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From:   Janne Grunau <j@jannau.net>
Date:   Tue, 17 Jan 2023 19:25:00 +0100
Subject: [PATCH v2 1/2] nvme-apple: Reset controller during shutdown
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Message-Id: <20230114-apple-nvme-suspend-fixes-v6.2-v2-1-9157bf633dba@jannau.net>
References: <20230114-apple-nvme-suspend-fixes-v6.2-v2-0-9157bf633dba@jannau.net>
In-Reply-To: <20230114-apple-nvme-suspend-fixes-v6.2-v2-0-9157bf633dba@jannau.net>
To:     Hector Martin <marcan@marcan.st>, Sven Peter <sven@svenpeter.dev>,
        Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
        Christoph Hellwig <hch@lst.de>,
        Sagi Grimberg <sagi@grimberg.me>
Cc:     Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Eric Curtin <ecurtin@redhat.com>, asahi@lists.linux.dev,
        linux-arm-kernel@lists.infradead.org,
        linux-nvme@lists.infradead.org, linux-kernel@vger.kernel.org,
        Janne Grunau <j@jannau.net>
Precedence: bulk

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@jannau.net>
Link: https://lore.kernel.org/all/20230110174745.GA3576@jannau.net/
Signed-off-by: Janne Grunau <j@jannau.net>
---
 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