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, 12 insertions, 0 deletions

diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 1429f3a2629e..5d6312e33490 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -37,6 +37,18 @@ config DEBUG_DRIVER
 
           If you are unsure about this, say N here.
 
+config DEBUG_DEVRES
+        bool "Managed device resources verbose debug messages"
+        depends on DEBUG_KERNEL
+        help
+          This option enables kernel parameter devres.log. If set to
+          non-zero, devres debug messages are printed. Select this if
+          you are having a problem with devres or want to debug
+          resource management for a managed device. devres.log can be
+          switched on and off from sysfs node.
+
+          If you are unsure about this, Say N here.
+
 config SYS_HYPERVISOR
         bool
         default n