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entropy: rpi_pico: implement entropy driver for RP2350
Use get_rand_64() from Pico SDK for entropy. Signed-off-by: Xudong Zheng <[email protected]>
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‎boards/raspberrypi/rpi_pico2/rpi_pico2.dtsi‎

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@@ -137,6 +137,10 @@
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status = "okay";
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};
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&rng {
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status = "okay";
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};
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zephyr_udc0: &usbd {
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status = "okay";
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};

‎drivers/entropy/CMakeLists.txt‎

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@@ -13,6 +13,7 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_MCUX_TRNG entropy_mcux_trng
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_MCUX_CAAM entropy_mcux_caam.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_NRF5_RNG entropy_nrf5.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_NRF_CRACEN_CTR_DRBG entropy_nrf_cracen.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_RPI_PICO_RNG entropy_rpi_pico.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_SAM_RNG entropy_sam.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_SMARTBOND_TRNG entropy_smartbond.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_STM32_RNG entropy_stm32.c)

‎drivers/entropy/Kconfig‎

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@@ -27,6 +27,7 @@ source "drivers/entropy/Kconfig.stm32"
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source "drivers/entropy/Kconfig.esp32"
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source "drivers/entropy/Kconfig.nrf5"
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source "drivers/entropy/Kconfig.nrf_cracen"
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source "drivers/entropy/Kconfig.rpi_pico"
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source "drivers/entropy/Kconfig.sam"
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source "drivers/entropy/Kconfig.smartbond"
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source "drivers/entropy/Kconfig.native_posix"

‎drivers/entropy/Kconfig.rpi_pico‎

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# Raspberry Pi Pico entropy generator driver configuration
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# Copyright (c) 2024 Xudong Zheng
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# SPDX-License-Identifier: Apache-2.0
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config ENTROPY_RPI_PICO_RNG
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bool "Raspberry Pi Pico entropy number generator driver"
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default y
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depends on DT_HAS_RASPBERRYPI_PICO_RNG_ENABLED
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depends on SOC_SERIES_RP2350
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select ENTROPY_HAS_DRIVER
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select PICOSDK_USE_CLAIM
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select PICOSDK_USE_RAND

‎drivers/entropy/entropy_rpi_pico.c‎

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/*
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* Copyright (c) 2024 Xudong Zheng
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <string.h>
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#include <pico/rand.h>
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#include <zephyr/drivers/entropy.h>
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#include <zephyr/spinlock.h>
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#define DT_DRV_COMPAT raspberrypi_pico_rng
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static struct k_spinlock entropy_lock;
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static int entropy_rpi_pico_get_entropy(const struct device *dev, uint8_t *buf, uint16_t len)
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{
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__ASSERT_NO_MSG(buf != NULL);
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uint8_t *buf_bytes = buf;
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while (len > 0) {
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uint64_t value;
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size_t to_copy = MIN(sizeof(value), len);
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K_SPINLOCK(&entropy_lock) {
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value = get_rand_64();
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}
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memcpy(buf_bytes, &value, to_copy);
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buf_bytes += to_copy;
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len -= to_copy;
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}
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return 0;
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}
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static DEVICE_API(entropy, entropy_rpi_pico_api_funcs) = {
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.get_entropy = entropy_rpi_pico_get_entropy
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};
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DEVICE_DT_INST_DEFINE(0,
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NULL, NULL, NULL, NULL,
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PRE_KERNEL_1, CONFIG_ENTROPY_INIT_PRIORITY,
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&entropy_rpi_pico_api_funcs);

‎dts/arm/raspberrypi/rpi_pico/rp2350.dtsi‎

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@@ -21,6 +21,10 @@
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die-temp0 = &die_temp;
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};
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chosen {
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zephyr,entropy = &rng;
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};
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cpus {
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#address-cells = <1>;
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#size-cells = <0>;
@@ -424,6 +428,12 @@
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resets = <&reset RPI_PICO_RESETS_RESET_PIO2>;
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status = "disabled";
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};
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rng: rng@400f0000 {
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compatible = "raspberrypi,pico-rng";
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reg = <0x400f0000 DT_SIZE_K(4)>;
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status = "disabled";
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};
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};
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pinctrl: pin-controller {

‎dts/bindings/rng/raspberrypi,pico-rng.yaml‎

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# Copyright (c) 2024 Xudong Zheng
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# SPDX-License-Identifier: Apache-2.0
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description: Raspberry Pi Pico RNG/Entropy
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compatible: "raspberrypi,pico-rng"
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include: base.yaml

‎modules/hal_rpi_pico/CMakeLists.txt‎

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@@ -151,6 +151,19 @@ if(CONFIG_HAS_RPI_PICO)
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zephyr_include_directories_ifdef(CONFIG_PICOSDK_USE_CLAIM
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${common_dir}/hardware_claim/include)
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zephyr_library_sources_ifdef(CONFIG_PICOSDK_USE_RAND
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${rp2_common_dir}/hardware_timer/timer.c
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${rp2_common_dir}/pico_rand/rand.c
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)
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zephyr_include_directories_ifdef(CONFIG_PICOSDK_USE_RAND
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${common_dir}/pico_sync/include
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${common_dir}/pico_time/include
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${rp2_common_dir}/pico_rand/include
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${rp2_common_dir}/pico_time_adapter/include
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${rp2_common_dir}/pico_unique_id/include
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)
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zephyr_linker_sources_ifdef(CONFIG_PICOSDK_USE_RAND DATA_SECTIONS uninit_data.ld)
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zephyr_library_sources_ifdef(CONFIG_SOC_SERIES_RP2350
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${rp2_common_dir}/pico_runtime_init/runtime_init.c)
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zephyr_include_directories_ifdef(CONFIG_SOC_SERIES_RP2350

‎modules/hal_rpi_pico/Kconfig‎

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@@ -54,3 +54,8 @@ config PICOSDK_USE_RTC
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bool
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help
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Use the RTC driver from pico-sdk
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config PICOSDK_USE_RAND
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bool
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help
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Use the "rand" driver from pico-sdk

‎modules/hal_rpi_pico/uninit_data.ld‎

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.uninitialized_data (NOLOAD): {
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. = ALIGN(4);
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*(.uninitialized_data*)
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} > RAM

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