From 58fb207fb10074be48f51e514422dea7ce5fa048 Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Fri, 6 Oct 2017 17:39:18 +0100
Subject: [PATCH 1/2] PCI: generic: Add support for Synopsys DesignWare RC in
ECAM mode
Some implementations of the Synopsys DesignWare PCIe controller implement
a so-called ECAM shift mode, which allows a static memory window to be
configured that covers the configuration space of the entire bus range.
Usually, when the firmware performs all the low level configuration that is
required to expose this controller in a fully ECAM compatible manner, we
can simply describe it as "pci-host-ecam-generic" and be done with it.
However, in some cases (e.g., the Marvell Armada 80x0 as well as the
Socionext SynQuacer Soc), the IP was synthesized with an ATU window
granularity that does not allow the first bus to be mapped in a way that
prevents the device on the downstream port from appearing more than once,
and so we still need special handling in software to drive this static
almost-ECAM configuration.
So extend the pci-host-generic driver so it can support these controllers
as well, by adding special config space accessors that take the above quirk
into account.
Note that, unlike most drivers for this IP, this driver does not expose a
fake bridge device at B/D/F 00:00.0. There is no point in doing so, given
that this is not a true bridge, and does not require any windows to be
configured in order for the downstream device to operate correctly.
Omitting it also prevents the PCI resource allocation routines from handing
out BAR space to it unnecessarily.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
[bhelgaas: factor out pci_dw_valid_device(), add pci_dw_ecam_map_bus() and
use generic read/write functions]
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Will Deacon <will.deacon@arm.com>
---
drivers/pci/host/pci-host-generic.c | 43 +++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/drivers/pci/host/pci-host-generic.c b/drivers/pci/host/pci-host-generic.c
index 7d709a7e0aa8a..2f05511ce718c 100644
--- a/drivers/pci/host/pci-host-generic.c
+++ b/drivers/pci/host/pci-host-generic.c
@@ -35,6 +35,40 @@ static struct pci_ecam_ops gen_pci_cfg_cam_bus_ops = {
}
};
+static bool pci_dw_valid_device(struct pci_bus *bus, unsigned int devfn)
+{
+ struct pci_config_window *cfg = bus->sysdata;
+
+ /*
+ * The Synopsys DesignWare PCIe controller in ECAM mode will not filter
+ * type 0 config TLPs sent to devices 1 and up on its downstream port,
+ * resulting in devices appearing multiple times on bus 0 unless we
+ * filter out those accesses here.
+ */
+ if (bus->number == cfg->busr.start && PCI_SLOT(devfn) > 0)
+ return false;
+
+ return true;
+}
+
+static void __iomem *pci_dw_ecam_map_bus(struct pci_bus *bus,
+ unsigned int devfn, int where)
+{
+ if (!pci_dw_valid_device(bus, devfn))
+ return NULL;
+
+ return pci_ecam_map_bus(bus, devfn, where);
+}
+
+static struct pci_ecam_ops pci_dw_ecam_bus_ops = {
+ .bus_shift = 20,
+ .pci_ops = {
+ .map_bus = pci_dw_ecam_map_bus,
+ .read = pci_generic_config_read,
+ .write = pci_generic_config_write,
+ }
+};
+
static const struct of_device_id gen_pci_of_match[] = {
{ .compatible = "pci-host-cam-generic",
.data = &gen_pci_cfg_cam_bus_ops },
@@ -42,6 +76,15 @@ static const struct of_device_id gen_pci_of_match[] = {
{ .compatible = "pci-host-ecam-generic",
.data = &pci_generic_ecam_ops },
+ { .compatible = "marvell,armada8k-pcie-ecam",
+ .data = &pci_dw_ecam_bus_ops },
+
+ { .compatible = "socionext,synquacer-pcie-ecam",
+ .data = &pci_dw_ecam_bus_ops },
+
+ { .compatible = "snps,dw-pcie-ecam",
+ .data = &pci_dw_ecam_bus_ops },
+
{ },
};
From 19f3f22aade704f9ce82a55c853381e672629a1d Mon Sep 17 00:00:00 2001
From: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Date: Fri, 6 Oct 2017 17:39:19 +0100
Subject: [PATCH 2/2] dt-bindings: PCI: designware: Add binding for Designware
PCIe in ECAM mode
Describe the binding for firmware-configured instances of the Synopsys
DesignWare PCIe controller in RC mode, that are almost but not quite ECAM
compliant.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Bjorn Helgaas <helgaas@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
---
.../bindings/pci/designware-pcie-ecam.txt | 42 +++++++++++++++++++
1 file changed, 42 insertions(+)
create mode 100644 Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
diff --git a/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt b/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
new file mode 100644
index 0000000000000..515b2f9542e54
--- /dev/null
+++ b/Documentation/devicetree/bindings/pci/designware-pcie-ecam.txt
@@ -0,0 +1,42 @@
+* Synopsys DesignWare PCIe root complex in ECAM shift mode
+
+In some cases, firmware may already have configured the Synopsys DesignWare
+PCIe controller in RC mode with static ATU window mappings that cover all
+config, MMIO and I/O spaces in a [mostly] ECAM compatible fashion.
+In this case, there is no need for the OS to perform any low level setup
+of clocks, PHYs or device registers, nor is there any reason for the driver
+to reconfigure ATU windows for config and/or IO space accesses at runtime.
+
+In cases where the IP was synthesized with a minimum ATU window size of
+64 KB, it cannot be supported by the generic ECAM driver, because it
+requires special config space accessors that filter accesses to device #1
+and beyond on the first bus.
+
+Required properties:
+- compatible: "marvell,armada8k-pcie-ecam" or
+ "socionext,synquacer-pcie-ecam" or
+ "snps,dw-pcie-ecam" (must be preceded by a more specific match)
+
+Please refer to the binding document of "pci-host-ecam-generic" in the
+file host-generic-pci.txt for a description of the remaining required
+and optional properties.
+
+Example:
+
+ pcie1: pcie@7f000000 {
+ compatible = "socionext,synquacer-pcie-ecam", "snps,dw-pcie-ecam";
+ device_type = "pci";
+ reg = <0x0 0x7f000000 0x0 0xf00000>;
+ bus-range = <0x0 0xe>;
+ #address-cells = <3>;
+ #size-cells = <2>;
+ ranges = <0x1000000 0x00 0x00010000 0x00 0x7ff00000 0x0 0x00010000>,
+ <0x2000000 0x00 0x70000000 0x00 0x70000000 0x0 0x0f000000>,
+ <0x3000000 0x3f 0x00000000 0x3f 0x00000000 0x1 0x00000000>;
+
+ #interrupt-cells = <0x1>;
+ interrupt-map-mask = <0x0 0x0 0x0 0x0>;
+ interrupt-map = <0x0 0x0 0x0 0x0 &gic 0x0 0x0 0x0 182 0x4>;
+ msi-map = <0x0 &its 0x0 0x10000>;
+ dma-coherent;
+ };