/* SPDX-License-Identifier: GPL-2.0-only */ #include #include #include /** * Round a number up to an alignment. * * @param val The starting value. * @param pow Alignment as a power of two. * @return Rounded up number. */ static resource_t round(resource_t val, unsigned long pow) { resource_t mask; mask = (1ULL << pow) - 1ULL; val += mask; val &= ~mask; return val; } static const char *resource2str(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"; } /** * This function is the guts of the resource allocator. * * The problem. * - Allocate resource locations for every device. * - Don't overlap, and follow the rules of bridges. * - Don't overlap with resources in fixed locations. * - Be efficient so we don't have ugly strategies. * * The strategy. * - Devices that have fixed addresses are the minority so don't * worry about them too much. Instead only use part of the address * space for devices with programmable addresses. This easily handles * everything except bridges. * * - PCI devices are required to have their sizes and their alignments * equal. In this case an optimal solution to the packing problem * exists. Allocate all devices from highest alignment to least * alignment or vice versa. Use this. * * - So we can handle more than PCI run two allocation passes on bridges. The * first to see how large the resources are behind the bridge, and what * their alignment requirements are. The second to assign a safe address to * the devices behind the bridge. This allows us to treat a bridge as just * a device with a couple of resources, and not need to special case it in * the allocator. Also this allows handling of other types of bridges. * * @param bus The bus we are traversing. * @param bridge The bridge resource which must contain the bus' resources. * @param type_mask This value gets ANDed with the resource type. * @param type This value must match the result of the AND. * @return TODO */ static void compute_resources(struct bus *bus, struct resource *bridge, unsigned long type_mask, unsigned long type) { const struct device *dev; struct resource *resource; resource_t base; base = round(bridge->base, bridge->align); if (!bus) return; printk(BIOS_SPEW, "%s %s: base: %llx size: %llx align: %d gran: %d" " limit: %llx\n", dev_path(bus->dev), resource2str(bridge), base, bridge->size, bridge->align, bridge->gran, bridge->limit); /* For each child which is a bridge, compute the resource needs. */ for (dev = bus->children; dev; dev = dev->sibling) { struct resource *child_bridge; if (!dev->link_list) continue; /* Find the resources with matching type flags. */ for (child_bridge = dev->resource_list; child_bridge; child_bridge = child_bridge->next) { struct bus* link; if (!(child_bridge->flags & IORESOURCE_BRIDGE) || (child_bridge->flags & type_mask) != type) continue; /* * Split prefetchable memory if combined. Many domains * use the same address space for prefetchable memory * and non-prefetchable memory. Bridges below them need * it separated. Add the PREFETCH flag to the type_mask * and type. */ link = dev->link_list; while (link && link->link_num != IOINDEX_LINK(child_bridge->index)) link = link->next; if (link == NULL) { printk(BIOS_ERR, "link %ld not found on %s\n", IOINDEX_LINK(child_bridge->index), dev_path(dev)); } compute_resources(link, child_bridge, type_mask | IORESOURCE_PREFETCH, type | (child_bridge->flags & IORESOURCE_PREFETCH)); } } /* Remember we haven't found anything yet. */ resource = NULL; /* * Walk through all the resources on the current bus and compute the * amount of address space taken by them. Take granularity and * alignment into account. */ while ((dev = largest_resource(bus, &resource, type_mask, type))) { /* Size 0 resources can be skipped. */ if (!resource->size) continue; /* Propagate the resource alignment to the bridge resource. */ if (resource->align > bridge->align) bridge->align = resource->align; /* Propagate the resource limit to the bridge register. */ if (bridge->limit > resource->limit) bridge->limit = resource->limit; /* Warn if it looks like APICs aren't declared. */ if ((resource->limit == 0xffffffff) && (resource->flags & IORESOURCE_ASSIGNED)) { printk(BIOS_ERR, "Resource limit looks wrong! (no APIC?)\n"); printk(BIOS_ERR, "%s %02lx limit %08llx\n", dev_path(dev), resource->index, resource->limit); } if (resource->flags & IORESOURCE_IO) { /* * Don't allow potential aliases over the legacy PCI * expansion card addresses. The legacy PCI decodes * only 10 bits, uses 0x100 - 0x3ff. Therefore, only * 0x00 - 0xff can be used out of each 0x400 block of * I/O space. */ if ((base & 0x300) != 0) { base = (base & ~0x3ff) + 0x400; } /* * Don't allow allocations in the VGA I/O range. * PCI has special cases for that. */ else if ((base >= 0x3b0) && (base <= 0x3df)) { base = 0x3e0; } } /* Base must be aligned. */ base = round(base, resource->align); resource->base = base; base += resource->size; printk(BIOS_SPEW, "%s %02lx * [0x%llx - 0x%llx] %s\n", dev_path(dev), resource->index, resource->base, resource->base + resource->size - 1, resource2str(resource)); } /* * A PCI bridge resource does not need to be a power of two size, but * it does have a minimum granularity. Round the size up to that * minimum granularity so we know not to place something else at an * address positively decoded by the bridge. */ bridge->size = round(base, bridge->gran) - round(bridge->base, bridge->align); printk(BIOS_SPEW, "%s %s: base: %llx size: %llx align: %d gran: %d" " limit: %llx done\n", dev_path(bus->dev), resource2str(bridge), base, bridge->size, bridge->align, bridge->gran, bridge->limit); } /** * This function is the second part of the resource allocator. * * See the compute_resources function for a more detailed explanation. * * This function assigns the resources a value. * * @param bus The bus we are traversing. * @param bridge The bridge resource which must contain the bus' resources. * @param type_mask This value gets ANDed with the resource type. * @param type This value must match the result of the AND. * * @see compute_resources */ static void __allocate_resources(struct bus *bus, struct resource *bridge, unsigned long type_mask, unsigned long type) { const struct device *dev; struct resource *resource; resource_t base; base = bridge->base; if (!bus) return; printk(BIOS_SPEW, "%s %s: base:%llx size:%llx align:%d gran:%d " "limit:%llx\n", dev_path(bus->dev), resource2str(bridge), base, bridge->size, bridge->align, bridge->gran, bridge->limit); /* Remember we haven't found anything yet. */ resource = NULL; /* * Walk through all the resources on the current bus and allocate them * address space. */ while ((dev = largest_resource(bus, &resource, type_mask, type))) { /* Propagate the bridge limit to the resource register. */ if (resource->limit > bridge->limit) resource->limit = bridge->limit; /* Size 0 resources can be skipped. */ if (!resource->size) continue; if (resource->flags & IORESOURCE_IO) { /* * Don't allow potential aliases over the legacy PCI * expansion card addresses. The legacy PCI decodes * only 10 bits, uses 0x100 - 0x3ff. Therefore, only * 0x00 - 0xff can be used out of each 0x400 block of * I/O space. */ if ((base & 0x300) != 0) { base = (base & ~0x3ff) + 0x400; } /* * Don't allow allocations in the VGA I/O range. * PCI has special cases for that. */ else if ((base >= 0x3b0) && (base <= 0x3df)) { base = 0x3e0; } } if ((round(base, resource->align) + resource->size - 1) <= resource->limit) { /* Base must be aligned. */ base = round(base, resource->align); resource->base = base; resource->limit = resource->base + resource->size - 1; resource->flags |= IORESOURCE_ASSIGNED; resource->flags &= ~IORESOURCE_STORED; base += resource->size; } else { printk(BIOS_ERR, "!! Resource didn't fit !!\n"); printk(BIOS_ERR, " aligned base %llx size %llx " "limit %llx\n", round(base, resource->align), resource->size, resource->limit); printk(BIOS_ERR, " %llx needs to be <= %llx " "(limit)\n", (round(base, resource->align) + resource->size) - 1, resource->limit); printk(BIOS_ERR, " %s%s %02lx * [0x%llx - 0x%llx]" " %s\n", (resource->flags & IORESOURCE_ASSIGNED) ? "Assigned: " : "", dev_path(dev), resource->index, resource->base, resource->base + resource->size - 1, resource2str(resource)); } printk(BIOS_SPEW, "%s %02lx * [0x%llx - 0x%llx] %s\n", dev_path(dev), resource->index, resource->base, resource->size ? resource->base + resource->size - 1 : resource->base, resource2str(resource)); } /* * A PCI bridge resource does not need to be a power of two size, but * it does have a minimum granularity. Round the size up to that * minimum granularity so we know not to place something else at an * address positively decoded by the bridge. */ bridge->flags |= IORESOURCE_ASSIGNED; printk(BIOS_SPEW, "%s %s: next_base: %llx size: %llx align: %d " "gran: %d done\n", dev_path(bus->dev), resource2str(bridge), base, bridge->size, bridge->align, bridge->gran); /* For each child which is a bridge, __allocate_resources. */ for (dev = bus->children; dev; dev = dev->sibling) { struct resource *child_bridge; if (!dev->link_list) continue; /* Find the resources with matching type flags. */ for (child_bridge = dev->resource_list; child_bridge; child_bridge = child_bridge->next) { struct bus* link; if (!(child_bridge->flags & IORESOURCE_BRIDGE) || (child_bridge->flags & type_mask) != type) continue; /* * Split prefetchable memory if combined. Many domains * use the same address space for prefetchable memory * and non-prefetchable memory. Bridges below them need * it separated. Add the PREFETCH flag to the type_mask * and type. */ link = dev->link_list; while (link && link->link_num != IOINDEX_LINK(child_bridge->index)) link = link->next; if (link == NULL) printk(BIOS_ERR, "link %ld not found on %s\n", IOINDEX_LINK(child_bridge->index), dev_path(dev)); __allocate_resources(link, child_bridge, type_mask | IORESOURCE_PREFETCH, type | (child_bridge->flags & IORESOURCE_PREFETCH)); } } } static int resource_is(struct resource *res, u32 type) { return (res->flags & IORESOURCE_TYPE_MASK) == type; } struct constraints { struct resource io, mem; }; static struct resource *resource_limit(struct constraints *limits, struct resource *res) { struct resource *lim = NULL; /* MEM, or I/O - skip any others. */ if (resource_is(res, IORESOURCE_MEM)) lim = &limits->mem; else if (resource_is(res, IORESOURCE_IO)) lim = &limits->io; return lim; } static void constrain_resources(const struct device *dev, struct constraints* limits) { const struct device *child; struct resource *res; struct resource *lim; struct bus *link; /* Constrain limits based on the fixed resources of this device. */ for (res = dev->resource_list; res; res = res->next) { if (!(res->flags & IORESOURCE_FIXED)) continue; if (!res->size) { /* It makes no sense to have 0-sized, fixed resources.*/ printk(BIOS_ERR, "skipping %s@%lx fixed resource, " "size=0!\n", dev_path(dev), res->index); continue; } lim = resource_limit(limits, res); if (!lim) continue; /* * Is it a fixed resource outside the current known region? * If so, we don't have to consider it - it will be handled * correctly and doesn't affect current region's limits. */ if (((res->base + res->size -1) < lim->base) || (res->base > lim->limit)) continue; printk(BIOS_SPEW, "%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)); /* * Choose to be above or below fixed resources. This check is * signed so that "negative" amounts of space are handled * correctly. */ if ((signed long long)(lim->limit - (res->base + res->size -1)) > (signed long long)(res->base - lim->base)) lim->base = res->base + res->size; else lim->limit = res->base -1; } /* Descend into every enabled child and look for fixed resources. */ for (link = dev->link_list; link; link = link->next) { for (child = link->children; child; child = child->sibling) { if (child->enabled) constrain_resources(child, limits); } } } static void avoid_fixed_resources(const struct device *dev) { struct constraints limits; struct resource *res; struct resource *lim; printk(BIOS_SPEW, "%s: %s\n", __func__, dev_path(dev)); /* Initialize constraints to maximum size. */ limits.io.base = 0; limits.io.limit = 0xffffffffffffffffULL; limits.mem.base = 0; limits.mem.limit = 0xffffffffffffffffULL; /* Constrain the limits to dev's initial resources. */ for (res = dev->resource_list; res; res = res->next) { if ((res->flags & IORESOURCE_FIXED)) continue; printk(BIOS_SPEW, "%s:@%s %02lx limit %08llx\n", __func__, dev_path(dev), res->index, res->limit); lim = resource_limit(&limits, res); if (!lim) continue; if (res->base > lim->base) lim->base = res->base; if (res->limit < lim->limit) lim->limit = res->limit; } /* Look through the tree for fixed resources and update the limits. */ constrain_resources(dev, &limits); /* Update dev's resources with new limits. */ for (res = dev->resource_list; res; res = res->next) { if ((res->flags & IORESOURCE_FIXED)) continue; lim = resource_limit(&limits, res); if (!lim) continue; /* Is the resource outside the limits? */ if (lim->base > res->base) res->base = lim->base; if (res->limit > lim->limit) res->limit = lim->limit; /* MEM resources need to start at the highest address manageable. */ if (res->flags & IORESOURCE_MEM) res->base = resource_max(res); printk(BIOS_SPEW, "%s:@%s %02lx base %08llx limit %08llx\n", __func__, dev_path(dev), res->index, res->base, res->limit); } } void allocate_resources(const struct device *root) { struct resource *res; const struct device *child; /* Compute resources for all domains. */ for (child = root->link_list->children; child; child = child->sibling) { if (!(child->path.type == DEVICE_PATH_DOMAIN)) continue; post_log_path(child); for (res = child->resource_list; res; res = res->next) { if (res->flags & IORESOURCE_FIXED) continue; if (res->flags & IORESOURCE_MEM) { compute_resources(child->link_list, res, IORESOURCE_TYPE_MASK, IORESOURCE_MEM); continue; } if (res->flags & IORESOURCE_IO) { compute_resources(child->link_list, res, IORESOURCE_TYPE_MASK, IORESOURCE_IO); continue; } } } /* For all domains. */ for (child = root->link_list->children; child; child=child->sibling) if (child->path.type == DEVICE_PATH_DOMAIN) avoid_fixed_resources(child); /* Store the computed resource allocations into device registers ... */ printk(BIOS_INFO, "Setting resources...\n"); for (child = root->link_list->children; child; child = child->sibling) { if (!(child->path.type == DEVICE_PATH_DOMAIN)) continue; post_log_path(child); for (res = child->resource_list; res; res = res->next) { if (res->flags & IORESOURCE_FIXED) continue; if (res->flags & IORESOURCE_MEM) { __allocate_resources(child->link_list, res, IORESOURCE_TYPE_MASK, IORESOURCE_MEM); continue; } if (res->flags & IORESOURCE_IO) { __allocate_resources(child->link_list, res, IORESOURCE_TYPE_MASK, IORESOURCE_IO); continue; } } } }