diff mbox series

[3/9] lib: devres: provide new variants for devm_ioremap_resource()

Message ID 20190829143742.24726-4-brgl@bgdev.pl
State New
Headers show
Series drivers: add new variants of devm_platform_ioremap_resource() | expand

Commit Message

Bartosz Golaszewski Aug. 29, 2019, 2:37 p.m. UTC 
From: Bartosz Golaszewski <bgolaszewski@baylibre.com>

Provide two new variants of devm_ioremap_resource() - one for nocache
and one for write-combined ioremap.

Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
---
 .../driver-api/driver-model/devres.rst        |  2 ++
 include/linux/device.h                        |  4 +++
 lib/devres.c                                  | 29 +++++++++++++++++++
 3 files changed, 35 insertions(+)

Comments

Arnd Bergmann Aug. 29, 2019, 3:09 p.m. UTC | #1 
On Thu, Aug 29, 2019 at 4:38 PM Bartosz Golaszewski <brgl@bgdev.pl> wrote:

> @@ -710,6 +710,10 @@ extern void devm_free_pages(struct device *dev, unsigned long addr);
>
>  void __iomem *devm_ioremap_resource(struct device *dev,
>                                     const struct resource *res);
> +void __iomem *devm_ioremap_resource_nocache(struct device *dev,
> +                                           const struct resource *res);
> +void __iomem *devm_ioremap_resource_wc(struct device *dev,
> +                                      const struct resource *res);
>
>  void __iomem *devm_of_iomap(struct device *dev,
>                             struct device_node *node, int index,
> diff --git a/lib/devres.c b/lib/devres.c

I think adding devm_ioremap_resource_wc() and
devm_platform_ioremap_resource_wc() makes sense, but I think we're
better off without devm_ioremap_resource_nocache() and
devm_ioremap_resource_cache().

The only architecture that actually has a difference between
ioremap() and ioremap_nocache() seems to be ia64. I would
generally assume that any driver using ioremap_nocache()
that is not ia64 specific should just use ioremap().

The ia64 version of ioremap() tries to guess whether it needs
a cached or uncached mapping, everyone else always
gets uncached these days.

       Arnd
diff mbox series

Patch

diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst
index 8e3087662daf..20c4be0389ab 100644
--- a/Documentation/driver-api/driver-model/devres.rst
+++ b/Documentation/driver-api/driver-model/devres.rst
@@ -316,6 +316,8 @@  IOMAP
   devm_ioremap_nocache()
   devm_ioremap_wc()
   devm_ioremap_resource() : checks resource, requests memory region, ioremaps
+  devm_ioremap_resource_nocache()
+  devm_ioremap_resource_wc()
   devm_platform_ioremap_resource() : calls devm_ioremap_resource() for platform device
   devm_iounmap()
   pcim_iomap()
diff --git a/include/linux/device.h b/include/linux/device.h
index 6717adee33f0..e8aa916e8eb2 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -710,6 +710,10 @@  extern void devm_free_pages(struct device *dev, unsigned long addr);
 
 void __iomem *devm_ioremap_resource(struct device *dev,
 				    const struct resource *res);
+void __iomem *devm_ioremap_resource_nocache(struct device *dev,
+					    const struct resource *res);
+void __iomem *devm_ioremap_resource_wc(struct device *dev,
+				       const struct resource *res);
 
 void __iomem *devm_of_iomap(struct device *dev,
 			    struct device_node *node, int index,
diff --git a/lib/devres.c b/lib/devres.c
index a14c727128c1..f1297bcc8891 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -169,6 +169,35 @@  void __iomem *devm_ioremap_resource(struct device *dev,
 }
 EXPORT_SYMBOL(devm_ioremap_resource);
 
+/**
+ * devm_ioremap_resource_nocache() - nocache variant of devm_ioremap_resource()
+ * @dev: generic device to handle the resource for
+ * @res: resource to be handled
+ *
+ * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure. Usage example:
+ */
+void __iomem *devm_ioremap_resource_nocache(struct device *dev,
+					    const struct resource *res)
+{
+	return __devm_ioremap_resource(dev, res, DEVM_IOREMAP_NC);
+}
+
+/**
+ * devm_ioremap_resource_wc() - write-combined variant of
+ *				devm_ioremap_resource()
+ * @dev: generic device to handle the resource for
+ * @res: resource to be handled
+ *
+ * Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
+ * on failure. Usage example:
+ */
+void __iomem *devm_ioremap_resource_wc(struct device *dev,
+				       const struct resource *res)
+{
+	return __devm_ioremap_resource(dev, res, DEVM_IOREMAP_WC);
+}
+
 /*
  * devm_of_iomap - Requests a resource and maps the memory mapped IO
  *		   for a given device_node managed by a given device