl)) || pciehp_device_replaced(ctrl))
+ pciehp_request(ctrl, PCI_EXP_SLTSTA_DLLSC);
up_read(&ctrl->reset_lock);
}
@@ -921,7 +894,7 @@ 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 b0f4d98036cddddd88e2011da09aa6719b738651..50b53fc4092ccb6df2dc801b76f70f9df08447de 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4919,7 +4919,6 @@ 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);
@@ -4935,8 +4934,7 @@ 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) <= 0)
return -ENOTTY;
return pci_dev_wait(child, reset_type,
@@ -6241,6 +6239,30 @@ 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 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.
+ *
+ * Return: true if link is active, or -ENODEV if the config read fails.
+ */
+int 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 -ENODEV;
+
+ pci_dbg(pdev, "lnk_status = %#06x\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/drivers/pci/pci.h b/drivers/pci/pci.h
index 34f65d69662e9f61f0c489ec58de2ce17d21c0c6..5368a27f3a208ce95d39752459f1029beea2fcca 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -228,6 +228,7 @@ static inline int pci_proc_detach_bus(struct pci_bus *bus) { return 0; }
/* Functions for PCI Hotplug drivers to use */
int pci_hp_add_bridge(struct pci_dev *dev);
bool pci_hp_spurious_link_change(struct pci_dev *pdev);
+int pcie_link_is_active(struct pci_dev *dev);
#if defined(CONFIG_SYSFS) && defined(HAVE_PCI_LEGACY)
void pci_create_legacy_files(struct pci_bus *bus);
--
2.34.1
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