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PCI: Add ability to mmap legacy_io on some platforms
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This adds the ability to mmap legacy IO space to the legacy_io files
in sysfs on platforms that support it. This will allow to clean up
X to use this instead of /dev/mem for legacy IO accesses such as
those performed by Int10.

While at it I moved pci_create/remove_legacy_files() to pci-sysfs.c
where I think they belong, thus making more things statis in there
and cleaned up some spurrious prototypes in the ia64 pci.h file

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
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Benjamin Herrenschmidt authored and Jesse Barnes committed Oct 20, 2008
1 parent f393d9b commit f19aeb1
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Showing 5 changed files with 102 additions and 82 deletions.
12 changes: 2 additions & 10 deletions arch/ia64/include/asm/pci.h
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Original file line number Diff line number Diff line change
Expand Up @@ -95,16 +95,8 @@ extern int pci_mmap_page_range (struct pci_dev *dev, struct vm_area_struct *vma,
enum pci_mmap_state mmap_state, int write_combine);
#define HAVE_PCI_LEGACY
extern int pci_mmap_legacy_page_range(struct pci_bus *bus,
struct vm_area_struct *vma);
extern ssize_t pci_read_legacy_io(struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count);
extern ssize_t pci_write_legacy_io(struct kobject *kobj,
struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count);
extern int pci_mmap_legacy_mem(struct kobject *kobj,
struct bin_attribute *attr,
struct vm_area_struct *vma);
struct vm_area_struct *vma,
enum pci_mmap_state mmap_state);

#define pci_get_legacy_mem platform_pci_get_legacy_mem
#define pci_legacy_read platform_pci_legacy_read
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7 changes: 6 additions & 1 deletion arch/ia64/pci/pci.c
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Original file line number Diff line number Diff line change
Expand Up @@ -614,12 +614,17 @@ char *ia64_pci_get_legacy_mem(struct pci_bus *bus)
* vector to get the base address.
*/
int
pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma)
pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma,
enum pci_mmap_state mmap_state)
{
unsigned long size = vma->vm_end - vma->vm_start;
pgprot_t prot;
char *addr;

/* We only support mmap'ing of legacy memory space */
if (mmap_state != pci_mmap_mem)
return -ENOSYS;

/*
* Avoid attribute aliasing. See Documentation/ia64/aliasing.txt
* for more details.
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93 changes: 88 additions & 5 deletions drivers/pci/pci-sysfs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -423,7 +423,7 @@ pci_write_vpd(struct kobject *kobj, struct bin_attribute *bin_attr,
* Reads 1, 2, or 4 bytes from legacy I/O port space using an arch specific
* callback routine (pci_legacy_read).
*/
ssize_t
static ssize_t
pci_read_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
Expand All @@ -448,7 +448,7 @@ pci_read_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
* Writes 1, 2, or 4 bytes from legacy I/O port space using an arch specific
* callback routine (pci_legacy_write).
*/
ssize_t
static ssize_t
pci_write_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
char *buf, loff_t off, size_t count)
{
Expand All @@ -468,19 +468,102 @@ pci_write_legacy_io(struct kobject *kobj, struct bin_attribute *bin_attr,
* @attr: struct bin_attribute for this file
* @vma: struct vm_area_struct passed to mmap
*
* Uses an arch specific callback, pci_mmap_legacy_page_range, to mmap
* Uses an arch specific callback, pci_mmap_legacy_mem_page_range, to mmap
* legacy memory space (first meg of bus space) into application virtual
* memory space.
*/
int
static int
pci_mmap_legacy_mem(struct kobject *kobj, struct bin_attribute *attr,
struct vm_area_struct *vma)
{
struct pci_bus *bus = to_pci_bus(container_of(kobj,
struct device,
kobj));

return pci_mmap_legacy_page_range(bus, vma);
return pci_mmap_legacy_page_range(bus, vma, pci_mmap_mem);
}

/**
* pci_mmap_legacy_io - map legacy PCI IO into user memory space
* @kobj: kobject corresponding to device to be mapped
* @attr: struct bin_attribute for this file
* @vma: struct vm_area_struct passed to mmap
*
* Uses an arch specific callback, pci_mmap_legacy_io_page_range, to mmap
* legacy IO space (first meg of bus space) into application virtual
* memory space. Returns -ENOSYS if the operation isn't supported
*/
static int
pci_mmap_legacy_io(struct kobject *kobj, struct bin_attribute *attr,
struct vm_area_struct *vma)
{
struct pci_bus *bus = to_pci_bus(container_of(kobj,
struct device,
kobj));

return pci_mmap_legacy_page_range(bus, vma, pci_mmap_io);
}

/**
* pci_create_legacy_files - create legacy I/O port and memory files
* @b: bus to create files under
*
* Some platforms allow access to legacy I/O port and ISA memory space on
* a per-bus basis. This routine creates the files and ties them into
* their associated read, write and mmap files from pci-sysfs.c
*
* On error unwind, but don't propogate the error to the caller
* as it is ok to set up the PCI bus without these files.
*/
void pci_create_legacy_files(struct pci_bus *b)
{
int error;

b->legacy_io = kzalloc(sizeof(struct bin_attribute) * 2,
GFP_ATOMIC);
if (!b->legacy_io)
goto kzalloc_err;

b->legacy_io->attr.name = "legacy_io";
b->legacy_io->size = 0xffff;
b->legacy_io->attr.mode = S_IRUSR | S_IWUSR;
b->legacy_io->read = pci_read_legacy_io;
b->legacy_io->write = pci_write_legacy_io;
b->legacy_io->mmap = pci_mmap_legacy_io;
error = device_create_bin_file(&b->dev, b->legacy_io);
if (error)
goto legacy_io_err;

/* Allocated above after the legacy_io struct */
b->legacy_mem = b->legacy_io + 1;
b->legacy_mem->attr.name = "legacy_mem";
b->legacy_mem->size = 1024*1024;
b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
b->legacy_mem->mmap = pci_mmap_legacy_mem;
error = device_create_bin_file(&b->dev, b->legacy_mem);
if (error)
goto legacy_mem_err;

return;

legacy_mem_err:
device_remove_bin_file(&b->dev, b->legacy_io);
legacy_io_err:
kfree(b->legacy_io);
b->legacy_io = NULL;
kzalloc_err:
printk(KERN_WARNING "pci: warning: could not create legacy I/O port "
"and ISA memory resources to sysfs\n");
return;
}

void pci_remove_legacy_files(struct pci_bus *b)
{
if (b->legacy_io) {
device_remove_bin_file(&b->dev, b->legacy_io);
device_remove_bin_file(&b->dev, b->legacy_mem);
kfree(b->legacy_io); /* both are allocated here */
}
}
#endif /* HAVE_PCI_LEGACY */

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6 changes: 6 additions & 0 deletions drivers/pci/pci.h
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Original file line number Diff line number Diff line change
Expand Up @@ -82,7 +82,13 @@ static inline int pci_proc_detach_bus(struct pci_bus *bus) { return 0; }
/* Functions for PCI Hotplug drivers to use */
extern unsigned int pci_do_scan_bus(struct pci_bus *bus);

#ifdef HAVE_PCI_LEGACY
extern void pci_create_legacy_files(struct pci_bus *bus);
extern void pci_remove_legacy_files(struct pci_bus *bus);
#else
static inline void pci_create_legacy_files(struct pci_bus *bus) { return; }
static inline void pci_remove_legacy_files(struct pci_bus *bus) { return; }
#endif

/* Lock for read/write access to pci device and bus lists */
extern struct rw_semaphore pci_bus_sem;
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66 changes: 0 additions & 66 deletions drivers/pci/probe.c
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Original file line number Diff line number Diff line change
Expand Up @@ -42,72 +42,6 @@ int no_pci_devices(void)
}
EXPORT_SYMBOL(no_pci_devices);

#ifdef HAVE_PCI_LEGACY
/**
* pci_create_legacy_files - create legacy I/O port and memory files
* @b: bus to create files under
*
* Some platforms allow access to legacy I/O port and ISA memory space on
* a per-bus basis. This routine creates the files and ties them into
* their associated read, write and mmap files from pci-sysfs.c
*
* On error unwind, but don't propogate the error to the caller
* as it is ok to set up the PCI bus without these files.
*/
static void pci_create_legacy_files(struct pci_bus *b)
{
int error;

b->legacy_io = kzalloc(sizeof(struct bin_attribute) * 2,
GFP_ATOMIC);
if (!b->legacy_io)
goto kzalloc_err;

b->legacy_io->attr.name = "legacy_io";
b->legacy_io->size = 0xffff;
b->legacy_io->attr.mode = S_IRUSR | S_IWUSR;
b->legacy_io->read = pci_read_legacy_io;
b->legacy_io->write = pci_write_legacy_io;
error = device_create_bin_file(&b->dev, b->legacy_io);
if (error)
goto legacy_io_err;

/* Allocated above after the legacy_io struct */
b->legacy_mem = b->legacy_io + 1;
b->legacy_mem->attr.name = "legacy_mem";
b->legacy_mem->size = 1024*1024;
b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
b->legacy_mem->mmap = pci_mmap_legacy_mem;
error = device_create_bin_file(&b->dev, b->legacy_mem);
if (error)
goto legacy_mem_err;

return;

legacy_mem_err:
device_remove_bin_file(&b->dev, b->legacy_io);
legacy_io_err:
kfree(b->legacy_io);
b->legacy_io = NULL;
kzalloc_err:
printk(KERN_WARNING "pci: warning: could not create legacy I/O port "
"and ISA memory resources to sysfs\n");
return;
}

void pci_remove_legacy_files(struct pci_bus *b)
{
if (b->legacy_io) {
device_remove_bin_file(&b->dev, b->legacy_io);
device_remove_bin_file(&b->dev, b->legacy_mem);
kfree(b->legacy_io); /* both are allocated here */
}
}
#else /* !HAVE_PCI_LEGACY */
static inline void pci_create_legacy_files(struct pci_bus *bus) { return; }
void pci_remove_legacy_files(struct pci_bus *bus) { return; }
#endif /* HAVE_PCI_LEGACY */

/*
* PCI Bus Class Devices
*/
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