From: Manivannan Sadhasivam <m...@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.sadhasi...@linaro.org>
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasi...@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
b29264aa2be33b18a58b3b3db1d1fb0f6483e5e8..39310422634a9551efc8aded565b7cc30f4989d0
100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5768,6 +5768,7 @@ 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
