@@ -86,6 +86,23 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
DEV_PCIE_PORT_2, loongson_mrrs_quirk);
+static void loongson_bmaster_quirk(struct pci_dev *pdev)
+{
+ /*
+ * Some Loongson PCIe ports will cause CPU deadlock if disable
+ * the Bus Master bit during poweroff/reboot.
+ */
+ struct pci_host_bridge *bridge = pci_find_host_bridge(pdev->bus);
+
+ bridge->no_dis_bmaster = 1;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+ DEV_PCIE_PORT_0, loongson_bmaster_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+ DEV_PCIE_PORT_1, loongson_bmaster_quirk);
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_LOONGSON,
+ DEV_PCIE_PORT_2, loongson_bmaster_quirk);
+
static struct loongson_pci *pci_bus_to_loongson_pci(struct pci_bus *bus)
{
struct pci_config_window *cfg;
@@ -493,7 +493,6 @@ void pcie_port_device_remove(struct pci_dev *dev)
{
device_for_each_child(&dev->dev, NULL, remove_iter);
pci_free_irq_vectors(dev);
- pci_disable_device(dev);
}
/**
@@ -148,6 +148,24 @@ static void pcie_portdrv_remove(struct pci_dev *dev)
}
pcie_port_device_remove(dev);
+
+ pci_disable_device(dev);
+}
+
+static void pcie_portdrv_shutdown(struct pci_dev *dev)
+{
+ struct pci_host_bridge *bridge = pci_find_host_bridge(dev->bus);
+
+ 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);
+
+ if (!bridge->no_dis_bmaster)
+ pci_disable_device(dev);
}
static pci_ers_result_t pcie_portdrv_error_detected(struct pci_dev *dev,
@@ -198,7 +216,7 @@ 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,
@@ -570,6 +570,7 @@ struct pci_host_bridge {
unsigned int ignore_reset_delay:1; /* For entire hierarchy */
unsigned int no_ext_tags:1; /* No Extended Tags */
unsigned int no_inc_mrrs:1; /* No Increase MRRS */
+ unsigned int no_dis_bmaster:1; /* No Disable Bus Master */
unsigned int native_aer:1; /* OS may use PCIe AER */
unsigned int native_pcie_hotplug:1; /* OS may use PCIe hotplug */
unsigned int native_shpc_hotplug:1; /* OS may use SHPC hotplug */
cc27b735ad3a7557 ("PCI/portdrv: Turn off PCIe services during shutdown") causes poweroff/reboot failure on systems with LS7A chipset. We found that if we remove "pci_command &= ~PCI_COMMAND_MASTER" in do_pci_disable _device(), it can work well. The hardware engineer says that the root cause 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 does not send TIMEOUT to CPU, which causes CPU wait forever (hardware deadlock). This behavior is a PCIe protocol violation (Bus Master should not be involved in CPU MMIO transactions), and it will be fixed in new revisions of hardware (add timeout mechanism for CPU read request, whether or not Bus Master bit is cleared). On some x86 platforms, radeon/amdgpu devices can cause similar problems [1][2]. Once before I wanted to make a single patch to solve "all of these problems" together, but it seems unreasonable because maybe they are not exactly the same problem. So, this patch add a new function pcie_portdrv_shutdown(), a slight modified copy of pcie_portdrv_remove() dedicated for the shutdown path, and then add a quirk just for LS7A to avoid clearing Bus Master bit in pcie_portdrv_shutdown(). Leave other platforms behave as before. [1] https://bugs.freedesktop.org/show_bug.cgi?id=97980 [2] https://bugs.freedesktop.org/show_bug.cgi?id=98638 Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> --- drivers/pci/controller/pci-loongson.c | 17 +++++++++++++++++ drivers/pci/pcie/portdrv_core.c | 1 - drivers/pci/pcie/portdrv_pci.c | 20 +++++++++++++++++++- include/linux/pci.h | 1 + 4 files changed, 37 insertions(+), 2 deletions(-)