1 /*
2 * Copyright (c) 2019 Aurelien Jarno
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <device.h>
8 #include <drivers/hwinfo.h>
9 #include <init.h>
10 #include <soc.h>
11 #include <string.h>
12
13 static uint8_t sam_uid[16];
14
z_impl_hwinfo_get_device_id(uint8_t * buffer,size_t length)15 ssize_t z_impl_hwinfo_get_device_id(uint8_t *buffer, size_t length)
16 {
17 if (length > sizeof(sam_uid)) {
18 length = sizeof(sam_uid);
19 }
20
21 memcpy(buffer, sam_uid, length);
22
23 return length;
24 }
25
26 /* On the Atmel SAM SoC series, the device id is located in the flash
27 * controller. The controller can either present the flash area containing
28 * the code, the unique identifier or the user signature area at the flash
29 * location. Therefore the function reading the device id must be executed
30 * from RAM with the interrupts disabled. To avoid executing this complex
31 * code each time the device id is requested, we do this at boot time at save
32 * the 128-bit value into RAM.
33 */
hwinfo_sam_read_device_id(void)34 __ramfunc static void hwinfo_sam_read_device_id(void)
35 {
36 Efc *efc = (Efc *)DT_REG_ADDR(DT_INST(0, atmel_sam_flash_controller));
37 uint8_t *flash = (uint8_t *)CONFIG_FLASH_BASE_ADDRESS;
38 int i;
39
40 /* Switch the flash controller to the unique identifier area. The flash
41 * is not available anymore, hence we have to wait for it to be *NOT*
42 * ready.
43 */
44 efc->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_STUI;
45 while ((efc->EEFC_FSR & EEFC_FSR_FRDY) == EEFC_FSR_FRDY) {
46 /* Wait */
47 }
48
49 /* Copy the 128-bit unique ID. We cannot use memcpy as it would
50 * execute code from flash.
51 */
52 for (i = 0; i < sizeof(sam_uid); i++) {
53 sam_uid[i] = flash[i];
54 }
55
56 /* Switch back the controller to the flash area and wait for it to
57 * be ready.
58 */
59 efc->EEFC_FCR = EEFC_FCR_FKEY_PASSWD | EEFC_FCR_FCMD_SPUI;
60 while ((efc->EEFC_FSR & EEFC_FSR_FRDY) != EEFC_FSR_FRDY) {
61 /* Wait */
62 }
63 }
64
hwinfo_sam_init(const struct device * arg)65 static int hwinfo_sam_init(const struct device *arg)
66 {
67 Efc *efc = (Efc *)DT_REG_ADDR(DT_INST(0, atmel_sam_flash_controller));
68 uint32_t fmr;
69 int key;
70
71 /* Disable interrupts. */
72 key = irq_lock();
73
74 /* Disable code loop optimization and sequential code optimization. */
75 fmr = efc->EEFC_FMR;
76
77 #ifndef CONFIG_SOC_SERIES_SAM3X
78 efc->EEFC_FMR = (fmr & (~EEFC_FMR_CLOE)) | EEFC_FMR_SCOD;
79 #else
80 /* SAM3x does not have loop optimization (EEFC_FMR_CLOE) */
81 efc->EEFC_FMR |= EEFC_FMR_SCOD;
82 #endif
83
84 /* Read the device ID using code in RAM */
85 hwinfo_sam_read_device_id();
86
87 /* Restore code optimization settings. */
88 efc->EEFC_FMR = fmr;
89
90 /* Re-enable interrupts */
91 irq_unlock(key);
92
93 return 0;
94 }
95
96 SYS_INIT(hwinfo_sam_init, POST_KERNEL, CONFIG_KERNEL_INIT_PRIORITY_DEVICE);
97
