mb/google/brya: Don't add MPTS to both DSDT and SSDT

commit 52ccd293d7 ("mb/google/brya: Implement shutdown function for
dGPU") started unconditionally adding MPTS to the SSDT. On variants
with HAVE_WWAN_POWER_SEQUENCE selected, MPTS is already added to the
DSDT via wwan_power.asl. The duplicate definition results in a kernel
error:
ERR kernel: [    0.109237] ACPI BIOS Error (bug): Failure creating named object [\_SB.MPTS], AE_ALREADY_EXISTS (20210730/dswload2-327)
ERR kernel: [    0.109242] ACPI Error: AE_ALREADY_EXISTS, During name lookup/catalog (20210730/psobject-220)

Don't add MPTS to the SSDT if HAVE_WWAN_POWER_SEQUENCE is selected.
There are no variants which use both, so this should only result in
empty MPTS methods being removed.

BUG=b:260380268
TEST=On pujjo, the SSDT no longer contains an empty MPTS method, there's
no kernel error, and the WWAN power-off sequence is met.

Change-Id: I9f411aae81ea87aa9c8fc7754c3709e398771a32
Signed-off-by: Reka Norman <rekanorman@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70146
Reviewed-by: Kangheui Won <khwon@chromium.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

1 files changed, 31 insertions, 12 deletions

diff --git a/src/mainboard/google/brya/mainboard.c b/src/mainboard/google/brya/mainboard.c
index 4e0cf080d2..966f19eef4 100644
--- a/src/mainboard/google/brya/mainboard.c
+++ b/src/mainboard/google/brya/mainboard.c
@@ -132,6 +132,36 @@ static void mainboard_generate_dgpu_shutdown(const struct device *dev)
 		acpigen_emit_namestring(acpi_device_path_join(parent, "PGPR._OFF"));
 }
 
+static void mainboard_generate_mpts(void)
+{
+	const struct device *wwan = DEV_PTR(rp6_wwan);
+	const struct device *dgpu = DEV_PTR(dgpu);
+
+	/*
+	 * If HAVE_WWAN_POWER_SEQUENCE is selected, MPTS will be added to the
+	 * DSDT via wwan_power.asl. We can't add MPTS to the SSDT as well,
+	 * since the duplicate definition will result in a kernel error.
+	 *
+	 * This special case can be removed in the future if the power-off
+	 * sequences for all WWAN devices used on brya are moved to the SSDT.
+	 */
+	if (CONFIG(HAVE_WWAN_POWER_SEQUENCE)) {
+		if (wwan || dgpu)
+			printk(BIOS_ERR, "Skip adding duplicate MPTS entry to SSDT\n");
+		return;
+	}
+
+	acpigen_write_scope("\\_SB");
+	acpigen_write_method_serialized("MPTS", 1);
+	if (wwan)
+		mainboard_generate_wwan_shutdown(wwan);
+	if (dgpu)
+		mainboard_generate_dgpu_shutdown(dgpu);
+
+	acpigen_write_method_end(); /* Method */
+	acpigen_write_scope_end(); /* Scope */
+}
+
 static void mainboard_generate_s0ix_hook(void)
 {
 	acpigen_write_if_lequal_op_int(ARG0_OP, 1);
@@ -151,18 +181,7 @@ static void mainboard_generate_s0ix_hook(void)
 
 static void mainboard_fill_ssdt(const struct device *dev)
 {
-	const struct device *wwan = DEV_PTR(rp6_wwan);
-	const struct device *dgpu = DEV_PTR(dgpu);
-
-	acpigen_write_scope("\\_SB");
-	acpigen_write_method_serialized("MPTS", 1);
-	if (wwan)
-		mainboard_generate_wwan_shutdown(wwan);
-	if (dgpu)
-		mainboard_generate_dgpu_shutdown(dgpu);
-
-	acpigen_write_method_end(); /* Method */
-	acpigen_write_scope_end(); /* Scope */
+	mainboard_generate_mpts();
 
 	/* for variant to fill additional SSDT */
 	variant_fill_ssdt(dev);