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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #include <plat/cmsis.h>
     18 #include <cpu/pendsv.h>
     19 #include <stdio.h>
     20 
     21 
     22 static PendsvCallbackF mSubscribers[MAX_PENDSV_SUBSCRIBERS] = {0,};
     23 
     24 bool pendsvSubscribe(PendsvCallbackF cbk)
     25 {
     26     int32_t i, free = -1;
     27 
     28     //check for dupes and also look fro a free slot
     29     for (i = 0; i < MAX_PENDSV_SUBSCRIBERS; i++) {
     30         if (!mSubscribers[i])
     31             free = i;
     32         if (mSubscribers[i] == cbk)
     33             return false;
     34     }
     35 
     36     //make sure we found a slot
     37     if (free < 0)
     38         return false;
     39 
     40     mSubscribers[free] = cbk;
     41     return true;
     42 }
     43 
     44 bool pendsvUnsubscribe(PendsvCallbackF cbk)
     45 {
     46     uint32_t i;
     47 
     48     for (i = 0; i < MAX_PENDSV_SUBSCRIBERS; i++) {
     49         if (mSubscribers[i] == cbk) {
     50             mSubscribers[i] = NULL;
     51             return true;
     52         }
     53     }
     54 
     55     return false;
     56 }
     57 
     58 void pendsvTrigger(void)
     59 {
     60     SCB->ICSR = 1UL << 28;
     61 }
     62 
     63 void pendsvClear(void)
     64 {
     65     SCB->ICSR = 1UL << 27;
     66 }
     67 
     68 bool pendsvIsPending(void)
     69 {
     70     return !!(SCB->ICSR & (1UL << 28));
     71 }
     72 
     73 static void __attribute__((used)) pendSvHandleC(struct PendsvRegsLow *loRegs, struct PendsvRegsHi *hiRegs)
     74 {
     75     uint32_t i;
     76 
     77     for (i = 0; i < MAX_PENDSV_SUBSCRIBERS; i++) {
     78         if (mSubscribers[i])
     79             mSubscribers[i](loRegs, hiRegs);
     80     }
     81 }
     82 
     83 void PendSV_Handler(void);
     84 void PendSV_Handler(void)
     85 {
     86     asm volatile(
     87         "tst lr, #4         \n"
     88         "ite eq             \n"
     89         "mrseq r0, msp      \n"
     90         "mrsne r0, psp      \n"
     91         "push  {r4-r11}     \n"
     92         "mov   r1, sp       \n"
     93         "b     pendSvHandleC\n"
     94     );
     95 }
     96 
     97 
     98 
     99 
    100