[PATCH v3] PCI: dw-rockchip: Add support for slot reset on link down event

[Niklas Cassel]

On Fri, May 09, 2025 at 12:30:12PM +1000, Wilfred Mallawa wrote:
> From: Wilfred Mallawa <wilfred.mallawa at wdc.com>
> 
> The PCIe link may go down in cases like firmware crashes or unstable
> connections. When this occurs, the PCIe slot must be reset to restore
> functionality. However, the current driver lacks link down handling,
> forcing users to reboot the system to recover.
> 
> This patch implements the `reset_slot` callback for link down handling
> for DWC PCIe host controller. In which, the RC is reset, reconfigured
> and link training initiated to recover from the link down event.
> 
> This patch by extension fixes issues with sysfs initiated bus resets.
> In that, currently, when a sysfs initiated bus reset is issued, the
> endpoint device is non-functional after (may link up with downgraded link
> status). With this patch adding support for link down recovery, a sysfs
> initiated bus reset works as intended. Testing conducted on a ROCK5B board
> with an M.2 NVMe drive.
> 
> Signed-off-by: Wilfred Mallawa <wilfred.mallawa at wdc.com>
> ---

Looks good to me:
Reviewed-by: Niklas Cassel <cassel at kernel.org>