[PATCH v5 0/4] PCI: Add support for resetting the Root Ports in a platform specific way

[PATCH v5 0/4] PCI: Add support for resetting the Root Ports in a platform specific way

[Manivannan Sadhasivam]

Hi,

Currently, in the event of AER/DPC, PCI core will try to reset the slot (Root
Port) and its subordinate devices by invoking bridge control reset and FLR. But
in some cases like AER Fatal error, it might be necessary to reset the Root
Ports using the PCI host bridge drivers in a platform specific way (as indicated
by the TODO in the pcie_do_recovery() function in drivers/pci/pcie/err.c).
Otherwise, the PCI link won't be recovered successfully.

So this series adds a new callback 'pci_host_bridge::reset_root_port' for the
host bridge drivers to reset the Root Port when a fatal error happens.

Also, this series allows the host bridge drivers to handle PCI link down event
by resetting the Root Ports and recovering the bus. This is accomplished by the
help of the new 'pci_host_handle_link_down()' API. Host bridge drivers are
expected to call this API (preferrably from a threaded IRQ handler) with
relevant Root Port 'pci_dev' when a link down event is detected for the port.
The API will reuse the pcie_do_recovery() function to recover the link if AER
support is enabled, otherwise it will directly call the reset_root_port()
callback of the host bridge driver (if exists).

For reference, I've modified the pcie-qcom driver to call
pci_host_handle_link_down() API with Root Port 'pci_dev' after receiving the
LINK_DOWN global_irq event and populated 'pci_host_bridge::reset_root_port()'
callback to reset the Root Port. Since the Qcom PCIe controllers support only
a single Root Port (slot) per controller instance, the API is going to be
invoked only once. For multi Root Port controllers, the controller driver is
expected to detect the Root Port that received the link down event and call
the pci_host_handle_link_down() API with 'pci_dev' of that Root Port.

Testing
-------

I've lost access to my test setup now. So Krishna (Cced) will help with testing
on the Qcom platform and Wilfred or Niklas should be able to test it on Rockchip
platform. For the moment, this series is compile tested only.

Changes in v5:
* Reworked the pci_host_handle_link_down() to accept Root Port instead of
  resetting all Root Ports in the event of link down.
* Renamed 'reset_slot' to 'reset_root_port' to avoid confusion as both terms
  were used interchangibly and the series is intended to reset Root Port only.
* Added the Rockchip driver change to this series.
* Dropped the applied patches and review/tested tags due to rework.
* Rebased on top of v6.16-rc1.

Changes in v4:
- Handled link down first in the irq handler
- Updated ICC & OPP bandwidth after link up in reset_slot() callback
- Link to v3: https://lore.kernel.org/r/20250417-pcie-reset-slot-v3-0-59a10811c962@linaro.org

Changes in v3:
- Made the pci-host-common driver as a common library for host controller
  drivers
- Moved the reset slot code to pci-host-common library
- Link to v2: https://lore.kernel.org/r/20250416-pcie-reset-slot-v2-0-efe76b278c10@linaro.org

Changes in v2:
- Moved calling reset_slot() callback from pcie_do_recovery() to pcibios_reset_secondary_bus()
- Link to v1: https://lore.kernel.org/r/20250404-pcie-reset-slot-v1-0-98952918bf90@linaro.org

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
Manivannan Sadhasivam (3):
      PCI/ERR: Add support for resetting the Root Ports in a platform specific way
      PCI: host-common: Add link down handling for Root Ports
      PCI: qcom: Add support for resetting the Root Port due to link down event

Wilfred Mallawa (1):
      PCI: dw-rockchip: Add support to reset Root Port upon link down event

 drivers/pci/controller/dwc/Kconfig            |   2 +
 drivers/pci/controller/dwc/pcie-dw-rockchip.c |  91 ++++++++++++++++++-
 drivers/pci/controller/dwc/pcie-qcom.c        | 120 ++++++++++++++++++++++++--
 drivers/pci/controller/pci-host-common.c      |  33 +++++++
 drivers/pci/controller/pci-host-common.h      |   1 +
 drivers/pci/pci.c                             |  13 +++
 drivers/pci/pcie/err.c                        |   6 +-
 include/linux/pci.h                           |   1 +
 8 files changed, 252 insertions(+), 15 deletions(-)
---
base-commit: 19272b37aa4f83ca52bdf9c16d5d81bdd1354494
change-id: 20250715-pci-port-reset-4d9519570123

Best regards,
-- 
Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>

[PATCH v5 1/4] PCI/ERR: Add support for resetting the Root Ports in a platform specific way

[Manivannan Sadhasivam]

From: Manivannan Sadhasivam <mani@kernel.org>

Some host bridge devices require resetting the Root Ports in a platform
specific way to recover them from error conditions such as Fatal AER
errors, Link Down etc... So introduce pci_host_bridge::reset_root_port
callback and call it from pcibios_reset_secondary_bus() if available.

The 'reset_root_port' callback is responsible for resetting the given Root
Port referenced by the 'pci_dev' pointer in a platform specific way and
bring it back to the working state if possible. If any error occurs during
the reset operation, relevant errno should be returned.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/pci.c      | 12 ++++++++++++
 drivers/pci/pcie/err.c |  5 -----
 include/linux/pci.h    |  1 +
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e9448d55113bdfd2263d8e2f6b3ec802f56b712e..82c56fbd58ca4aaafac4f1638e7e0225c07958cb 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -4964,7 +4964,19 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
 
 void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
 {
+	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
+	int ret;
+
+	if (host->reset_root_port) {
+		ret = host->reset_root_port(host, dev);
+		if (ret)
+			pci_err(dev, "Failed to reset Root Port: %d\n", ret);
+
+		return;
+	}
+
 	pci_reset_secondary_bus(dev);
+
 }
 
 /**
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index de6381c690f5c21f00021cdc7bde8d93a5c7db52..b834fc0d705938540d3d7d3d8739770c09fe7cf1 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -234,11 +234,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	}
 
 	if (status == PCI_ERS_RESULT_NEED_RESET) {
-		/*
-		 * TODO: Should call platform-specific
-		 * functions to reset slot before calling
-		 * drivers' slot_reset callbacks?
-		 */
 		status = PCI_ERS_RESULT_RECOVERED;
 		pci_dbg(bridge, "broadcast slot_reset message\n");
 		pci_walk_bridge(bridge, report_slot_reset, &status);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 05e68f35f39238f8b9ce08df97b384d1c1e89bbe..e7c118a961910a307ec365f17b8fe4f2585267e8 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -599,6 +599,7 @@ struct pci_host_bridge {
 	void (*release_fn)(struct pci_host_bridge *);
 	int (*enable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
 	void (*disable_device)(struct pci_host_bridge *bridge, struct pci_dev *dev);
+	int (*reset_root_port)(struct pci_host_bridge *bridge, struct pci_dev *dev);
 	void		*release_data;
 	unsigned int	ignore_reset_delay:1;	/* For entire hierarchy */
 	unsigned int	no_ext_tags:1;		/* No Extended Tags */

-- 
2.45.2

[PATCH v5 2/4] PCI: host-common: Add link down handling for Root Ports

[Manivannan Sadhasivam]

From: Manivannan Sadhasivam <mani@kernel.org>

The PCI link, when down, needs to be recovered to bring it back. But on
some platforms, that cannot be done in a generic way as link recovery
procedure is platform specific. So add a new API
pci_host_handle_link_down() that could be called by the host bridge drivers
for a specific Root Port when the link goes down.

The API accepts the 'pci_dev' corresponding to the Root Port which observed
the link down event. If CONFIG_PCIEAER is enabled, the API calls
pcie_do_recovery() function with 'pci_channel_io_frozen' as the state. This
will result in the execution of the AER Fatal error handling code. Since
the link down recovery is pretty much the same as AER Fatal error handling,
pcie_do_recovery() helper is reused here. First, the AER error_detected()
callback will be triggered for the bridge and then for the downstream
devices. Finally, pci_host_reset_root_port() will be called for the Root
Port, which will reset the Root Port using 'reset_root_port' callback to
recover the link. Once that's done, resume message will be broadcasted to
the bridge and the downstream devices, indicating successful link recovery.

But if CONFIG_PCIEAER is not enabled in the kernel, only
pci_host_reset_root_port() API will be called, which will in turn call
pci_bus_error_reset() to just reset the Root Port as there is no way we
could inform the drivers about link recovery.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/controller/pci-host-common.c | 33 ++++++++++++++++++++++++++++++++
 drivers/pci/controller/pci-host-common.h |  1 +
 drivers/pci/pci.c                        |  1 +
 drivers/pci/pcie/err.c                   |  1 +
 4 files changed, 36 insertions(+)

diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index b0992325dd65f0da8e216ec8a2153af365225d1d..51eacb6cb57443338e995f17afd3b2564bbd1f83 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -12,9 +12,11 @@
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_pci.h>
+#include <linux/pci.h>
 #include <linux/pci-ecam.h>
 #include <linux/platform_device.h>
 
+#include "../pci.h"
 #include "pci-host-common.h"
 
 static void gen_pci_unmap_cfg(void *ptr)
@@ -104,5 +106,36 @@ void pci_host_common_remove(struct platform_device *pdev)
 }
 EXPORT_SYMBOL_GPL(pci_host_common_remove);
 
+static pci_ers_result_t pci_host_reset_root_port(struct pci_dev *dev)
+{
+	int ret;
+
+	ret = pci_bus_error_reset(dev);
+	if (ret) {
+		pci_err(dev, "Failed to reset Root Port: %d\n", ret);
+		return PCI_ERS_RESULT_DISCONNECT;
+	}
+
+	pci_info(dev, "Root Port has been reset\n");
+
+	return PCI_ERS_RESULT_RECOVERED;
+}
+
+static void pci_host_recover_root_port(struct pci_dev *port)
+{
+#if IS_ENABLED(CONFIG_PCIEAER)
+	pcie_do_recovery(port, pci_channel_io_frozen, pci_host_reset_root_port);
+#else
+	pci_host_reset_root_port(port);
+#endif
+}
+
+void pci_host_handle_link_down(struct pci_dev *port)
+{
+	pci_info(port, "Recovering Root Port due to Link Down\n");
+	pci_host_recover_root_port(port);
+}
+EXPORT_SYMBOL_GPL(pci_host_handle_link_down);
+
 MODULE_DESCRIPTION("Common library for PCI host controller drivers");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/pci/controller/pci-host-common.h b/drivers/pci/controller/pci-host-common.h
index 65bd9e032353827221a6af59858c46fdbe5916bf..cb0a07c8773ec87838164e994b34a62d2c8118be 100644
--- a/drivers/pci/controller/pci-host-common.h
+++ b/drivers/pci/controller/pci-host-common.h
@@ -16,5 +16,6 @@ int pci_host_common_probe(struct platform_device *pdev);
 int pci_host_common_init(struct platform_device *pdev,
 			 const struct pci_ecam_ops *ops);
 void pci_host_common_remove(struct platform_device *pdev);
+void pci_host_handle_link_down(struct pci_dev *port);
 
 #endif
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 82c56fbd58ca4aaafac4f1638e7e0225c07958cb..2353342beb9e535cf1291cfa7a60c3e6c8f5bf86 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5760,6 +5760,7 @@ int pci_bus_error_reset(struct pci_dev *bridge)
 	mutex_unlock(&pci_slot_mutex);
 	return pci_bus_reset(bridge->subordinate, PCI_RESET_DO_RESET);
 }
+EXPORT_SYMBOL_GPL(pci_bus_error_reset);
 
 /**
  * pci_probe_reset_bus - probe whether a PCI bus can be reset
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index b834fc0d705938540d3d7d3d8739770c09fe7cf1..3e3084bb7cb7fa06b526e6fab60e77927aba0ad0 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -270,3 +270,4 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 
 	return status;
 }
+EXPORT_SYMBOL_GPL(pcie_do_recovery);

-- 
2.45.2

[PATCH v5 3/4] PCI: qcom: Add support for resetting the Root Port due to link down event

[Manivannan Sadhasivam]

From: Manivannan Sadhasivam <mani@kernel.org>

The PCIe link can go down under circumstances such as the device firmware
crash, link instability, etc... When that happens, the PCIe Root Port needs
to be reset to make it operational again. Currently, the driver is not
handling the link down event, due to which the users have to restart the
machine to make PCIe link operational again. So fix it by detecting the
link down event and resetting the Root Port.

Since the Qcom PCIe controllers report the link down event through the
'global' IRQ, enable the link down event by setting PARF_INT_ALL_LINK_DOWN
bit in PARF_INT_ALL_MASK register.

In the case of the event, iterate through the available Root Ports and call
pci_host_handle_link_down() API with Root Port 'pci_dev' to let the PCI
core handle the link down condition. Note that both link up and link down
events could be set at a time when the handler runs. So always handle link
down first. Since Qcom PCIe controllers only support one Root Port per
controller instance, the API will be called only once. But the looping is
necessary as there is no PCI API available to fetch the Root Port instance
without the child 'pci_dev'.

The API will internally call, 'pci_host_bridge::reset_root_port()' callback
to reset the Root Port in a platform specific way. So implement the
callback to reset the Root Port by first resetting the PCIe core, followed
by reinitializing the resources and then finally starting the link again.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/Kconfig     |   1 +
 drivers/pci/controller/dwc/pcie-qcom.c | 120 ++++++++++++++++++++++++++++++---
 2 files changed, 113 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index d9f0386396edf66ad0e514a0f545ed24d89fcb6c..ce04ee6fbd99cbcce5d2f3a75ebd72a17070b7b7 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -296,6 +296,7 @@ config PCIE_QCOM
 	select PCIE_DW_HOST
 	select CRC8
 	select PCIE_QCOM_COMMON
+	select PCI_HOST_COMMON
 	help
 	  Say Y here to enable PCIe controller support on Qualcomm SoCs. The
 	  PCIe controller uses the DesignWare core plus Qualcomm-specific
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index c789e3f856550bcfa1ce09962ba9c086d117de05..5f7b2b80aace742780e5bc5b479f4f64ab778453 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -34,6 +34,7 @@
 #include <linux/units.h>
 
 #include "../../pci.h"
+#include "../pci-host-common.h"
 #include "pcie-designware.h"
 #include "pcie-qcom-common.h"
 
@@ -55,6 +56,7 @@
 #define PARF_INT_ALL_STATUS			0x224
 #define PARF_INT_ALL_CLEAR			0x228
 #define PARF_INT_ALL_MASK			0x22c
+#define PARF_STATUS				0x230
 #define PARF_SID_OFFSET				0x234
 #define PARF_BDF_TRANSLATE_CFG			0x24c
 #define PARF_DBI_BASE_ADDR_V2			0x350
@@ -130,9 +132,14 @@
 
 /* PARF_LTSSM register fields */
 #define LTSSM_EN				BIT(8)
+#define SW_CLEAR_FLUSH_MODE			BIT(10)
+#define FLUSH_MODE				BIT(11)
 
 /* PARF_INT_ALL_{STATUS/CLEAR/MASK} register fields */
-#define PARF_INT_ALL_LINK_UP			BIT(13)
+#define INT_ALL_LINK_DOWN			1
+#define INT_ALL_LINK_UP				13
+#define PARF_INT_ALL_LINK_DOWN			BIT(INT_ALL_LINK_DOWN)
+#define PARF_INT_ALL_LINK_UP			BIT(INT_ALL_LINK_UP)
 #define PARF_INT_MSI_DEV_0_7			GENMASK(30, 23)
 
 /* PARF_NO_SNOOP_OVERRIDE register fields */
@@ -145,6 +152,9 @@
 /* PARF_BDF_TO_SID_CFG fields */
 #define BDF_TO_SID_BYPASS			BIT(0)
 
+/* PARF_STATUS fields */
+#define FLUSH_COMPLETED				BIT(8)
+
 /* ELBI_SYS_CTRL register fields */
 #define ELBI_SYS_CTRL_LT_ENABLE			BIT(0)
 
@@ -169,6 +179,7 @@
 						PCIE_CAP_SLOT_POWER_LIMIT_SCALE)
 
 #define PERST_DELAY_US				1000
+#define FLUSH_TIMEOUT_US			100
 
 #define QCOM_PCIE_CRC8_POLYNOMIAL		(BIT(2) | BIT(1) | BIT(0))
 
@@ -274,11 +285,14 @@ struct qcom_pcie {
 	struct icc_path *icc_cpu;
 	const struct qcom_pcie_cfg *cfg;
 	struct dentry *debugfs;
+	int global_irq;
 	bool suspended;
 	bool use_pm_opp;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
+static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
+				  struct pci_dev *pdev);
 
 static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
 {
@@ -1263,6 +1277,8 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 			goto err_assert_reset;
 	}
 
+	pp->bridge->reset_root_port = qcom_pcie_reset_root_port;
+
 	return 0;
 
 err_assert_reset:
@@ -1517,6 +1533,78 @@ static void qcom_pcie_icc_opp_update(struct qcom_pcie *pcie)
 	}
 }
 
+/*
+ * Qcom PCIe controllers only support one Root Port per controller instance. So
+ * this function ignores the 'pci_dev' associated with the Root Port and just
+ * resets the host bridge, which in turn resets the Root Port also.
+ */
+static int qcom_pcie_reset_root_port(struct pci_host_bridge *bridge,
+				  struct pci_dev *pdev)
+{
+	struct pci_bus *bus = bridge->bus;
+	struct dw_pcie_rp *pp = bus->sysdata;
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct qcom_pcie *pcie = to_qcom_pcie(pci);
+	struct device *dev = pcie->pci->dev;
+	u32 val;
+	int ret;
+
+	/* Wait for the pending transactions to be completed */
+	ret = readl_relaxed_poll_timeout(pcie->parf + PARF_STATUS, val,
+					 val & FLUSH_COMPLETED, 10,
+					 FLUSH_TIMEOUT_US);
+	if (ret) {
+		dev_err(dev, "Flush completion failed: %d\n", ret);
+		goto err_host_deinit;
+	}
+
+	/* Clear the FLUSH_MODE to allow the core to be reset */
+	val = readl(pcie->parf + PARF_LTSSM);
+	val |= SW_CLEAR_FLUSH_MODE;
+	writel(val, pcie->parf + PARF_LTSSM);
+
+	/* Wait for the FLUSH_MODE to clear */
+	ret = readl_relaxed_poll_timeout(pcie->parf + PARF_LTSSM, val,
+					 !(val & FLUSH_MODE), 10,
+					 FLUSH_TIMEOUT_US);
+	if (ret) {
+		dev_err(dev, "Flush mode clear failed: %d\n", ret);
+		goto err_host_deinit;
+	}
+
+	qcom_pcie_host_deinit(pp);
+
+	ret = qcom_pcie_host_init(pp);
+	if (ret) {
+		dev_err(dev, "Host init failed\n");
+		return ret;
+	}
+
+	ret = dw_pcie_setup_rc(pp);
+	if (ret)
+		goto err_host_deinit;
+
+	/*
+	 * Re-enable global IRQ events as the PARF_INT_ALL_MASK register is
+	 * non-sticky.
+	 */
+	if (pcie->global_irq)
+		writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_ALL_LINK_DOWN |
+			       PARF_INT_MSI_DEV_0_7, pcie->parf + PARF_INT_ALL_MASK);
+
+	qcom_pcie_start_link(pci);
+	dw_pcie_wait_for_link(pci);
+
+	dev_dbg(dev, "Root Port reset completed\n");
+
+	return 0;
+
+err_host_deinit:
+	qcom_pcie_host_deinit(pp);
+
+	return ret;
+}
+
 static int qcom_pcie_link_transition_count(struct seq_file *s, void *data)
 {
 	struct qcom_pcie *pcie = (struct qcom_pcie *)dev_get_drvdata(s->private);
@@ -1559,11 +1647,24 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data)
 	struct qcom_pcie *pcie = data;
 	struct dw_pcie_rp *pp = &pcie->pci->pp;
 	struct device *dev = pcie->pci->dev;
-	u32 status = readl_relaxed(pcie->parf + PARF_INT_ALL_STATUS);
+	struct pci_dev *port;
+	unsigned long status = readl_relaxed(pcie->parf + PARF_INT_ALL_STATUS);
 
 	writel_relaxed(status, pcie->parf + PARF_INT_ALL_CLEAR);
 
-	if (FIELD_GET(PARF_INT_ALL_LINK_UP, status)) {
+	/*
+	 * It is possible that both Link Up and Link Down events might have
+	 * happended. So always handle Link Down first.
+	 */
+	if (test_and_clear_bit(INT_ALL_LINK_DOWN, &status)) {
+		dev_dbg(dev, "Received Link down event\n");
+		for_each_pci_bridge(port, pp->bridge->bus) {
+			if (pci_pcie_type(port) == PCI_EXP_TYPE_ROOT_PORT)
+				pci_host_handle_link_down(port);
+		}
+	}
+
+	if (test_and_clear_bit(INT_ALL_LINK_UP, &status)) {
 		dev_dbg(dev, "Received Link up event. Starting enumeration!\n");
 		/* Rescan the bus to enumerate endpoint devices */
 		pci_lock_rescan_remove();
@@ -1571,11 +1672,12 @@ static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data)
 		pci_unlock_rescan_remove();
 
 		qcom_pcie_icc_opp_update(pcie);
-	} else {
-		dev_WARN_ONCE(dev, 1, "Received unknown event. INT_STATUS: 0x%08x\n",
-			      status);
 	}
 
+	if (status)
+		dev_WARN_ONCE(dev, 1, "Received unknown event. INT_STATUS: 0x%08x\n",
+			      (u32) status);
+
 	return IRQ_HANDLED;
 }
 
@@ -1732,8 +1834,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 			goto err_host_deinit;
 		}
 
-		writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_MSI_DEV_0_7,
-			       pcie->parf + PARF_INT_ALL_MASK);
+		writel_relaxed(PARF_INT_ALL_LINK_UP | PARF_INT_ALL_LINK_DOWN |
+			       PARF_INT_MSI_DEV_0_7, pcie->parf + PARF_INT_ALL_MASK);
+
+		pcie->global_irq = irq;
 	}
 
 	qcom_pcie_icc_opp_update(pcie);

-- 
2.45.2

[PATCH v5 4/4] PCI: dw-rockchip: Add support to reset Root Port upon link down event

[Manivannan Sadhasivam]

From: Wilfred Mallawa <wilfred.mallawa@wdc.com>

The PCIe link may go down in cases like firmware crashes or unstable
connections. When this occurs, the PCIe Root Port must be reset to restore
the functionality. However, the current driver lacks link down handling,
forcing users to reboot the system to recover.

This patch implements the `reset_root_port` callback for link down handling
for Rockchip DWC PCIe host controller. In which, the RC is reset,
reconfigured and link training initiated to recover from the link down
event.

This also by extension fixes issues with sysfs initiated bus resets. In
that, currently, when a sysfs initiated bus reset is issued, the endpoint
device is non-functional after (may link up with downgraded link status).
With the link down handling support, a sysfs initiated bus reset works as
intended. Testing conducted on a ROCK5B board with an M.2 NVMe drive.

Signed-off-by: Wilfred Mallawa <wilfred.mallawa@wdc.com>
[mani: rebased on top of the new version of reset_root_port series]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@oss.qualcomm.com>
---
 drivers/pci/controller/dwc/Kconfig            |  1 +
 drivers/pci/controller/dwc/pcie-dw-rockchip.c | 91 ++++++++++++++++++++++++++-
 2 files changed, 90 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index ce04ee6fbd99cbcce5d2f3a75ebd72a17070b7b7..01e2650242ccc345bdd0568d08219527f00ed395 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -348,6 +348,7 @@ config PCIE_ROCKCHIP_DW_HOST
 	depends on OF
 	select PCIE_DW_HOST
 	select PCIE_ROCKCHIP_DW
+	select PCI_HOST_COMMON
 	help
 	  Enables support for the DesignWare PCIe controller in the
 	  Rockchip SoC (except RK3399) to work in host mode.
diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 93171a3928794915ad1e8c03c017ce0afc1f9169..8f1a34c5fbabaacbd9624048ca4c4f8dc29f2171 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -23,6 +23,7 @@
 #include <linux/reset.h>
 
 #include "../../pci.h"
+#include "../pci-host-common.h"
 #include "pcie-designware.h"
 
 /*
@@ -84,6 +85,9 @@ struct rockchip_pcie_of_data {
 	const struct pci_epc_features *epc_features;
 };
 
+static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
+				       struct pci_dev *pdev);
+
 static int rockchip_pcie_readl_apb(struct rockchip_pcie *rockchip, u32 reg)
 {
 	return readl_relaxed(rockchip->apb_base + reg);
@@ -257,6 +261,7 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
 					 rockchip);
 
 	rockchip_pcie_enable_l0s(pci);
+	pp->bridge->reset_root_port = rockchip_pcie_rc_reset_root_port;
 
 	return 0;
 }
@@ -448,6 +453,7 @@ static irqreturn_t rockchip_pcie_rc_sys_irq_thread(int irq, void *arg)
 	struct dw_pcie *pci = &rockchip->pci;
 	struct dw_pcie_rp *pp = &pci->pp;
 	struct device *dev = pci->dev;
+	struct pci_dev *port;
 	u32 reg;
 
 	reg = rockchip_pcie_readl_apb(rockchip, PCIE_CLIENT_INTR_STATUS_MISC);
@@ -456,6 +462,14 @@ static irqreturn_t rockchip_pcie_rc_sys_irq_thread(int irq, void *arg)
 	dev_dbg(dev, "PCIE_CLIENT_INTR_STATUS_MISC: %#x\n", reg);
 	dev_dbg(dev, "LTSSM_STATUS: %#x\n", rockchip_pcie_get_ltssm(rockchip));
 
+	if (reg & PCIE_LINK_REQ_RST_NOT_INT) {
+		dev_dbg(dev, "hot reset or link-down reset\n");
+		for_each_pci_bridge(port, pp->bridge->bus) {
+			if (pci_pcie_type(port) == PCI_EXP_TYPE_ROOT_PORT)
+				pci_host_handle_link_down(port);
+		}
+	}
+
 	if (reg & PCIE_RDLH_LINK_UP_CHGED) {
 		if (rockchip_pcie_link_up(pci)) {
 			dev_dbg(dev, "Received Link up event. Starting enumeration!\n");
@@ -537,8 +551,8 @@ static int rockchip_pcie_configure_rc(struct platform_device *pdev,
 		return ret;
 	}
 
-	/* unmask DLL up/down indicator */
-	val = HIWORD_UPDATE(PCIE_RDLH_LINK_UP_CHGED, 0);
+	/* unmask DLL up/down indicator and hot reset/link-down reset irq */
+	val = HIWORD_UPDATE(PCIE_RDLH_LINK_UP_CHGED | PCIE_LINK_REQ_RST_NOT_INT, 0);
 	rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_INTR_MASK_MISC);
 
 	return ret;
@@ -689,6 +703,79 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 	return ret;
 }
 
+static int rockchip_pcie_rc_reset_root_port(struct pci_host_bridge *bridge,
+					    struct pci_dev *pdev)
+{
+	struct pci_bus *bus = bridge->bus;
+	struct dw_pcie_rp *pp = bus->sysdata;
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct rockchip_pcie *rockchip = to_rockchip_pcie(pci);
+	struct device *dev = rockchip->pci.dev;
+	u32 val;
+	int ret;
+
+	dw_pcie_stop_link(pci);
+	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
+	rockchip_pcie_phy_deinit(rockchip);
+
+	ret = reset_control_assert(rockchip->rst);
+	if (ret)
+		return ret;
+
+	ret = rockchip_pcie_phy_init(rockchip);
+	if (ret)
+		goto disable_regulator;
+
+	ret = reset_control_deassert(rockchip->rst);
+	if (ret)
+		goto deinit_phy;
+
+	ret = rockchip_pcie_clk_init(rockchip);
+	if (ret)
+		goto deinit_phy;
+
+	ret = pp->ops->init(pp);
+	if (ret) {
+		dev_err(dev, "Host init failed: %d\n", ret);
+		goto deinit_clk;
+	}
+
+	/* LTSSM enable control mode */
+	val = HIWORD_UPDATE_BIT(PCIE_LTSSM_ENABLE_ENHANCE);
+	rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_HOT_RESET_CTRL);
+
+	rockchip_pcie_writel_apb(rockchip, PCIE_CLIENT_RC_MODE, PCIE_CLIENT_GENERAL_CON);
+
+	ret = dw_pcie_setup_rc(pp);
+	if (ret) {
+		dev_err(dev, "Failed to setup RC: %d\n", ret);
+		goto deinit_clk;
+	}
+
+	/* unmask DLL up/down indicator and hot reset/link-down reset irq */
+	val = HIWORD_UPDATE(PCIE_RDLH_LINK_UP_CHGED | PCIE_LINK_REQ_RST_NOT_INT, 0);
+	rockchip_pcie_writel_apb(rockchip, val, PCIE_CLIENT_INTR_MASK_MISC);
+
+	ret = dw_pcie_start_link(pci);
+	if (ret)
+		goto deinit_clk;
+
+	/* Ignore errors, the link may come up later */
+	dw_pcie_wait_for_link(pci);
+	dev_dbg(dev, "Root Port reset completed\n");
+	return ret;
+
+deinit_clk:
+	clk_bulk_disable_unprepare(rockchip->clk_cnt, rockchip->clks);
+deinit_phy:
+	rockchip_pcie_phy_deinit(rockchip);
+disable_regulator:
+	if (rockchip->vpcie3v3)
+		regulator_disable(rockchip->vpcie3v3);
+
+	return ret;
+}
+
 static const struct rockchip_pcie_of_data rockchip_pcie_rc_of_data_rk3568 = {
 	.mode = DW_PCIE_RC_TYPE,
 };

-- 
2.45.2

Re: [PATCH v5 1/4] PCI/ERR: Add support for resetting the Root Ports in a platform specific way

[Lukas Wunner]

On Tue, Jul 15, 2025 at 01:29:18PM +0530, Manivannan Sadhasivam wrote:
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4964,7 +4964,19 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
>  
>  void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
>  {
> +	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> +	int ret;
> +
> +	if (host->reset_root_port) {
> +		ret = host->reset_root_port(host, dev);
> +		if (ret)
> +			pci_err(dev, "Failed to reset Root Port: %d\n", ret);
> +
> +		return;
> +	}
> +

There used to be a pci_is_root_bus() check here:

https://lore.kernel.org/r/20250524185304.26698-2-manivannan.sadhasivam@linaro.org/

Thanks,

Lukas

Re: [PATCH v5 1/4] PCI/ERR: Add support for resetting the Root Ports in a platform specific way

[Manivannan Sadhasivam]

On Tue, Jul 15, 2025 at 10:16:27AM GMT, Lukas Wunner wrote:
> On Tue, Jul 15, 2025 at 01:29:18PM +0530, Manivannan Sadhasivam wrote:
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -4964,7 +4964,19 @@ void pci_reset_secondary_bus(struct pci_dev *dev)
> >  
> >  void __weak pcibios_reset_secondary_bus(struct pci_dev *dev)
> >  {
> > +	struct pci_host_bridge *host = pci_find_host_bridge(dev->bus);
> > +	int ret;
> > +
> > +	if (host->reset_root_port) {
> > +		ret = host->reset_root_port(host, dev);
> > +		if (ret)
> > +			pci_err(dev, "Failed to reset Root Port: %d\n", ret);
> > +
> > +		return;
> > +	}
> > +
> 
> There used to be a pci_is_root_bus() check here:
> 
> https://lore.kernel.org/r/20250524185304.26698-2-manivannan.sadhasivam@linaro.org/
> 

Right. I forgot to include that series, but somehow managed to remember the
s/slot/root_port change.

Will incorporate in next revision, thanks!

- Mani

-- 
மணிவண்ணன் சதாசிவம்

Re: [PATCH v5 2/4] PCI: host-common: Add link down handling for Root Ports

[kernel test robot]

Hi Manivannan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on 19272b37aa4f83ca52bdf9c16d5d81bdd1354494]

url:    https://github.com/intel-lab-lkp/linux/commits/Manivannan-Sadhasivam/PCI-ERR-Add-support-for-resetting-the-Root-Ports-in-a-platform-specific-way/20250715-160430
base:   19272b37aa4f83ca52bdf9c16d5d81bdd1354494
patch link:    https://lore.kernel.org/r/20250715-pci-port-reset-v5-2-26a5d278db40%40oss.qualcomm.com
patch subject: [PATCH v5 2/4] PCI: host-common: Add link down handling for Root Ports
config: i386-buildonly-randconfig-003-20250716 (https://download.01.org/0day-ci/archive/20250716/202507160557.oy6ZGYI7-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14+deb12u1) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250716/202507160557.oy6ZGYI7-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202507160557.oy6ZGYI7-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/nfc/s3fwrn5/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/s3fwrn5/phy_common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st-nci/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st-nci/ndlc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st-nci/se.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st-nci/vendor_cmds.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st21nfca/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st21nfca/dep.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st21nfca/se.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st21nfca/vendor_cmds.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nfc/st95hf/spi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/ntb/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/ntb/msi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nubus/bus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nubus/nubus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/btt.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/btt_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/bus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/claim.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/dax_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/dimm_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/namespace_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/nd_perf.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/nd_virtio.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/pfn_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvdimm/region_devs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/common/auth.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/common/keyring.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/auth.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/constants.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/fabrics.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/fault_inject.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/fc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/multipath.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/host/sysfs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/target/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvme/target/fc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/nvmem/layouts.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/address.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/base.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/cpu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/device.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/dynamic.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/fdt.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/irq.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/module.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/of_kunit_helpers.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/of_reserved_mem.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/overlay.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/platform.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/property.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/of/resolver.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parisc/eisa.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parisc/gsc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parisc/iosapic.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parisc/sba_iommu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parport/ieee1284.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parport/ieee1284_ops.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parport/parport_pc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/parport/share.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/access.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/bus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/cadence/pcie-cadence-ep.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/cadence/pcie-cadence-host.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/cadence/pcie-cadence.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/dwc/pcie-designware-ep.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/dwc/pcie-designware-host.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/dwc/pcie-designware.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/dwc/pcie-qcom-common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/pci-host-common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/pci-hyperv-intf.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/pcie-iproc-msi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/pcie-iproc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/pcie-rockchip.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/controller/plda/pcie-plda-host.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/devres.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/doe.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/ecam.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/endpoint/pci-ep-cfs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/endpoint/pci-epc-core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/endpoint/pci-epc-mem.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/endpoint/pci-epf-core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/host-bridge.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/acpi_pcihp.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/acpiphp_core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/cpci_hotplug_core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/pci_hotplug_core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/pnv_php.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/rpaphp_core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/hotplug/rpaphp_slot.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/msi/irqdomain.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/of.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/p2pdma.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pci-acpi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pci-bridge-emul.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pci-driver.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pci.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pcie/aer.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pcie/aspm.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
>> drivers/pci/pcie/err.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pcie/portdrv.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/pcie/ptm.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/probe.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/remove.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/search.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/setup-bus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/slot.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/switch/switchtec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/tph.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pci/vgaarb.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/cistpl.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/cs.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/ds.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/max1600.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/pcmcia_cis.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/pcmcia_resource.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/pxa2xx_base.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/rsrc_iodyn.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/rsrc_mgr.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/rsrc_nonstatic.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/sa11xx_base.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pcmcia/soc_common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/peci/cpu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/peci/device.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/perf/arm_cspmu/arm_cspmu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/perf/hisilicon/hisi_uncore_pmu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/perf/riscv_pmu_sbi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/allwinner/phy-sun4i-usb.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/tegra/xusb-tegra124.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/tegra/xusb-tegra186.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/tegra/xusb-tegra210.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/tegra/xusb.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/ti/phy-omap-control.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/phy/ti/phy-omap-usb2.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/devicetree.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/freescale/pinctrl-imx.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/freescale/pinctrl-scu.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/intel/pinctrl-intel.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/mediatek/mtk-eint.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/mediatek/pinctrl-mtk-common-v2.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/mediatek/pinctrl-paris.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/meson/pinctrl-meson-axg-pmx.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/meson/pinctrl-meson.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/meson/pinctrl-meson8-pmx.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/pinconf-generic.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/pinmux.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/pxa/pinctrl-pxa2xx.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/qcom/pinctrl-lpass-lpi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/qcom/pinctrl-msm.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/realtek/pinctrl-rtd.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/sprd/pinctrl-sprd.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/starfive/pinctrl-starfive-jh7110.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pinctrl/tegra/pinctrl-tegra-xusb.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/arm64/huawei-gaokun-ec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/arm64/lenovo-yoga-c630.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/cros_ec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/cros_ec_lpc_mec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/cros_ec_proto.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/cros_ec_sensorhub_ring.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/cros_usbpd_notify.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/chrome/wilco_ec/mailbox.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/cznic/turris-omnia-mcu-base.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/cznic/turris-signing-key.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/olpc/olpc-ec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/surface/aggregator/bus.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/surface/aggregator/controller.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/surface/aggregator/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/surface/aggregator/ssh_packet_layer.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/surface/surface_acpi_notify.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/amd/hsmp/hsmp.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/amd/hsmp/hwmon.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/amd/wbrf.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/asus-wmi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/dell/dcdbas.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/dell/dell-rbtn.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/dell/dell-smbios-base.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/dell/dell-wmi-descriptor.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/dell/dell-wmi-privacy.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/firmware_attributes_class.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/ideapad-laptop.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/int3472/common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/int3472/discrete.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/pmc/ssram_telemetry.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/pmt/class.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/pmt/telemetry.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/punit_ipc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/speed_select_if/isst_if_common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/speed_select_if/isst_tpmi_core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/telemetry/core.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/uncore-frequency/uncore-frequency-common.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/vsec.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel/vsec_tpmi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel_ips.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/intel_scu_ipc.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/mxm-wmi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/siemens/simatic-ipc-batt.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/platform/x86/wmi.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pmdomain/actions/owl-sps-helper.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pmdomain/rockchip/pm-domains.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing
   drivers/pnp/card.c: warning: EXPORT_SYMBOL() is used, but #include <linux/export.h> is missing

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https://github.com/intel/lkp-tests/wiki