rpi4_64: make the I2C/Sense HAT path work on 64-bit

build/meta-bsp/recipes-bsp/bsp/files/bsp_rpi4_64.inc

@@ -16,6 +16,13 @@ def __do_platform_deploy(d):
     uboot_path = d.getVar('IB_UBOOT_PATH')
 
     run(f"cp -r {filedirname}/../bsp/rpi4/* {dst}/p1")
+
+    # bsp/rpi4/config.txt is shared with the 32-bit BSP and deliberately holds
+    # no arm_64bit/kernel setting; append the 64-bit half of the chain.
+    # FILE_DIRNAME is the *recipe's* directory (recipes-bsp/so3), not this
+    # include's — hence the ../bsp hop, as in the copy above.
+    run(f"cat {filedirname}/../bsp/files/config_rpi4_arm64.txt >> {dst}/p1/config.txt")
+
     run(f"cp {uboot_path}/u-boot.bin {dst}/p1/kernel8.img")
 
     __deploy_arm_common(d)

build/meta-bsp/recipes-bsp/bsp/files/config_rpi4_arm32.txt

@@ -0,0 +1,7 @@
+
+# --- 32-bit boot chain (appended by bsp_rpi4.inc) ---
+# The deploy installs the arm32 U-Boot as kernel7l.img. arm_64bit=0 is the
+# firmware default, but state both explicitly so the loaded file never depends
+# on the firmware's 32/64-bit filename default.
+arm_64bit=0
+kernel=kernel7l.img

build/meta-bsp/recipes-bsp/bsp/files/config_rpi4_arm64.txt

@@ -0,0 +1,9 @@
+
+# --- 64-bit boot chain (appended by bsp_rpi4_64.inc) ---
+# The deploy installs the aarch64 U-Boot as kernel8.img. This firmware
+# (bcm2711, Aug 2021) defaults arm_64bit to 0, so without this it starts the
+# cores in 32-bit mode and looks for kernel7l.img, never finds it, and boots
+# nothing at all — no serial output whatsoever. kernel= is stated explicitly so
+# the loaded file never depends on the firmware's filename default.
+arm_64bit=1
+kernel=kernel8.img

build/meta-bsp/recipes-bsp/bsp/rpi4/config.txt

@@ -65,3 +65,24 @@ max_framebuffers=2
 #dtoverlay=vc4-fkms-v3d
 
 enable_uart=1
+
+# Don't read an attached HAT's EEPROM. The firmware would merge the HAT's own
+# overlay into the device tree it hands to U-Boot, and that DT carries no
+# /chosen/stdout-path — so U-Boot picks its console by DT node order, which the
+# merge perturbs: with a Sense HAT fitted, U-Boot drives the wrong UART and
+# boots in complete silence. SO3 talks to the HAT through its own rpisense
+# driver and never needs the overlay. Applies to both 32- and 64-bit.
+force_eeprom_read=0
+
+# The 32/64-bit boot settings are NOT here: this file is shared by every rpi4
+# BSP, and the two chains need opposite values (kernel7l.img vs kernel8.img).
+# bsp_rpi4.inc / bsp_rpi4_64.inc append the right config_rpi4_arm{32,64}.txt
+# fragment after copying this directory.
+
+# Diagnostic only — echoes the firmware's own boot stage on the UART, which is
+# how you tell a failure *before* U-Boot from a dead board. Leave it OFF for
+# normal boots: to print, the firmware muxes GPIO14/15 to the PL011 and resets
+# its baud, while the DT gives serial0 = the mini-UART (7e215040, the one SO3
+# drives). The pins then stay on the wrong peripheral and U-Boot's output never
+# reaches the wire.
+#uart_2ndstage=1

so3/so3/devices/i2c/Kconfig

@@ -2,4 +2,4 @@ config I2C_BSC
     default y
     depends on I2C
 	bool "I2C Broadcom Serial Controller (BSC) interface"
-	depends on RPI4
+	depends on RPI4 || RPI4_64

so3/so3/devices/i2c/i2c_bsc.c

@@ -211,7 +211,12 @@ static int i2c_bsc_init(dev_t *dev, int fdt_offset)
 	const struct fdt_property *prop;
 	int prop_len;
 	uint32_t mask;
-	uint32_t gpio_regs_addr;
+
+	/* addr_t, not uint32_t: io_map() hands back a virtual address, which on
+	 * arm64 sits at CONFIG_IO_MAPPING_BASE (0xffff9000_00000000) and would
+	 * lose its top half in a 32-bit variable.
+	 */
+	addr_t gpio_regs_addr;
 
 	LOG_DEBUG("I2C broadcom - Initialization\n");
 

so3/so3/devices/rpisense/Kconfig

@@ -1,5 +1,5 @@
 config RPI_SENSE
 	bool "Driver for the Sense Hat extension board"
-	depends on RPI4
+	depends on RPI4 || RPI4_64
 
 

so3/so3/devices/rpisense/rpisense.c

@@ -35,7 +35,11 @@
 
 #include <device/arch/rpisense.h>
 
-static uint32_t gpio_regs_addr;
+/* addr_t, not uint32_t: io_map() hands back a virtual address, which on arm64
+ * sits at CONFIG_IO_MAPPING_BASE (0xffff9000_00000000) and would lose its top
+ * half in a 32-bit variable.
+ */
+static addr_t gpio_regs_addr;
 
 uint8_t leds_array[SIZE_FB];