1 /***************************************************************************//**
2  * @file
3  * @brief CMSIS Cortex-M3/M4 System Layer for EFR32 devices.
4  *******************************************************************************
5  * # License
6  * <b>Copyright 2020 Silicon Laboratories Inc. www.silabs.com</b>
7  *******************************************************************************
8  *
9  * SPDX-License-Identifier: Zlib
10  *
11  * The licensor of this software is Silicon Laboratories Inc.
12  *
13  * This software is provided 'as-is', without any express or implied
14  * warranty. In no event will the authors be held liable for any damages
15  * arising from the use of this software.
16  *
17  * Permission is granted to anyone to use this software for any purpose,
18  * including commercial applications, and to alter it and redistribute it
19  * freely, subject to the following restrictions:
20  *
21  * 1. The origin of this software must not be misrepresented; you must not
22  *    claim that you wrote the original software. If you use this software
23  *    in a product, an acknowledgment in the product documentation would be
24  *    appreciated but is not required.
25  * 2. Altered source versions must be plainly marked as such, and must not be
26  *    misrepresented as being the original software.
27  * 3. This notice may not be removed or altered from any source distribution.
28  *
29  ******************************************************************************/
30 
31 #include <stdint.h>
32 #include "em_device.h"
33 
34 /*******************************************************************************
35  ******************************   DEFINES   ************************************
36  ******************************************************************************/
37 
38 /** LFRCO frequency, tuned to below frequency during manufacturing. */
39 #define EFR32_LFRCO_FREQ  (32768UL)
40 /** ULFRCO frequency */
41 #define EFR32_ULFRCO_FREQ (1000UL)
42 
43 /*******************************************************************************
44  **************************   LOCAL VARIABLES   ********************************
45  ******************************************************************************/
46 
47 /* System oscillator frequencies. These frequencies are normally constant */
48 /* for a target, but they are made configurable in order to allow run-time */
49 /* handling of different boards. The crystal oscillator clocks can be set */
50 /* compile time to a non-default value by defining respective EFR32_nFXO_FREQ */
51 /* values according to board design. By defining the EFR32_nFXO_FREQ to 0, */
52 /* one indicates that the oscillator is not present, in order to save some */
53 /* SW footprint. */
54 
55 #ifndef EFR32_HFRCO_MAX_FREQ
56 /** Maximum HFRCO frequency */
57 #define EFR32_HFRCO_MAX_FREQ            (38000000UL)
58 #endif
59 
60 #ifndef EFR32_HFXO_FREQ
61 /** HFXO frequency */
62 #define EFR32_HFXO_FREQ                 (38400000UL)
63 #endif
64 
65 #ifndef EFR32_HFRCO_STARTUP_FREQ
66 /** HFRCO startup frequency */
67 #define EFR32_HFRCO_STARTUP_FREQ        (19000000UL)
68 #endif
69 
70 /* Do not define variable if HF crystal oscillator not present */
71 #if (EFR32_HFXO_FREQ > 0U)
72 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
73 /** System HFXO clock. */
74 static uint32_t SystemHFXOClock = EFR32_HFXO_FREQ;
75 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
76 #endif
77 
78 #ifndef EFR32_LFXO_FREQ
79 /** LFXO frequency */
80 #define EFR32_LFXO_FREQ (EFR32_LFRCO_FREQ)
81 #endif
82 /* Do not define variable if LF crystal oscillator not present */
83 #if (EFR32_LFXO_FREQ > 0U)
84 /** @cond DO_NOT_INCLUDE_WITH_DOXYGEN */
85 /** System LFXO clock. */
86 static uint32_t SystemLFXOClock = EFR32_LFXO_FREQ;
87 /** @endcond (DO_NOT_INCLUDE_WITH_DOXYGEN) */
88 #endif
89 
90 /*******************************************************************************
91  **************************   GLOBAL VARIABLES   *******************************
92  ******************************************************************************/
93 
94 /**
95  * @brief
96  *   System System Clock Frequency (Core Clock).
97  *
98  * @details
99  *   Required CMSIS global variable that must be kept up-to-date.
100  */
101 uint32_t SystemCoreClock = EFR32_HFRCO_STARTUP_FREQ;
102 
103 /**
104  * @brief
105  *   System HFRCO frequency
106  *
107  * @note
108  *   This is an EFR32 proprietary variable, not part of the CMSIS definition.
109  *
110  * @details
111  *   Frequency of the system HFRCO oscillator
112  */
113 uint32_t SystemHfrcoFreq = EFR32_HFRCO_STARTUP_FREQ;
114 
115 /*******************************************************************************
116  **************************   GLOBAL FUNCTIONS   *******************************
117  ******************************************************************************/
118 
119 /***************************************************************************//**
120  * @brief
121  *   Get the current core clock frequency.
122  *
123  * @details
124  *   Calculate and get the current core clock frequency based on the current
125  *   configuration. Assuming that the SystemCoreClock global variable is
126  *   maintained, the core clock frequency is stored in that variable as well.
127  *   This function will however calculate the core clock based on actual HW
128  *   configuration. It will also update the SystemCoreClock global variable.
129  *
130  * @note
131  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
132  *
133  * @return
134  *   The current core clock frequency in Hz.
135  ******************************************************************************/
SystemCoreClockGet(void)136 uint32_t SystemCoreClockGet(void)
137 {
138   uint32_t ret;
139   uint32_t presc;
140 
141   ret   = SystemHFClockGet();
142   presc = (CMU->HFCOREPRESC & _CMU_HFCOREPRESC_PRESC_MASK)
143           >> _CMU_HFCOREPRESC_PRESC_SHIFT;
144   ret  /= presc + 1U;
145 
146   /* Keep CMSIS system clock variable up-to-date */
147   SystemCoreClock = ret;
148 
149   return ret;
150 }
151 
152 /***************************************************************************//**
153  * @brief
154  *   Get the maximum core clock frequency.
155  *
156  * @note
157  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
158  *
159  * @return
160  *   The maximum core clock frequency in Hz.
161  ******************************************************************************/
SystemMaxCoreClockGet(void)162 uint32_t SystemMaxCoreClockGet(void)
163 {
164 #if (EFR32_HFRCO_MAX_FREQ > EFR32_HFXO_FREQ)
165   return EFR32_HFRCO_MAX_FREQ;
166 #else
167   return EFR32_HFXO_FREQ;
168 #endif
169 }
170 
171 /***************************************************************************//**
172  * @brief
173  *   Get the current HFCLK frequency.
174  *
175  * @note
176  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
177  *
178  * @return
179  *   The current HFCLK frequency in Hz.
180  ******************************************************************************/
SystemHFClockGet(void)181 uint32_t SystemHFClockGet(void)
182 {
183   uint32_t ret;
184 
185   switch (CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK) {
186     case CMU_HFCLKSTATUS_SELECTED_LFXO:
187 #if (EFR32_LFXO_FREQ > 0U)
188       ret = SystemLFXOClock;
189 #else
190       /* We should not get here, since core should not be clocked. May */
191       /* be caused by a misconfiguration though. */
192       ret = 0U;
193 #endif
194       break;
195 
196     case CMU_HFCLKSTATUS_SELECTED_LFRCO:
197       ret = EFR32_LFRCO_FREQ;
198       break;
199 
200     case CMU_HFCLKSTATUS_SELECTED_HFXO:
201 #if (EFR32_HFXO_FREQ > 0U)
202       ret = SystemHFXOClock;
203 #else
204       /* We should not get here, since core should not be clocked. May */
205       /* be caused by a misconfiguration though. */
206       ret = 0U;
207 #endif
208       break;
209 
210     default: /* CMU_HFCLKSTATUS_SELECTED_HFRCO */
211       ret = SystemHfrcoFreq;
212       break;
213   }
214 
215   return ret / (1U + ((CMU->HFPRESC & _CMU_HFPRESC_PRESC_MASK)
216                       >> _CMU_HFPRESC_PRESC_SHIFT));
217 }
218 
219 /***************************************************************************//**
220  * @brief
221  *   Get high frequency crystal oscillator clock frequency for target system.
222  *
223  * @note
224  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
225  *
226  * @return
227  *   HFXO frequency in Hz.
228  ******************************************************************************/
SystemHFXOClockGet(void)229 uint32_t SystemHFXOClockGet(void)
230 {
231   /* External crystal oscillator present? */
232 #if (EFR32_HFXO_FREQ > 0U)
233   return SystemHFXOClock;
234 #else
235   return 0U;
236 #endif
237 }
238 
239 /***************************************************************************//**
240  * @brief
241  *   Set high frequency crystal oscillator clock frequency for target system.
242  *
243  * @note
244  *   This function is mainly provided for being able to handle target systems
245  *   with different HF crystal oscillator frequencies run-time. If used, it
246  *   should probably only be used once during system startup.
247  *
248  * @note
249  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
250  *
251  * @param[in] freq
252  *   HFXO frequency in Hz used for target.
253  ******************************************************************************/
SystemHFXOClockSet(uint32_t freq)254 void SystemHFXOClockSet(uint32_t freq)
255 {
256   /* External crystal oscillator present? */
257 #if (EFR32_HFXO_FREQ > 0U)
258   SystemHFXOClock = freq;
259 
260   /* Update core clock frequency if HFXO is used to clock core */
261   if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
262       == CMU_HFCLKSTATUS_SELECTED_HFXO) {
263     /* The function will update the global variable */
264     (void)SystemCoreClockGet();
265   }
266 #else
267   (void)freq; /* Unused parameter */
268 #endif
269 }
270 
271 /***************************************************************************//**
272  * @brief
273  *   Initialize the system.
274  *
275  * @details
276  *   Do required generic HW system init.
277  *
278  * @note
279  *   This function is invoked during system init, before the main() routine
280  *   and any data has been initialized. For this reason, it cannot do any
281  *   initialization of variables etc.
282  ******************************************************************************/
SystemInit(void)283 void SystemInit(void)
284 {
285 #if defined(__VTOR_PRESENT) && (__VTOR_PRESENT == 1U)
286   SCB->VTOR = (uint32_t)&__Vectors;
287 #endif
288 
289 #if (__FPU_PRESENT == 1U) && (__FPU_USED == 1U)
290   /* Set floating point coprosessor access mode. */
291   SCB->CPACR |= ((3UL << 10 * 2)                    /* set CP10 Full Access */
292                  | (3UL << 11 * 2));                /* set CP11 Full Access */
293 #endif
294 
295 #if defined(UNALIGNED_SUPPORT_DISABLE)
296   SCB->CCR |= SCB_CCR_UNALIGN_TRP_Msk;
297 #endif
298 
299   /****************************
300    * Fix for errata DCDC_E206
301    * Enable bypass switch as errata workaround. The bypass current limit will be
302    * disabled again in CHIP_Init() to avoid added current consumption. */
303 
304   EMU->DCDCCLIMCTRL |= 1U << _EMU_DCDCCLIMCTRL_BYPLIMEN_SHIFT;
305   EMU->DCDCCTRL = (EMU->DCDCCTRL & ~_EMU_DCDCCTRL_DCDCMODE_MASK)
306                   | EMU_DCDCCTRL_DCDCMODE_BYPASS;
307   *(volatile uint32_t *)(0x400E3074) &= ~(0x1UL << 0);
308   *(volatile uint32_t *)(0x400E3060) &= ~(0x1UL << 28);
309 }
310 
311 /***************************************************************************//**
312  * @brief
313  *   Get low frequency RC oscillator clock frequency for target system.
314  *
315  * @note
316  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
317  *
318  * @return
319  *   LFRCO frequency in Hz.
320  ******************************************************************************/
SystemLFRCOClockGet(void)321 uint32_t SystemLFRCOClockGet(void)
322 {
323   /* Currently we assume that this frequency is properly tuned during */
324   /* manufacturing and is not changed after reset. If future requirements */
325   /* for re-tuning by user, we can add support for that. */
326   return EFR32_LFRCO_FREQ;
327 }
328 
329 /***************************************************************************//**
330  * @brief
331  *   Get ultra low frequency RC oscillator clock frequency for target system.
332  *
333  * @note
334  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
335  *
336  * @return
337  *   ULFRCO frequency in Hz.
338  ******************************************************************************/
SystemULFRCOClockGet(void)339 uint32_t SystemULFRCOClockGet(void)
340 {
341   /* The ULFRCO frequency is not tuned, and can be very inaccurate */
342   return EFR32_ULFRCO_FREQ;
343 }
344 
345 /***************************************************************************//**
346  * @brief
347  *   Get low frequency crystal oscillator clock frequency for target system.
348  *
349  * @note
350  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
351  *
352  * @return
353  *   LFXO frequency in Hz.
354  ******************************************************************************/
SystemLFXOClockGet(void)355 uint32_t SystemLFXOClockGet(void)
356 {
357   /* External crystal oscillator present? */
358 #if (EFR32_LFXO_FREQ > 0U)
359   return SystemLFXOClock;
360 #else
361   return 0U;
362 #endif
363 }
364 
365 /***************************************************************************//**
366  * @brief
367  *   Set low frequency crystal oscillator clock frequency for target system.
368  *
369  * @note
370  *   This function is mainly provided for being able to handle target systems
371  *   with different HF crystal oscillator frequencies run-time. If used, it
372  *   should probably only be used once during system startup.
373  *
374  * @note
375  *   This is an EFR32 proprietary function, not part of the CMSIS definition.
376  *
377  * @param[in] freq
378  *   LFXO frequency in Hz used for target.
379  ******************************************************************************/
SystemLFXOClockSet(uint32_t freq)380 void SystemLFXOClockSet(uint32_t freq)
381 {
382   /* External crystal oscillator present? */
383 #if (EFR32_LFXO_FREQ > 0U)
384   SystemLFXOClock = freq;
385 
386   /* Update core clock frequency if LFXO is used to clock core */
387   if ((CMU->HFCLKSTATUS & _CMU_HFCLKSTATUS_SELECTED_MASK)
388       == CMU_HFCLKSTATUS_SELECTED_LFXO) {
389     /* The function will update the global variable */
390     (void)SystemCoreClockGet();
391   }
392 #else
393   (void)freq; /* Unused parameter */
394 #endif
395 }
396