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linux-next/lib/devres.c
Dan Carpenter 7ae731a844 lib: devres: add a comment about the devm_of_iomap() function
We recently introduced a bug when we tried to convert of_iomap() to
devm_of_iomap().  The problem was that there were two drivers mapping
the same io region.  The first driver was using of_iomap() and the
second driver was using devm_of_iomap() and the kernel booted fine.
When we converted the first drive to use devm_of_iomap() then the second
driver failed with -EBUSY and the kernel couldn't boot.

Let's add a comment to prevent this sort of mistake in the future.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200609104642.GA43074@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-10 14:15:55 +02:00

501 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
#include <linux/err.h>
#include <linux/pci.h>
#include <linux/io.h>
#include <linux/gfp.h>
#include <linux/export.h>
#include <linux/of_address.h>
enum devm_ioremap_type {
DEVM_IOREMAP = 0,
DEVM_IOREMAP_UC,
DEVM_IOREMAP_WC,
};
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;
}
static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset,
resource_size_t size,
enum devm_ioremap_type type)
{
void __iomem **ptr, *addr = NULL;
ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return NULL;
switch (type) {
case DEVM_IOREMAP:
addr = ioremap(offset, size);
break;
case DEVM_IOREMAP_UC:
addr = ioremap_uc(offset, size);
break;
case DEVM_IOREMAP_WC:
addr = ioremap_wc(offset, size);
break;
}
if (addr) {
*ptr = addr;
devres_add(dev, ptr);
} else
devres_free(ptr);
return addr;
}
/**
* devm_ioremap - Managed ioremap()
* @dev: Generic device to remap IO address for
* @offset: Resource address to map
* @size: Size of map
*
* Managed ioremap(). Map is automatically unmapped on driver detach.
*/
void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
resource_size_t size)
{
return __devm_ioremap(dev, offset, size, DEVM_IOREMAP);
}
EXPORT_SYMBOL(devm_ioremap);
/**
* devm_ioremap_uc - Managed ioremap_uc()
* @dev: Generic device to remap IO address for
* @offset: Resource address to map
* @size: Size of map
*
* Managed ioremap_uc(). Map is automatically unmapped on driver detach.
*/
void __iomem *devm_ioremap_uc(struct device *dev, resource_size_t offset,
resource_size_t size)
{
return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_UC);
}
EXPORT_SYMBOL_GPL(devm_ioremap_uc);
/**
* devm_ioremap_wc - Managed ioremap_wc()
* @dev: Generic device to remap IO address for
* @offset: Resource address to map
* @size: Size of map
*
* Managed ioremap_wc(). Map is automatically unmapped on driver detach.
*/
void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,
resource_size_t size)
{
return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_WC);
}
EXPORT_SYMBOL(devm_ioremap_wc);
/**
* 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)
{
WARN_ON(devres_destroy(dev, devm_ioremap_release, devm_ioremap_match,
(__force void *)addr));
iounmap(addr);
}
EXPORT_SYMBOL(devm_iounmap);
static void __iomem *
__devm_ioremap_resource(struct device *dev, const struct resource *res,
enum devm_ioremap_type type)
{
resource_size_t size;
void __iomem *dest_ptr;
char *pretty_name;
BUG_ON(!dev);
if (!res || resource_type(res) != IORESOURCE_MEM) {
dev_err(dev, "invalid resource\n");
return IOMEM_ERR_PTR(-EINVAL);
}
size = resource_size(res);
if (res->name)
pretty_name = devm_kasprintf(dev, GFP_KERNEL, "%s %s",
dev_name(dev), res->name);
else
pretty_name = devm_kstrdup(dev, dev_name(dev), GFP_KERNEL);
if (!pretty_name)
return IOMEM_ERR_PTR(-ENOMEM);
if (!devm_request_mem_region(dev, res->start, size, pretty_name)) {
dev_err(dev, "can't request region for resource %pR\n", res);
return IOMEM_ERR_PTR(-EBUSY);
}
dest_ptr = __devm_ioremap(dev, res->start, size, type);
if (!dest_ptr) {
dev_err(dev, "ioremap failed for resource %pR\n", res);
devm_release_mem_region(dev, res->start, size);
dest_ptr = IOMEM_ERR_PTR(-ENOMEM);
}
return dest_ptr;
}
/**
* devm_ioremap_resource() - check, request region, and ioremap resource
* @dev: generic device to handle the resource for
* @res: resource to be handled
*
* Checks that a resource is a valid memory region, requests the memory
* region and ioremaps it. All operations are managed and will be undone
* on driver detach.
*
* Returns a pointer to the remapped memory or an ERR_PTR() encoded error code
* on failure. Usage example:
*
* res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
* base = devm_ioremap_resource(&pdev->dev, res);
* if (IS_ERR(base))
* return PTR_ERR(base);
*/
void __iomem *devm_ioremap_resource(struct device *dev,
const struct resource *res)
{
return __devm_ioremap_resource(dev, res, DEVM_IOREMAP);
}
EXPORT_SYMBOL(devm_ioremap_resource);
/**
* 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
*
* Checks that a resource is a valid memory region, requests the memory
* region and ioremaps it. All operations are managed and will be undone
* on driver detach of the device.
*
* This is to be used when a device requests/maps resources described
* by other device tree nodes (children or otherwise).
*
* @dev: The device "managing" the resource
* @node: The device-tree node where the resource resides
* @index: index of the MMIO range in the "reg" property
* @size: Returns the size of the resource (pass NULL if not needed)
* Returns a pointer to the requested and mapped memory or an ERR_PTR() encoded
* error code on failure. Usage example:
*
* base = devm_of_iomap(&pdev->dev, node, 0, NULL);
* if (IS_ERR(base))
* return PTR_ERR(base);
*
* Please Note: This is not a one-to-one replacement for of_iomap() because the
* of_iomap() function does not track whether the region is already mapped. If
* two drivers try to map the same memory, the of_iomap() function will succeed
* but the the devm_of_iomap() function will return -EBUSY.
*
*/
void __iomem *devm_of_iomap(struct device *dev, struct device_node *node, int index,
resource_size_t *size)
{
struct resource res;
if (of_address_to_resource(node, index, &res))
return IOMEM_ERR_PTR(-EINVAL);
if (size)
*size = resource_size(&res);
return devm_ioremap_resource(dev, &res);
}
EXPORT_SYMBOL(devm_of_iomap);
#ifdef CONFIG_HAS_IOPORT_MAP
/*
* 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, (__force void *)addr));
}
EXPORT_SYMBOL(devm_ioport_unmap);
#endif /* CONFIG_HAS_IOPORT_MAP */
#ifdef CONFIG_PCI
/*
* PCI iomap devres
*/
#define PCIM_IOMAP_MAX PCI_STD_NUM_BARS
struct pcim_iomap_devres {
void __iomem *table[PCIM_IOMAP_MAX];
};
static void pcim_iomap_release(struct device *gendev, void *res)
{
struct pci_dev *dev = to_pci_dev(gendev);
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);
/**
* pcim_iomap_regions - Request and iomap PCI BARs
* @pdev: PCI device to map IO resources for
* @mask: Mask of BARs to request and iomap
* @name: Name used when requesting regions
*
* Request and iomap regions specified by @mask.
*/
int pcim_iomap_regions(struct pci_dev *pdev, int mask, const char *name)
{
void __iomem * const *iomap;
int i, rc;
iomap = pcim_iomap_table(pdev);
if (!iomap)
return -ENOMEM;
for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) {
unsigned long len;
if (!(mask & (1 << i)))
continue;
rc = -EINVAL;
len = pci_resource_len(pdev, i);
if (!len)
goto err_inval;
rc = pci_request_region(pdev, i, name);
if (rc)
goto err_inval;
rc = -ENOMEM;
if (!pcim_iomap(pdev, i, 0))
goto err_region;
}
return 0;
err_region:
pci_release_region(pdev, i);
err_inval:
while (--i >= 0) {
if (!(mask & (1 << i)))
continue;
pcim_iounmap(pdev, iomap[i]);
pci_release_region(pdev, i);
}
return rc;
}
EXPORT_SYMBOL(pcim_iomap_regions);
/**
* pcim_iomap_regions_request_all - Request all BARs and iomap specified ones
* @pdev: PCI device to map IO resources for
* @mask: Mask of BARs to iomap
* @name: Name used when requesting regions
*
* Request all PCI BARs and iomap regions specified by @mask.
*/
int pcim_iomap_regions_request_all(struct pci_dev *pdev, int mask,
const char *name)
{
int request_mask = ((1 << 6) - 1) & ~mask;
int rc;
rc = pci_request_selected_regions(pdev, request_mask, name);
if (rc)
return rc;
rc = pcim_iomap_regions(pdev, mask, name);
if (rc)
pci_release_selected_regions(pdev, request_mask);
return rc;
}
EXPORT_SYMBOL(pcim_iomap_regions_request_all);
/**
* pcim_iounmap_regions - Unmap and release PCI BARs
* @pdev: PCI device to map IO resources for
* @mask: Mask of BARs to unmap and release
*
* Unmap and release regions specified by @mask.
*/
void pcim_iounmap_regions(struct pci_dev *pdev, int mask)
{
void __iomem * const *iomap;
int i;
iomap = pcim_iomap_table(pdev);
if (!iomap)
return;
for (i = 0; i < PCIM_IOMAP_MAX; i++) {
if (!(mask & (1 << i)))
continue;
pcim_iounmap(pdev, iomap[i]);
pci_release_region(pdev, i);
}
}
EXPORT_SYMBOL(pcim_iounmap_regions);
#endif /* CONFIG_PCI */