[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>
> ---
> base-commit: 08733088b566b58283f0f12fb73f5db6a9a9de30
> change-id: 20250430-b4-pci_dwc_reset_support-d720dbafb7ea
> prerequisite-change-id: 20250404-pcie-reset-slot-730bfa71a202:v4
> prerequisite-patch-id: 2dad85eb26838d89569b12c19d70f392fa592667
> prerequisite-patch-id: 6238a682bd8e9476e5911b7a59263c3fc618d63e
> prerequisite-patch-id: 37cab00bc255a62b1e8396a48a3afba5e1751abd
> prerequisite-patch-id: ff711f65cf9926374646b76cd38bdd823d576764
> prerequisite-patch-id: 1654cca919d024b9a9190b28e90f722975c797e8

Now when all the prerequisite-patches have been merged to the
pci/slot-reset branch, any chance of getting this patch queued
up on pci/slot-reset branch as well?


Kind regards,
Niklas