linux-kernel - Re: [PATCH v5 7/7] PCI: dwc: Add validation that PCIe core is set to correct mode

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Message-ID: <20190905142723.GC9720@e119886-lin.cambridge.arm.com>
Date:   Thu, 5 Sep 2019 15:27:25 +0100
From:   Andrew Murray <andrew.murray@....com>
To:     Jonathan Chocron <jonnyc@...zon.com>
Cc:     lorenzo.pieralisi@....com, bhelgaas@...gle.com,
        jingoohan1@...il.com, gustavo.pimentel@...opsys.com,
        robh+dt@...nel.org, mark.rutland@....com, dwmw@...zon.co.uk,
        benh@...nel.crashing.org, alisaidi@...zon.com, ronenk@...zon.com,
        barakw@...zon.com, talel@...zon.com, hanochu@...zon.com,
        hhhawa@...zon.com, linux-pci@...r.kernel.org,
        linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v5 7/7] PCI: dwc: Add validation that PCIe core is set to
 correct mode

On Thu, Sep 05, 2019 at 05:01:44PM +0300, Jonathan Chocron wrote:
> Some PCIe controllers can be set to either Host or EP according to some
> early boot FW. To make sure there is no discrepancy (e.g. FW configured
> the port to EP mode while the DT specifies it as a host bridge or vice
> versa), a check has been added for each mode.
> 
> Signed-off-by: Jonathan Chocron <jonnyc@...zon.com>
> Acked-by: Gustavo Pimentel <gustavo.pimentel@...opsys.com>
> ---
>  drivers/pci/controller/dwc/pcie-designware-ep.c  |  8 ++++++++
>  .../pci/controller/dwc/pcie-designware-host.c    | 16 ++++++++++++++++
>  2 files changed, 24 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> index 65f479250087..3dd2e2697294 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
> @@ -498,6 +498,7 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>  	int ret;
>  	u32 reg;
>  	void *addr;
> +	u8 hdr_type;
>  	unsigned int nbars;
>  	unsigned int offset;
>  	struct pci_epc *epc;
> @@ -562,6 +563,13 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>  	if (ep->ops->ep_init)
>  		ep->ops->ep_init(ep);
>  
> +	hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE);
> +	if (hdr_type != PCI_HEADER_TYPE_NORMAL) {
> +		dev_err(pci->dev, "PCIe controller is not set to EP mode (hdr_type:0x%x)!\n",
> +			hdr_type);
> +		return -EIO;
> +	}
> +
>  	ret = of_property_read_u8(np, "max-functions", &epc->max_functions);
>  	if (ret < 0)
>  		epc->max_functions = 1;
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index d3156446ff27..0f36a926059a 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -323,6 +323,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  	struct pci_bus *child;
>  	struct pci_host_bridge *bridge;
>  	struct resource *cfg_res;
> +	u32 hdr_type;
>  	int ret;
>  
>  	raw_spin_lock_init(&pci->pp.lock);
> @@ -464,6 +465,21 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  			goto err_free_msi;
>  	}
>  
> +	ret = dw_pcie_rd_own_conf(pp, PCI_HEADER_TYPE, 1, &hdr_type);
> +	if (ret != PCIBIOS_SUCCESSFUL) {
> +		dev_err(pci->dev, "Failed reading PCI_HEADER_TYPE cfg space reg (ret: 0x%x)\n",
> +			ret);
> +		ret = pcibios_err_to_errno(ret);
> +		goto err_free_msi;
> +	}
> +	if (hdr_type != PCI_HEADER_TYPE_BRIDGE) {
> +		dev_err(pci->dev,
> +			"PCIe controller is not set to bridge type (hdr_type: 0x%x)!\n",
> +			hdr_type);
> +		ret = -EIO;
> +		goto err_free_msi;
> +	}
> +

Reviewed-by: Andrew Murray <andrew.murray@....com>

>  	pp->root_bus_nr = pp->busn->start;
>  
>  	bridge->dev.parent = dev;
> -- 
> 2.17.1
>