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SubjectRe: [PATCH v2] PCI: altera: Retrain link in rootport mode only
On Fri, Aug 19, 2016 at 04:24:38PM +0800, Ley Foon Tan wrote:
> Altera PCIe IP can be configured as rootport or device and they might have
> same vendor ID. It will cause the system hang issue if Altera PCIe is in
> endpoint mode and work with other PCIe rootport that from other vendors.
> So, add the rootport mode checking in link retrain fixup function.
>
> Signed-off-by: Ley Foon Tan <lftan@altera.com>
> ---
> v2: change to check PCIe type is PCI_EXP_TYPE_ROOT_PORT
> ---
> drivers/pci/host/pcie-altera.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/pci/host/pcie-altera.c b/drivers/pci/host/pcie-altera.c
> index 58eef99..33b6968 100644
> --- a/drivers/pci/host/pcie-altera.c
> +++ b/drivers/pci/host/pcie-altera.c
> @@ -139,6 +139,9 @@ static void altera_pcie_retrain(struct pci_dev *dev)
> u16 linkcap, linkstat;
> struct altera_pcie *pcie = dev->bus->sysdata;
>
> + if (pci_pcie_type(dev) != PCI_EXP_TYPE_ROOT_PORT)
> + return;
> +
> if (!altera_pcie_link_is_up(pcie))
> return;

Instead of making this a PCI fixup, can you make an
altera_pcie_host_init() function, call it from altera_pcie_probe(),
and do the link retrain there? Then you wouldn't need to worry about
whether this is a Root Port or an Endpoint, plus it would make the
altera driver structure more like the other drivers.

You would call altera_pcie_host_init() before pci_scan_root_bus(), so
you wouldn't have a pci_dev yet, so you wouldn't be able to use
pcie_capability_set_word() to set the PCI_EXP_LNKCTL_RL bit. But I
assume there's some device-dependent way to access it using
cra_writel()?

Bjorn

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