devres: device resource management

Implement device resource management, in short, devres.  A device
driver can allocate arbirary size of devres data which is associated
with a release function.  On driver detach, release function is
invoked on the devres data, then, devres data is freed.

devreses are typed by associated release functions.  Some devreses are
better represented by single instance of the type while others need
multiple instances sharing the same release function.  Both usages are
supported.

devreses can be grouped using devres group such that a device driver
can easily release acquired resources halfway through initialization
or selectively release resources (e.g. resources for port 1 out of 4
ports).

This patch adds devres core including documentation and the following
managed interfaces.

* alloc/free	: devm_kzalloc(), devm_kzfree()
* IO region	: devm_request_region(), devm_release_region()
* IRQ		: devm_request_irq(), devm_free_irq()
* DMA		: dmam_alloc_coherent(), dmam_free_coherent(),
		  dmam_declare_coherent_memory(), dmam_pool_create(),
		  dmam_pool_destroy()
* PCI		: pcim_enable_device(), pcim_pin_device(), pci_is_managed()
* iomap		: devm_ioport_map(), devm_ioport_unmap(), devm_ioremap(),
		  devm_ioremap_nocache(), devm_iounmap(), pcim_iomap_table(),
		  pcim_iomap(), pcim_iounmap()

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/include/linux/ioport.h b/include/linux/ioport.h
index 15228d79c5b..6859a3b1408 100644
--- a/include/linux/ioport.h
+++ b/include/linux/ioport.h
@@ -137,4 +137,24 @@ static inline int __deprecated check_region(resource_size_t s,
 {
 	return __check_region(&ioport_resource, s, n);
 }
+
+/* Wrappers for managed devices */
+struct device;
+#define devm_request_region(dev,start,n,name) \
+	__devm_request_region(dev, &ioport_resource, (start), (n), (name))
+#define devm_request_mem_region(dev,start,n,name) \
+	__devm_request_region(dev, &iomem_resource, (start), (n), (name))
+
+extern struct resource * __devm_request_region(struct device *dev,
+				struct resource *parent, resource_size_t start,
+				resource_size_t n, const char *name);
+
+#define devm_release_region(start,n) \
+	__devm_release_region(dev, &ioport_resource, (start), (n))
+#define devm_release_mem_region(start,n) \
+	__devm_release_region(dev, &iomem_resource, (start), (n))
+
+extern void __devm_release_region(struct device *dev, struct resource *parent,
+				  resource_size_t start, resource_size_t n);
+
 #endif	/* _LINUX_IOPORT_H */