From 2de4744dae572b6ba9c1c3e3a40b377e53994630 Mon Sep 17 00:00:00 2001 From: Simon Glass Date: Wed, 4 Nov 2020 09:57:31 -0700 Subject: [PATCH] x86: acpi: Allow the SSDT to be empty If there is nothing in the SSDT we should not include it in the tables. Update the implementation to check this. Signed-off-by: Simon Glass Reviewed-by: Bin Meng --- arch/x86/lib/acpi_table.c | 22 +++++++++++++++------- 1 file changed, 15 insertions(+), 7 deletions(-) diff --git a/arch/x86/lib/acpi_table.c b/arch/x86/lib/acpi_table.c index f0f342d..c5c5c6e 100644 --- a/arch/x86/lib/acpi_table.c +++ b/arch/x86/lib/acpi_table.c @@ -470,8 +470,9 @@ static void acpi_create_spcr(struct acpi_spcr *spcr) header->checksum = table_compute_checksum((void *)spcr, header->length); } -void acpi_create_ssdt(struct acpi_ctx *ctx, struct acpi_table_header *ssdt, - const char *oem_table_id) +static int acpi_create_ssdt(struct acpi_ctx *ctx, + struct acpi_table_header *ssdt, + const char *oem_table_id) { memset((void *)ssdt, '\0', sizeof(struct acpi_table_header)); @@ -484,9 +485,19 @@ void acpi_create_ssdt(struct acpi_ctx *ctx, struct acpi_table_header *ssdt, acpi_fill_ssdt(ctx); - /* (Re)calculate length and checksum. */ + /* (Re)calculate length and checksum */ ssdt->length = ctx->current - (void *)ssdt; ssdt->checksum = table_compute_checksum((void *)ssdt, ssdt->length); + log_debug("SSDT at %p, length %x\n", ssdt, ssdt->length); + + /* Drop the table if it is empty */ + if (ssdt->length == sizeof(struct acpi_table_header)) { + ctx->current = ssdt; + return -ENOENT; + } + acpi_align(ctx); + + return 0; } /* @@ -596,11 +607,8 @@ ulong write_acpi_tables(ulong start_addr) debug("ACPI: * SSDT\n"); ssdt = (struct acpi_table_header *)ctx->current; - acpi_create_ssdt(ctx, ssdt, OEM_TABLE_ID); - if (ssdt->length > sizeof(struct acpi_table_header)) { - acpi_inc_align(ctx, ssdt->length); + if (!acpi_create_ssdt(ctx, ssdt, OEM_TABLE_ID)) acpi_add_table(ctx, ssdt); - } debug("ACPI: * MCFG\n"); mcfg = ctx->current; -- 2.7.4