RE: [PATCH] PCI:cadence:Driver refactored to use as a core library.

[Tom Joseph]

Hi Andrew,
 
 Thanks for the kind review. 

> -----Original Message-----
> From: Andrew Murray <andrew.murray@xxxxxxx>
> Sent: 01 October 2019 11:07
> To: Tom Joseph <tjoseph@xxxxxxxxxxx>
> Cc: linux-pci@xxxxxxxxxxxxxxx; Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>;
> Bjorn Helgaas <bhelgaas@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH] PCI:cadence:Driver refactored to use as a core library.
> 
> EXTERNAL MAIL
> 
> 
> Hi Tom,
> 
> Thanks for the patch.
> 
> I'd suggest that you rename the subject of this series to "PCI: cadence: ..."
> to be consistent with the existing commit history, e.g. git log
> --oneline drivers/pci/controller/pcie-cadence* - you'll also see that you
> don't need a full stop at the end, and you ought to also change the tense
> of the subject, e.g. Refactor driver to ...

I agree. I will alter it as suggested.
  
> 
> See comments inline...
> 
> On Mon, Sep 30, 2019 at 05:42:48PM +0100, Tom Joseph wrote:
> > All the platform related APIs/Structures in the driver has been extracted
> >  out to a separate file (pcie-cadence-plat.c). This will enable the
> >  driver to be used as a core library, which could be used by other
> >  platform drivers.Testing was done using simulation environment.
> 
> Also change the tense for this description.

Ok. I will re-word it as : All the platform related APIs/Structures in the 
driver is extracted out to a separate file (pcie-cadence-plat.c). 
This enables the driver to be used as a core library, which could now
 be used by other platform drivers. Testing done using simulation environment.

> 
> This patch appears to take the dwc approach of spliting itself into consise
> parts, such that you can have a generic Cadence driver, yet also leave room
> and share functionality with/for Cadence derivatives - this seems like a
> sensible approach. Though, as you'll see in my comments below, because
> there
> are no other platform drivers yet - we end up with unused code and
> confusing
> Kconfig options.
> 
> Is there an immediate plan to add another Cadence based controller? - if so

As Kishon mentioned J721E is coming up. But it make sense to separate those
unused codes from this patch. I will update accordingly.  

> I'd suggest that you include this patch in that patchset for this new
> controller. Otherwise I'm happy with these changes once the Kconfig and
> unused
> code are fixed.
> 
> >
> > Signed-off-by: Tom Joseph <tjoseph@xxxxxxxxxxx>
> > ---
> >  drivers/pci/controller/Kconfig             |  35 +++++++
> >  drivers/pci/controller/Makefile            |   1 +
> >  drivers/pci/controller/pcie-cadence-ep.c   |  78 ++-------------
> >  drivers/pci/controller/pcie-cadence-host.c |  77 +++------------
> >  drivers/pci/controller/pcie-cadence-plat.c | 154
> +++++++++++++++++++++++++++++
> >  drivers/pci/controller/pcie-cadence.h      |  69 +++++++++++++
> >  6 files changed, 278 insertions(+), 136 deletions(-)
> >  create mode 100644 drivers/pci/controller/pcie-cadence-plat.c
> >
> > diff --git a/drivers/pci/controller/Kconfig b/drivers/pci/controller/Kconfig
> > index fe9f9f1..c175b21 100644
> > --- a/drivers/pci/controller/Kconfig
> > +++ b/drivers/pci/controller/Kconfig
> > @@ -48,6 +48,41 @@ config PCIE_CADENCE_EP
> >  	  endpoint mode. This PCIe controller may be embedded into many
> >  	  different vendors SoCs.
> >
> > +config PCIE_CADENCE_PLAT
> > +	bool "Cadence PCIe endpoint controller"
> > +	depends on OF
> > +	depends on PCI_ENDPOINT
> > +	select PCIE_CADENCE
> > +	help
> > +	  Say Y here if you want to support the Cadence PCIe  controller in
> > +	  endpoint mode. This PCIe controller may be embedded into many
> > +	  different vendors SoCs.
> > +
> > +config PCIE_CADENCE_PLAT_HOST
> > +	bool "Cadence PCIe platform host controller"
> > +	depends on OF
> > +	depends on PCI
> > +	select IRQ_DOMAIN
> > +	select PCIE_CADENCE
> > +	select PCIE_CADENCE_HOST
> > +	select PCIE_CADENCE_PLAT
> > +	help
> > +	  Say Y here if you want to support the Cadence PCIe platform
> controller in
> > +	  host mode. This PCIe controller may be embedded into many
> different
> > +	  vendors SoCs.
> > +
> > +config PCIE_CADENCE_PLAT_EP
> > +	bool "Cadence PCIe platform endpoint controller"
> > +	depends on OF
> > +	depends on PCI_ENDPOINT
> > +	select PCIE_CADENCE
> > +	select PCIE_CADENCE_EP
> > +	select PCIE_CADENCE_PLAT
> > +	help
> > +	  Say Y here if you want to support the Cadence PCIe  platform
> controller in
> > +	  endpoint mode. This PCIe controller may be embedded into many
> > +	  different vendors SoCs.
> > +
> 
> I find this too confusing, if I navigate to Cadence PCIe controllers support
> in menuconfig I see these options:
> 
> Cadence PCIe host controller
> Cadence PCIe endpoint controller
> Cadence PCIe endpoint controller (NEW)
> Cadence PCIe platform host controller (NEW)
> Cadence PCIe platform endpoint controller (NEW)
> 
> I don't think users need to care about the platform/library support, surely
> all they care about is enabling the EP or host bridge controllers for their
> hardware (and then rely on Kconfig to select what is needed).

I agree. I will remove the string, depends/select etc  from config PCIE_CADENCE_PLAT

> 
> >  endmenu
> >
> >  config PCIE_XILINX_NWL
> > diff --git a/drivers/pci/controller/Makefile
> b/drivers/pci/controller/Makefile
> > index d56a507..676a41e 100644
> > --- a/drivers/pci/controller/Makefile
> > +++ b/drivers/pci/controller/Makefile
> > @@ -2,6 +2,7 @@
> >  obj-$(CONFIG_PCIE_CADENCE) += pcie-cadence.o
> >  obj-$(CONFIG_PCIE_CADENCE_HOST) += pcie-cadence-host.o
> >  obj-$(CONFIG_PCIE_CADENCE_EP) += pcie-cadence-ep.o
> > +obj-$(CONFIG_PCIE_CADENCE_PLAT) += pcie-cadence-plat.o
> >  obj-$(CONFIG_PCI_FTPCI100) += pci-ftpci100.o
> >  obj-$(CONFIG_PCI_HYPERV) += pci-hyperv.o
> >  obj-$(CONFIG_PCI_MVEBU) += pci-mvebu.o
> > diff --git a/drivers/pci/controller/pcie-cadence-ep.c
> b/drivers/pci/controller/pcie-cadence-ep.c
> > index def7820..617a71f 100644
> > --- a/drivers/pci/controller/pcie-cadence-ep.c
> > +++ b/drivers/pci/controller/pcie-cadence-ep.c
> > @@ -17,35 +17,6 @@
> >  #define CDNS_PCIE_EP_IRQ_PCI_ADDR_NONE		0x1
> >  #define CDNS_PCIE_EP_IRQ_PCI_ADDR_LEGACY	0x3
> >
> > -/**
> > - * struct cdns_pcie_ep - private data for this PCIe endpoint controller
> driver
> > - * @pcie: Cadence PCIe controller
> > - * @max_regions: maximum number of regions supported by hardware
> > - * @ob_region_map: bitmask of mapped outbound regions
> > - * @ob_addr: base addresses in the AXI bus where the outbound regions
> start
> > - * @irq_phys_addr: base address on the AXI bus where the MSI/legacy
> IRQ
> > - *		   dedicated outbound regions is mapped.
> > - * @irq_cpu_addr: base address in the CPU space where a write access
> triggers
> > - *		  the sending of a memory write (MSI) / normal message
> (legacy
> > - *		  IRQ) TLP through the PCIe bus.
> > - * @irq_pci_addr: used to save the current mapping of the MSI/legacy IRQ
> > - *		  dedicated outbound region.
> > - * @irq_pci_fn: the latest PCI function that has updated the mapping of
> > - *		the MSI/legacy IRQ dedicated outbound region.
> > - * @irq_pending: bitmask of asserted legacy IRQs.
> > - */
> > -struct cdns_pcie_ep {
> > -	struct cdns_pcie		pcie;
> > -	u32				max_regions;
> > -	unsigned long			ob_region_map;
> > -	phys_addr_t			*ob_addr;
> > -	phys_addr_t			irq_phys_addr;
> > -	void __iomem			*irq_cpu_addr;
> > -	u64				irq_pci_addr;
> > -	u8				irq_pci_fn;
> > -	u8				irq_pending;
> > -};
> > -
> >  static int cdns_pcie_ep_write_header(struct pci_epc *epc, u8 fn,
> >  				     struct pci_epf_header *hdr)
> >  {
> > @@ -396,6 +367,9 @@ static int cdns_pcie_ep_start(struct pci_epc *epc)
> >  		cfg |= BIT(epf->func_no);
> >  	cdns_pcie_writel(pcie, CDNS_PCIE_LM_EP_FUNC_CFG, cfg);
> >
> > +	if (pcie->ops->cdns_start_link)
> > +		return  pcie->ops->cdns_start_link(pcie, true);
> > +
> >  	return 0;
> >  }
> >
> > @@ -424,30 +398,18 @@ static const struct pci_epc_ops
> cdns_pcie_epc_ops = {
> >  	.get_features	= cdns_pcie_ep_get_features,
> >  };
> >
> > -static const struct of_device_id cdns_pcie_ep_of_match[] = {
> > -	{ .compatible = "cdns,cdns-pcie-ep" },
> > -
> > -	{ },
> > -};
> >
> > -static int cdns_pcie_ep_probe(struct platform_device *pdev)
> > +int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep)
> >  {
> > -	struct device *dev = &pdev->dev;
> > +	struct device *dev = ep->dev;
> > +	struct platform_device *pdev = to_platform_device(dev);
> >  	struct device_node *np = dev->of_node;
> > -	struct cdns_pcie_ep *ep;
> > -	struct cdns_pcie *pcie;
> > +	struct cdns_pcie *pcie = &ep->pcie;
> >  	struct pci_epc *epc;
> >  	struct resource *res;
> >  	int ret;
> >  	int phy_count;
> >
> > -	ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> > -	if (!ep)
> > -		return -ENOMEM;
> > -
> > -	pcie = &ep->pcie;
> > -	pcie->is_rc = false;
> > -
> >  	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> "reg");
> >  	pcie->reg_base = devm_ioremap_resource(dev, res);
> >  	if (IS_ERR(pcie->reg_base)) {
> > @@ -537,29 +499,3 @@ static int cdns_pcie_ep_probe(struct
> platform_device *pdev)
> >
> >  	return ret;
> >  }
> > -
> > -static void cdns_pcie_ep_shutdown(struct platform_device *pdev)
> > -{
> > -	struct device *dev = &pdev->dev;
> > -	struct cdns_pcie *pcie = dev_get_drvdata(dev);
> > -	int ret;
> > -
> > -	ret = pm_runtime_put_sync(dev);
> > -	if (ret < 0)
> > -		dev_dbg(dev, "pm_runtime_put_sync failed\n");
> > -
> > -	pm_runtime_disable(dev);
> > -
> > -	cdns_pcie_disable_phy(pcie);
> > -}
> > -
> > -static struct platform_driver cdns_pcie_ep_driver = {
> > -	.driver = {
> > -		.name = "cdns-pcie-ep",
> > -		.of_match_table = cdns_pcie_ep_of_match,
> > -		.pm	= &cdns_pcie_pm_ops,
> > -	},
> > -	.probe = cdns_pcie_ep_probe,
> > -	.shutdown = cdns_pcie_ep_shutdown,
> > -};
> > -builtin_platform_driver(cdns_pcie_ep_driver);
> > diff --git a/drivers/pci/controller/pcie-cadence-host.c
> b/drivers/pci/controller/pcie-cadence-host.c
> > index 97e2510..55c2085 100644
> > --- a/drivers/pci/controller/pcie-cadence-host.c
> > +++ b/drivers/pci/controller/pcie-cadence-host.c
> > @@ -11,33 +11,6 @@
> >
> >  #include "pcie-cadence.h"
> >
> > -/**
> > - * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
> > - * @pcie: Cadence PCIe controller
> > - * @dev: pointer to PCIe device
> > - * @cfg_res: start/end offsets in the physical system memory to map PCI
> > - *           configuration space accesses
> > - * @bus_range: first/last buses behind the PCIe host controller
> > - * @cfg_base: IO mapped window to access the PCI configuration space of
> a
> > - *            single function at a time
> > - * @max_regions: maximum number of regions supported by the
> hardware
> > - * @no_bar_nbits: Number of bits to keep for inbound (PCIe -> CPU)
> address
> > - *                translation (nbits sets into the "no BAR match" register)
> > - * @vendor_id: PCI vendor ID
> > - * @device_id: PCI device ID
> > - */
> > -struct cdns_pcie_rc {
> > -	struct cdns_pcie	pcie;
> > -	struct device		*dev;
> > -	struct resource		*cfg_res;
> > -	struct resource		*bus_range;
> > -	void __iomem		*cfg_base;
> > -	u32			max_regions;
> > -	u32			no_bar_nbits;
> > -	u16			vendor_id;
> > -	u16			device_id;
> > -};
> > -
> >  static void __iomem *cdns_pci_map_bus(struct pci_bus *bus, unsigned
> int devfn,
> >  				      int where)
> >  {
> > @@ -92,11 +65,6 @@ static struct pci_ops cdns_pcie_host_ops = {
> >  	.write		= pci_generic_config_write,
> >  };
> >
> > -static const struct of_device_id cdns_pcie_host_of_match[] = {
> > -	{ .compatible = "cdns,cdns-pcie-host" },
> > -
> > -	{ },
> > -};
> >
> >  static int cdns_pcie_host_init_root_port(struct cdns_pcie_rc *rc)
> >  {
> > @@ -233,27 +201,23 @@ static int cdns_pcie_host_init(struct device *dev,
> >  	return err;
> >  }
> >
> > -static int cdns_pcie_host_probe(struct platform_device *pdev)
> > +int cdns_pcie_host_setup(struct cdns_pcie_rc *rc)
> >  {
> > -	struct device *dev = &pdev->dev;
> > +	struct device *dev = rc->dev;
> > +	struct platform_device *pdev = to_platform_device(dev);
> >  	struct device_node *np = dev->of_node;
> >  	struct pci_host_bridge *bridge;
> >  	struct list_head resources;
> > -	struct cdns_pcie_rc *rc;
> >  	struct cdns_pcie *pcie;
> >  	struct resource *res;
> >  	int ret;
> >  	int phy_count;
> >
> > -	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> > +	bridge = pci_host_bridge_from_priv(rc);
> >  	if (!bridge)
> >  		return -ENOMEM;
> >
> > -	rc = pci_host_bridge_priv(bridge);
> > -	rc->dev = dev;
> > -
> >  	pcie = &rc->pcie;
> > -	pcie->is_rc = true;
> >
> >  	rc->max_regions = 32;
> >  	of_property_read_u32(np, "cdns,max-outbound-regions", &rc-
> >max_regions);
> > @@ -303,6 +267,14 @@ static int cdns_pcie_host_probe(struct
> platform_device *pdev)
> >  		goto err_get_sync;
> >  	}
> >
> > +	if (pcie->ops->cdns_start_link) {
> > +		ret =  pcie->ops->cdns_start_link(pcie, true);
> > +		if (ret) {
> > +			dev_err(dev, "Failed to start link\n");
> > +			return ret;
> > +		}
> > +	}
> > +
> >  	ret = cdns_pcie_host_init(dev, &resources, rc);
> >  	if (ret)
> >  		goto err_init;
> > @@ -335,28 +307,3 @@ static int cdns_pcie_host_probe(struct
> platform_device *pdev)
> >
> >  	return ret;
> >  }
> > -
> > -static void cdns_pcie_shutdown(struct platform_device *pdev)
> > -{
> > -	struct device *dev = &pdev->dev;
> > -	struct cdns_pcie *pcie = dev_get_drvdata(dev);
> > -	int ret;
> > -
> > -	ret = pm_runtime_put_sync(dev);
> > -	if (ret < 0)
> > -		dev_dbg(dev, "pm_runtime_put_sync failed\n");
> > -
> > -	pm_runtime_disable(dev);
> > -	cdns_pcie_disable_phy(pcie);
> > -}
> > -
> > -static struct platform_driver cdns_pcie_host_driver = {
> > -	.driver = {
> > -		.name = "cdns-pcie-host",
> > -		.of_match_table = cdns_pcie_host_of_match,
> > -		.pm	= &cdns_pcie_pm_ops,
> > -	},
> > -	.probe = cdns_pcie_host_probe,
> > -	.shutdown = cdns_pcie_shutdown,
> > -};
> > -builtin_platform_driver(cdns_pcie_host_driver);
> > diff --git a/drivers/pci/controller/pcie-cadence-plat.c
> b/drivers/pci/controller/pcie-cadence-plat.c
> > new file mode 100644
> > index 0000000..274615d
> > --- /dev/null
> > +++ b/drivers/pci/controller/pcie-cadence-plat.c
> > @@ -0,0 +1,154 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright (c) 2019 Cadence
> > +// Cadence PCIe platform  driver.
> > +// Author: Tom Joseph <tjoseph@xxxxxxxxxxx>
> > +
> 
> The style of this comment block is consistent with the other cadence files in
> the tree, however the cadence files aren't consistent with the other PCI
> controller drivers (or probably much of the kernel). I don't have any
> objections
> with this, but ideally we'd eventually move to this:
> 
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Cadence PCIe platform driver.
> + *
> + * Copyright (c) 2019 Cadence
> + *
> + * Author: Tom Joseph <tjoseph@xxxxxxxxxxx>
> + */

I will update it, as suggested.

> 
> > +#include <linux/kernel.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_pci.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/of_device.h>
> > +#include "pcie-cadence.h"
> > +
> > +/**
> > + * struct cdns_plat_pcie - private data for this PCIe platform driver
> > + * @pcie: Cadence PCIe controller
> > + * @regmap: pointer to PCIe device
> 
> regmap? A leftover from pcie-designware-plat.c?

Yes:). Thanks for the catch. I will remove it.

> 
> > + * @is_rc: Set to 1 indicates the PCIe controller mode is Root Complex,
> > + *         if 0 it is in Endpoint mode.
> > + */
> > +struct cdns_plat_pcie {
> > +	struct cdns_pcie        *pcie;
> > +	bool is_rc;
> > +};
> > +
> > +struct cdns_plat_pcie_of_data {
> > +	bool is_rc;
> > +};
> > +
> > +static const struct of_device_id cdns_plat_pcie_of_match[];
> > +
> > +int cdns_plat_pcie_link_control(struct cdns_pcie *pcie, bool start)
> > +{
> > +	pr_debug(" %s called\n", __func__);
> > +	return 0;
> > +}
> > +
> > +bool cdns_plat_pcie_link_status(struct cdns_pcie *pcie)
> > +{
> > +	pr_debug(" %s called\n", __func__);
> > +	return 0;
> > +}
> 
> Given that these above two functions are only called through the
> cdns_pcie_common_ops abstraction, they should be declared static.
> 
> I also don't understand why they are here in *this* patch -
> cdns_plat_pcie_link_status isn't called anywhere, and even though
> cdns_plat_pcie_link_control is called it doesn't do anything (start
> is always true which makes me wonder if you'll ever get a caller
> that sets it to false).
> 
> I'd suggest removing these two functions (and related logic) until
> there is a user. This also makes reviewing the patch easier.

Ok. I will separate these as a different patch. 
> 
> > +
> > +static const struct cdns_pcie_common_ops cdns_pcie_common_ops = {
> > +	.cdns_start_link = cdns_plat_pcie_link_control,
> > +	.cdns_is_link_up = cdns_plat_pcie_link_status,
> > +};
> > +
> > +static int cdns_plat_pcie_probe(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct cdns_plat_pcie *cdns_plat_pcie;
> > +	const struct of_device_id *match;
> > +	const struct cdns_plat_pcie_of_data *data;
> > +	struct pci_host_bridge *bridge;
> > +	struct cdns_pcie_rc *rc;
> > +	struct cdns_pcie_ep *ep;
> > +	int ret;
> > +	bool is_rc;
> > +
> > +	match = of_match_device(cdns_plat_pcie_of_match, dev);
> > +	if (!match)
> > +		return -EINVAL;
> 
> Add a new line here.
> 
> > +	data = (struct cdns_plat_pcie_of_data *)match->data;
> > +	is_rc = data->is_rc;
> > +
> > +	pr_debug(" Started %s with is_rc: %d\n", __func__, is_rc);
> > +	cdns_plat_pcie = devm_kzalloc(dev, sizeof(*cdns_plat_pcie),
> GFP_KERNEL);
> > +	if (!cdns_plat_pcie)
> > +		return -ENOMEM;
> > +
> > +	platform_set_drvdata(pdev, cdns_plat_pcie);
> > +	if (is_rc) {
> > +		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_PLAT_HOST))
> > +			return -ENODEV;
> > +
> > +		bridge = devm_pci_alloc_host_bridge(dev, sizeof(*rc));
> > +		if (!bridge)
> > +			return -ENOMEM;
> > +
> > +		rc = pci_host_bridge_priv(bridge);
> > +		rc->dev = dev;
> > +		rc->pcie.ops = &cdns_pcie_common_ops;
> > +		cdns_plat_pcie->pcie = &rc->pcie;
> > +		cdns_plat_pcie->is_rc = is_rc;
> > +
> > +		ret = cdns_pcie_host_setup(rc);
> > +		if (ret < 0)
> > +			return ret;
> > +	} else {
> > +		if (!IS_ENABLED(CONFIG_PCIE_CADENCE_PLAT_EP))
> > +			return -ENODEV;
> > +
> > +		ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
> > +		if (!ep)
> > +			return -ENOMEM;
> > +		ep->dev = dev;
> > +		ep->pcie.ops = &cdns_pcie_common_ops;
> > +		cdns_plat_pcie->pcie = &ep->pcie;
> > +		cdns_plat_pcie->is_rc = is_rc;
> > +
> > +		ret = cdns_pcie_ep_setup(ep);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +	return 0;
> > +}
> > +
> > +
> > +static void cdns_plat_pcie_shutdown(struct platform_device *pdev)
> > +{
> > +	struct device *dev = &pdev->dev;
> > +	struct cdns_pcie *pcie = dev_get_drvdata(dev);
> > +	int ret;
> > +
> > +	ret = pm_runtime_put_sync(dev);
> > +	if (ret < 0)
> > +		dev_dbg(dev, "pm_runtime_put_sync failed\n");
> > +
> > +	pm_runtime_disable(dev);
> > +
> > +	cdns_pcie_disable_phy(pcie);
> > +}
> > +
> > +static const struct cdns_plat_pcie_of_data cdns_plat_pcie_host_of_data = {
> > +	.is_rc = true,
> > +};
> > +
> > +static const struct cdns_plat_pcie_of_data cdns_plat_pcie_ep_of_data = {
> > +	.is_rc = false,
> > +};
> > +
> > +static const struct of_device_id cdns_plat_pcie_of_match[] = {
> > +	{
> > +		.compatible = "cdns,cdns-pcie-host",
> > +		.data = &cdns_plat_pcie_host_of_data,
> > +	},
> > +	{
> > +		.compatible = "cdns,cdns-pcie-ep",
> > +		.data = &cdns_plat_pcie_ep_of_data,
> > +	},
> > +	{},
> > +};
> > +
> > +static struct platform_driver cdns_plat_pcie_driver = {
> > +	.driver = {
> > +		.name = "cdns-pcie",
> > +		.of_match_table = cdns_plat_pcie_of_match,
> > +		.pm	= &cdns_pcie_pm_ops,
> > +	},
> > +	.probe = cdns_plat_pcie_probe,
> > +	.shutdown = cdns_plat_pcie_shutdown,
> > +};
> > +builtin_platform_driver(cdns_plat_pcie_driver);
> > diff --git a/drivers/pci/controller/pcie-cadence.h b/drivers/pci/controller/pcie-cadence.h
> > index ae6bf2a..3df902a 100644
> > --- a/drivers/pci/controller/pcie-cadence.h
> > +++ b/drivers/pci/controller/pcie-cadence.h
> > @@ -190,6 +190,8 @@ enum cdns_pcie_rp_bar {
> >  	(((code) << 8) & CDNS_PCIE_NORMAL_MSG_CODE_MASK)
> >  #define CDNS_PCIE_MSG_NO_DATA			BIT(16)
> >
> > +struct cdns_pcie;
> > +
> >  enum cdns_pcie_msg_code {
> >  	MSG_CODE_ASSERT_INTA	= 0x20,
> >  	MSG_CODE_ASSERT_INTB	= 0x21,
> > @@ -221,6 +223,11 @@ enum cdns_pcie_msg_routing {
> >  	MSG_ROUTING_GATHER,
> >  };
> >
> > +
> > +struct cdns_pcie_common_ops {
> > +	int	(*cdns_start_link)(struct cdns_pcie *pcie, bool start);
> > +	bool	(*cdns_is_link_up)(struct cdns_pcie *pcie);
> > +};
> >  /**
> >   * struct cdns_pcie - private data for Cadence PCIe controller drivers
> >   * @reg_base: IO mapped register base
> > @@ -236,8 +243,67 @@ struct cdns_pcie {
> >  	int			phy_count;
> >  	struct phy		**phy;
> >  	struct device_link	**link;
> > +	const struct cdns_pcie_common_ops *ops;
> > +};
> > +
> > +/**
> > + * struct cdns_pcie_rc - private data for this PCIe Root Complex driver
> > + * @pcie: Cadence PCIe controller
> > + * @dev: pointer to PCIe device
> > + * @cfg_res: start/end offsets in the physical system memory to map PCI
> > + *           configuration space accesses
> > + * @bus_range: first/last buses behind the PCIe host controller
> > + * @cfg_base: IO mapped window to access the PCI configuration space
> of a
> > + *            single function at a time
> > + * @max_regions: maximum number of regions supported by the
> hardware
> > + * @no_bar_nbits: Number of bits to keep for inbound (PCIe -> CPU)
> address
> > + *                translation (nbits sets into the "no BAR match" register)
> > + * @vendor_id: PCI vendor ID
> > + * @device_id: PCI device ID
> > + */
> > +struct cdns_pcie_rc {
> > +	struct cdns_pcie	pcie;
> > +	struct device		*dev;
> > +	struct resource		*cfg_res;
> > +	struct resource		*bus_range;
> > +	void __iomem		*cfg_base;
> > +	u32			max_regions;
> > +	u32			no_bar_nbits;
> > +	u16			vendor_id;
> > +	u16			device_id;
> >  };
> >
> > +/**
> > + * struct cdns_pcie_ep - private data for this PCIe endpoint controller
> driver
> > + * @pcie: Cadence PCIe controller
> > + * @max_regions: maximum number of regions supported by hardware
> > + * @ob_region_map: bitmask of mapped outbound regions
> > + * @ob_addr: base addresses in the AXI bus where the outbound regions
> start
> > + * @irq_phys_addr: base address on the AXI bus where the MSI/legacy
> IRQ
> > + *		   dedicated outbound regions is mapped.
> > + * @irq_cpu_addr: base address in the CPU space where a write access
> triggers
> > + *		  the sending of a memory write (MSI) / normal message
> (legacy
> > + *		  IRQ) TLP through the PCIe bus.
> > + * @irq_pci_addr: used to save the current mapping of the MSI/legacy
> IRQ
> > + *		  dedicated outbound region.
> > + * @irq_pci_fn: the latest PCI function that has updated the mapping of
> > + *		the MSI/legacy IRQ dedicated outbound region.
> > + * @irq_pending: bitmask of asserted legacy IRQs.
> > + */
> > +struct cdns_pcie_ep {
> > +	struct cdns_pcie	pcie;
> > +	struct device		*dev;
> > +	u32			max_regions;
> > +	unsigned long		ob_region_map;
> > +	phys_addr_t		*ob_addr;
> > +	phys_addr_t		irq_phys_addr;
> > +	void __iomem		*irq_cpu_addr;
> > +	u64			irq_pci_addr;
> > +	u8			irq_pci_fn;
> > +	u8			irq_pending;
> > +};
> > +
> > +
> >  /* Register access */
> >  static inline void cdns_pcie_writeb(struct cdns_pcie *pcie, u32 reg, u8
> value)
> >  {
> > @@ -306,6 +372,9 @@ static inline u32 cdns_pcie_ep_fn_readl(struct
> cdns_pcie *pcie, u8 fn, u32 reg)
> >  	return readl(pcie->reg_base + CDNS_PCIE_EP_FUNC_BASE(fn) +
> reg);
> >  }
> >
> > +int cdns_pcie_host_setup(struct cdns_pcie_rc *rc);
> > +int cdns_pcie_ep_setup(struct cdns_pcie_ep *ep);
> > +
> 
> What happens if a user only selects the host bridge, will you get a build
> error relating to cdns_plat_pcie_probe not being able to find an
> implementation of cdns_pcie_ep_setup?

Yes. I will add stub function to deal with such scenario.

> 
> Thanks,
> 
> Andrew Murray
> 
> >  void cdns_pcie_set_outbound_region(struct cdns_pcie *pcie, u8 fn,
> >  				   u32 r, bool is_io,
> >  				   u64 cpu_addr, u64 pci_addr, size_t size);
> > --
> > 2.2.2
> >