[PATCH v2 1/2] nvme-apple: Reset controller during shutdown

[Janne Grunau]

This is a functional revert of c76b8308e4c9 ("nvme-apple: fix controller
shutdown in apple_nvme_disable").

The commit broke suspend/resume since apple_nvme_reset_work() tries to
disable the controller on resume. This does not work for the apple NVMe
controller since register access only works while the co-processor
firmware is running.

Disabling the NVMe controller in the shutdown path is also required
for shutting the co-processor down. The original code was appropriate
for this hardware. Add a comment to prevent a similar breaking changes
in the future.

Fixes: c76b8308e4c9 ("nvme-apple: fix controller shutdown in apple_nvme_disable")
Reported-by: Janne Grunau <j@xxxxxxxxxx>
Link: https://lore.kernel.org/all/20230110174745.GA3576@xxxxxxxxxx/
Signed-off-by: Janne Grunau <j@xxxxxxxxxx>
---
 drivers/nvme/host/apple.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/nvme/host/apple.c b/drivers/nvme/host/apple.c
index bf1c60edb7f9..2a1f11b30615 100644
--- a/drivers/nvme/host/apple.c
+++ b/drivers/nvme/host/apple.c
@@ -829,7 +829,13 @@ static void apple_nvme_disable(struct apple_nvme *anv, bool shutdown)
 			apple_nvme_remove_cq(anv);
 		}
 
-		nvme_disable_ctrl(&anv->ctrl, shutdown);
+		/*
+		 * Always reset the NVMe controller on shutdown. The reset is
+		 * required to shutdown the co-processor cleanly.
+		 */
+		if (shutdown)
+			nvme_disable_ctrl(&anv->ctrl, shutdown);
+		nvme_disable_ctrl(&anv->ctrl, false);
 	}
 
 	WRITE_ONCE(anv->ioq.enabled, false);

-- 
2.38.2