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Subject: Re: [PATCH 2/8] PCI: dwc: designware: Add support for endpoint mode
To:     Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        <bhelgaas@google.com>, <lorenzo.pieralisi@arm.com>,
        <Joao.Pinto@synopsys.com>, <jingoohan1@gmail.com>,
        <robh+dt@kernel.org>, <mark.rutland@arm.com>
References: <cover.1522235224.git.gustavo.pimentel@synopsys.com>
 <93aafb03af86885994e633da240ef58dbd3f4d53.1522235224.git.gustavo.pimentel@synopsys.com>
CC:     <linux-pci@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>
From:   Kishon Vijay Abraham I <kishon@ti.com>
Message-ID: <df477a39-25b9-68f6-bd10-aa45226101e4@ti.com>
Date:   Mon, 2 Apr 2018 11:04:01 +0530
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,

On Wednesday 28 March 2018 05:08 PM, Gustavo Pimentel wrote:
> The PCIe controller dual mode is capable of operating in host mode as well
> as endpoint mode by configuration, therefore this patch aims to add
> endpoint mode support to the designware driver.
> 
> Signed-off-by: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> ---
>  drivers/pci/dwc/Kconfig                       |  45 ++++++--
>  drivers/pci/dwc/pcie-designware-plat.c        | 157 ++++++++++++++++++++++++--
>  drivers/pci/endpoint/functions/pci-epf-test.c |   5 +
>  3 files changed, 187 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/pci/dwc/Kconfig b/drivers/pci/dwc/Kconfig
> index 2f3f5c5..3fd7daf 100644
> --- a/drivers/pci/dwc/Kconfig
> +++ b/drivers/pci/dwc/Kconfig
> @@ -7,8 +7,7 @@ config PCIE_DW
>  
>  config PCIE_DW_HOST
>          bool
> -	depends on PCI
> -	depends on PCI_MSI_IRQ_DOMAIN
> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
>          select PCIE_DW
>  
>  config PCIE_DW_EP
> @@ -52,16 +51,42 @@ config PCI_DRA7XX_EP
>  
>  config PCIE_DW_PLAT
>  	bool "Platform bus based DesignWare PCIe Controller"
> -	depends on PCI
> -	depends on PCI_MSI_IRQ_DOMAIN
> -	select PCIE_DW_HOST
> -	---help---
> -	 This selects the DesignWare PCIe controller support. Select this if
> -	 you have a PCIe controller on Platform bus.
> +	help
> +	  There are two instances of PCIe controller in Designware IP.
> +	  This controller can work either as EP or RC. In order to enable
> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
> +	  order to enable device-specific features PCIE_DW_PLAT_EP must be
> +	  selected.
>  
> -	 If you have a controller with this interface, say Y or M here.
> +config PCIE_DW_PLAT_HOST
> +	bool "Platform bus based DesignWare PCIe Controller - Host mode"
> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> +	select PCIE_DW_HOST
> +	select PCIE_DW_PLAT
> +	default y
> +	help
> +	  Enables support for the PCIe controller in the Designware IP to
> +	  work in host mode. There are two instances of PCIe controller in
> +	  Designware IP.
> +	  This controller can work either as EP or RC. In order to enable
> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
> +	  order to enable device-specific features PCI_DW_PLAT_EP must be
> +	  selected.
>  
> -	 If unsure, say N.
> +config PCIE_DW_PLAT_EP
> +	bool "Platform bus based DesignWare PCIe Controller - Endpoint mode"
> +	depends on PCI && PCI_MSI_IRQ_DOMAIN
> +	depends on PCI_ENDPOINT
> +	select PCIE_DW_EP
> +	select PCIE_DW_PLAT
> +	help
> +	  Enables support for the PCIe controller in the Designware IP to
> +	  work in endpoint mode. There are two instances of PCIe controller
> +	  in Designware IP.
> +	  This controller can work either as EP or RC. In order to enable
> +	  host-specific features PCIE_DW_PLAT_HOST must be selected and in
> +	  order to enable device-specific features PCI_DW_PLAT_EP must be
> +	  selected.
>  
>  config PCI_EXYNOS
>  	bool "Samsung Exynos PCIe controller"
> diff --git a/drivers/pci/dwc/pcie-designware-plat.c b/drivers/pci/dwc/pcie-designware-plat.c
> index 5416aa8..921ab07 100644
> --- a/drivers/pci/dwc/pcie-designware-plat.c
> +++ b/drivers/pci/dwc/pcie-designware-plat.c
> @@ -12,19 +12,29 @@
>  #include <linux/interrupt.h>
>  #include <linux/kernel.h>
>  #include <linux/init.h>
> +#include <linux/of_device.h>
>  #include <linux/of_gpio.h>
>  #include <linux/pci.h>
>  #include <linux/platform_device.h>
>  #include <linux/resource.h>
>  #include <linux/signal.h>
>  #include <linux/types.h>
> +#include <linux/regmap.h>
>  
>  #include "pcie-designware.h"
>  
>  struct dw_plat_pcie {
> -	struct dw_pcie		*pci;
> +	struct dw_pcie			*pci;
> +	struct regmap			*regmap;
> +	enum dw_pcie_device_mode	mode;
>  };
>  
> +struct dw_plat_pcie_of_data {
> +	enum dw_pcie_device_mode	mode;
> +};
> +
> +static const struct of_device_id dw_plat_pcie_of_match[];
> +
>  static int dw_plat_pcie_host_init(struct pcie_port *pp)
>  {
>  	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
> @@ -42,9 +52,61 @@ static const struct dw_pcie_host_ops dw_plat_pcie_host_ops = {
>  	.host_init = dw_plat_pcie_host_init,
>  };
>  
> -static int dw_plat_add_pcie_port(struct pcie_port *pp,
> +static int dw_plat_pcie_establish_link(struct dw_pcie *pci)
> +{
> +	dw_pcie_ep_linkup(&pci->ep);

.start_link ops is used incorrectly here. .start_link is used when all the
endpoint side configuration is done and "is ready" to establish a link with the
host. But dw_pcie_ep_linkup is used to inform the function devices that the
link "has been" established.
> +
> +	return 0;
> +}
> +
> +static void dw_plat_pcie_stop_link(struct dw_pcie *pci)
> +{
> +
> +}

Not necessary to have empty function here. pci-epc-core will not try to invoke
ops which are not populated.
> +
> +static const struct dw_pcie_ops dw_pcie_ops = {
> +	.start_link = dw_plat_pcie_establish_link,
> +	.stop_link = dw_plat_pcie_stop_link,
> +};
> +
> +static void dw_plat_pcie_ep_init(struct dw_pcie_ep *ep)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +	enum pci_barno bar;
> +
> +	for (bar = BAR_0; bar <= BAR_5; bar++)
> +		dw_pcie_ep_reset_bar(pci, bar);
> +}
> +
> +static int dw_plat_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				     enum pci_epc_irq_type type,
> +				     u8 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_EPC_IRQ_LEGACY:
> +		dev_err(pci->dev, "EP cannot trigger legacy IRQs\n");
> +		return -EINVAL;
> +	case PCI_EPC_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
> +	}
> +
> +	return 0;
> +}
> +
> +static struct dw_pcie_ep_ops pcie_ep_ops = {
> +	.ep_init = dw_plat_pcie_ep_init,
> +	.raise_irq = dw_plat_pcie_ep_raise_irq,
> +};
> +
> +static int dw_plat_add_pcie_port(struct dw_plat_pcie *dw_plat_pcie,
>  				 struct platform_device *pdev)
>  {
> +	struct dw_pcie *pci = dw_plat_pcie->pci;
> +	struct pcie_port *pp = &pci->pp;
>  	struct device *dev = &pdev->dev;
>  	int ret;
>  
> @@ -63,15 +125,44 @@ static int dw_plat_add_pcie_port(struct pcie_port *pp,
>  
>  	ret = dw_pcie_host_init(pp);
>  	if (ret) {
> -		dev_err(dev, "failed to initialize host\n");
> +		dev_err(dev, "Failed to initialize host\n");
>  		return ret;
>  	}
>  
>  	return 0;
>  }
>  
> -static const struct dw_pcie_ops dw_pcie_ops = {
> -};
> +static int dw_plat_add_pcie_ep(struct dw_plat_pcie *dw_plat_pcie,
> +			       struct platform_device *pdev)
> +{
> +	int ret;
> +	struct dw_pcie_ep *ep;
> +	struct resource *res;
> +	struct device *dev = &pdev->dev;
> +	struct dw_pcie *pci = dw_plat_pcie->pci;
> +
> +	ep = &pci->ep;
> +	ep->ops = &pcie_ep_ops;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi2");
> +	pci->dbi_base2 = devm_ioremap(dev, res->start, resource_size(res));
> +	if (IS_ERR(pci->dbi_base2))
> +		return PTR_ERR(pci->dbi_base2);
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "addr_space");
> +	if (!res)
> +		return -EINVAL;
> +
> +	ep->phys_base = res->start;
> +	ep->addr_size = resource_size(res);
> +
> +	ret = dw_pcie_ep_init(ep);
> +	if (ret) {
> +		dev_err(dev, "Failed to initialize endpoint\n");
> +		return ret;
> +	}
> +	return 0;
> +}
>  
>  static int dw_plat_pcie_probe(struct platform_device *pdev)
>  {
> @@ -80,6 +171,16 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  	struct dw_pcie *pci;
>  	struct resource *res;  /* Resource from DT */
>  	int ret;
> +	const struct of_device_id *match;
> +	const struct dw_plat_pcie_of_data *data;
> +	enum dw_pcie_device_mode mode;
> +
> +	match = of_match_device(dw_plat_pcie_of_match, dev);
> +	if (!match)
> +		return -EINVAL;
> +
> +	data = (struct dw_plat_pcie_of_data *)match->data;
> +	mode = (enum dw_pcie_device_mode)data->mode;
>  
>  	dw_plat_pcie = devm_kzalloc(dev, sizeof(*dw_plat_pcie), GFP_KERNEL);
>  	if (!dw_plat_pcie)
> @@ -93,23 +194,59 @@ static int dw_plat_pcie_probe(struct platform_device *pdev)
>  	pci->ops = &dw_pcie_ops;
>  
>  	dw_plat_pcie->pci = pci;
> +	dw_plat_pcie->mode = mode;
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "dbi");
> +	if (!res)
> +		res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  
> -	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>  	pci->dbi_base = devm_ioremap_resource(dev, res);
>  	if (IS_ERR(pci->dbi_base))
>  		return PTR_ERR(pci->dbi_base);
>  
>  	platform_set_drvdata(pdev, dw_plat_pcie);
>  
> -	ret = dw_plat_add_pcie_port(&pci->pp, pdev);
> -	if (ret < 0)
> -		return ret;
> +	switch (dw_plat_pcie->mode) {
> +	case DW_PCIE_RC_TYPE:
> +		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_HOST))
> +			return -ENODEV;
> +
> +		ret = dw_plat_add_pcie_port(dw_plat_pcie, pdev);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	case DW_PCIE_EP_TYPE:
> +		if (!IS_ENABLED(CONFIG_PCIE_DW_PLAT_EP))
> +			return -ENODEV;
> +
> +		ret = dw_plat_add_pcie_ep(dw_plat_pcie, pdev);
> +		if (ret < 0)
> +			return ret;
> +		break;
> +	default:
> +		dev_err(dev, "INVALID device type %d\n", dw_plat_pcie->mode);
> +	}
>  
>  	return 0;
>  }
>  
> +static const struct dw_plat_pcie_of_data dw_plat_pcie_rc_of_data = {
> +	.mode = DW_PCIE_RC_TYPE,
> +};
> +
> +static const struct dw_plat_pcie_of_data dw_plat_pcie_ep_of_data = {
> +	.mode = DW_PCIE_EP_TYPE,
> +};
> +
>  static const struct of_device_id dw_plat_pcie_of_match[] = {
> -	{ .compatible = "snps,dw-pcie", },
> +	{
> +		.compatible = "snps,dw-pcie",
> +		.data = &dw_plat_pcie_rc_of_data,
> +	},
> +	{
> +		.compatible = "snps,dw-pcie-ep",
> +		.data = &dw_plat_pcie_ep_of_data,
> +	},
>  	{},
>  };
>  
> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
> index 64d8a17..d7de684 100644
> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> @@ -451,9 +451,14 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>  	return 0;
>  }
>  
> +static const struct pci_epf_test_data pci_epf_data = {
> +	.linkup_notifier = false
> +};
> +
>  static const struct pci_epf_device_id pci_epf_test_ids[] = {
>  	{
>  		.name = "pci_epf_test",
> +		.driver_data = (kernel_ulong_t)&pci_epf_data,

This will disable linkup_notifier for existing devices. Please add a new entry
to the table to make any modifications to driver data. (I have a configfs fix
for this to work. Will post that today).

Thanks
Kishon