linux-kernel - [PATCH v4 02/20] usb: host: ehci-tegra: Correct teardown order of driver's removal

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Date:   Mon,  6 Jan 2020 04:33:58 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Peter Chen <Peter.Chen@....com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Felipe Balbi <balbi@...nel.org>,
        Michał Mirosław <mirq-linux@...e.qmqm.pl>
Cc:     linux-usb@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH v4 02/20] usb: host: ehci-tegra: Correct teardown order of driver's removal

I found that PHY's enable refcounting was broken and after fixing it
I also found that machine started to hang after EHCI driver module
removal. Turned out that the teardown order is incorrect because HCD must
be unregistered *before* PHY's disabling. Note that it is also not correct
to assert the shared reset during of driver's removal because PHY takes
care of resetting shared pads and thus it's better to remove that part
from the EHCI driver.

Signed-off-by: Dmitry Osipenko <digetx@...il.com>
---
 drivers/usb/host/ehci-tegra.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c
index 4d2cdec4cb78..32483bef046b 100644
--- a/drivers/usb/host/ehci-tegra.c
+++ b/drivers/usb/host/ehci-tegra.c
@@ -521,16 +521,10 @@ static int tegra_ehci_remove(struct platform_device *pdev)
 	struct tegra_ehci_hcd *tegra =
 		(struct tegra_ehci_hcd *)hcd_to_ehci(hcd)->priv;
 
+	usb_remove_hcd(hcd);
 	otg_set_host(hcd->usb_phy->otg, NULL);
-
 	usb_phy_shutdown(hcd->usb_phy);
-	usb_remove_hcd(hcd);
-
-	reset_control_assert(tegra->rst);
-	udelay(1);
-
 	clk_disable_unprepare(tegra->clk);
-
 	usb_put_hcd(hcd);
 
 	return 0;
-- 
2.24.0