resource_allocator_common.c

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/* SPDX-License-Identifier: GPL-2.0-only */
 
#include <device/device.h>
 
struct pick_largest_state {
        struct resource *last;
        const struct device *result_dev;
        struct resource *result;
        int seen_last;
};
 
static void pick_largest_resource(void *gp, struct device *dev,
                                  struct resource *resource)
{
        struct pick_largest_state *state = gp;
        struct resource *last;
 
        last = state->last;
 
        /* Be certain to pick the successor to last. */
        if (resource == last) {
                state->seen_last = 1;
                return;
        }
        if (resource->flags & IORESOURCE_FIXED)
                return; /* Skip it. */
        if (last && ((last->align < resource->align) ||
                     ((last->align == resource->align) &&
                      (last->size < resource->size)) ||
                     ((last->align == resource->align) &&
                      (last->size == resource->size) && (!state->seen_last)))) {
                return;
        }
        if (!state->result ||
            (state->result->align < resource->align) ||
            ((state->result->align == resource->align) &&
             (state->result->size < resource->size))) {
                state->result_dev = dev;
                state->result = resource;
        }
}
 
const struct device *largest_resource(struct bus *bus,
                                      struct resource **result_res,
                                      unsigned long type_mask,
                                      unsigned long type)
{
        struct pick_largest_state state;
 
        state.last = *result_res;
        state.result_dev = NULL;
        state.result = NULL;
        state.seen_last = 0;
 
        search_bus_resources(bus, type_mask, type, pick_largest_resource,
                             &state);
 
        *result_res = state.result;
        return state.result_dev;
}