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Date:   Fri, 30 Nov 2018 16:22:15 +0000
From:   Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To:     Xiaowei Bao <xiaowei.bao@nxp.com>
Cc:     bhelgaas@google.com, robh+dt@kernel.org, mark.rutland@arm.com,
        shawnguo@kernel.org, leoyang.li@nxp.com, kishon@ti.com,
        arnd@arndb.de, gregkh@linuxfoundation.org, minghuan.Lian@nxp.com,
        mingkai.hu@nxp.com, roy.zang@nxp.com, kstewart@linuxfoundation.org,
        cyrille.pitchen@free-electrons.com, pombredanne@nexb.com,
        shawn.lin@rock-chips.com, niklas.cassel@axis.com,
        linux-pci@vger.kernel.org, devicetree@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCHv2 5/6] pci: layerscape: Add the EP mode support.
Message-ID: <20181130162214.GA23332@e107981-ln.cambridge.arm.com>
References: <20181105084653.26597-1-xiaowei.bao@nxp.com>
 <20181105084653.26597-5-xiaowei.bao@nxp.com>
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On Mon, Nov 05, 2018 at 04:46:52PM +0800, Xiaowei Bao wrote:
> Add the PCIe EP mode support for layerscape platform.
> 
> Signed-off-by: Xiaowei Bao <xiaowei.bao@nxp.com>
> ---
> v2:
>  - remove the EP mode check function.
> 
>  drivers/pci/controller/dwc/Makefile            |    2 +-
>  drivers/pci/controller/dwc/pci-layerscape-ep.c |  147 ++++++++++++++++++++++++
>  2 files changed, 148 insertions(+), 1 deletions(-)
>  create mode 100644 drivers/pci/controller/dwc/pci-layerscape-ep.c
> 
> diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile
> index 5d2ce72..b26d617 100644
> --- a/drivers/pci/controller/dwc/Makefile
> +++ b/drivers/pci/controller/dwc/Makefile
> @@ -8,7 +8,7 @@ obj-$(CONFIG_PCI_EXYNOS) += pci-exynos.o
>  obj-$(CONFIG_PCI_IMX6) += pci-imx6.o
>  obj-$(CONFIG_PCIE_SPEAR13XX) += pcie-spear13xx.o
>  obj-$(CONFIG_PCI_KEYSTONE) += pci-keystone-dw.o pci-keystone.o
> -obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o
> +obj-$(CONFIG_PCI_LAYERSCAPE) += pci-layerscape.o pci-layerscape-ep.o
>  obj-$(CONFIG_PCIE_QCOM) += pcie-qcom.o
>  obj-$(CONFIG_PCIE_ARMADA_8K) += pcie-armada8k.o
>  obj-$(CONFIG_PCIE_ARTPEC6) += pcie-artpec6.o
> diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> new file mode 100644
> index 0000000..289618b
> --- /dev/null
> +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> @@ -0,0 +1,147 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * PCIe controller EP driver for Freescale Layerscape SoCs
> + *
> + * Copyright (C) 2018 NXP Semiconductor.
> + *
> + * Author: Xiaowei Bao <xiaowei.bao@nxp.com>
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/of_address.h>
> +#include <linux/pci.h>
> +#include <linux/platform_device.h>
> +#include <linux/resource.h>
> +
> +#include "pcie-designware.h"
> +
> +#define PCIE_DBI2_OFFSET		0x1000	/* DBI2 base address*/
> +
> +struct ls_pcie_ep {
> +	struct dw_pcie		*pci;
> +};

I am not really sure why you need an additional struct.

> +#define to_ls_pcie_ep(x)	dev_get_drvdata((x)->dev)

Unused.

> +
> +static int ls_pcie_establish_link(struct dw_pcie *pci)
> +{
> +	return 0;
> +}
> +
> +static const struct dw_pcie_ops ls_pcie_ep_ops = {
> +	.start_link = ls_pcie_establish_link,
> +};
> +
> +static const struct of_device_id ls_pcie_ep_of_match[] = {
> +	{ .compatible = "fsl,ls-pcie-ep",},
> +	{ },
> +};
> +
> +static void ls_pcie_ep_init(struct dw_pcie_ep *ep)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +	struct pci_epc *epc = ep->epc;
> +	enum pci_barno bar;
> +
> +	for (bar = BAR_0; bar <= BAR_5; bar++)
> +		dw_pcie_ep_reset_bar(pci, bar);
> +
> +	epc->features |= EPC_FEATURE_NO_LINKUP_NOTIFIER;
> +}
> +
> +static int ls_pcie_ep_raise_irq(struct dw_pcie_ep *ep, u8 func_no,
> +				  enum pci_epc_irq_type type, u16 interrupt_num)
> +{
> +	struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
> +
> +	switch (type) {
> +	case PCI_EPC_IRQ_LEGACY:
> +		return dw_pcie_ep_raise_legacy_irq(ep, func_no);
> +	case PCI_EPC_IRQ_MSI:
> +		return dw_pcie_ep_raise_msi_irq(ep, func_no, interrupt_num);
> +	case PCI_EPC_IRQ_MSIX:
> +		return dw_pcie_ep_raise_msix_irq(ep, func_no, interrupt_num);
> +	default:
> +		dev_err(pci->dev, "UNKNOWN IRQ type\n");
> +	}
> +
> +	return 0;

So if it falls through to the default, we log an error but return 0 ? This
does not make much sense.

I know you probably copy/pasted code from DWC platform, that code must
be fixed too I suppose.

Lorenzo

> +}
> +
> +static struct dw_pcie_ep_ops pcie_ep_ops = {
> +	.ep_init = ls_pcie_ep_init,
> +	.raise_irq = ls_pcie_ep_raise_irq,
> +};
> +
> +static int __init ls_add_pcie_ep(struct ls_pcie_ep *pcie,
> +					struct platform_device *pdev)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +	struct device *dev = pci->dev;
> +	struct dw_pcie_ep *ep;
> +	struct resource *res;
> +	int ret;
> +
> +	ep = &pci->ep;
> +	ep->ops = &pcie_ep_ops;
> +
> +	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 __init ls_pcie_ep_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct dw_pcie *pci;
> +	struct ls_pcie_ep *pcie;
> +	struct resource *dbi_base;
> +	int ret;
> +
> +	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
> +	if (!pcie)
> +		return -ENOMEM;
> +
> +	pci = devm_kzalloc(dev, sizeof(*pci), GFP_KERNEL);
> +	if (!pci)
> +		return -ENOMEM;
> +
> +	dbi_base = platform_get_resource_byname(pdev, IORESOURCE_MEM, "regs");
> +	pci->dbi_base = devm_pci_remap_cfg_resource(dev, dbi_base);
> +	if (IS_ERR(pci->dbi_base))
> +		return PTR_ERR(pci->dbi_base);
> +
> +	pci->dbi_base2 = pci->dbi_base + PCIE_DBI2_OFFSET;
> +	pci->dev = dev;
> +	pci->ops = &ls_pcie_ep_ops;
> +	pcie->pci = pci;
> +
> +	platform_set_drvdata(pdev, pcie);
> +
> +	ret = ls_add_pcie_ep(pcie, pdev);
> +
> +	return ret;
> +}
> +
> +static struct platform_driver ls_pcie_ep_driver = {
> +	.driver = {
> +		.name = "layerscape-pcie-ep",
> +		.of_match_table = ls_pcie_ep_of_match,
> +		.suppress_bind_attrs = true,
> +	},
> +};
> +builtin_platform_driver_probe(ls_pcie_ep_driver, ls_pcie_ep_probe);
> -- 
> 1.7.1
>