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Message-ID: <1581123048.1308046.1750170680177.JavaMail.zimbra@raptorengineeringinc.com>
Date: Tue, 17 Jun 2025 09:31:20 -0500 (CDT)
From: Timothy Pearson <tpearson@...torengineering.com>
To: Shawn Anastasio <sanastasio@...torengineering.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>,
Lorenzo Pieralisi <lpieralisi@...nel.org>,
Krzysztof Wilczyński <kw@...ux.com>,
Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
Rob Herring <robh@...nel.o>,
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>, quic_vbadigan@...cnic.com,
amitk@...nel.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
jorge.ramirez@....qualcomm.com, Dmitry Baryshkov <lumag@...nel.org>
Subject: [PATCH v7] PCI: Add pcie_link_is_active() to determine if the PCIe
link
is active
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@....qualcomm.com>
Signed-off-by: Shawn Anastasio <sanastasio@...torengineering.com>
Signed-off-by: Timothy Pearson <tpearson@...torengineering.com>
---
arch/powerpc/kernel/eeh_driver.c | 8 +++++++-
drivers/pci/hotplug/pciehp.h | 1 -
drivers/pci/hotplug/pciehp_ctrl.c | 2 +-
drivers/pci/hotplug/pciehp_hpc.c | 33 +++----------------------------
drivers/pci/pci.c | 31 ++++++++++++++++++++++++++---
include/linux/pci.h | 4 ++++
6 files changed, 43 insertions(+), 36 deletions(-)
diff --git a/arch/powerpc/kernel/eeh_driver.c b/arch/powerpc/kernel/eeh_driver.c
index 441a3562bddd..4fdd62432f2c 100644
--- a/arch/powerpc/kernel/eeh_driver.c
+++ b/arch/powerpc/kernel/eeh_driver.c
@@ -1097,8 +1097,14 @@ void eeh_handle_normal_event(struct eeh_pe *pe)
eeh_pe_dev_mode_mark(pe, EEH_DEV_REMOVED);
pci_lock_rescan_remove();
- pci_hp_remove_devices(bus);
+ bus = eeh_pe_bus_get(pe);
+ if (bus)
+ pci_hp_remove_devices(bus);
+ else
+ pr_err("%s: PCI bus for PHB#%x-PE#%x disappeared\n",
+ __func__, pe->phb->global_number, pe->addr);
pci_unlock_rescan_remove();
+
/* The passed PE should no longer be used */
return;
}
diff --git a/drivers/pci/hotplug/pciehp.h b/drivers/pci/hotplug/pciehp.h
index debc79b0adfb..79df49cc9946 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 bcc938d4420f..6cc1b27b3b11 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 ebd342bda235..d29ce3715a44 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)
@@ -614,7 +587,7 @@ 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))
+ if (!pcie_link_is_active(ctrl_dev(ctrl)) || pciehp_device_replaced(ctrl))
pciehp_request(ctrl, ignored_events);
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 e9448d55113b..ad639e60f3bd 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4908,7 +4908,6 @@ 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);
@@ -4924,8 +4923,7 @@ 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,
@@ -6230,6 +6228,33 @@ 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 physical link is active or not. Note it is
+ * possible that the card is removed immediately after this so the
+ * caller may need to take it into account.
+ *
+ * If the PCI device itself is not available anymore returns
+ * %-ENODEV.
+ *
+ * Return: link state, or -ENODEV if the config read failes.
+ */
+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 = %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 05e68f35f392..5d1c9f718ac8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -1993,6 +1993,7 @@ pci_release_mem_regions(struct pci_dev *pdev)
pci_select_bars(pdev, IORESOURCE_MEM));
}
+int pcie_link_is_active(struct pci_dev *dev);
#else /* CONFIG_PCI is not enabled */
static inline void pci_set_flags(int flags) { }
@@ -2141,6 +2142,9 @@ 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 */
--
2.39.5
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