// SPDX-License-Identifier: GPL-2.0
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#include <linux/ioport.h>
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#include <asm/e820/api.h>
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static void resource_clip(struct resource *res, resource_size_t start,
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resource_size_t end)
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{
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resource_size_t low = 0, high = 0;
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if (res->end < start || res->start > end)
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return; /* no conflict */
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if (res->start < start)
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low = start - res->start;
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if (res->end > end)
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high = res->end - end;
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/* Keep the area above or below the conflict, whichever is larger */
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if (low > high)
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res->end = start - 1;
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else
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res->start = end + 1;
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}
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static void remove_e820_regions(struct resource *avail)
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{
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int i;
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struct e820_entry *entry;
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for (i = 0; i < e820_table->nr_entries; i++) {
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entry = &e820_table->entries[i];
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resource_clip(avail, entry->addr,
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entry->addr + entry->size - 1);
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}
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}
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void arch_remove_reservations(struct resource *avail)
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{
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/*
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* Trim out BIOS area (high 2MB) and E820 regions. We do not remove
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* the low 1MB unconditionally, as this area is needed for some ISA
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* cards requiring a memory range, e.g. the i82365 PCMCIA controller.
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*/
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if (avail->flags & IORESOURCE_MEM) {
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resource_clip(avail, BIOS_ROM_BASE, BIOS_ROM_END);
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remove_e820_regions(avail);
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}
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}
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