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, 28 insertions, 1 deletions

diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index ff203c4..9a663c6 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -66,6 +66,33 @@ dma_mark_declared_memory_occupied(struct device *dev,
 }
 #endif
 
-#endif
+/*
+ * Managed DMA API
+ */
+extern void *dmam_alloc_coherent(struct device *dev, size_t size,
+				 dma_addr_t *dma_handle, gfp_t gfp);
+extern void dmam_free_coherent(struct device *dev, size_t size, void *vaddr,
+			       dma_addr_t dma_handle);
+extern void *dmam_alloc_noncoherent(struct device *dev, size_t size,
+				    dma_addr_t *dma_handle, gfp_t gfp);
+extern void dmam_free_noncoherent(struct device *dev, size_t size, void *vaddr,
+				  dma_addr_t dma_handle);
+#ifdef ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY
+extern int dmam_declare_coherent_memory(struct device *dev, dma_addr_t bus_addr,
+					dma_addr_t device_addr, size_t size,
+					int flags);
+extern void dmam_release_declared_memory(struct device *dev);
+#else /* ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY */
+static inline int dmam_declare_coherent_memory(struct device *dev,
+				dma_addr_t bus_addr, dma_addr_t device_addr,
+				size_t size, gfp_t gfp)
+{
+	return 0;
+}
 
+static inline void dmam_release_declared_memory(struct device *dev)
+{
+}
+#endif /* ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY */
 
+#endif