blob: fcb7807ea8b73de79163bb99c20091f4b202da0d [file] [log] [blame]
/*
* drivers/acpi/resource.c - ACPI device resources interpretation.
*
* Copyright (C) 2012, Intel Corp.
* Author: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as published
* by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/export.h>
#include <linux/ioport.h>
#include <linux/list.h>
#include <linux/slab.h>
#ifdef CONFIG_X86
#define valid_IRQ(i) (((i) != 0) && ((i) != 2))
#else
#define valid_IRQ(i) (true)
#endif
static bool acpi_dev_resource_len_valid(u64 start, u64 end, u64 len, bool io)
{
u64 reslen = end - start + 1;
/*
* CHECKME: len might be required to check versus a minimum
* length as well. 1 for io is fine, but for memory it does
* not make any sense at all.
* Note: some BIOSes report incorrect length for ACPI address space
* descriptor, so remove check of 'reslen == len' to avoid regression.
*/
if (len && reslen && start <= end)
return true;
pr_debug("ACPI: invalid or unassigned resource %s [%016llx - %016llx] length [%016llx]\n",
io ? "io" : "mem", start, end, len);
return false;
}
static void acpi_dev_memresource_flags(struct resource *res, u64 len,
u8 write_protect)
{
res->flags = IORESOURCE_MEM;
if (!acpi_dev_resource_len_valid(res->start, res->end, len, false))
res->flags |= IORESOURCE_DISABLED | IORESOURCE_UNSET;
if (write_protect == ACPI_READ_WRITE_MEMORY)
res->flags |= IORESOURCE_MEM_WRITEABLE;
}
static void acpi_dev_get_memresource(struct resource *res, u64 start, u64 len,
u8 write_protect)
{
res->start = start;
res->end = start + len - 1;
acpi_dev_memresource_flags(res, len, write_protect);
}
/**
* acpi_dev_resource_memory - Extract ACPI memory resource information.
* @ares: Input ACPI resource object.
* @res: Output generic resource object.
*
* Check if the given ACPI resource object represents a memory resource and
* if that's the case, use the information in it to populate the generic
* resource object pointed to by @res.
*
* Return:
* 1) false with res->flags setting to zero: not the expected resource type
* 2) false with IORESOURCE_DISABLED in res->flags: valid unassigned resource
* 3) true: valid assigned resource
*/
bool acpi_dev_resource_memory(struct acpi_resource *ares, struct resource *res)
{
struct acpi_resource_memory24 *memory24;
struct acpi_resource_memory32 *memory32;
struct acpi_resource_fixed_memory32 *fixed_memory32;
switch (ares->type) {
case ACPI_RESOURCE_TYPE_MEMORY24:
memory24 = &ares->data.memory24;
acpi_dev_get_memresource(res, memory24->minimum << 8,
memory24->address_length << 8,
memory24->write_protect);
break;
case ACPI_RESOURCE_TYPE_MEMORY32:
memory32 = &ares->data.memory32;
acpi_dev_get_memresource(res, memory32->minimum,
memory32->address_length,
memory32->write_protect);
break;
case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
fixed_memory32 = &ares->data.fixed_memory32;
acpi_dev_get_memresource(res, fixed_memory32->address,
fixed_memory32->address_length,
fixed_memory32->write_protect);
break;
default:
res->flags = 0;
return false;
}
return !(res->flags & IORESOURCE_DISABLED);
}
EXPORT_SYMBOL_GPL(acpi_dev_resource_memory);
static void acpi_dev_ioresource_flags(struct resource *res, u64 len,
u8 io_decode)
{
res->flags = IORESOURCE_IO;
if (!acpi_dev_resource_len_valid(res->start, res->end, len, true))
res->flags |= IORESOURCE_DISABLED | IORESOURCE_UNSET;
if (res->end >= 0x10003)
res->flags |= IORESOURCE_DISABLED | IORESOURCE_UNSET;
if (io_decode == ACPI_DECODE_16)
res->flags |= IORESOURCE_IO_16BIT_ADDR;
}
static void acpi_dev_get_ioresource(struct resource *res, u64 start, u64 len,
u8 io_decode)
{
res->start = start;
res->end = start + len - 1;
acpi_dev_ioresource_flags(res, len, io_decode);
}
/**
* acpi_dev_resource_io - Extract ACPI I/O resource information.
* @ares: Input ACPI resource object.
* @res: Output generic resource object.
*
* Check if the given ACPI resource object represents an I/O resource and
* if that's the case, use the information in it to populate the generic
* resource object pointed to by @res.
*
* Return:
* 1) false with res->flags setting to zero: not the expected resource type
* 2) false with IORESOURCE_DISABLED in res->flags: valid unassigned resource
* 3) true: valid assigned resource
*/
bool acpi_dev_resource_io(struct acpi_resource *ares, struct resource *res)
{
struct acpi_resource_io *io;
struct acpi_resource_fixed_io *fixed_io;
switch (ares->type) {
case ACPI_RESOURCE_TYPE_IO:
io = &ares->data.io;
acpi_dev_get_ioresource(res, io->minimum,
io->address_length,
io->io_decode);
break;
case ACPI_RESOURCE_TYPE_FIXED_IO:
fixed_io = &ares->data.fixed_io;
acpi_dev_get_ioresource(res, fixed_io->address,
fixed_io->address_length,
ACPI_DECODE_10);
break;
default:
res->flags = 0;
return false;
}
return !(res->flags & IORESOURCE_DISABLED);
}
EXPORT_SYMBOL_GPL(acpi_dev_resource_io);
static bool acpi_decode_space(struct resource_win *win,
struct acpi_resource_address *addr,
struct acpi_address64_attribute *attr)
{
u8 iodec = attr->granularity == 0xfff ? ACPI_DECODE_10 : ACPI_DECODE_16;
bool wp = addr->info.mem.write_protect;
u64 len = attr->address_length;
struct resource *res = &win->res;
/*
* Filter out invalid descriptor according to ACPI Spec 5.0, section
* 6.4.3.5 Address Space Resource Descriptors.
*/
if ((addr->min_address_fixed != addr->max_address_fixed && len) ||
(addr->min_address_fixed && addr->max_address_fixed && !len))
pr_debug("ACPI: Invalid address space min_addr_fix %d, max_addr_fix %d, len %llx\n",
addr->min_address_fixed, addr->max_address_fixed, len);
res->start = attr->minimum;
res->end = attr->maximum;
/*
* For bridges that translate addresses across the bridge,
* translation_offset is the offset that must be added to the
* address on the secondary side to obtain the address on the
* primary side. Non-bridge devices must list 0 for all Address
* Translation offset bits.
*/
if (addr->producer_consumer == ACPI_PRODUCER) {
res->start += attr->translation_offset;
res->end += attr->translation_offset;
} else if (attr->translation_offset) {
pr_debug("ACPI: translation_offset(%lld) is invalid for non-bridge device.\n",
attr->translation_offset);
}
switch (addr->resource_type) {
case ACPI_MEMORY_RANGE:
acpi_dev_memresource_flags(res, len, wp);
break;
case ACPI_IO_RANGE:
acpi_dev_ioresource_flags(res, len, iodec);
break;
case ACPI_BUS_NUMBER_RANGE:
res->flags = IORESOURCE_BUS;
break;
default:
return false;
}
win->offset = attr->translation_offset;
if (addr->producer_consumer == ACPI_PRODUCER)
res->flags |= IORESOURCE_WINDOW;
if (addr->info.mem.caching == ACPI_PREFETCHABLE_MEMORY)
res->flags |= IORESOURCE_PREFETCH;
return !(res->flags & IORESOURCE_DISABLED);
}
/**
* acpi_dev_resource_address_space - Extract ACPI address space information.
* @ares: Input ACPI resource object.
* @win: Output generic resource object.
*
* Check if the given ACPI resource object represents an address space resource
* and if that's the case, use the information in it to populate the generic
* resource object pointed to by @win.
*
* Return:
* 1) false with win->res.flags setting to zero: not the expected resource type
* 2) false with IORESOURCE_DISABLED in win->res.flags: valid unassigned
* resource
* 3) true: valid assigned resource
*/
bool acpi_dev_resource_address_space(struct acpi_resource *ares,
struct resource_win *win)
{
struct acpi_resource_address64 addr;
win->res.flags = 0;
if (ACPI_FAILURE(acpi_resource_to_address64(ares, &addr)))
return false;
return acpi_decode_space(win, (struct acpi_resource_address *)&addr,
&addr.address);
}
EXPORT_SYMBOL_GPL(acpi_dev_resource_address_space);
/**
* acpi_dev_resource_ext_address_space - Extract ACPI address space information.
* @ares: Input ACPI resource object.
* @win: Output generic resource object.
*
* Check if the given ACPI resource object represents an extended address space
* resource and if that's the case, use the information in it to populate the
* generic resource object pointed to by @win.
*
* Return:
* 1) false with win->res.flags setting to zero: not the expected resource type
* 2) false with IORESOURCE_DISABLED in win->res.flags: valid unassigned
* resource
* 3) true: valid assigned resource
*/
bool acpi_dev_resource_ext_address_space(struct acpi_resource *ares,
struct resource_win *win)
{
struct acpi_resource_extended_address64 *ext_addr;
win->res.flags = 0;
if (ares->type != ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64)
return false;
ext_addr = &ares->data.ext_address64;
return acpi_decode_space(win, (struct acpi_resource_address *)ext_addr,
&ext_addr->address);
}
EXPORT_SYMBOL_GPL(acpi_dev_resource_ext_address_space);
/**
* acpi_dev_irq_flags - Determine IRQ resource flags.
* @triggering: Triggering type as provided by ACPI.
* @polarity: Interrupt polarity as provided by ACPI.
* @shareable: Whether or not the interrupt is shareable.
*/
unsigned long acpi_dev_irq_flags(u8 triggering, u8 polarity, u8 shareable)
{
unsigned long flags;
if (triggering == ACPI_LEVEL_SENSITIVE)
flags = polarity == ACPI_ACTIVE_LOW ?
IORESOURCE_IRQ_LOWLEVEL : IORESOURCE_IRQ_HIGHLEVEL;
else
flags = polarity == ACPI_ACTIVE_LOW ?
IORESOURCE_IRQ_LOWEDGE : IORESOURCE_IRQ_HIGHEDGE;
if (shareable == ACPI_SHARED)
flags |= IORESOURCE_IRQ_SHAREABLE;
return flags | IORESOURCE_IRQ;
}
EXPORT_SYMBOL_GPL(acpi_dev_irq_flags);
static void acpi_dev_irqresource_disabled(struct resource *res, u32 gsi)
{
res->start = gsi;
res->end = gsi;
res->flags = IORESOURCE_IRQ | IORESOURCE_DISABLED | IORESOURCE_UNSET;
}
static void acpi_dev_get_irqresource(struct resource *res, u32 gsi,
u8 triggering, u8 polarity, u8 shareable,
bool legacy)
{
int irq, p, t;
if (!valid_IRQ(gsi)) {
acpi_dev_irqresource_disabled(res, gsi);
return;
}
/*
* In IO-APIC mode, use overrided attribute. Two reasons:
* 1. BIOS bug in DSDT
* 2. BIOS uses IO-APIC mode Interrupt Source Override
*
* We do this only if we are dealing with IRQ() or IRQNoFlags()
* resource (the legacy ISA resources). With modern ACPI 5 devices
* using extended IRQ descriptors we take the IRQ configuration
* from _CRS directly.
*/
if (legacy && !acpi_get_override_irq(gsi, &t, &p)) {
u8 trig = t ? ACPI_LEVEL_SENSITIVE : ACPI_EDGE_SENSITIVE;
u8 pol = p ? ACPI_ACTIVE_LOW : ACPI_ACTIVE_HIGH;
if (triggering != trig || polarity != pol) {
pr_warning("ACPI: IRQ %d override to %s, %s\n", gsi,
t ? "level" : "edge", p ? "low" : "high");
triggering = trig;
polarity = pol;
}
}
res->flags = acpi_dev_irq_flags(triggering, polarity, shareable);
irq = acpi_register_gsi(NULL, gsi, triggering, polarity);
if (irq >= 0) {
res->start = irq;
res->end = irq;
} else {
acpi_dev_irqresource_disabled(res, gsi);
}
}
/**
* acpi_dev_resource_interrupt - Extract ACPI interrupt resource information.
* @ares: Input ACPI resource object.
* @index: Index into the array of GSIs represented by the resource.
* @res: Output generic resource object.
*
* Check if the given ACPI resource object represents an interrupt resource
* and @index does not exceed the resource's interrupt count (true is returned
* in that case regardless of the results of the other checks)). If that's the
* case, register the GSI corresponding to @index from the array of interrupts
* represented by the resource and populate the generic resource object pointed
* to by @res accordingly. If the registration of the GSI is not successful,
* IORESOURCE_DISABLED will be set it that object's flags.
*
* Return:
* 1) false with res->flags setting to zero: not the expected resource type
* 2) false with IORESOURCE_DISABLED in res->flags: valid unassigned resource
* 3) true: valid assigned resource
*/
bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
struct resource *res)
{
struct acpi_resource_irq *irq;
struct acpi_resource_extended_irq *ext_irq;
switch (ares->type) {
case ACPI_RESOURCE_TYPE_IRQ:
/*
* Per spec, only one interrupt per descriptor is allowed in
* _CRS, but some firmware violates this, so parse them all.
*/
irq = &ares->data.irq;
if (index >= irq->interrupt_count) {
acpi_dev_irqresource_disabled(res, 0);
return false;
}
acpi_dev_get_irqresource(res, irq->interrupts[index],
irq->triggering, irq->polarity,
irq->sharable, true);
break;
case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
ext_irq = &ares->data.extended_irq;
if (index >= ext_irq->interrupt_count) {
acpi_dev_irqresource_disabled(res, 0);
return false;
}
acpi_dev_get_irqresource(res, ext_irq->interrupts[index],
ext_irq->triggering, ext_irq->polarity,
ext_irq->sharable, false);
break;
default:
res->flags = 0;
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(acpi_dev_resource_interrupt);
/**
* acpi_dev_free_resource_list - Free resource from %acpi_dev_get_resources().
* @list: The head of the resource list to free.
*/
void acpi_dev_free_resource_list(struct list_head *list)
{
resource_list_free(list);
}
EXPORT_SYMBOL_GPL(acpi_dev_free_resource_list);
struct res_proc_context {
struct list_head *list;
int (*preproc)(struct acpi_resource *, void *);
void *preproc_data;
int count;
int error;
};
static acpi_status acpi_dev_new_resource_entry(struct resource_win *win,
struct res_proc_context *c)
{
struct resource_entry *rentry;
rentry = resource_list_create_entry(NULL, 0);
if (!rentry) {
c->error = -ENOMEM;
return AE_NO_MEMORY;
}
*rentry->res = win->res;
rentry->offset = win->offset;
resource_list_add_tail(rentry, c->list);
c->count++;
return AE_OK;
}
static acpi_status acpi_dev_process_resource(struct acpi_resource *ares,
void *context)
{
struct res_proc_context *c = context;
struct resource_win win;
struct resource *res = &win.res;
int i;
if (c->preproc) {
int ret;
ret = c->preproc(ares, c->preproc_data);
if (ret < 0) {
c->error = ret;
return AE_CTRL_TERMINATE;
} else if (ret > 0) {
return AE_OK;
}
}
memset(&win, 0, sizeof(win));
if (acpi_dev_resource_memory(ares, res)
|| acpi_dev_resource_io(ares, res)
|| acpi_dev_resource_address_space(ares, &win)
|| acpi_dev_resource_ext_address_space(ares, &win))
return acpi_dev_new_resource_entry(&win, c);
for (i = 0; acpi_dev_resource_interrupt(ares, i, res); i++) {
acpi_status status;
status = acpi_dev_new_resource_entry(&win, c);
if (ACPI_FAILURE(status))
return status;
}
return AE_OK;
}
/**
* acpi_dev_get_resources - Get current resources of a device.
* @adev: ACPI device node to get the resources for.
* @list: Head of the resultant list of resources (must be empty).
* @preproc: The caller's preprocessing routine.
* @preproc_data: Pointer passed to the caller's preprocessing routine.
*
* Evaluate the _CRS method for the given device node and process its output by
* (1) executing the @preproc() rountine provided by the caller, passing the
* resource pointer and @preproc_data to it as arguments, for each ACPI resource
* returned and (2) converting all of the returned ACPI resources into struct
* resource objects if possible. If the return value of @preproc() in step (1)
* is different from 0, step (2) is not applied to the given ACPI resource and
* if that value is negative, the whole processing is aborted and that value is
* returned as the final error code.
*
* The resultant struct resource objects are put on the list pointed to by
* @list, that must be empty initially, as members of struct resource_entry
* objects. Callers of this routine should use %acpi_dev_free_resource_list() to
* free that list.
*
* The number of resources in the output list is returned on success, an error
* code reflecting the error condition is returned otherwise.
*/
int acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list,
int (*preproc)(struct acpi_resource *, void *),
void *preproc_data)
{
struct res_proc_context c;
acpi_status status;
if (!adev || !adev->handle || !list_empty(list))
return -EINVAL;
if (!acpi_has_method(adev->handle, METHOD_NAME__CRS))
return 0;
c.list = list;
c.preproc = preproc;
c.preproc_data = preproc_data;
c.count = 0;
c.error = 0;
status = acpi_walk_resources(adev->handle, METHOD_NAME__CRS,
acpi_dev_process_resource, &c);
if (ACPI_FAILURE(status)) {
acpi_dev_free_resource_list(list);
return c.error ? c.error : -EIO;
}
return c.count;
}
EXPORT_SYMBOL_GPL(acpi_dev_get_resources);
/**
* acpi_dev_filter_resource_type - Filter ACPI resource according to resource
* types
* @ares: Input ACPI resource object.
* @types: Valid resource types of IORESOURCE_XXX
*
* This is a helper function to support acpi_dev_get_resources(), which filters
* ACPI resource objects according to resource types.
*/
int acpi_dev_filter_resource_type(struct acpi_resource *ares,
unsigned long types)
{
unsigned long type = 0;
switch (ares->type) {
case ACPI_RESOURCE_TYPE_MEMORY24:
case ACPI_RESOURCE_TYPE_MEMORY32:
case ACPI_RESOURCE_TYPE_FIXED_MEMORY32:
type = IORESOURCE_MEM;
break;
case ACPI_RESOURCE_TYPE_IO:
case ACPI_RESOURCE_TYPE_FIXED_IO:
type = IORESOURCE_IO;
break;
case ACPI_RESOURCE_TYPE_IRQ:
case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
type = IORESOURCE_IRQ;
break;
case ACPI_RESOURCE_TYPE_DMA:
case ACPI_RESOURCE_TYPE_FIXED_DMA:
type = IORESOURCE_DMA;
break;
case ACPI_RESOURCE_TYPE_GENERIC_REGISTER:
type = IORESOURCE_REG;
break;
case ACPI_RESOURCE_TYPE_ADDRESS16:
case ACPI_RESOURCE_TYPE_ADDRESS32:
case ACPI_RESOURCE_TYPE_ADDRESS64:
case ACPI_RESOURCE_TYPE_EXTENDED_ADDRESS64:
if (ares->data.address.resource_type == ACPI_MEMORY_RANGE)
type = IORESOURCE_MEM;
else if (ares->data.address.resource_type == ACPI_IO_RANGE)
type = IORESOURCE_IO;
else if (ares->data.address.resource_type ==
ACPI_BUS_NUMBER_RANGE)
type = IORESOURCE_BUS;
break;
default:
break;
}
return (type & types) ? 0 : 1;
}
EXPORT_SYMBOL_GPL(acpi_dev_filter_resource_type);
struct reserved_region {
struct list_head node;
u64 start;
u64 end;
};
static LIST_HEAD(reserved_io_regions);
static LIST_HEAD(reserved_mem_regions);
static int request_range(u64 start, u64 end, u8 space_id, unsigned long flags,
char *desc)
{
unsigned int length = end - start + 1;
struct resource *res;
res = space_id == ACPI_ADR_SPACE_SYSTEM_IO ?
request_region(start, length, desc) :
request_mem_region(start, length, desc);
if (!res)
return -EIO;
res->flags &= ~flags;
return 0;
}
static int add_region_before(u64 start, u64 end, u8 space_id,
unsigned long flags, char *desc,
struct list_head *head)
{
struct reserved_region *reg;
int error;
reg = kmalloc(sizeof(*reg), GFP_KERNEL);
if (!reg)
return -ENOMEM;
error = request_range(start, end, space_id, flags, desc);
if (error)
return error;
reg->start = start;
reg->end = end;
list_add_tail(&reg->node, head);
return 0;
}
/**
* acpi_reserve_region - Reserve an I/O or memory region as a system resource.
* @start: Starting address of the region.
* @length: Length of the region.
* @space_id: Identifier of address space to reserve the region from.
* @flags: Resource flags to clear for the region after requesting it.
* @desc: Region description (for messages).
*
* Reserve an I/O or memory region as a system resource to prevent others from
* using it. If the new region overlaps with one of the regions (in the given
* address space) already reserved by this routine, only the non-overlapping
* parts of it will be reserved.
*
* Returned is either 0 (success) or a negative error code indicating a resource
* reservation problem. It is the code of the first encountered error, but the
* routine doesn't abort until it has attempted to request all of the parts of
* the new region that don't overlap with other regions reserved previously.
*
* The resources requested by this routine are never released.
*/
int acpi_reserve_region(u64 start, unsigned int length, u8 space_id,
unsigned long flags, char *desc)
{
struct list_head *regions;
struct reserved_region *reg;
u64 end = start + length - 1;
int ret = 0, error = 0;
if (space_id == ACPI_ADR_SPACE_SYSTEM_IO)
regions = &reserved_io_regions;
else if (space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
regions = &reserved_mem_regions;
else
return -EINVAL;
if (list_empty(regions))
return add_region_before(start, end, space_id, flags, desc, regions);
list_for_each_entry(reg, regions, node)
if (reg->start == end + 1) {
/* The new region can be prepended to this one. */
ret = request_range(start, end, space_id, flags, desc);
if (!ret)
reg->start = start;
return ret;
} else if (reg->start > end) {
/* No overlap. Add the new region here and get out. */
return add_region_before(start, end, space_id, flags,
desc, &reg->node);
} else if (reg->end == start - 1) {
goto combine;
} else if (reg->end >= start) {
goto overlap;
}
/* The new region goes after the last existing one. */
return add_region_before(start, end, space_id, flags, desc, regions);
overlap:
/*
* The new region overlaps an existing one.
*
* The head part of the new region immediately preceding the existing
* overlapping one can be combined with it right away.
*/
if (reg->start > start) {
error = request_range(start, reg->start - 1, space_id, flags, desc);
if (error)
ret = error;
else
reg->start = start;
}
combine:
/*
* The new region is adjacent to an existing one. If it extends beyond
* that region all the way to the next one, it is possible to combine
* all three of them.
*/
while (reg->end < end) {
struct reserved_region *next = NULL;
u64 a = reg->end + 1, b = end;
if (!list_is_last(&reg->node, regions)) {
next = list_next_entry(reg, node);
if (next->start <= end)
b = next->start - 1;
}
error = request_range(a, b, space_id, flags, desc);
if (!error) {
if (next && next->start == b + 1) {
reg->end = next->end;
list_del(&next->node);
kfree(next);
} else {
reg->end = end;
break;
}
} else if (next) {
if (!ret)
ret = error;
reg = next;
} else {
break;
}
}
return ret ? ret : error;
}
EXPORT_SYMBOL_GPL(acpi_reserve_region);