[PATCH 1/1] PCI: layerscape: Add the workaround for A-010305

[Frank Li]

> Subject: [PATCH 1/1] PCI: layerscape: Add the workaround for A-010305
> 
> From: Xiaowei Bao <xiaowei.bao at nxp.com>
> 
> When a link down or hot reset event occurs, the PCI Express EP
> controller's Link Capabilities Register should retain the values of
> the Maximum Link Width and Supported Link Speed configured by RCW.
> 
> Signed-off-by: Xiaowei Bao <xiaowei.bao at nxp.com>
> Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou at nxp.com>
> Signed-off-by: Frank Li <Frank.Li at nxp.com>
> ---

Ping

>  .../pci/controller/dwc/pci-layerscape-ep.c    | 112 +++++++++++++++++-
>  1 file changed, 111 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> index ed5cfc9408d9..1b884854c18e 100644
> --- a/drivers/pci/controller/dwc/pci-layerscape-ep.c
> +++ b/drivers/pci/controller/dwc/pci-layerscape-ep.c
> @@ -18,6 +18,22 @@
> 
>  #include "pcie-designware.h"
> 
> +#define PCIE_LINK_CAP			0x7C	/* PCIe Link
> Capabilities*/
> +#define MAX_LINK_SP_MASK		0x0F
> +#define MAX_LINK_W_MASK			0x3F
> +#define MAX_LINK_W_SHIFT		4
> +
> +/* PEX PFa PCIE pme and message interrupt registers*/
> +#define PEX_PF0_PME_MES_DR             0xC0020
> +#define PEX_PF0_PME_MES_DR_LUD         (1 << 7)
> +#define PEX_PF0_PME_MES_DR_LDD         (1 << 9)
> +#define PEX_PF0_PME_MES_DR_HRD         (1 << 10)
> +
> +#define PEX_PF0_PME_MES_IER            0xC0028
> +#define PEX_PF0_PME_MES_IER_LUDIE      (1 << 7)
> +#define PEX_PF0_PME_MES_IER_LDDIE      (1 << 9)
> +#define PEX_PF0_PME_MES_IER_HRDIE      (1 << 10)
> +
>  #define to_ls_pcie_ep(x)	dev_get_drvdata((x)->dev)
> 
>  struct ls_pcie_ep_drvdata {
> @@ -30,8 +46,90 @@ struct ls_pcie_ep {
>  	struct dw_pcie			*pci;
>  	struct pci_epc_features		*ls_epc;
>  	const struct ls_pcie_ep_drvdata *drvdata;
> +	u8				max_speed;
> +	u8				max_width;
> +	bool				big_endian;
> +	int				irq;
>  };
> 
> +static u32 ls_lut_readl(struct ls_pcie_ep *pcie, u32 offset)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +
> +	if (pcie->big_endian)
> +		return ioread32be(pci->dbi_base + offset);
> +	else
> +		return ioread32(pci->dbi_base + offset);
> +}
> +
> +static void ls_lut_writel(struct ls_pcie_ep *pcie, u32 offset,
> +			  u32 value)
> +{
> +	struct dw_pcie *pci = pcie->pci;
> +
> +	if (pcie->big_endian)
> +		iowrite32be(value, pci->dbi_base + offset);
> +	else
> +		iowrite32(value, pci->dbi_base + offset);
> +}
> +
> +static irqreturn_t ls_pcie_ep_event_handler(int irq, void *dev_id)
> +{
> +	struct ls_pcie_ep *pcie = (struct ls_pcie_ep *)dev_id;
> +	struct dw_pcie *pci = pcie->pci;
> +	u32 val;
> +
> +	val = ls_lut_readl(pcie, PEX_PF0_PME_MES_DR);
> +	if (!val)
> +		return IRQ_NONE;
> +
> +	if (val & PEX_PF0_PME_MES_DR_LUD)
> +		dev_info(pci->dev, "Detect the link up state !\n");
> +	else if (val & PEX_PF0_PME_MES_DR_LDD)
> +		dev_info(pci->dev, "Detect the link down state !\n");
> +	else if (val & PEX_PF0_PME_MES_DR_HRD)
> +		dev_info(pci->dev, "Detect the hot reset state !\n");
> +
> +	dw_pcie_dbi_ro_wr_en(pci);
> +	dw_pcie_writew_dbi(pci, PCIE_LINK_CAP,
> +			   (pcie->max_width << MAX_LINK_W_SHIFT) |
> +			   pcie->max_speed);
> +	dw_pcie_dbi_ro_wr_dis(pci);
> +
> +	ls_lut_writel(pcie, PEX_PF0_PME_MES_DR, val);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int ls_pcie_ep_interrupt_init(struct ls_pcie_ep *pcie,
> +				     struct platform_device *pdev)
> +{
> +	u32 val;
> +	int ret;
> +
> +	pcie->irq = platform_get_irq_byname(pdev, "pme");
> +	if (pcie->irq < 0) {
> +		dev_err(&pdev->dev, "Can't get 'pme' irq.\n");
> +		return pcie->irq;
> +	}
> +
> +	ret = devm_request_irq(&pdev->dev, pcie->irq,
> +			       ls_pcie_ep_event_handler, IRQF_SHARED,
> +			       pdev->name, pcie);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Can't register PCIe IRQ.\n");
> +		return ret;
> +	}
> +
> +	/* Enable interrupts */
> +	val = ls_lut_readl(pcie, PEX_PF0_PME_MES_IER);
> +	val |=  PEX_PF0_PME_MES_IER_LDDIE |
> PEX_PF0_PME_MES_IER_HRDIE |
> +		PEX_PF0_PME_MES_IER_LUDIE;
> +	ls_lut_writel(pcie, PEX_PF0_PME_MES_IER, val);
> +
> +	return 0;
> +}
> +
>  static const struct pci_epc_features*
>  ls_pcie_ep_get_features(struct dw_pcie_ep *ep)
>  {
> @@ -125,6 +223,7 @@ static int __init ls_pcie_ep_probe(struct
> platform_device *pdev)
>  	struct ls_pcie_ep *pcie;
>  	struct pci_epc_features *ls_epc;
>  	struct resource *dbi_base;
> +	int ret;
> 
>  	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
>  	if (!pcie)
> @@ -155,9 +254,20 @@ static int __init ls_pcie_ep_probe(struct
> platform_device *pdev)
> 
>  	pci->ep.ops = &ls_pcie_ep_ops;
> 
> +	pcie->big_endian = of_property_read_bool(dev->of_node, "big-
> endian");
> +
> +	pcie->max_speed = dw_pcie_readw_dbi(pci, PCIE_LINK_CAP) &
> +			  MAX_LINK_SP_MASK;
> +	pcie->max_width = (dw_pcie_readw_dbi(pci, PCIE_LINK_CAP) >>
> +			  MAX_LINK_W_SHIFT) & MAX_LINK_W_MASK;
> +
>  	platform_set_drvdata(pdev, pcie);
> 
> -	return dw_pcie_ep_init(&pci->ep);
> +	ret = dw_pcie_ep_init(&pci->ep);
> +	if (ret)
> +		return  ret;
> +
> +	return  ls_pcie_ep_interrupt_init(pcie, pdev);
>  }
> 
>  static struct platform_driver ls_pcie_ep_driver = {
> --
> 2.34.1