[PATCH v3 3/3] PCI: rockchip: Add system PM support

[Bjorn Helgaas]

Hi Shawn,

On Thu, Nov 24, 2016 at 09:54:22AM +0800, Shawn Lin wrote:
> This patch adds system PM support for Rockchip's RC.
> For pre S3, the EP is configured into D3 state which guarantees
> the link state should be in L1. So we could send PME_Turn_Off message
> to the EP and wait for its ACK to make the link state into L2 or L3
> without the aux-supply. This could help save more power which I think
> should be very important for mobile devices.
> 
> As note that there is a 5s timeout for RC to wait for the PMA_ACK
> aftering send PME_Turn_Off. Technically it should depends on the
> hierarchy of devices but seems PCIe core framework doesn't handle the
> L2/3 for S3 at all. So that means we should presume to set a default
> value for PME_ACK. From the bug report[1], we could find a statment that
> Microsoft Windows versions typically wait for 5 seconds. So we are prone
> to take 5s for this timeout here.
> 
> [1] https://lists.launchpad.net/kernel-packages/msg123315.html
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
> 
> Reviewed-by: Brian Norris <briannorris at chromium.org>

> @@ -1196,8 +1207,96 @@ static int rockchip_cfg_atu(struct rockchip_pcie *rockchip)
>  		}
>  	}
>  
> +	/* assign message regions */
> +	rockchip_pcie_prog_ob_atu(rockchip, reg_no + 1 + offset,
> +				  AXI_WRAPPER_NOR_MSG,
> +				  20 - 1, 0, 0);
> +	if (rockchip->msg_region)
> +		goto out;
> +
> +	rockchip->msg_region = devm_ioremap(rockchip->dev,
> +					    rockchip->mem_bus_addr +
> +					    ((reg_no + offset) << 20),
> +					    SZ_1M);
> +	if (!rockchip->msg_region)
> +		err = -ENOMEM;

I don't really like this strategy of "if msg_region is already mapped,
skip it; otherwise map it."  The ioremap() looks like something that
should be done at probe-time and does not need to be re-done at
resume-time.

Bjorn