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From:   Masahiro Yamada <yamada.masahiro@socionext.com>
To:     Felipe Balbi <felipe.balbi@linux.intel.com>
Cc:     linux-usb@vger.kernel.org,
        Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
        Masahiro Yamada <yamada.masahiro@socionext.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Felipe Balbi <balbi@kernel.org>, linux-kernel@vger.kernel.org
Subject: [PATCH] usb: dwc3: move core validatation after clock enable and reset deassert
Date:   Mon, 20 May 2019 18:28:56 +0900
Message-Id: <20190520092856.26307-1-yamada.masahiro@socionext.com>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Since commit b873e2d0ea1e ("usb: dwc3: Do core validation early on
probe"), the DWC3 USB3 does not work for Socionext UniPhier platform.

It moved dwc3_core_is_valid() really early, where no clock is enabled,
no reset is deasserted. Any attempt to register access causes the
system stall on my platform.

Move it after clk_bulk_enable(), and still before dwc3_get_dr_mode().

Fixes: b873e2d0ea1e ("usb: dwc3: Do core validation early on probe")
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
---

 drivers/usb/dwc3/core.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 4aff1d8dbc4f..93b96e6abddb 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1423,11 +1423,6 @@ static int dwc3_probe(struct platform_device *pdev)
 	dwc->regs	= regs;
 	dwc->regs_size	= resource_size(&dwc_res);
 
-	if (!dwc3_core_is_valid(dwc)) {
-		dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
-		return -ENODEV;
-	}
-
 	dwc3_get_properties(dwc);
 
 	dwc->reset = devm_reset_control_get_optional_shared(dev, NULL);
@@ -1460,6 +1455,12 @@ static int dwc3_probe(struct platform_device *pdev)
 	if (ret)
 		goto unprepare_clks;
 
+	if (!dwc3_core_is_valid(dwc)) {
+		dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
+		ret = -ENODEV;
+		goto disable_clks;
+	}
+
 	platform_set_drvdata(pdev, dwc);
 	dwc3_cache_hwparams(dwc);
 
@@ -1524,7 +1525,7 @@ static int dwc3_probe(struct platform_device *pdev)
 err1:
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
-
+disable_clks:
 	clk_bulk_disable(dwc->num_clks, dwc->clks);
 unprepare_clks:
 	clk_bulk_unprepare(dwc->num_clks, dwc->clks);
-- 
2.17.1