drivers: hwinfo: Added unique ID support for RPi Pico

Added support for hwinfo's hwinfo_get_device_id for the
RPi Pico series.

Signed-off-by: Yonatan Schachter <yonatan.schachter@gmail.com>

drivers/hwinfo/CMakeLists.txt

@@ -16,6 +16,7 @@ zephyr_library_sources_ifdef(CONFIG_HWINFO_MCUX_SRC    hwinfo_mcux_src.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_MCUX_SYSCON hwinfo_mcux_syscon.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_NRF         hwinfo_nrf.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_PSOC6       hwinfo_psoc6.c)
+zephyr_library_sources_ifdef(CONFIG_HWINFO_RPI_PICO    hwinfo_rpi_pico.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_SAM_RSTC    hwinfo_sam_rstc.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_SAM         hwinfo_sam.c)
 zephyr_library_sources_ifdef(CONFIG_HWINFO_SAM0        hwinfo_sam0.c)

drivers/hwinfo/Kconfig

@@ -70,6 +70,14 @@ config HWINFO_IMXRT
 	help
 	  Enable NXP i.mx RT hwinfo driver.
 
+config HWINFO_RPI_PICO
+	bool "Raspberry Pi Pico hwinfo driver"
+	default y
+	depends on SOC_SERIES_RP2XXX
+	select PICOSDK_USE_FLASH
+	help
+	  Enable Raspberry Pi Pico hwinfo driver.
+
 config HWINFO_SAM_RSTC
 	bool "Atmel SAM reset cause"
 	default y

drivers/hwinfo/hwinfo_rpi_pico.c

@@ -0,0 +1,34 @@
+/*
+ * Copyright (c) 2022 Yonatan Schachter
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <string.h>
+#include <drivers/hwinfo.h>
+#include <hardware/flash.h>
+
+#define FLASH_RUID_DATA_BYTES 8
+
+ssize_t z_impl_hwinfo_get_device_id(uint8_t *buffer, size_t length)
+{
+	uint8_t id[FLASH_RUID_DATA_BYTES];
+	uint32_t key;
+
+	/*
+	 * flash_get_unique_id temporarily disables XIP to query the
+	 * flash for its ID. If the CPU is interrupted while XIP is
+	 * disabled, it will halt. Therefore, interrupts must be disabled
+	 * before fetching the ID.
+	 */
+	key = irq_lock();
+	flash_get_unique_id(id);
+	irq_unlock(key);
+
+	if (length > sizeof(id)) {
+		length = sizeof(id);
+	}
+	memcpy(buffer, id, length);
+
+	return length;
+}

modules/hal_rpi_pico/CMakeLists.txt

@@ -80,4 +80,21 @@ if(CONFIG_HAS_RPI_PICO)
           ${rp2_common_dir}/hardware_uart/uart.c)
   zephyr_include_directories_ifdef(CONFIG_PICOSDK_USE_UART
           ${rp2_common_dir}/hardware_uart/include)
+
+  zephyr_library_sources_ifdef(CONFIG_PICOSDK_USE_FLASH
+          ${rp2_common_dir}/hardware_flash/flash.c)
+  zephyr_include_directories_ifdef(CONFIG_PICOSDK_USE_FLASH
+          ${rp2_common_dir}/hardware_flash/include)
+
+  # Some flash driver functions must be executed from the RAM.
+  # Originally pico-sdk places them in the RW data section, so this
+  # implementation does the same.
+  zephyr_linker_sources_ifdef(CONFIG_PICOSDK_USE_FLASH RWDATA timecritical.ld)
+
+  # A function in flash.c adds 1 to a function pointer, causing a warning
+  set_source_files_properties(
+    ${rp2_common_dir}/hardware_flash/flash.c
+    PROPERTIES
+    COMPILE_FLAGS $<TARGET_PROPERTY:compiler,warning_no_pointer_arithmetic>
+  )
 endif()

modules/hal_rpi_pico/Kconfig

@@ -13,3 +13,8 @@ config PICOSDK_USE_GPIO
 	bool
 	help
 	  Use the GPIO driver from pico-sdk
+
+config PICOSDK_USE_FLASH
+	bool
+	help
+	  Use the flash driver from pico-sdk

modules/hal_rpi_pico/pico/config_autogen.h

@@ -35,4 +35,11 @@
 #define __always_inline ALWAYS_INLINE
 #endif /* __always_inline */
 
+/* Two definitions required for the flash driver */
+#define __STRING(x) #x
+
+#ifndef __noinline
+#define __noinline __attribute__((noinline))
+#endif
+
 #endif

modules/hal_rpi_pico/timecritical.ld

@@ -0,0 +1 @@
+*(.time_critical*)