[PATCH] ARM: Kirkwood: Support basic hotplug for PCI-E

[Jason Cooper]

On Wed, Nov 21, 2012 at 11:25:28AM -0700, Jason Gunthorpe wrote:
> Unconditionally register the PCI-E bus, even if the link is currently
> down. 

How does this affect clock gating on boards without PCI-E devices?  Will
the SoC then power this unconditionally?

thx,

Jason.

> When the link is brought up the bus can be scanned through
> /sys/bus/pci/rescan or otherwise. Since the HW has no interrupt for
> link up, userspace will have to take care of the timing.
> 
> An earlier version of this was contingent on CONFIG_HOTPLUG, but
> that is being removed from the kernel.
> 
> This also fixes printing the link up/down message to be displayed
> on one line (structured logging broke this?)
> 
> Signed-off-by: Jason Gunthorpe <jgunthorpe at obsidianresearch.com>
> ---
>  arch/arm/mach-kirkwood/pcie.c |   10 +++-------
>  1 files changed, 3 insertions(+), 7 deletions(-)
> 
> All PCI-E ports are required to support hot plug at the link training
> level. Our systems support it electrically, and userspace sequences
> everything to work properly. But the PCI-E root port needs to be
> registered with the kernel to initiate a rescan via sysfs when things
> are ready.
> 
> diff --git a/arch/arm/mach-kirkwood/pcie.c b/arch/arm/mach-kirkwood/pcie.c
> index 59c97fe..80fd4f2 100644
> --- a/arch/arm/mach-kirkwood/pcie.c
> +++ b/arch/arm/mach-kirkwood/pcie.c
> @@ -244,13 +244,9 @@ static struct hw_pci kirkwood_pci __initdata = {
>  
>  static void __init add_pcie_port(int index, void __iomem *base)
>  {
> -	printk(KERN_INFO "Kirkwood PCIe port %d: ", index);
> -
> -	if (orion_pcie_link_up(base)) {
> -		printk(KERN_INFO "link up\n");
> -		pcie_port_map[num_pcie_ports++] = index;
> -	} else
> -		printk(KERN_INFO "link down, ignoring\n");
> +	pcie_port_map[num_pcie_ports++] = index;
> +	pr_info("Kirkwood PCIe port %d: link %s\n", index,
> +		orion_pcie_link_up(base) ? "up" : "down");
>  }
>  
>  void __init kirkwood_pcie_init(unsigned int portmask)
> -- 
> 1.7.5.4
>