linux-kernel - [PATCH v3 1/2] usb: dwc3: use local copy of resource to fix-up register offset

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Date:   Wed, 16 May 2018 11:41:06 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     linux-usb@...r.kernel.org,
        Felipe Balbi <felipe.balbi@...ux.intel.com>
Cc:     Rob Herring <robh@...nel.org>, Roger Quadros <rogerq@...com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Jassi Brar <jaswinder.singh@...aro.org>,
        Kunihiko Hayashi <hayashi.kunihiko@...ionext.com>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>, linux-kernel@...r.kernel.org
Subject: [PATCH v3 1/2] usb: dwc3: use local copy of resource to fix-up register offset

It is not a good idea to directly modify the resource of a platform
device.  Modify its local copy, and pass it to devm_ioremap_resource()
so that we do not need to restore it in the failure path and the remove
hook.

Signed-off-by: Masahiro Yamada <yamada.masahiro@...ionext.com>
Reviewed-by: Masami Hiramatsu <mhiramat@...nel.org>
---

Changes in v3: None
Changes in v2: None

 drivers/usb/dwc3/core.c | 32 ++++++++------------------------
 1 file changed, 8 insertions(+), 24 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index a15648d..8e66edd 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -1245,7 +1245,7 @@ static void dwc3_check_params(struct dwc3 *dwc)
 static int dwc3_probe(struct platform_device *pdev)
 {
 	struct device		*dev = &pdev->dev;
-	struct resource		*res;
+	struct resource		*res, dwc_res;
 	struct dwc3		*dwc;
 
 	int			ret;
@@ -1270,20 +1270,19 @@ static int dwc3_probe(struct platform_device *pdev)
 	dwc->xhci_resources[0].flags = res->flags;
 	dwc->xhci_resources[0].name = res->name;
 
-	res->start += DWC3_GLOBALS_REGS_START;
-
 	/*
 	 * Request memory region but exclude xHCI regs,
 	 * since it will be requested by the xhci-plat driver.
 	 */
-	regs = devm_ioremap_resource(dev, res);
-	if (IS_ERR(regs)) {
-		ret = PTR_ERR(regs);
-		goto err0;
-	}
+	dwc_res = *res;
+	dwc_res.start += DWC3_GLOBALS_REGS_START;
+
+	regs = devm_ioremap_resource(dev, &dwc_res);
+	if (IS_ERR(regs))
+		return PTR_ERR(regs);
 
 	dwc->regs	= regs;
-	dwc->regs_size	= resource_size(res);
+	dwc->regs_size	= resource_size(&dwc_res);
 
 	dwc3_get_properties(dwc);
 
@@ -1350,29 +1349,14 @@ static int dwc3_probe(struct platform_device *pdev)
 	pm_runtime_put_sync(&pdev->dev);
 	pm_runtime_disable(&pdev->dev);
 
-err0:
-	/*
-	 * restore res->start back to its original value so that, in case the
-	 * probe is deferred, we don't end up getting error in request the
-	 * memory region the next time probe is called.
-	 */
-	res->start -= DWC3_GLOBALS_REGS_START;
-
 	return ret;
 }
 
 static int dwc3_remove(struct platform_device *pdev)
 {
 	struct dwc3	*dwc = platform_get_drvdata(pdev);
-	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 
 	pm_runtime_get_sync(&pdev->dev);
-	/*
-	 * restore res->start back to its original value so that, in case the
-	 * probe is deferred, we don't end up getting error in request the
-	 * memory region the next time probe is called.
-	 */
-	res->start -= DWC3_GLOBALS_REGS_START;
 
 	dwc3_debugfs_exit(dwc);
 	dwc3_core_exit_mode(dwc);
-- 
2.7.4