91 lines
2.3 KiB
C
91 lines
2.3 KiB
C
/*
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* Copyright (c) 2019 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 <hwinfo.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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static u8_t sam_uid[16];
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ssize_t z_impl_hwinfo_get_device_id(u8_t *buffer, size_t length)
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{
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if (length > sizeof(sam_uid)) {
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length = sizeof(sam_uid);
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}
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memcpy(buffer, sam_uid, length);
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return length;
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}
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/* On the Atmel SAM SoC series, the device id is located in the flash
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* controller. The controller can either present the flash area containing
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* the code, the unique identifier or the user signature area at the flash
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* location. Therefore the function reading the device id must be executed
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* from RAM with the interrupts disabled. To avoid executing this complex
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* code each time the device id is requested, we do this at boot time at save
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* the 128-bit value into RAM.
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*/
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__ramfunc static void hwinfo_sam_read_device_id(void)
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{
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Efc *efc = (Efc *)DT_FLASH_DEV_BASE_ADDRESS;
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u8_t *flash = (u8_t *)CONFIG_FLASH_BASE_ADDRESS;
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int i;
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/* Switch the flash controller to the unique identifier area. The flash
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* is not available anymore, hence we have to wait for it to be *NOT*
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* ready.
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*/
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efc->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_STUI;
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while ((efc->EEFC_FSR & EEFC_FSR_FRDY) == EEFC_FSR_FRDY) {
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/* Wait */
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}
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/* Copy the 128-bit unique ID. We cannot use memcpy as it would
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* execute code from flash.
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*/
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for (i = 0; i < sizeof(sam_uid); i++) {
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sam_uid[i] = flash[i];
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}
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/* Switch back the controller to the flash area and wait for it to
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* be ready.
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*/
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efc->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_SPUI;
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while ((efc->EEFC_FSR & EEFC_FSR_FRDY) != EEFC_FSR_FRDY) {
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/* Wait */
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}
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}
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static int hwinfo_sam_init(struct device *arg)
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{
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Efc *efc = (Efc *)DT_FLASH_DEV_BASE_ADDRESS;
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u32_t fmr;
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int key;
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/* Disable interrupts. */
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key = irq_lock();
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/* Disable code loop optimization and sequential code optimization. */
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fmr = efc->EEFC_FMR;
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efc->EEFC_FMR = (fmr & (~EEFC_FMR_CLOE)) | EEFC_FMR_SCOD;
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/* Read the device ID using code in RAM */
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hwinfo_sam_read_device_id();
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/* Restore code optimization settings. */
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efc->EEFC_FMR = fmr;
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/* Re-enable interrupts */
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irq_unlock(key);
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return 0;
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}
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SYS_INIT(hwinfo_sam_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
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