// SPDX-License-Identifier: GPL-2.0-only /* * drivers/acpi/resource.c - ACPI device resources interpretation. * * Copyright (C) 2012, Intel Corp. * Author: Rafael J. Wysocki * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ * * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ */ #include #include #include #include #include #include #include #ifdef CONFIG_X86 #define valid_IRQ(i) (((i) != 0) && ((i) != 2)) static inline bool acpi_iospace_resource_valid(struct resource *res) { /* On X86 IO space is limited to the [0 - 64K] IO port range */ return res->end < 0x10003; } #else #define valid_IRQ(i) (true) /* * ACPI IO descriptors on arches other than X86 contain MMIO CPU physical * addresses mapping IO space in CPU physical address space, IO space * resources can be placed anywhere in the 64-bit physical address space. */ static inline bool acpi_iospace_resource_valid(struct resource *res) { return true; } #endif #if IS_ENABLED(CONFIG_ACPI_GENERIC_GSI) static inline bool is_gsi(struct acpi_resource_extended_irq *ext_irq) { return ext_irq->resource_source.string_length == 0 && ext_irq->producer_consumer == ACPI_CONSUMER; } #else static inline bool is_gsi(struct acpi_resource_extended_irq *ext_irq) { return 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, u8 translation_type) { res->flags = IORESOURCE_IO; if (!acpi_dev_resource_len_valid(res->start, res->end, len, true)) res->flags |= IORESOURCE_DISABLED | IORESOURCE_UNSET; if (!acpi_iospace_resource_valid(res)) res->flags |= IORESOURCE_DISABLED | IORESOURCE_UNSET; if (io_decode == ACPI_DECODE_16) res->flags |= IORESOURCE_IO_16BIT_ADDR; if (translation_type == ACPI_SPARSE_TRANSLATION) res->flags |= IORESOURCE_IO_SPARSE; } 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, 0); } /** * 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; u64 start, end, offset = 0; 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); /* * 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) offset = attr->translation_offset; else if (attr->translation_offset) pr_debug("ACPI: translation_offset(%lld) is invalid for non-bridge device.\n", attr->translation_offset); start = attr->minimum + offset; end = attr->maximum + offset; win->offset = offset; res->start = start; res->end = end; if (sizeof(resource_size_t) < sizeof(u64) && (offset != win->offset || start != res->start || end != res->end)) { pr_warn("acpi resource window ([%#llx-%#llx] ignored, not CPU addressable)\n", attr->minimum, attr->maximum); return false; } 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, addr->info.io.translation_type); break; case ACPI_BUS_NUMBER_RANGE: res->flags = IORESOURCE_BUS; break; default: return false; } 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); /** * acpi_dev_get_irq_type - Determine irq type. * @triggering: Triggering type as provided by ACPI. * @polarity: Interrupt polarity as provided by ACPI. */ unsigned int acpi_dev_get_irq_type(int triggering, int polarity) { switch (polarity) { case ACPI_ACTIVE_LOW: return triggering == ACPI_EDGE_SENSITIVE ? IRQ_TYPE_EDGE_FALLING : IRQ_TYPE_LEVEL_LOW; case ACPI_ACTIVE_HIGH: return triggering == ACPI_EDGE_SENSITIVE ? IRQ_TYPE_EDGE_RISING : IRQ_TYPE_LEVEL_HIGH; case ACPI_ACTIVE_BOTH: if (triggering == ACPI_EDGE_SENSITIVE) return IRQ_TYPE_EDGE_BOTH; fallthrough; default: return IRQ_TYPE_NONE; } } EXPORT_SYMBOL_GPL(acpi_dev_get_irq_type); static const struct dmi_system_id medion_laptop[] = { { .ident = "MEDION P15651", .matches = { DMI_MATCH(DMI_SYS_VENDOR, "MEDION"), DMI_MATCH(DMI_BOARD_NAME, "M15T"), }, }, { .ident = "MEDION S17405", .matches = { DMI_MATCH(DMI_SYS_VENDOR, "MEDION"), DMI_MATCH(DMI_BOARD_NAME, "M17T"), }, }, { } }; struct irq_override_cmp { const struct dmi_system_id *system; unsigned char irq; unsigned char triggering; unsigned char polarity; unsigned char shareable; }; static const struct irq_override_cmp skip_override_table[] = { { medion_laptop, 1, ACPI_LEVEL_SENSITIVE, ACPI_ACTIVE_LOW, 0 }, }; static bool acpi_dev_irq_override(u32 gsi, u8 triggering, u8 polarity, u8 shareable) { int i; #ifdef CONFIG_X86 /* * IRQ override isn't needed on modern AMD Zen systems and * this override breaks active low IRQs on AMD Ryzen 6000 and * newer systems. Skip it. */ if (boot_cpu_has(X86_FEATURE_ZEN)) return false; #endif for (i = 0; i < ARRAY_SIZE(skip_override_table); i++) { const struct irq_override_cmp *entry = &skip_override_table[i]; if (dmi_check_system(entry->system) && entry->irq == gsi && entry->triggering == triggering && entry->polarity == polarity && entry->shareable == shareable) return false; } return true; } static void acpi_dev_get_irqresource(struct resource *res, u32 gsi, u8 triggering, u8 polarity, u8 shareable, bool check_override) { int irq, p, t; if (!valid_IRQ(gsi)) { irqresource_disabled(res, gsi); return; } /* * In IO-APIC mode, use overridden 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 (check_override && acpi_dev_irq_override(gsi, triggering, polarity, shareable) && !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_warn("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 { 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) { irqresource_disabled(res, 0); return false; } acpi_dev_get_irqresource(res, irq->interrupts[index], irq->triggering, irq->polarity, irq->shareable, true); break; case ACPI_RESOURCE_TYPE_EXTENDED_IRQ: ext_irq = &ares->data.extended_irq; if (index >= ext_irq->interrupt_count) { irqresource_disabled(res, 0); return false; } if (is_gsi(ext_irq)) acpi_dev_get_irqresource(res, ext_irq->interrupts[index], ext_irq->triggering, ext_irq->polarity, ext_irq->shareable, false); else irqresource_disabled(res, 0); 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_ABORT_METHOD; } 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; } static int __acpi_dev_get_resources(struct acpi_device *adev, struct list_head *list, int (*preproc)(struct acpi_resource *, void *), void *preproc_data, char *method) { struct res_proc_context c; acpi_status status; if (!adev || !adev->handle || !list_empty(list)) return -EINVAL; if (!acpi_has_method(adev->handle, method)) 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, acpi_dev_process_resource, &c); if (ACPI_FAILURE(status)) { acpi_dev_free_resource_list(list); return c.error ? c.error : -EIO; } return c.count; } /** * 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() routine 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) { return __acpi_dev_get_resources(adev, list, preproc, preproc_data, METHOD_NAME__CRS); } EXPORT_SYMBOL_GPL(acpi_dev_get_resources); static int is_memory(struct acpi_resource *ares, void *not_used) { struct resource_win win; struct resource *res = &win.res; memset(&win, 0, sizeof(win)); return !(acpi_dev_resource_memory(ares, res) || acpi_dev_resource_address_space(ares, &win) || acpi_dev_resource_ext_address_space(ares, &win)); } /** * acpi_dev_get_dma_resources - Get current DMA resources of a device. * @adev: ACPI device node to get the resources for. * @list: Head of the resultant list of resources (must be empty). * * Evaluate the _DMA method for the given device node and process its * output. * * 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_dma_resources(struct acpi_device *adev, struct list_head *list) { return __acpi_dev_get_resources(adev, list, is_memory, NULL, METHOD_NAME__DMA); } EXPORT_SYMBOL_GPL(acpi_dev_get_dma_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); static int acpi_dev_consumes_res(struct acpi_device *adev, struct resource *res) { struct list_head resource_list; struct resource_entry *rentry; int ret, found = 0; INIT_LIST_HEAD(&resource_list); ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL); if (ret < 0) return 0; list_for_each_entry(rentry, &resource_list, node) { if (resource_contains(rentry->res, res)) { found = 1; break; } } acpi_dev_free_resource_list(&resource_list); return found; } static acpi_status acpi_res_consumer_cb(acpi_handle handle, u32 depth, void *context, void **ret) { struct resource *res = context; struct acpi_device **consumer = (struct acpi_device **) ret; struct acpi_device *adev = acpi_fetch_acpi_dev(handle); if (!adev) return AE_OK; if (acpi_dev_consumes_res(adev, res)) { *consumer = adev; return AE_CTRL_TERMINATE; } return AE_OK; } /** * acpi_resource_consumer - Find the ACPI device that consumes @res. * @res: Resource to search for. * * Search the current resource settings (_CRS) of every ACPI device node * for @res. If we find an ACPI device whose _CRS includes @res, return * it. Otherwise, return NULL. */ struct acpi_device *acpi_resource_consumer(struct resource *res) { struct acpi_device *consumer = NULL; acpi_get_devices(NULL, acpi_res_consumer_cb, res, (void **) &consumer); return consumer; }