iot2050: Add support for configuring M.2 connector

The M.2 slots of the related IOT2050 variant need to be configured
according to the plugged cards. This tries to detect the card using the
M.2 configuration pins of the B-key slot. If that fails, a U-Boot
environment variable can be set to configure manually. This variable is
write-permitted also in secure boot mode as it is not able to undermine
the integrity of the booted system.

The configuration is then applied to mux the serdes and to fix up the
device tree passed to or loaded by the bootloader. The fix-ups are
coming from device tree overlays that are embedded into the firmware
image and there also integrity protected. The OS remains free to load
a device tree to which they do not apply: U-Boot will not fail to boot
in that case.

Based on original patch by Chao Zeng.

Signed-off-by: Jan Kiszka <[email protected]>

4 files changed, 114 insertions, 2 deletions

diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 79ed4ac0825..b25570d1d79 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -1260,7 +1260,9 @@ dtb-$(CONFIG_SOC_K3_AM654) += \
 	k3-am6528-iot2050-basic-pg2.dtb \
 	k3-am6548-iot2050-advanced.dtb \
 	k3-am6548-iot2050-advanced-pg2.dtb \
-	k3-am6548-iot2050-advanced-m2.dtb
+	k3-am6548-iot2050-advanced-m2.dtb \
+	k3-am6548-iot2050-advanced-m2-bkey-usb3-overlay.dtbo \
+	k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-overlay.dtbo
 dtb-$(CONFIG_SOC_K3_J721E) += k3-j721e-common-proc-board.dtb \
 			      k3-j721e-r5-common-proc-board.dtb \
 			      k3-j7200-common-proc-board.dtb \
diff --git a/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi b/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
index a2fc8bbc123..03ccc543293 100644
--- a/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
+++ b/arch/arm/dts/k3-am65-iot2050-boot-image.dtsi
@@ -61,6 +61,36 @@
 					};
 				};
 
+#ifdef CONFIG_TARGET_IOT2050_A53_PG2
+				bkey-usb3-overlay {
+					description = "M.2-bkey-usb3-overlay";
+					type = "blob";
+					load = <0x82100000>;
+					arch = "arm64";
+					compression = "none";
+					blob-ext {
+						filename = "k3-am6548-iot2050-advanced-m2-bkey-usb3-overlay.dtbo";
+					};
+					hash {
+						algo = "sha256";
+					};
+				};
+
+				bkey-ekey-pcie-overlay {
+					description = "M.2-bkey-ekey-pcie-overlay";
+					type = "blob";
+					load = <0x82110000>;
+					arch = "arm64";
+					compression = "none";
+					blob-ext {
+						filename = "k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-overlay.dtbo";
+					};
+					hash {
+						algo = "sha256";
+					};
+				};
+#endif
+
 #ifdef CONFIG_WDT_K3_RTI_FW_FILE
 				k3-rti-wdt-firmware {
 					type = "firmware";
@@ -84,9 +114,15 @@
 					description = "NAME";
 					firmware = "u-boot";
 					fdt = "fdt-SEQ";
+					loadables =
+#ifdef CONFIG_TARGET_IOT2050_A53_PG2
+						"bkey-usb3-overlay",
+						"bkey-ekey-pcie-overlay",
+#endif
 #ifdef CONFIG_WDT_K3_RTI_FW_FILE
-					loadables = "k3-rti-wdt-firmware";
+						"k3-rti-wdt-firmware",
 #endif
+						<>;
 					signature {
 						sign-images = "firmware", "fdt", "loadables";
 					};
diff --git a/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-overlay.dts b/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-overlay.dts
new file mode 100644
index 00000000000..c9e736098f9
--- /dev/null
+++ b/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-ekey-pcie-overlay.dts
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOT2050 M.2 variant, overlay for B-key PCIE0_LANE0 + E-key PCIE1_LANE0
+ * Copyright (c) Siemens AG, 2022
+ *
+ * Authors:
+ *   Chao Zeng <[email protected]>
+ *   Jan Kiszka <[email protected]>
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/phy/phy.h>
+#include <dt-bindings/gpio/gpio.h>
+
+&pcie0_rc {
+	num-lanes = <1>;
+	phys = <&serdes0 PHY_TYPE_PCIE 1>;
+	phy-names = "pcie-phy0";
+	reset-gpios = <&main_gpio1 15 GPIO_ACTIVE_HIGH>;
+	status = "okay";
+};
+
+&pcie1_rc {
+	status = "okay";
+};
diff --git a/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-usb3-overlay.dts b/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-usb3-overlay.dts
new file mode 100644
index 00000000000..72fc011bd54
--- /dev/null
+++ b/arch/arm/dts/k3-am6548-iot2050-advanced-m2-bkey-usb3-overlay.dts
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * IOT2050 M.2 variant, overlay for B-key USB3.0 + E-key PCIE1_LANE0
+ * Copyright (c) Siemens AG, 2022
+ *
+ * Authors:
+ *   Chao Zeng <[email protected]>
+ *   Jan Kiszka <[email protected]>
+ */
+
+/dts-v1/;
+/plugin/;
+
+#include <dt-bindings/phy/phy.h>
+#include <dt-bindings/gpio/gpio.h>
+
+&serdes0 {
+	assigned-clock-parents = <&k3_clks 153 7>, <&k3_clks 153 4>;
+};
+
+&pcie0_rc {
+	status = "disabled";
+};
+
+&pcie1_rc {
+	pinctrl-names = "default";
+	pinctrl-0 = <&minipcie_pins_default>;
+
+	num-lanes = <1>;
+	phys = <&serdes1 PHY_TYPE_PCIE 0>;
+	phy-names = "pcie-phy0";
+	reset-gpios = <&wkup_gpio0 27 GPIO_ACTIVE_HIGH>;
+	status = "okay";
+};
+
+&dwc3_0 {
+	assigned-clock-parents = <&k3_clks 151 4>,  /* set REF_CLK to 20MHz i.e. PER0_PLL/48 */
+				 <&k3_clks 151 8>;  /* set PIPE3_TXB_CLK to WIZ8B2M4VSB */
+	phys = <&serdes0 PHY_TYPE_USB3 0>;
+	phy-names = "usb3-phy";
+};
+
+&usb0 {
+	maximum-speed = "super-speed";
+	snps,dis-u1-entry-quirk;
+	snps,dis-u2-entry-quirk;
+};