/* SPDX-License-Identifier: GPL-2.0-only */ #include #include #include #include static const char *resource2str(const struct resource *res) { if (res->flags & IORESOURCE_IO) return "io"; if (res->flags & IORESOURCE_PREFETCH) return "prefmem"; if (res->flags & IORESOURCE_MEM) return "mem"; return "undefined"; } static bool dev_has_children(const struct device *dev) { const struct bus *bus = dev->link_list; return bus && bus->children; } #define res_printk(depth, str, ...) printk(BIOS_DEBUG, "%*c"str, depth, ' ', __VA_ARGS__) /* * During pass 1, once all the requirements for downstream devices of a * bridge are gathered, this function calculates the overall resource * requirement for the bridge. It starts by picking the largest resource * requirement downstream for the given resource type and works by * adding requirements in descending order. * * Additionally, it takes alignment and limits of the downstream devices * into consideration and ensures that they get propagated to the bridge * resource. This is required to guarantee that the upstream bridge/ * domain honors the limit and alignment requirements for this bridge * based on the tightest constraints downstream. */ static void update_bridge_resource(const struct device *bridge, struct resource *bridge_res, unsigned long type_match, int print_depth) { const struct device *child; struct resource *child_res; resource_t base; const unsigned long type_mask = IORESOURCE_TYPE_MASK | IORESOURCE_PREFETCH; struct bus *bus = bridge->link_list; child_res = NULL; /* * `base` keeps track of where the next allocation for child resources * can take place from within the bridge resource window. Since the * bridge resource window allocation is not performed yet, it can start * at 0. Base gets updated every time a resource requirement is * accounted for in the loop below. After scanning all these resources, * base will indicate the total size requirement for the current bridge * resource window. */ base = 0; res_printk(print_depth, "%s %s: size: %llx align: %d gran: %d limit: %llx\n", dev_path(bridge), resource2str(bridge_res), bridge_res->size, bridge_res->align, bridge_res->gran, bridge_res->limit); while ((child = largest_resource(bus, &child_res, type_mask, type_match))) { /* Size 0 resources can be skipped. */ if (!child_res->size) continue; /* * Propagate the resource alignment to the bridge resource. The * condition can only be true for the first (largest) resource. For all * other children resources, alignment is taken care of by updating the * base to round up as per the child resource alignment. It is * guaranteed that pass 2 follows the exact same method of picking the * resource for allocation using largest_resource(). Thus, as long as * the alignment for the largest child resource is propagated up to the * bridge resource, it can be guaranteed that the alignment for all * resources is appropriately met. */ if (child_res->align > bridge_res->align) bridge_res->align = child_res->align; /* * Propagate the resource limit to the bridge resource only if child * resource limit is non-zero. If a downstream device has stricter * requirements w.r.t. limits for any resource, that constraint needs to * be propagated back up to the downstream bridges of the domain. This * guarantees that the resource allocation which starts at the domain * level takes into account all these constraints thus working on a * global view. */ if (child_res->limit && (child_res->limit < bridge_res->limit)) bridge_res->limit = child_res->limit; /* * Propagate the downstream resource request to allocate above 4G * boundary to upstream bridge resource. This ensures that during * pass 2, the resource allocator at domain level has a global view * of all the downstream device requirements and thus address space * is allocated as per updated flags in the bridge resource. * * Since the bridge resource is a single window, all the downstream * resources of this bridge resource will be allocated in space above * the 4G boundary. */ if (child_res->flags & IORESOURCE_ABOVE_4G) bridge_res->flags |= IORESOURCE_ABOVE_4G; /* * Alignment value of 0 means that the child resource has no alignment * requirements and so the base value remains unchanged here. */ base = ALIGN_UP(base, POWER_OF_2(child_res->align)); res_printk(print_depth + 1, "%s %02lx * [0x%llx - 0x%llx] %s\n", dev_path(child), child_res->index, base, base + child_res->size - 1, resource2str(child_res)); base += child_res->size; } /* * After all downstream device resources are scanned, `base` represents * the total size requirement for the current bridge resource window. * This size needs to be rounded up to the granularity requirement of * the bridge to ensure that the upstream bridge/domain allocates big * enough window. */ bridge_res->size = ALIGN_UP(base, POWER_OF_2(bridge_res->gran)); res_printk(print_depth, "%s %s: size: %llx align: %d gran: %d limit: %llx done\n", dev_path(bridge), resource2str(bridge_res), bridge_res->size, bridge_res->align, bridge_res->gran, bridge_res->limit); } /* * During pass 1, at the bridge level, the resource allocator gathers * requirements from downstream devices and updates its own resource * windows for the provided resource type. */ static void compute_bridge_resources(const struct device *bridge, unsigned long type_match, int print_depth) { const struct device *child; struct resource *res; struct bus *bus = bridge->link_list; const unsigned long type_mask = IORESOURCE_TYPE_MASK | IORESOURCE_PREFETCH; for (res = bridge->resource_list; res; res = res->next) { if (!(res->flags & IORESOURCE_BRIDGE)) continue; if ((res->flags & type_mask) != type_match) continue; /* * Ensure that the resource requirements for all downstream bridges are * gathered before updating the window for current bridge resource. */ for (child = bus->children; child; child = child->sibling) { if (!dev_has_children(child)) continue; compute_bridge_resources(child, type_match, print_depth + 1); } /* * Update the window for current bridge resource now that all downstream * requirements are gathered. */ update_bridge_resource(bridge, res, type_match, print_depth); } } /* * During pass 1, the resource allocator walks down the entire sub-tree * of a domain. It gathers resource requirements for every downstream * bridge by looking at the resource requests of its children. Thus, the * requirement gathering begins at the leaf devices and is propagated * back up to the downstream bridges of the domain. * * At the domain level, it identifies every downstream bridge and walks * down that bridge to gather requirements for each resource type i.e. * i/o, mem and prefmem. Since bridges have separate windows for mem and * prefmem, requirements for each need to be collected separately. * * Domain resource windows are fixed ranges and hence requirement * gathering does not result in any changes to these fixed ranges. */ static void compute_domain_resources(const struct device *domain) { const struct device *child; const int print_depth = 1; if (domain->link_list == NULL) return; for (child = domain->link_list->children; child; child = child->sibling) { /* Skip if this is not a bridge or has no children under it. */ if (!dev_has_children(child)) continue; compute_bridge_resources(child, IORESOURCE_IO, print_depth); compute_bridge_resources(child, IORESOURCE_MEM, print_depth); compute_bridge_resources(child, IORESOURCE_MEM | IORESOURCE_PREFETCH, print_depth); } } static unsigned char get_alignment_by_resource_type(const struct resource *res) { if (res->flags & IORESOURCE_MEM) return 12; /* Page-aligned --> log2(4KiB) */ else if (res->flags & IORESOURCE_IO) return 0; /* No special alignment required --> log2(1) */ die("Unexpected resource type: flags(%d)!\n", res->flags); } /* * If the resource is NULL or if the resource is not assigned, then it * cannot be used for allocation for downstream devices. */ static bool is_resource_invalid(const struct resource *res) { return (res == NULL) || !(res->flags & IORESOURCE_ASSIGNED); } static void initialize_domain_io_resource_memranges(struct memranges *ranges, const struct resource *res, unsigned long memrange_type) { memranges_insert(ranges, res->base, res->limit - res->base + 1, memrange_type); } static void initialize_domain_mem_resource_memranges(struct memranges *ranges, const struct resource *res, unsigned long memrange_type) { resource_t res_base; resource_t res_limit; const resource_t limit_4g = 0xffffffff; res_base = res->base; res_limit = res->limit; /* * Split the resource into two separate ranges if it crosses the 4G * boundary. Memrange type is set differently to ensure that memrange * does not merge these two ranges. For the range above 4G boundary, * given memrange type is ORed with IORESOURCE_ABOVE_4G. */ if (res_base <= limit_4g) { resource_t range_limit; /* Clip the resource limit at 4G boundary if necessary. */ range_limit = MIN(res_limit, limit_4g); memranges_insert(ranges, res_base, range_limit - res_base + 1, memrange_type); /* * If the resource lies completely below the 4G boundary, nothing more * needs to be done. */ if (res_limit <= limit_4g) return; /* * If the resource window crosses the 4G boundary, then update res_base * to add another entry for the range above the boundary. */ res_base = limit_4g + 1; } if (res_base > res_limit) return; /* * If resource lies completely above the 4G boundary or if the resource * was clipped to add two separate ranges, the range above 4G boundary * has the resource flag IORESOURCE_ABOVE_4G set. This allows domain to * handle any downstream requests for resource allocation above 4G * differently. */ memranges_insert(ranges, res_base, res_limit - res_base + 1, memrange_type | IORESOURCE_ABOVE_4G); } /* * This function initializes memranges for domain device. If the * resource crosses 4G boundary, then this function splits it into two * ranges -- one for the window below 4G and the other for the window * above 4G. The latter range has IORESOURCE_ABOVE_4G flag set to * satisfy resource requests from downstream devices for allocations * above 4G. */ static void initialize_domain_memranges(struct memranges *ranges, const struct resource *res, unsigned long memrange_type) { unsigned char align = get_alignment_by_resource_type(res); memranges_init_empty_with_alignment(ranges, NULL, 0, align); if (is_resource_invalid(res)) return; if (res->flags & IORESOURCE_IO) initialize_domain_io_resource_memranges(ranges, res, memrange_type); else initialize_domain_mem_resource_memranges(ranges, res, memrange_type); } /* * This function initializes memranges for bridge device. Unlike domain, * bridge does not need to care about resource window crossing 4G * boundary. This is handled by the resource allocator at domain level * to ensure that all downstream bridges are allocated space either * above or below 4G boundary as per the state of IORESOURCE_ABOVE_4G * for the respective bridge resource. * * So, this function creates a single range of the entire resource * window available for the bridge resource. Thus all downstream * resources of the bridge for the given resource type get allocated * space from the same window. If there is any downstream resource of * the bridge which requests allocation above 4G, then all other * downstream resources of the same type under the bridge get allocated * above 4G. */ static void initialize_bridge_memranges(struct memranges *ranges, const struct resource *res, unsigned long memrange_type) { unsigned char align = get_alignment_by_resource_type(res); memranges_init_empty_with_alignment(ranges, NULL, 0, align); if (is_resource_invalid(res)) return; memranges_insert(ranges, res->base, res->limit - res->base + 1, memrange_type); } static void print_resource_ranges(const struct device *dev, const struct memranges *ranges) { const struct range_entry *r; printk(BIOS_INFO, " %s: Resource ranges:\n", dev_path(dev)); if (memranges_is_empty(ranges)) printk(BIOS_INFO, " * EMPTY!!\n"); memranges_each_entry(r, ranges) { printk(BIOS_INFO, " * Base: %llx, Size: %llx, Tag: %lx\n", range_entry_base(r), range_entry_size(r), range_entry_tag(r)); } } /* * This is where the actual allocation of resources happens during * pass 2. Given the list of memory ranges corresponding to the * resource of given type, it finds the biggest unallocated resource * using the type mask on the downstream bus. This continues in a * descending order until all resources of given type are allocated * address space within the current resource window. */ static void allocate_child_resources(struct bus *bus, struct memranges *ranges, unsigned long type_mask, unsigned long type_match) { struct resource *resource = NULL; const struct device *dev; while ((dev = largest_resource(bus, &resource, type_mask, type_match))) { if (!resource->size) continue; if (memranges_steal(ranges, resource->limit, resource->size, resource->align, type_match, &resource->base) == false) { printk(BIOS_ERR, " ERROR: Resource didn't fit!!! "); printk(BIOS_DEBUG, " %s %02lx * size: 0x%llx limit: %llx %s\n", dev_path(dev), resource->index, resource->size, resource->limit, resource2str(resource)); continue; } resource->limit = resource->base + resource->size - 1; resource->flags |= IORESOURCE_ASSIGNED; printk(BIOS_DEBUG, " %s %02lx * [0x%llx - 0x%llx] limit: %llx %s\n", dev_path(dev), resource->index, resource->base, resource->size ? resource->base + resource->size - 1 : resource->base, resource->limit, resource2str(resource)); } } static void update_constraints(struct memranges *ranges, const struct device *dev, const struct resource *res) { if (!res->size) return; printk(BIOS_DEBUG, " %s: %s %02lx base %08llx limit %08llx %s (fixed)\n", __func__, dev_path(dev), res->index, res->base, res->base + res->size - 1, resource2str(res)); memranges_create_hole(ranges, res->base, res->size); } /* * Scan the entire tree to identify any fixed resources allocated by * any device to ensure that the address map for domain resources are * appropriately updated. * * Domains can typically provide a memrange for entire address space. * So, this function punches holes in the address space for all fixed * resources that are already defined. Both I/O and normal memory * resources are added as fixed. Both need to be removed from address * space where dynamic resource allocations are sourced. */ static void avoid_fixed_resources(struct memranges *ranges, const struct device *dev, unsigned long mask_match) { const struct resource *res; const struct device *child; const struct bus *bus; for (res = dev->resource_list; res != NULL; res = res->next) { if ((res->flags & mask_match) != mask_match) continue; update_constraints(ranges, dev, res); } bus = dev->link_list; if (bus == NULL) return; for (child = bus->children; child != NULL; child = child->sibling) avoid_fixed_resources(ranges, child, mask_match); } static void constrain_domain_resources(const struct device *domain, struct memranges *ranges, unsigned long type) { unsigned long mask_match = type | IORESOURCE_FIXED; if (type == IORESOURCE_IO) { /* * Don't allow allocations in the VGA I/O range. PCI has special * cases for that. */ memranges_create_hole(ranges, 0x3b0, 0x3df - 0x3b0 + 1); /* * Resource allocator no longer supports the legacy behavior where * I/O resource allocation is guaranteed to avoid aliases over legacy * PCI expansion card addresses. */ } avoid_fixed_resources(ranges, domain, mask_match); } /* * This function creates a list of memranges of given type using the * resource that is provided. If the given resource is NULL or if the * resource window size is 0, then it creates an empty list. This * results in resource allocation for that resource type failing for * all downstream devices since there is nothing to allocate from. * * In case of domain, it applies additional constraints to ensure that * the memranges do not overlap any of the fixed resources under that * domain. Domain typically seems to provide memrange for entire address * space. Thus, it is up to the chipset to add DRAM and all other * windows which cannot be used for resource allocation as fixed * resources. */ static void setup_resource_ranges(const struct device *dev, const struct resource *res, unsigned long type, struct memranges *ranges) { printk(BIOS_DEBUG, "%s %s: base: %llx size: %llx align: %d gran: %d limit: %llx\n", dev_path(dev), resource2str(res), res->base, res->size, res->align, res->gran, res->limit); if (dev->path.type == DEVICE_PATH_DOMAIN) { initialize_domain_memranges(ranges, res, type); constrain_domain_resources(dev, ranges, type); } else { initialize_bridge_memranges(ranges, res, type); } print_resource_ranges(dev, ranges); } static void cleanup_resource_ranges(const struct device *dev, struct memranges *ranges, const struct resource *res) { memranges_teardown(ranges); printk(BIOS_DEBUG, "%s %s: base: %llx size: %llx align: %d gran: %d limit: %llx done\n", dev_path(dev), resource2str(res), res->base, res->size, res->align, res->gran, res->limit); } /* * Pass 2 of the resource allocator at the bridge level loops through * all the resources for the bridge and generates a list of memory * ranges similar to that at the domain level. However, there is no need * to apply any additional constraints since the window allocated to the * bridge is guaranteed to be non-overlapping by the allocator at domain * level. * * Allocation at the bridge level works the same as at domain level * (starts with the biggest resource requirement from downstream devices * and continues in descending order). One major difference at the * bridge level is that it considers prefmem resources separately from * mem resources. * * Once allocation at the current bridge is complete, resource allocator * continues walking down the downstream bridges until it hits the leaf * devices. */ static void allocate_bridge_resources(const struct device *bridge) { struct memranges ranges; const struct resource *res; struct bus *bus = bridge->link_list; unsigned long type_match; struct device *child; const unsigned long type_mask = IORESOURCE_TYPE_MASK | IORESOURCE_PREFETCH; for (res = bridge->resource_list; res; res = res->next) { if (!res->size) continue; if (!(res->flags & IORESOURCE_BRIDGE)) continue; type_match = res->flags & type_mask; setup_resource_ranges(bridge, res, type_match, &ranges); allocate_child_resources(bus, &ranges, type_mask, type_match); cleanup_resource_ranges(bridge, &ranges, res); } for (child = bus->children; child; child = child->sibling) { if (!dev_has_children(child)) continue; allocate_bridge_resources(child); } } static const struct resource *find_domain_resource(const struct device *domain, unsigned long type) { const struct resource *res; for (res = domain->resource_list; res; res = res->next) { if (res->flags & IORESOURCE_FIXED) continue; if ((res->flags & IORESOURCE_TYPE_MASK) == type) return res; } return NULL; } /* * Pass 2 of resource allocator begins at the domain level. Every domain * has two types of resources - io and mem. For each of these resources, * this function creates a list of memory ranges that can be used for * downstream resource allocation. This list is constrained to remove * any fixed resources in the domain sub-tree of the given resource * type. It then uses the memory ranges to apply best fit on the * resource requirements of the downstream devices. * * Once resources are allocated to all downstream devices of the domain, * it walks down each downstream bridge to continue the same process * until resources are allocated to all devices under the domain. */ static void allocate_domain_resources(const struct device *domain) { struct memranges ranges; struct device *child; const struct resource *res; /* Resource type I/O */ res = find_domain_resource(domain, IORESOURCE_IO); if (res) { setup_resource_ranges(domain, res, IORESOURCE_IO, &ranges); allocate_child_resources(domain->link_list, &ranges, IORESOURCE_TYPE_MASK, IORESOURCE_IO); cleanup_resource_ranges(domain, &ranges, res); } /* * Resource type Mem: * Domain does not distinguish between mem and prefmem resources. Thus, * the resource allocation at domain level considers mem and prefmem * together when finding the best fit based on the biggest resource * requirement. * * However, resource requests for allocation above 4G boundary need to * be handled separately if the domain resource window crosses this * boundary. There is a single window for resource of type * IORESOURCE_MEM. When creating memranges, this resource is split into * two separate ranges -- one for the window below 4G boundary and other * for the window above 4G boundary (with IORESOURCE_ABOVE_4G flag set). * Thus, when allocating child resources, requests for below and above * the 4G boundary are handled separately by setting the type_mask and * type_match to allocate_child_resources() accordingly. */ res = find_domain_resource(domain, IORESOURCE_MEM); if (res) { setup_resource_ranges(domain, res, IORESOURCE_MEM, &ranges); allocate_child_resources(domain->link_list, &ranges, IORESOURCE_TYPE_MASK | IORESOURCE_ABOVE_4G, IORESOURCE_MEM); allocate_child_resources(domain->link_list, &ranges, IORESOURCE_TYPE_MASK | IORESOURCE_ABOVE_4G, IORESOURCE_MEM | IORESOURCE_ABOVE_4G); cleanup_resource_ranges(domain, &ranges, res); } for (child = domain->link_list->children; child; child = child->sibling) { if (!dev_has_children(child)) continue; /* Continue allocation for all downstream bridges. */ allocate_bridge_resources(child); } } /* * This function forms the guts of the resource allocator. It walks * through the entire device tree for each domain two times. * * Every domain has a fixed set of ranges. These ranges cannot be * relaxed based on the requirements of the downstream devices. They * represent the available windows from which resources can be allocated * to the different devices under the domain. * * In order to identify the requirements of downstream devices, resource * allocator walks in a DFS fashion. It gathers the requirements from * leaf devices and propagates those back up to their upstream bridges * until the requirements for all the downstream devices of the domain * are gathered. This is referred to as pass 1 of the resource allocator. * * Once the requirements for all the devices under the domain are * gathered, the resource allocator walks a second time to allocate * resources to downstream devices as per the requirements. It always * picks the biggest resource request as per the type (i/o and mem) to * allocate space from its fixed window to the immediate downstream * device of the domain. In order to accomplish best fit for the * resources, a list of ranges is maintained by each resource type (i/o * and mem). At the domain level we don't differentiate between mem and * prefmem. Since they are allocated space from the same window, the * resource allocator at the domain level ensures that the biggest * requirement is selected independent of the prefetch type. Once the * resource allocation for all immediate downstream devices is complete * at the domain level, the resource allocator walks down the subtree * for each downstream bridge to continue the allocation process at the * bridge level. Since bridges have separate windows for i/o, mem and * prefmem, best fit algorithm at bridge level looks for the biggest * requirement considering prefmem resources separately from non-prefmem * resources. This continues until resource allocation is performed for * all downstream bridges in the domain sub-tree. This is referred to as * pass 2 of the resource allocator. * * Some rules that are followed by the resource allocator: * - Allocate resource locations for every device as long as * the requirements can be satisfied. * - Don't overlap with resources in fixed locations. * - Don't overlap and follow the rules of bridges -- downstream * devices of bridges should use parts of the address space * allocated to the bridge. */ void allocate_resources(const struct device *root) { const struct device *child; if ((root == NULL) || (root->link_list == NULL)) return; for (child = root->link_list->children; child; child = child->sibling) { if (child->path.type != DEVICE_PATH_DOMAIN) continue; post_log_path(child); /* Pass 1 - Gather requirements. */ printk(BIOS_INFO, "=== Resource allocator: %s - Pass 1 (gathering requirements) ===\n", dev_path(child)); compute_domain_resources(child); /* Pass 2 - Allocate resources as per gathered requirements. */ printk(BIOS_INFO, "=== Resource allocator: %s - Pass 2 (allocating resources) ===\n", dev_path(child)); allocate_domain_resources(child); printk(BIOS_INFO, "=== Resource allocator: %s - resource allocation complete ===\n", dev_path(child)); } }