[PATCH 0/3] pcie-designware: support for external MSI controller

[PATCH 0/3] pcie-designware: support for external MSI controller

[Thomas Petazzoni]

Hello,

This short patch series extends the pcie-designware code to support
using an external MSI controller, rather than the built-in MSI
controller. It does so by making the pcie-designware driver handle the
"msi-parent" DT property.

The first patch updates the Device Tree binding documentation, the
second patch makes the change to the Designware PCIe controller driver
itself, and finally the third patch updates the Marvell Armada 7K/8K
Device Tree to use the msi-parent property.

Thanks,

Thomas

Thomas Petazzoni (3):
  dt-bindings: designware-pcie: document optional msi-parent property
  pci: pcie-designware: add support for external MSI controller
  arm64: dts: marvell: enable MSI for PCIe on Armada 7K/8K

 .../devicetree/bindings/pci/designware-pcie.txt    |  2 ++
 .../boot/dts/marvell/armada-cp110-master.dtsi      |  3 +++
 .../arm64/boot/dts/marvell/armada-cp110-slave.dtsi |  3 +++
 drivers/pci/host/pcie-designware.c                 | 24 ++++++++++++++++------
 4 files changed, 26 insertions(+), 6 deletions(-)

-- 
2.7.4

[PATCH 1/3] dt-bindings: designware-pcie: document optional msi-parent property

[Thomas Petazzoni]

This commit updates the Designware PCIe Device Tree binding
documentation to document the optional msi-parent property. This
property allows to point to an external MSI controller, which can
optionally be provided. If provided, this external MSI controller is
used in preference over the internal MSI controller of the Designware
PCIe IP.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 Documentation/devicetree/bindings/pci/designware-pcie.txt | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Documentation/devicetree/bindings/pci/designware-pcie.txt b/Documentation/devicetree/bindings/pci/designware-pcie.txt
index 6c5322c..7a729bb 100644
--- a/Documentation/devicetree/bindings/pci/designware-pcie.txt
+++ b/Documentation/devicetree/bindings/pci/designware-pcie.txt
@@ -28,6 +28,8 @@ Optional properties:
 - clock-names: Must include the following entries:
 	- "pcie"
 	- "pcie_bus"
+- msi-parent: Pointer to an external MSI controller. If not provided,
+  the built-in MSI controller is used.
 
 Example configuration:
 
-- 
2.7.4

[PATCH 2/3] pci: pcie-designware: add support for external MSI controller

[Thomas Petazzoni]

The Designware PCIe controllers have a built-in MSI controller, which is
already supported by the existing. However, in some situations, it might
be a better choice to use an external MSI controller, especially when it
provides a higher number of MSI interrupts than the built-in one.

Therefore, this commit extends the pcie-designware driver to support the
"msi-parent" DT property, already used by other drivers. It contains a
phandle pointing to the external MSI controller to be used.

Following this commit, the pcie-designware code supports three
possibilities, in this order:

 1. If msi-parent is provided, then the MSI controller pointed by this
    property is used.

 2. Otherwise, and if no ->msi_host_init() function is provided by the
    platform-specific "glue", then the built-in MSI controller of the
    Designware controller is used.

 3. Otherwise, the ->msi_host_init() function of the platform-specific
    "glue" is used to do some additional initialization, but it's still
    the built-in MSI controller that is used.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
 drivers/pci/host/pcie-designware.c | 24 ++++++++++++++++++------
 1 file changed, 18 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
index 12afce1..1e18a85 100644
--- a/drivers/pci/host/pcie-designware.c
+++ b/drivers/pci/host/pcie-designware.c
@@ -437,6 +437,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	int i, ret;
 	LIST_HEAD(res);
 	struct resource_entry *win;
+	struct msi_controller *msi = NULL;
 
 	cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
 	if (cfg_res) {
@@ -525,10 +526,21 @@ int dw_pcie_host_init(struct pcie_port *pp)
 		pp->lanes = 0;
 
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
-		if (!pp->ops->msi_host_init) {
+		if (of_find_property(pp->dev->of_node, "msi-parent", NULL)) {
+			struct device_node *msi_node;
+
+			msi_node = of_parse_phandle(pp->dev->of_node,
+						    "msi-parent", 0);
+			if (!msi_node)
+				return -ENODEV;
+
+			msi = of_pci_find_msi_chip_by_node(msi_node);
+		} else if (!pp->ops->msi_host_init) {
+			msi = &dw_pcie_msi_chip;
+			msi->dev = pp->dev;
 			pp->irq_domain = irq_domain_add_linear(pp->dev->of_node,
 						MAX_MSI_IRQS, &msi_domain_ops,
-						&dw_pcie_msi_chip);
+						msi);
 			if (!pp->irq_domain) {
 				dev_err(pp->dev, "irq domain init failed\n");
 				ret = -ENXIO;
@@ -538,7 +550,9 @@ int dw_pcie_host_init(struct pcie_port *pp)
 			for (i = 0; i < MAX_MSI_IRQS; i++)
 				irq_create_mapping(pp->irq_domain, i);
 		} else {
-			ret = pp->ops->msi_host_init(pp, &dw_pcie_msi_chip);
+			msi = &dw_pcie_msi_chip;
+			msi->dev = pp->dev;
+			ret = pp->ops->msi_host_init(pp, msi);
 			if (ret < 0)
 				goto error;
 		}
@@ -550,9 +564,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 	pp->root_bus_nr = pp->busn->start;
 	if (IS_ENABLED(CONFIG_PCI_MSI)) {
 		bus = pci_scan_root_bus_msi(pp->dev, pp->root_bus_nr,
-					    &dw_pcie_ops, pp, &res,
-					    &dw_pcie_msi_chip);
-		dw_pcie_msi_chip.dev = pp->dev;
+					    &dw_pcie_ops, pp, &res, msi);
 	} else
 		bus = pci_scan_root_bus(pp->dev, pp->root_bus_nr, &dw_pcie_ops,
 					pp, &res);
-- 
2.7.4

[PATCH 3/3] arm64: dts: marvell: enable MSI for PCIe on Armada 7K/8K

[Thomas Petazzoni]

This commit adds a reference to the appropriate MSI controller in the
description of the PCIe controllers on Marvel Armada 7K and 8K
platforms.

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
---
Please only apply once the DT binding and the driver change have been
accepted.

 arch/arm64/boot/dts/marvell/armada-cp110-master.dtsi | 3 +++
 arch/arm64/boot/dts/marvell/armada-cp110-slave.dtsi  | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/marvell/armada-cp110-master.dtsi b/arch/arm64/boot/dts/marvell/armada-cp110-master.dtsi
index ceb83b0..ff469e1 100644
--- a/arch/arm64/boot/dts/marvell/armada-cp110-master.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-cp110-master.dtsi
@@ -177,6 +177,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
@@ -202,6 +203,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
@@ -228,6 +230,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
diff --git a/arch/arm64/boot/dts/marvell/armada-cp110-slave.dtsi b/arch/arm64/boot/dts/marvell/armada-cp110-slave.dtsi
index 2d863f2..43cecf0 100644
--- a/arch/arm64/boot/dts/marvell/armada-cp110-slave.dtsi
+++ b/arch/arm64/boot/dts/marvell/armada-cp110-slave.dtsi
@@ -177,6 +177,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
@@ -202,6 +203,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
@@ -228,6 +230,7 @@
 			#interrupt-cells = <1>;
 			device_type = "pci";
 			dma-coherent;
+			msi-parent = <&gic_v2m0>;
 
 			bus-range = <0 0xff>;
 			ranges =
-- 
2.7.4

[PATCH 2/3] pci: pcie-designware: add support for external MSI controller

[Andrew Lunn]

On Tue, Aug 30, 2016 at 02:57:09PM +0200, Thomas Petazzoni wrote:
> The Designware PCIe controllers have a built-in MSI controller, which is
> already supported by the existing. However, in some situations, it might

                                   ^ driver.

> be a better choice to use an external MSI controller, especially when it
> provides a higher number of MSI interrupts than the built-in one.
> 
> Therefore, this commit extends the pcie-designware driver to support the
> "msi-parent" DT property, already used by other drivers. It contains a
> phandle pointing to the external MSI controller to be used.
> 
> Following this commit, the pcie-designware code supports three
> possibilities, in this order:
> 
>  1. If msi-parent is provided, then the MSI controller pointed by this

                                                                 ^ to  

>     property is used.

>  	if (IS_ENABLED(CONFIG_PCI_MSI)) {
> -		if (!pp->ops->msi_host_init) {
> +		if (of_find_property(pp->dev->of_node, "msi-parent", NULL)) {
> +			struct device_node *msi_node;
> +
> +			msi_node = of_parse_phandle(pp->dev->of_node,
> +						    "msi-parent", 0);
> +			if (!msi_node)
> +				return -ENODEV;
> +
> +			msi = of_pci_find_msi_chip_by_node(msi_node);

By this point, device tree tells us the external MSI controller
should exist. So if we get a NULL here, should we not return
-EPROBE_DIFFERED?

	Andrew

[PATCH 0/3] pcie-designware: support for external MSI controller

[Thomas Petazzoni]

Hello,

On Tue, 30 Aug 2016 14:57:07 +0200, Thomas Petazzoni wrote:

> Thomas Petazzoni (3):
>   dt-bindings: designware-pcie: document optional msi-parent property
>   pci: pcie-designware: add support for external MSI controller
>   arm64: dts: marvell: enable MSI for PCIe on Armada 7K/8K

Please discard this patch series, it's just pure crap. No changes at
all are needed on the pcie-designware driver, using the msi-parent
property already works, and my new code does nothing good.

The of_pci_find_msi_chip_by_node() API is on its way to being removed,
and it doesn't return anything useful.

Only PATCH 3/3 is needed, which I'll resubmit separately.

Sorry for the noise.

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[PATCH 0/3] pcie-designware: support for external MSI controller

[Jingoo Han]

On Tuesday, August 30, 2016 11:25 AM, Thomas Petazzoni wrote:
> 
> Hello,
> 
> On Tue, 30 Aug 2016 14:57:07 +0200, Thomas Petazzoni wrote:
> 
> > Thomas Petazzoni (3):
> >   dt-bindings: designware-pcie: document optional msi-parent property
> >   pci: pcie-designware: add support for external MSI controller
> >   arm64: dts: marvell: enable MSI for PCIe on Armada 7K/8K
> 
> Please discard this patch series, it's just pure crap. No changes at all
> are needed on the pcie-designware driver, using the msi-parent property
> already works, and my new code does nothing good.
> 
> The of_pci_find_msi_chip_by_node() API is on its way to being removed, and
> it doesn't return anything useful.
> 
> Only PATCH 3/3 is needed, which I'll resubmit separately.
> 
> Sorry for the noise.

Oh, good.
The support for External MSI controller is really necessary.
Thank you for your patch!

Best regards,
Jingoo Han

> 
> Thomas
> --
> Thomas Petazzoni, CTO, Free Electrons
> Embedded Linux and Kernel engineering
> http://free-electrons.com

[PATCH 0/3] pcie-designware: support for external MSI controller

[Thomas Petazzoni]

Hello,

On Tue, 30 Aug 2016 11:46:13 -0400, Jingoo Han wrote:

> > Please discard this patch series, it's just pure crap. No changes at all
> > are needed on the pcie-designware driver, using the msi-parent property
> > already works, and my new code does nothing good.
> > 
> > The of_pci_find_msi_chip_by_node() API is on its way to being removed, and
> > it doesn't return anything useful.
> > 
> > Only PATCH 3/3 is needed, which I'll resubmit separately.
> > 
> > Sorry for the noise.  
> 
> Oh, good.
> The support for External MSI controller is really necessary.
> Thank you for your patch!

Well, no change in the driver is needed to use an external MSI
controller. Just specify:

	msi-parent = <&....>

in the DT description of your Designware PCIe controller. And that's
it. I've tested it with the GIC v2m MSI controller on an ARM64
platform, and it works as expected.

Best regards,

Thomas
-- 
Thomas Petazzoni, CTO, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[PATCH 1/3] dt-bindings: designware-pcie: document optional msi-parent property

[Rob Herring]

On Tue, Aug 30, 2016 at 02:57:08PM +0200, Thomas Petazzoni wrote:
> This commit updates the Designware PCIe Device Tree binding
> documentation to document the optional msi-parent property. This
> property allows to point to an external MSI controller, which can
> optionally be provided. If provided, this external MSI controller is
> used in preference over the internal MSI controller of the Designware
> PCIe IP.
> 
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
> ---
>  Documentation/devicetree/bindings/pci/designware-pcie.txt | 2 ++
>  1 file changed, 2 insertions(+)

Acked-by: Rob Herring <robh@kernel.org>