diff options
Diffstat (limited to 'kernel/drivers/acpi/resource.c')
| -rw-r--r-- | kernel/drivers/acpi/resource.c | 783 |
1 files changed, 783 insertions, 0 deletions
diff --git a/kernel/drivers/acpi/resource.c b/kernel/drivers/acpi/resource.c new file mode 100644 index 000000000..fcb7807ea --- /dev/null +++ b/kernel/drivers/acpi/resource.c @@ -0,0 +1,783 @@ +/* + * 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(®->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, ®->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(®->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); |