linux-kernel - [PATCH 5.4 126/134] mmc: tmio: Further fixup runtime PM management at remove

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Date:   Tue, 16 Jun 2020 17:35:10 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Geert Uytterhoeven <geert+renesas@...der.be>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Ulf Hansson <ulf.hansson@...aro.org>
Subject: [PATCH 5.4 126/134] mmc: tmio: Further fixup runtime PM management at remove

From: Ulf Hansson <ulf.hansson@...aro.org>

commit 4bd784411aca022622e484eb262f5a0540ae732c upstream.

Before calling tmio_mmc_host_probe(), the caller is required to enable
clocks for its device, as to make it accessible when reading/writing
registers during probe.

Therefore, the responsibility to disable these clocks, in the error path of
->probe() and during ->remove(), is better managed outside
tmio_mmc_host_remove(). As a matter of fact, callers of
tmio_mmc_host_remove() already expects this to be the behaviour.

However, there's a problem with tmio_mmc_host_remove() when the Kconfig
option, CONFIG_PM, is set. More precisely, tmio_mmc_host_remove() may then
disable the clock via runtime PM, which leads to clock enable/disable
imbalance problems, when the caller of tmio_mmc_host_remove() also tries to
disable the same clocks.

To solve the problem, let's make sure tmio_mmc_host_remove() leaves the
device with clocks enabled, but also make sure to disable the IRQs, as we
normally do at ->runtime_suspend().

Reported-by: Geert Uytterhoeven <geert+renesas@...der.be>
Reviewed-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Tested-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
Cc: stable@...r.kernel.org
Link: https://lore.kernel.org/r/20200519152434.6867-1-ulf.hansson@linaro.org
Tested-by: Geert Uytterhoeven <geert+renesas@...der.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/mmc/host/tmio_mmc_core.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- a/drivers/mmc/host/tmio_mmc_core.c
+++ b/drivers/mmc/host/tmio_mmc_core.c
@@ -1285,12 +1285,14 @@ void tmio_mmc_host_remove(struct tmio_mm
 	cancel_work_sync(&host->done);
 	cancel_delayed_work_sync(&host->delayed_reset_work);
 	tmio_mmc_release_dma(host);
+	tmio_mmc_disable_mmc_irqs(host, TMIO_MASK_ALL);
 
-	pm_runtime_dont_use_autosuspend(&pdev->dev);
 	if (host->native_hotplug)
 		pm_runtime_put_noidle(&pdev->dev);
-	pm_runtime_put_sync(&pdev->dev);
+
 	pm_runtime_disable(&pdev->dev);
+	pm_runtime_dont_use_autosuspend(&pdev->dev);
+	pm_runtime_put_noidle(&pdev->dev);
 }
 EXPORT_SYMBOL_GPL(tmio_mmc_host_remove);