[PATCH 16/19] driver: make dev_platform_ioremap_resource() device-managed

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

From: Ahmad Fatoum <a.fatoum@barebox.org>

Unlike devm_platform_ioremap_resource() in Linux, the barebox stand-in
never releases its region. Most users call clk_get() or regulator_get()
after it, so a deferred probe leaves the region requested and the retry
fails with -EBUSY.

Implement it on top of devm_request_mem_resource() and move it out of
line to devres.c.

Assisted-by: Claude:opus-5-1m
Signed-off-by: Ahmad Fatoum <a.fatoum@barebox.org>
---
 drivers/base/devres.c  | 32 ++++++++++++++++++++++++++++++++
 include/linux/device.h | 11 +----------
 2 files changed, 33 insertions(+), 10 deletions(-)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index efc810a8898f..f68b8e7b6590 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -7,6 +7,7 @@
 
 #include <barebox.h>
 #include <driver.h>
+#include <io.h>
 #include <dma.h>
 #include <talloc.h>
 #include <xfuncs.h>
@@ -204,3 +205,34 @@ struct resource *devm_request_mem_resource(struct device *dev, int num)
 	return res;
 }
 EXPORT_SYMBOL(devm_request_mem_resource);
+
+/**
+ * dev_platform_ioremap_resource() - request and map resource 'num' for a device
+ * @dev: device to request the memory resource for
+ * @num: index of the memory resource
+ *
+ * barebox maps everything outside the RAM banks suitably for MMIO, so this
+ * only requests the device-managed region.
+ *
+ * Return: a pointer to the registers or an ERR_PTR() on failure.
+ */
+void __iomem *dev_platform_ioremap_resource(struct device *dev, int num)
+{
+	struct resource *res;
+
+	res = devm_request_mem_resource(dev, num);
+	if (IS_ERR(res))
+		return IOMEM_ERR_PTR(PTR_ERR(res));
+
+	/* As everything is mapped 1:1 by default, drivers on unlucky
+	 * platforms can end up successfully requesting memory, but
+	 * getting a base address that looks like an error pointer.
+	 * Let's warn loudly about this case, as these drivers
+	 * should be using devm_request_mem_resource instead.
+	 */
+	if (WARN_ON(IS_ERR_VALUE(res->start)))
+		return IOMEM_ERR_PTR(-EINVAL);
+
+	return IOMEM(res->start);
+}
+EXPORT_SYMBOL(dev_platform_ioremap_resource);
diff --git a/include/linux/device.h b/include/linux/device.h
index 9b14bc74fef6..2b33580cd573 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -146,16 +146,7 @@ static inline int devm_add_action_or_reset(struct device *dev,
 #define driver_unregister unregister_driver
 
 
-static inline void __iomem *dev_platform_ioremap_resource(struct device *dev,
-							  int resource)
-{
-	/*
-	 * barebox maps everything outside the RAM banks suitably for MMIO,
-	 * so we don't need to do anything besides requesting the regions
-	 * and can leave the memory attributes unchanged.
-	 */
-	return dev_request_mem_region(dev, resource);
-}
+void __iomem *dev_platform_ioremap_resource(struct device *dev, int num);
 
 static inline void __iomem *devm_ioremap(struct device *dev,
 					 resource_size_t start,
-- 
2.47.3