drivers: entropy: add Atmel SAM entropy generator driver
Tested on the Atmel SAM E70 Xplained board. Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
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@ -4,6 +4,7 @@ zephyr_library_sources_ifdef(CONFIG_ENTROPY_ESP32_RNG entropy_esp32.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_MCUX_RNGA entropy_mcux_rnga.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_MCUX_TRNG entropy_mcux_trng.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_SAM_RNG entropy_sam.c)
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zephyr_library_sources_ifdef(CONFIG_ENTROPY_STM32_RNG entropy_stm32.c)
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zephyr_library_sources_ifdef(CONFIG_FAKE_ENTROPY_NATIVE_POSIX fake_entropy_native_posix.c)
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zephyr_library_sources_ifdef(CONFIG_USERSPACE entropy_handlers.c)
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@ -17,6 +17,7 @@ source "drivers/entropy/Kconfig.mcux"
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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.sam"
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source "drivers/entropy/Kconfig.native_posix"
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config ENTROPY_HAS_DRIVER
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14
drivers/entropy/Kconfig.sam
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drivers/entropy/Kconfig.sam
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@ -0,0 +1,14 @@
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# Kconfig.sam - Atmel SAM TRNG configuration
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#
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# Copyright (c) 2018 Aurelien Jarno
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#
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# SPDX-License-Identifier: Apache-2.0
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menuconfig ENTROPY_SAM_RNG
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bool "Atmel SAM MCU Family True Random Number Generator (TRNG) Driver"
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depends on SOC_FAMILY_SAM
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depends on ENTROPY_GENERATOR
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select ENTROPY_HAS_DRIVER
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select HAS_DTS_ENTROPY
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help
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Enable True Random Number Generator (TRNG) driver for Atmel SAM MCUs.
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95
drivers/entropy/entropy_sam.c
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95
drivers/entropy/entropy_sam.c
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@ -0,0 +1,95 @@
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/*
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* Copyright (c) 2018 Aurelien Jarno
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <device.h>
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#include <entropy.h>
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#include <errno.h>
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#include <init.h>
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#include <soc.h>
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#include <string.h>
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struct trng_sam_dev_cfg {
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Trng *regs;
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};
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#define DEV_CFG(dev) \
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((const struct trng_sam_dev_cfg *const)(dev)->config->config_info)
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static int entropy_sam_wait_ready(Trng *const trng)
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{
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/* According to the reference manual, the generator provides
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* one 32-bit random value every 84 peripheral clock cycles.
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* MCK may not be smaller than HCLK/4, so it should not take
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* more than 336 HCLK ticks. Assuming the CPU can do 1
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* instruction per HCLK the number of times to loop before
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* the TRNG is ready is less than 1000. And that is when
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* assuming the loop only takes 1 instruction. So looping a
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* million times should be more than enough.
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*/
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int timeout = 1000000;
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while (!(trng->TRNG_ISR & TRNG_ISR_DATRDY)) {
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if (timeout-- == 0) {
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return -ETIMEDOUT;
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}
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k_yield();
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}
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return 0;
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}
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static int entropy_sam_get_entropy(struct device *dev, u8_t *buffer,
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u16_t length)
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{
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Trng *const trng = DEV_CFG(dev)->regs;
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while (length > 0) {
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size_t to_copy;
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u32_t value;
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int res;
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res = entropy_sam_wait_ready(trng);
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if (res < 0) {
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return res;
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}
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value = trng->TRNG_ODATA;
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to_copy = min(length, sizeof(value));
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memcpy(buffer, &value, to_copy);
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buffer += to_copy;
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length -= to_copy;
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}
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return 0;
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}
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static int entropy_sam_init(struct device *dev)
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{
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Trng *const trng = DEV_CFG(dev)->regs;
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/* Enable the user interface clock */
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soc_pmc_peripheral_enable(DT_ENTROPY_SAM_TRNG_PERIPHERAL_ID);
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/* Enable the TRNG */
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trng->TRNG_CR = TRNG_CR_KEY_PASSWD | TRNG_CR_ENABLE;
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return 0;
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}
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static const struct entropy_driver_api entropy_sam_api = {
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.get_entropy = entropy_sam_get_entropy
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};
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static const struct trng_sam_dev_cfg trng_sam_cfg = {
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.regs = (Trng *)DT_ENTROPY_SAM_TRNG_BASE_ADDRESS,
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};
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DEVICE_AND_API_INIT(entropy_sam, CONFIG_ENTROPY_NAME,
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entropy_sam_init, NULL, &trng_sam_cfg,
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PRE_KERNEL_1, CONFIG_KERNEL_INIT_PRIORITY_DEVICE,
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&entropy_sam_api);
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@ -252,6 +252,15 @@
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status = "disabled";
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label = "USBHS";
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};
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trng: random@40070000 {
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compatible = "atmel,sam-trng";
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reg = <0x40070000 0x4000>;
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interrupts = <57 0>;
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peripheral-id = <57>;
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status = "ok";
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label = "TRNG";
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};
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};
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};
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45
dts/bindings/rng/atmel,sam-trng.yaml
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45
dts/bindings/rng/atmel,sam-trng.yaml
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#
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# Copyright (c) 2018, Aurelien Jarno
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#
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# SPDX-License-Identifier: Apache-2.0
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#
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---
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title: Atmel SAM TRNG (True Random Number Generator)
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version: 0.1
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description: >
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This binding gives a base representation of the Atmel SAM RNG
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properties:
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compatible:
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type: string
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category: required
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description: compatible strings
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constraint: "atmel,sam-trng"
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generation: define
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reg:
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type: int
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description: mmio register space
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generation: define
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category: required
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interrupts:
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type: compound
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category: required
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description: required interrupts
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generation: define
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peripheral-id:
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type: int
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description: peripheral ID
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generation: define
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category: required
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label:
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type: string
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category: required
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description: Human readable string describing the device (used by Zephyr for API name)
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generation: define
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...
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@ -73,4 +73,9 @@ config USB_DC_SAM
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default y
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endif # USB
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if ENTROPY_GENERATOR
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config ENTROPY_SAM_RNG
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default y
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endif # ENTROPY_GENERATOR
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endif # SOC_SERIES_SAME70
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@ -128,4 +128,11 @@
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#define DT_USBHS_PERIPHERAL_ID DT_ATMEL_SAM_USBHS_40038000_PERIPHERAL_ID
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#define DT_USBHS_RAM_BASE_ADDRESS DT_ATMEL_SAM_USBHS_40038000_RAM_0
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#define DT_ENTROPY_SAM_TRNG_BASE_ADDRESS DT_ATMEL_SAM_TRNG_40070000_BASE_ADDRESS
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#define DT_ENTROPY_SAM_TRNG_IRQ DT_ATMEL_SAM_TRNG_40070000_IRQ_0
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#define DT_ENTROPY_SAM_TRNG_IRQ_PRI DT_ATMEL_SAM_TRNG_40070000_IRQ_0_PRIORITY
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#define DT_ENTROPY_SAM_TRNG_PERIPHERAL_ID DT_ATMEL_SAM_TRNG_40070000_PERIPHERAL_ID
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#define DT_ENTROPY_SAM_TRNG_NAME DT_ATMEL_SAM_TRNG_40070000_LABEL
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#define CONFIG_ENTROPY_NAME DT_ATMEL_SAM_TRNG_40070000_LABEL
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/* End of SoC Level DTS fixup file */
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