linux-kernel - [PATCH 1/2] lib: devres: provide devm_iounremap

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Date:   Sun, 20 Sep 2020 19:38:07 +0800
From:   pierre Kuo <vichy.kuo@...il.com>
To:     gregkh@...uxfoundation.org, rafael@...nel.org
Cc:     linux-kernel@...r.kernel.org, pierre Kuo <vichy.kuo@...il.com>
Subject: [PATCH 1/2] lib: devres: provide devm_iounremap_resource()

Driver doesn't have a single helper function to release memroy
allocated by devm_ioremap_resource(). That mean it needs respectively
to call devm_release_mem_region() and devm_iounmap() for memory release.

This patch creates a helper, devm_iounremap_resource(), to combine above
operations.

Signed-off-by: pierre Kuo <vichy.kuo@...il.com>
---
 include/linux/device.h |  2 ++
 lib/devres.c           | 25 +++++++++++++++++++++++++
 2 files changed, 27 insertions(+)

diff --git a/include/linux/device.h b/include/linux/device.h
index 9e6ea8931a52..33ec7e54c1a9 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -240,6 +240,8 @@ void devm_free_pages(struct device *dev, unsigned long addr);
 
 void __iomem *devm_ioremap_resource(struct device *dev,
 				    const struct resource *res);
+void devm_iounremap_resource(struct device *dev,
+			     const struct resource *res, void __iomem *addr);
 void __iomem *devm_ioremap_resource_wc(struct device *dev,
 				       const struct resource *res);
 
diff --git a/lib/devres.c b/lib/devres.c
index ebb1573d9ae3..cdda0cd0a263 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -113,6 +113,31 @@ void devm_iounmap(struct device *dev, void __iomem *addr)
 }
 EXPORT_SYMBOL(devm_iounmap);
 
+/**
+ * devm_iounremap_resource() - release mem region, and unremap address
+ * @dev: generic device to handle the resource for
+ * @res: resource of mem region to be release
+ * @addr: address to unmap
+ *
+ * Release memory region and unmap address.
+ */
+void devm_iounremap_resource(struct device *dev,
+			     const struct resource *res, void __iomem *addr)
+{
+	resource_size_t size;
+
+	BUG_ON(!dev);
+	if (!res || resource_type(res) != IORESOURCE_MEM) {
+		dev_err(dev, "invalid resource\n");
+		return;
+	}
+
+	size = resource_size(res);
+	devm_release_mem_region(dev, res->start, size);
+	devm_iounmap(dev, addr);
+}
+EXPORT_SYMBOL(devm_iounremap_resource);
+
 static void __iomem *
 __devm_ioremap_resource(struct device *dev, const struct resource *res,
 			enum devm_ioremap_type type)
-- 
2.17.1