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Subject[PATCH 5.15 071/262] PCI: mvebu: Fix support for PCI_BRIDGE_CTL_BUS_RESET on emulated bridge
Date
From: Pali Rohár <pali@kernel.org>

[ Upstream commit d75404cc08832206f173668bd35391c581fea121 ]

Hardware supports PCIe Hot Reset via PCIE_CTRL_OFF register. Use it for
implementing PCI_BRIDGE_CTL_BUS_RESET bit of PCI_BRIDGE_CONTROL register on
emulated bridge.

With this change the function pci_reset_secondary_bus() starts working and
can reset connected PCIe card.

Link: https://lore.kernel.org/r/20211125124605.25915-13-pali@kernel.org
Fixes: 1f08673eef12 ("PCI: mvebu: Convert to PCI emulated bridge config space")
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/pci/controller/pci-mvebu.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
index e2d4bd8442a80..3563301e772ae 100644
--- a/drivers/pci/controller/pci-mvebu.c
+++ b/drivers/pci/controller/pci-mvebu.c
@@ -56,6 +56,7 @@
#define PCIE_CTRL_OFF 0x1a00
#define PCIE_CTRL_X1_MODE 0x0001
#define PCIE_CTRL_RC_MODE BIT(1)
+#define PCIE_CTRL_MASTER_HOT_RESET BIT(24)
#define PCIE_STAT_OFF 0x1a04
#define PCIE_STAT_BUS 0xff00
#define PCIE_STAT_DEV 0x1f0000
@@ -462,6 +463,22 @@ mvebu_pci_bridge_emul_base_conf_read(struct pci_bridge_emul *bridge,
break;
}

+ 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 (mvebu_readl(port, PCIE_CTRL_OFF) & PCIE_CTRL_MASTER_HOT_RESET)
+ val |= PCI_BRIDGE_CTL_BUS_RESET << 16;
+ else
+ val &= ~(PCI_BRIDGE_CTL_BUS_RESET << 16);
+ *value = val;
+ break;
+ }
+
default:
return PCI_BRIDGE_EMUL_NOT_HANDLED;
}
@@ -549,6 +566,17 @@ mvebu_pci_bridge_emul_base_conf_write(struct pci_bridge_emul *bridge,
mvebu_pcie_set_local_bus_nr(port, conf->secondary_bus);
break;

+ case PCI_INTERRUPT_LINE:
+ if (mask & (PCI_BRIDGE_CTL_BUS_RESET << 16)) {
+ u32 ctrl = mvebu_readl(port, PCIE_CTRL_OFF);
+ if (new & (PCI_BRIDGE_CTL_BUS_RESET << 16))
+ ctrl |= PCIE_CTRL_MASTER_HOT_RESET;
+ else
+ ctrl &= ~PCIE_CTRL_MASTER_HOT_RESET;
+ mvebu_writel(port, ctrl, PCIE_CTRL_OFF);
+ }
+ break;
+
default:
break;
}
--
2.34.1


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