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>

2 files changed, 246 insertions, 3 deletions

diff --git a/lib/Makefile b/lib/Makefile
index 77b4bad..29b2e99 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -5,7 +5,7 @@
 lib-y := ctype.o string.o vsprintf.o cmdline.o \
 	 bust_spinlocks.o rbtree.o radix-tree.o dump_stack.o \
 	 idr.o div64.o int_sqrt.o bitmap.o extable.o prio_tree.o \
-	 sha1.o irq_regs.o reciprocal_div.o
+	 sha1.o irq_regs.o reciprocal_div.o iomap.o
 
 lib-$(CONFIG_MMU) += ioremap.o
 lib-$(CONFIG_SMP) += cpumask.o
@@ -41,7 +41,6 @@ obj-$(CONFIG_CRC_CCITT)	+= crc-ccitt.o
 obj-$(CONFIG_CRC16)	+= crc16.o
 obj-$(CONFIG_CRC32)	+= crc32.o
 obj-$(CONFIG_LIBCRC32C)	+= libcrc32c.o
-obj-$(CONFIG_GENERIC_IOMAP) += iomap.o
 obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
 
 obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
diff --git a/lib/iomap.c b/lib/iomap.c
index d6ccdd8..3214028 100644
--- a/lib/iomap.c
+++ b/lib/iomap.c
@@ -4,8 +4,10 @@
  * (C) Copyright 2004 Linus Torvalds
  */
 #include <linux/pci.h>
+#include <linux/io.h>
+
+#ifdef CONFIG_GENERIC_IOMAP
 #include <linux/module.h>
-#include <asm/io.h>
 
 /*
  * Read/write from/to an (offsettable) iomem cookie. It might be a PIO
@@ -254,3 +256,245 @@ void pci_iounmap(struct pci_dev *dev, void __iomem * addr)
 }
 EXPORT_SYMBOL(pci_iomap);
 EXPORT_SYMBOL(pci_iounmap);
+
+#endif /* CONFIG_GENERIC_IOMAP */
+
+/*
+ * Generic iomap devres
+ */
+static void devm_ioport_map_release(struct device *dev, void *res)
+{
+	ioport_unmap(*(void __iomem **)res);
+}
+
+static int devm_ioport_map_match(struct device *dev, void *res,
+				 void *match_data)
+{
+	return *(void **)res == match_data;
+}
+
+/**
+ * devm_ioport_map - Managed ioport_map()
+ * @dev: Generic device to map ioport for
+ * @port: Port to map
+ * @nr: Number of ports to map
+ *
+ * Managed ioport_map().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem * devm_ioport_map(struct device *dev, unsigned long port,
+			       unsigned int nr)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioport_map_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = ioport_map(port, nr);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_ioport_map);
+
+/**
+ * devm_ioport_unmap - Managed ioport_unmap()
+ * @dev: Generic device to unmap for
+ * @addr: Address to unmap
+ *
+ * Managed ioport_unmap().  @addr must have been mapped using
+ * devm_ioport_map().
+ */
+void devm_ioport_unmap(struct device *dev, void __iomem *addr)
+{
+	ioport_unmap(addr);
+	WARN_ON(devres_destroy(dev, devm_ioport_map_release,
+			       devm_ioport_map_match, (void *)addr));
+}
+EXPORT_SYMBOL(devm_ioport_unmap);
+
+static void devm_ioremap_release(struct device *dev, void *res)
+{
+	iounmap(*(void __iomem **)res);
+}
+
+static int devm_ioremap_match(struct device *dev, void *res, void *match_data)
+{
+	return *(void **)res == match_data;
+}
+
+/**
+ * devm_ioremap - Managed ioremap()
+ * @dev: Generic device to remap IO address for
+ * @offset: BUS offset to map
+ * @size: Size of map
+ *
+ * Managed ioremap().  Map is automatically unmapped on driver detach.
+ */
+void __iomem *devm_ioremap(struct device *dev, unsigned long offset,
+			   unsigned long size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = ioremap(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_ioremap);
+
+/**
+ * devm_ioremap_nocache - Managed ioremap_nocache()
+ * @dev: Generic device to remap IO address for
+ * @offset: BUS offset to map
+ * @size: Size of map
+ *
+ * Managed ioremap_nocache().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem *devm_ioremap_nocache(struct device *dev, unsigned long offset,
+				   unsigned long size)
+{
+	void __iomem **ptr, *addr;
+
+	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return NULL;
+
+	addr = ioremap_nocache(offset, size);
+	if (addr) {
+		*ptr = addr;
+		devres_add(dev, ptr);
+	} else
+		devres_free(ptr);
+
+	return addr;
+}
+EXPORT_SYMBOL(devm_ioremap_nocache);
+
+/**
+ * devm_iounmap - Managed iounmap()
+ * @dev: Generic device to unmap for
+ * @addr: Address to unmap
+ *
+ * Managed iounmap().  @addr must have been mapped using devm_ioremap*().
+ */
+void devm_iounmap(struct device *dev, void __iomem *addr)
+{
+	iounmap(addr);
+	WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match,
+			       (void *)addr));
+}
+EXPORT_SYMBOL(devm_iounmap);
+
+/*
+ * PCI iomap devres
+ */
+#define PCIM_IOMAP_MAX	PCI_ROM_RESOURCE
+
+struct pcim_iomap_devres {
+	void __iomem *table[PCIM_IOMAP_MAX];
+};
+
+static void pcim_iomap_release(struct device *gendev, void *res)
+{
+	struct pci_dev *dev = container_of(gendev, struct pci_dev, dev);
+	struct pcim_iomap_devres *this = res;
+	int i;
+
+	for (i = 0; i < PCIM_IOMAP_MAX; i++)
+		if (this->table[i])
+			pci_iounmap(dev, this->table[i]);
+}
+
+/**
+ * pcim_iomap_table - access iomap allocation table
+ * @pdev: PCI device to access iomap table for
+ *
+ * Access iomap allocation table for @dev.  If iomap table doesn't
+ * exist and @pdev is managed, it will be allocated.  All iomaps
+ * recorded in the iomap table are automatically unmapped on driver
+ * detach.
+ *
+ * This function might sleep when the table is first allocated but can
+ * be safely called without context and guaranteed to succed once
+ * allocated.
+ */
+void __iomem * const * pcim_iomap_table(struct pci_dev *pdev)
+{
+	struct pcim_iomap_devres *dr, *new_dr;
+
+	dr = devres_find(&pdev->dev, pcim_iomap_release, NULL, NULL);
+	if (dr)
+		return dr->table;
+
+	new_dr = devres_alloc(pcim_iomap_release, sizeof(*new_dr), GFP_KERNEL);
+	if (!new_dr)
+		return NULL;
+	dr = devres_get(&pdev->dev, new_dr, NULL, NULL);
+	return dr->table;
+}
+EXPORT_SYMBOL(pcim_iomap_table);
+
+/**
+ * pcim_iomap - Managed pcim_iomap()
+ * @pdev: PCI device to iomap for
+ * @bar: BAR to iomap
+ * @maxlen: Maximum length of iomap
+ *
+ * Managed pci_iomap().  Map is automatically unmapped on driver
+ * detach.
+ */
+void __iomem * pcim_iomap(struct pci_dev *pdev, int bar, unsigned long maxlen)
+{
+	void __iomem **tbl;
+
+	BUG_ON(bar >= PCIM_IOMAP_MAX);
+
+	tbl = (void __iomem **)pcim_iomap_table(pdev);
+	if (!tbl || tbl[bar])	/* duplicate mappings not allowed */
+		return NULL;
+
+	tbl[bar] = pci_iomap(pdev, bar, maxlen);
+	return tbl[bar];
+}
+EXPORT_SYMBOL(pcim_iomap);
+
+/**
+ * pcim_iounmap - Managed pci_iounmap()
+ * @pdev: PCI device to iounmap for
+ * @addr: Address to unmap
+ *
+ * Managed pci_iounmap().  @addr must have been mapped using pcim_iomap().
+ */
+void pcim_iounmap(struct pci_dev *pdev, void __iomem *addr)
+{
+	void __iomem **tbl;
+	int i;
+
+	pci_iounmap(pdev, addr);
+
+	tbl = (void __iomem **)pcim_iomap_table(pdev);
+	BUG_ON(!tbl);
+
+	for (i = 0; i < PCIM_IOMAP_MAX; i++)
+		if (tbl[i] == addr) {
+			tbl[i] = NULL;
+			return;
+		}
+	WARN_ON(1);
+}
+EXPORT_SYMBOL(pcim_iounmap);