Re: [PATCH] PCI: designware: check for iATU unroll support after initializing host

[Bjorn Helgaas]

On Fri, Oct 14, 2016 at 11:54:55PM +0200, Niklas Cassel wrote:
> From: Niklas Cassel <niklas.cassel@xxxxxxxx>
> 
> dw_pcie_iatu_unroll_enabled reads a dbi_base register.
> Reading any dbi_base register before pp->ops->host_init has been called
> causes "imprecise external abort" on platforms like ARTPEC-6, where the
> PCIe module is disabled at boot and first enabled in pp->ops->host_init.
> Move dw_pcie_iatu_unroll_enabled to dw_pcie_setup_rc, since it is after
> pp->ops->host_init, but before pp->iatu_unroll_enabled is actually used.
> 
> Fixes: a0601a470537 ("PCI: designware: Add iATU Unroll feature")
> Signed-off-by: Niklas Cassel <niklas.cassel@xxxxxxxx>

Applied to for-linus for v4.9 with acks and tested-by from Joao, Olof,
and James, thanks!

> ---
>  drivers/pci/host/pcie-designware.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 035f50c03281..bed19994c1e9 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -637,8 +637,6 @@ int dw_pcie_host_init(struct pcie_port *pp)
>  		}
>  	}
>  
> -	pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> -
>  	if (pp->ops->host_init)
>  		pp->ops->host_init(pp);
>  
> @@ -809,6 +807,11 @@ void dw_pcie_setup_rc(struct pcie_port *pp)
>  {
>  	u32 val;
>  
> +	/* get iATU unroll support */
> +	pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> +	dev_dbg(pp->dev, "iATU unroll: %s\n",
> +		pp->iatu_unroll_enabled ? "enabled" : "disabled");
> +
>  	/* set the number of lanes */
>  	val = dw_pcie_readl_rc(pp, PCIE_PORT_LINK_CONTROL);
>  	val &= ~PORT_LINK_MODE_MASK;
> -- 
> 2.1.4
> 
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