coreboot-kgpe-d16/src/device/resource_allocator_v4.c

686 lines
26 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
#include <console/console.h>
#include <device/device.h>
#include <memrange.h>
#include <post.h>
/**
* 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)
{
return ALIGN_UP(val, POWER_OF_2(pow));
}
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;
bool first_child_res = true;
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 resource 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 if this is the first
* child resource with non-zero size being considered. 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 first child resource
* is propagated up to the bridge resource, it can be guaranteed that the
* alignment for all resources is appropriately met.
*/
if (first_child_res && (child_res->align > bridge_res->align))
bridge_res->align = child_res->align;
first_child_res = false;
/*
* 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 space above 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 = round(base, 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 = round(base, 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, resource allocator at bridge level 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, 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 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 memrange for entire address space. So, this function
* punches holes in the address space for all fixed resources that are already
* defined. Both IO 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 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 resource allocator.
*
* Once the requirements for all the devices under the domain are gathered, 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). Domain does not 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 indepedent of the prefetch type. Once the
* resource allocation for all immediate downstream devices is complete at the domain level,
* 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 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.
* - If a resource cannot be allocated any address space, then that resource needs to be
* properly updated to ensure that it does not incorrectly overlap some address space reserved
* for a different purpose.
* - 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));
}
}