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PCI: aardvark: Fix support for PCI_BRIDGE_CTL_BUS_RESET on emulated bridge

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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: 8a3ebd8de3 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Pali Rohár 2021-11-25 01:26:14 +01:00 committed by Greg Kroah-Hartman
parent 7c517d7b88
commit 086226048b
1 changed files with 27 additions and 0 deletions
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27
drivers/pci/controller/pci-aardvark.c
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@ -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;
}