From: Pali Rohár pali@kernel.org
commit bc4fac42e5f8460af09c0a7f2f1915be09e20c71 upstream.
Aardvark supports PCIe Hot Reset via PCIE_CORE_CTRL1_REG.
Use it for implementing PCI_BRIDGE_CTL_BUS_RESET bit of PCI_BRIDGE_CONTROL register on emulated bridge.
With this, the function pci_reset_secondary_bus() starts working and can reset connected PCIe card. Custom userspace script [1] which uses setpci can trigger PCIe Hot Reset and reset the card manually.
[1] https://alexforencich.com/wiki/en/pcie/hot-reset-linux
Link: https://lore.kernel.org/r/20211028185659.20329-7-kabel@kernel.org Fixes: 8a3ebd8de328 ("PCI: aardvark: Implement emulated root PCI bridge config space") Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Marek Behún kabel@kernel.org Signed-off-by: Lorenzo Pieralisi lorenzo.pieralisi@arm.com Cc: stable@vger.kernel.org Signed-off-by: Marek Behún kabel@kernel.org --- drivers/pci/controller/pci-aardvark.c | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+)
diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c index 3265709bfba9..9e208294946c 100644 --- a/drivers/pci/controller/pci-aardvark.c +++ b/drivers/pci/controller/pci-aardvark.c @@ -764,6 +764,22 @@ advk_pci_bridge_emul_base_conf_read(struct pci_bridge_emul *bridge, *value = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG); return PCI_BRIDGE_EMUL_HANDLED;
+ case PCI_INTERRUPT_LINE: { + /* + * From the whole 32bit register we support reading from HW only + * one bit: PCI_BRIDGE_CTL_BUS_RESET. + * Other bits are retrieved only from emulated config buffer. + */ + __le32 *cfgspace = (__le32 *)&bridge->conf; + u32 val = le32_to_cpu(cfgspace[PCI_INTERRUPT_LINE / 4]); + if (advk_readl(pcie, PCIE_CORE_CTRL1_REG) & HOT_RESET_GEN) + val |= PCI_BRIDGE_CTL_BUS_RESET << 16; + else + val &= ~(PCI_BRIDGE_CTL_BUS_RESET << 16); + *value = val; + return PCI_BRIDGE_EMUL_HANDLED; + } + default: return PCI_BRIDGE_EMUL_NOT_HANDLED; } @@ -780,6 +796,17 @@ advk_pci_bridge_emul_base_conf_write(struct pci_bridge_emul *bridge, advk_writel(pcie, new, PCIE_CORE_CMD_STATUS_REG); break;
+ case PCI_INTERRUPT_LINE: + if (mask & (PCI_BRIDGE_CTL_BUS_RESET << 16)) { + u32 val = advk_readl(pcie, PCIE_CORE_CTRL1_REG); + if (new & (PCI_BRIDGE_CTL_BUS_RESET << 16)) + val |= HOT_RESET_GEN; + else + val &= ~HOT_RESET_GEN; + advk_writel(pcie, val, PCIE_CORE_CTRL1_REG); + } + break; + default: break; }