@@ -117,7 +117,7 @@ int pcie_port_device_resume(struct device *dev);
int pcie_port_device_runtime_suspend(struct device *dev);
int pcie_port_device_runtime_resume(struct device *dev);
#endif
-void pcie_port_device_remove(struct pci_dev *dev);
+void pcie_port_device_remove(struct pci_dev *dev, bool disable);
int __must_check pcie_port_bus_register(void);
void pcie_port_bus_unregister(void);
@@ -484,11 +484,13 @@ EXPORT_SYMBOL_GPL(pcie_port_find_device);
* Remove PCI Express port service devices associated with given port and
* disable MSI-X or MSI for the port.
*/
-void pcie_port_device_remove(struct pci_dev *dev)
+void pcie_port_device_remove(struct pci_dev *dev, bool disable)
{
device_for_each_child(&dev->dev, NULL, remove_iter);
pci_free_irq_vectors(dev);
- pci_disable_device(dev);
+
+ if (disable)
+ pci_disable_device(dev);
}
/**
@@ -147,7 +147,18 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
pm_runtime_dont_use_autosuspend(&dev->dev);
}
- pcie_port_device_remove(dev);
+ pcie_port_device_remove(dev, true);
+}
+
+static void pcie_portdrv_shutdown(struct pci_dev *dev)
+{
+ if (pci_bridge_d3_possible(dev)) {
+ pm_runtime_forbid(&dev->dev);
+ pm_runtime_get_noresume(&dev->dev);
+ pm_runtime_dont_use_autosuspend(&dev->dev);
+ }
+
+ pcie_port_device_remove(dev, false);
}
static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
@@ -219,7 +230,7 @@ static struct pci_driver pcie_portdriver = {
.probe = pcie_portdrv_probe,
.remove = pcie_portdrv_remove,
- .shutdown = pcie_portdrv_remove,
+ .shutdown = pcie_portdrv_shutdown,
.err_handler = &pcie_portdrv_err_handler,
Use separate remove()/shutdown() callback, and don't disable PCI device during shutdown. This can avoid some poweroff/reboot failures. The poweroff/reboot failures could easily be reproduced on Loongson platforms. I think this is not a Loongson-specific problem, instead, is a problem related to some specific PCI hosts. On some x86 platforms, radeon/amdgpu devices can cause the same problem [1][2], and commit faefba95c9e8ca3a ("drm/amdgpu: just suspend the hw on pci shutdown") can resolve it. As Tiezhu said, this occasionally shutdown or reboot failure is due to clear PCI_COMMAND_MASTER on the device in do_pci_disable_device() [3]. static void do_pci_disable_device(struct pci_dev *dev) { u16 pci_command; pci_read_config_word(dev, PCI_COMMAND, &pci_command); if (pci_command & PCI_COMMAND_MASTER) { pci_command &= ~PCI_COMMAND_MASTER; pci_write_config_word(dev, PCI_COMMAND, pci_command); } pcibios_disable_device(dev); } When remove "pci_command &= ~PCI_COMMAND_MASTER;", it can work well when shutdown or reboot. The root cause on Loongson platform is that CPU is still accessing PCIe devices while poweroff/reboot, and if we disable the Bus Master Bit at this time, the PCIe controller doesn't forward requests to downstream devices, and also doesn't send TIMEOUT to CPU, which causes CPU wait forever (hardware deadlock). This behavior is a PCIe protocol violation, and will be fixed in new revisions of hardware (add timeout mechanism for CPU read request, whether or not Bus Master bit is cleared). Radeon driver is more difficult than amdgpu due to its confusing symbol names, and I have maintained an out-of-tree patch for a long time [4]. Recently, we found more and more devices can cause the same problem, and it is very difficult to modify all problematic drivers as radeon/amdgpu does (the .shutdown callback should make sure there is no DMA activity). So, I think modify the PCIe port driver is a simple and effective way. Because there is no poweroff/reboot problems before cc27b735ad3a75574a6a ("PCI/portdrv: Turn off PCIe services during shutdown"). And as early discussed, kexec can still work fine after this patch [5]. [1] https://bugs.freedesktop.org/show_bug.cgi?id=97980 [2] https://bugs.freedesktop.org/show_bug.cgi?id=98638 [3] https://lore.kernel.org/patchwork/patch/1305067/ [4] https://github.com/chenhuacai/linux/commit/8da06f9b669831829416a3e9f4d1c57f217a42f0 [5] http://patchwork.ozlabs.org/project/linux-pci/patch/1600680138-10949-1-git-send-email-chenhc@lemote.com/ Cc: Sinan Kaya <okaya@kernel.org> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- drivers/pci/pcie/portdrv.h | 2 +- drivers/pci/pcie/portdrv_core.c | 6 ++++-- drivers/pci/pcie/portdrv_pci.c | 15 +++++++++++++-- 3 files changed, 18 insertions(+), 5 deletions(-)