Commit dc1b5d9a authored Jun 13, 2019 by Enric Balletbo i Serra Committed by Felipe Balbi Jun 18, 2019

usb: dwc3: Fix core validation in probe, move after clocks are enabled



The required clocks needs to be enabled before the first register
access. After commit fe8abf33 ("usb: dwc3: support clocks and resets
for DWC3 core"), this happens when the dwc3_core_is_valid function is
called, but the mentioned commit adds that call in the wrong place,
before the clocks are enabled. So, move that call after the
clk_bulk_enable() to ensure the clocks are enabled and the reset
deasserted.

I detected this while, as experiment, I tried to move the clocks and resets
from the glue layer to the DWC3 core on a Samsung Chromebook Plus.

That was not detected before because, in most cases, the glue layer
initializes SoC-specific things and then populates the child "snps,dwc3"
with those clocks already enabled.

Fixes: b873e2d0 ("usb: dwc3: Do core validation early on probe")
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>

parent 7f5d6a46

drivers/usb/dwc3/core.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -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);

		@@ -1525,6 +1526,7 @@ 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);

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