drm/asahi, drm/apple: J813 (M5 MacBook Air) GPU and display on the macOS 27.2 firmware

arch/arm64/boot/dts/apple/t8142-j813-gpu.dtsi

@@ -33,6 +33,18 @@
 			reg = <0x100 0x02444000 0x0 0x184000>;
 		};
 
+		/*
+		 * Both roles' __TEXT, contiguous (ADT gfx-asc and gfx1-asc segment-ranges),
+		 * which the driver identifies before it starts the firmware. Fixed at the
+		 * macOS 27.0 address like fw-data, until the bootloader fills it in; under
+		 * 27.2 (26B123) iBoot loads it at 0x100_00e5_4000 and the DATA at
+		 * 0x100_0245_8000.
+		 */
+		gpu_fw_text: fw-text {
+			reg = <0x100 0x00e44000 0x0 0x9c000>;
+			no-map;
+		};
+
 		uat_handoff: uat-handoff {
 			reg = <0 0 0 0>;
 		};
@@ -105,9 +117,10 @@
 		power-domains = <&ps_gfx>;
 		memory-region = <&uat_ttbs>, <&uat_pagetables>, <&uat_handoff>,
 				<&uat_l2_pagetables>, <&gfx_data>, <&gfx1_data>,
-				<&gpu_fw_data>;
+				<&gpu_fw_data>, <&gpu_fw_text>;
 		memory-region-names = "ttbs", "pagetables", "handoff",
-				      "shared-l2", "gfx-data", "gfx1-data", "fw-data";
+				      "shared-l2", "gfx-data", "gfx1-data", "fw-data",
+				      "fw-text";
 		operating-points-v2 = <&gpu_opp>;
 		/* Holds the DCS and fabric floor while GPU work is in flight. */
 		apple,clpc = <&clpc>;

drivers/gpu/drm/apple/dcp.c

@@ -5260,11 +5260,12 @@ static enum dcp_firmware_version dcp_check_firmware_version(struct device *dev)
 	 * T8142 (J813) on macOS 27.0: the H17P interface written for its 26.x
 	 * firmware makes the 27.0 DCP firmware panic right after the first
 	 * hotplug ("ap_link: callback failed with: 0x5"). It runs the T6050's
-	 * firmware-27 generation.
+	 * firmware-27 generation, and so does 27.2, with the 27.2 method table.
 	 */
 	if (of_device_is_compatible(dev->of_node, "apple,t8142-dcp")) {
 		ret = dcp_read_fw_version(dev, "apple,firmware-compat", compat_str);
-		if (ret >= 0 && !strcmp(compat_str, "27.0.0"))
+		if (ret >= 0 && (!strcmp(compat_str, "27.0.0") ||
+				 !strcmp(compat_str, "27.2.0")))
 			return DCP_FIRMWARE_V_27_0;
 	}
 

drivers/gpu/drm/apple/iomfb_v27.c

@@ -119,9 +119,9 @@ static const struct dcp_method_entry dcp_methods_27_0[dcpep_num_methods] = {
  * A400/A401, so IOMobileFramebufferAP moved up by 50 (start_signal A451,
  * get_color_remap_mode A477), and set_create_DFB and vi_set_temperature_hint
  * up by one. The UPPipe A0xx and A1xx IDs are unchanged. The firmware rejects
- * an unknown tag with a panic ("link_rpc_lookup callback not found"), so
- * dfb_ready_query, whose 27.2 tag has not been seen in a call, has no entry
- * here and is not sent to this build (boot_5()).
+ * an unknown tag with a panic ("link_rpc_lookup callback not found").
+ * dfb_ready_query is A385, one above its 27.0 ID: the 27.3 trace sends it
+ * there, and the J813's DCP answers it at A385 on 27.2.
  */
 static const struct dcp_method_entry dcp_methods_27_2[dcpep_num_methods] = {
 	IOMFB_METHOD("A000", dcpep_late_init_signal),
@@ -147,6 +147,7 @@ static const struct dcp_method_entry dcp_methods_27_2[dcpep_num_methods] = {
 	IOMFB_METHOD("A104", dcpep_set_dfb_dimensions),
 	IOMFB_METHOD("A105", dcpep_commit_dfb_info),
 	IOMFB_METHOD("A035", dcpep_dfb_query),
+	IOMFB_METHOD("A385", dcpep_dfb_ready_query),
 	IOMFB_METHOD("A353", dcpep_pipe_query_353),
 	IOMFB_METHOD("A352", dcpep_pipe_set_352),
 	IOMFB_METHOD("A465", dcpep_pipe_cfg_415),

drivers/gpu/drm/asahi/fwid.rs

@@ -585,4 +585,32 @@ mod tests {
             assert!(admit(t, d, &e[..1], h).is_none());
         }
     }
+
+    #[test]
+    fn t8142_identifies_each_build() {
+        use crate::g17::fw::m5::initdata::RootProfile;
+        let crate::g17::fw::variant::Firmware::Identified(builds) = crate::hw::t8142::CONFIG.firmware
+        else {
+            panic!("the J813 must identify its loaded firmware");
+        };
+        assert_eq!(builds.len(), 2);
+        // Same TEXT and DATA sizes for both builds, so each is told apart by its digest at its
+        // own record offsets.
+        t6050_admits_only(builds);
+        let [a428, b123] = [&builds[0].images[0], &builds[1].images[0]];
+        for (image, other) in [(a428, builds[1].images), (b123, builds[0].images)] {
+            assert!(lookup(other, image.text_size, image.data_size, |_| {
+                Some(image.text_sha256)
+            })
+            .is_none());
+        }
+        // 26A428 runs the board as probed; 26B123 runs it on the 26B123 graph.
+        assert!(builds[0].config.is_none());
+        let config = builds[1].config.unwrap();
+        assert_eq!(config.m5.unwrap().graph.profile, RootProfile::J873G18G26B123);
+        assert_eq!(
+            crate::hw::t8142::CONFIG.m5.unwrap().graph.profile,
+            RootProfile::J873G18G26A428
+        );
+    }
 }