[RFC] PCI: pci-imx6: Add delay to workaround kernel hang

[Lucas Stach]

Hi Fabio,

Am Dienstag, den 24.06.2014, 16:18 -0300 schrieb Fabio Estevam:
> From: Fabio Estevam <fabio.estevam at freescale.com>
> 
> When the mx6 PCI conctroller is initialized in the bootloader we see a kernel 
> hang inside imx6_add_pcie_port().
> 
> Adding a 30ms delay allows the kernel to boot.
> 
> Suggested-by: David Müller <d.mueller at elsoft.ch>
> Signed-off-by: Fabio Estevam <fabio.estevam at freescale.com>
> ---
> I am happy to get feedback on how to properly fix this.
> 
> Thanks
> 
>  drivers/pci/host/pci-imx6.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/pci/host/pci-imx6.c b/drivers/pci/host/pci-imx6.c
> index a568efa..669f771 100644
> --- a/drivers/pci/host/pci-imx6.c
> +++ b/drivers/pci/host/pci-imx6.c
> @@ -507,6 +507,8 @@ static int __init imx6_add_pcie_port(struct pcie_port *pp,
>  	pp->root_bus_nr = -1;
>  	pp->ops = &imx6_pcie_host_ops;
>  
> +	usleep_range(25000, 30000);
> +
>  	ret = dw_pcie_host_init(pp);
>  	if (ret) {
>  		dev_err(&pdev->dev, "failed to initialize host\n");

I would suspect the issue to be somewhere in imx6_pcie_host_init(). Can
you move the delay there (and to different positions in this function)
to narrow down where the hang happens?

Regards,
Lucas
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