xref: /kvm-unit-tests/lib/acpi.c (revision 74e927c7bdc651d59fcf83d33d4aea14f8b67869)

#include "libcflat.h"
#include "acpi.h"

#ifdef CONFIG_EFI
struct acpi_table_rsdp *efi_rsdp = NULL;

void set_efi_rsdp(struct acpi_table_rsdp *rsdp)
{
	efi_rsdp = rsdp;
}

static struct acpi_table_rsdp *get_rsdp(void)
{
	if (efi_rsdp == NULL)
		printf("Can't find RSDP from UEFI, maybe set_efi_rsdp() was not called\n");

	return efi_rsdp;
}
#else
static struct acpi_table_rsdp *get_rsdp(void)
{
	struct acpi_table_rsdp *rsdp;
	unsigned long addr;

	for (addr = 0xe0000; addr < 0x100000; addr += 16) {
		rsdp = (void *)addr;
		if (rsdp->signature == RSDP_SIGNATURE_8BYTE)
			break;
	}

	if (addr == 0x100000)
		return NULL;

	return rsdp;
}
#endif /* CONFIG_EFI */

void *find_acpi_table_addr(u32 sig)
{
	struct acpi_table_rsdt_rev1 *rsdt = NULL;
	struct acpi_table_xsdt *xsdt = NULL;
	struct acpi_table_rsdp *rsdp;
	void *end;
	int i;

	/* FACS is special... */
	if (sig == FACS_SIGNATURE) {
		struct acpi_table_fadt_rev1 *fadt;

		fadt = find_acpi_table_addr(FACP_SIGNATURE);
		if (!fadt)
			return NULL;
		return (void *)(ulong) fadt->firmware_ctrl;
	}

	rsdp = get_rsdp();
	if (rsdp == NULL) {
		printf("Can't find RSDP\n");
		return NULL;
	}

	if (sig == RSDP_SIGNATURE)
		return rsdp;

	rsdt = (void *)(ulong) rsdp->rsdt_physical_address;
	if (rsdt && rsdt->signature != RSDT_SIGNATURE)
		rsdt = NULL;

	if (sig == RSDT_SIGNATURE)
		return rsdt;

	if (rsdp->revision >= 2) {
		xsdt = (void *)(ulong) rsdp->xsdt_physical_address;
		if (xsdt && xsdt->signature != XSDT_SIGNATURE)
			xsdt = NULL;
	}

	if (sig == XSDT_SIGNATURE)
		return xsdt;

	/*
	 * When the system implements APCI 2.0 and above and XSDT is valid we
	 * have use XSDT to find other ACPI tables, otherwise, we use RSDT.
	 */
	if (xsdt) {
		end = (void *)xsdt + xsdt->length;
		for (i = 0; (void *)&xsdt->table_offset_entry[i] < end; i++) {
			struct acpi_table *t = (void *)(ulong) xsdt->table_offset_entry[i];

			if (t && t->signature == sig)
				return t;
		}
	} else if (rsdt) {
		end = (void *)rsdt + rsdt->length;
		for (i = 0; (void *)&rsdt->table_offset_entry[i] < end; i++) {
			struct acpi_table *t = (void *)(ulong) rsdt->table_offset_entry[i];

			if (t && t->signature == sig)
				return t;
		}
	}

	return NULL;
}