1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
|
/*
FreeRTOS V8.2.3 - Copyright (C) 2015 Real Time Engineers Ltd.
All rights reserved
VISIT http://www.FreeRTOS.org TO ENSURE YOU ARE USING THE LATEST VERSION.
This file is part of the FreeRTOS distribution and was contributed
to the project by Technolution B.V. (www.technolution.nl,
freertos-riscv@technolution.eu) under the terms of the FreeRTOS
contributors license.
FreeRTOS is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License (version 2) as published by the
Free Software Foundation >>>> AND MODIFIED BY <<<< the FreeRTOS exception.
***************************************************************************
>>! NOTE: The modification to the GPL is included to allow you to !<<
>>! distribute a combined work that includes FreeRTOS without being !<<
>>! obliged to provide the source code for proprietary components !<<
>>! outside of the FreeRTOS kernel. !<<
***************************************************************************
FreeRTOS is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. Full license text is available on the following
link: http://www.freertos.org/a00114.html
***************************************************************************
* *
* FreeRTOS provides completely free yet professionally developed, *
* robust, strictly quality controlled, supported, and cross *
* platform software that is more than just the market leader, it *
* is the industry's de facto standard. *
* *
* Help yourself get started quickly while simultaneously helping *
* to support the FreeRTOS project by purchasing a FreeRTOS *
* tutorial book, reference manual, or both: *
* http://www.FreeRTOS.org/Documentation *
* *
***************************************************************************
http://www.FreeRTOS.org/FAQHelp.html - Having a problem? Start by reading
the FAQ page "My application does not run, what could be wrong?". Have you
defined configASSERT()?
http://www.FreeRTOS.org/support - In return for receiving this top quality
embedded software for free we request you assist our global community by
participating in the support forum.
http://www.FreeRTOS.org/training - Investing in training allows your team to
be as productive as possible as early as possible. Now you can receive
FreeRTOS training directly from Richard Barry, CEO of Real Time Engineers
Ltd, and the world's leading authority on the world's leading RTOS.
http://www.FreeRTOS.org/plus - A selection of FreeRTOS ecosystem products,
including FreeRTOS+Trace - an indispensable productivity tool, a DOS
compatible FAT file system, and our tiny thread aware UDP/IP stack.
http://www.FreeRTOS.org/labs - Where new FreeRTOS products go to incubate.
Come and try FreeRTOS+TCP, our new open source TCP/IP stack for FreeRTOS.
http://www.OpenRTOS.com - Real Time Engineers ltd. license FreeRTOS to High
Integrity Systems ltd. to sell under the OpenRTOS brand. Low cost OpenRTOS
licenses offer ticketed support, indemnification and commercial middleware.
http://www.SafeRTOS.com - High Integrity Systems also provide a safety
engineered and independently SIL3 certified version for use in safety and
mission critical applications that require provable dependability.
1 tab == 4 spaces!
*/
/*-----------------------------------------------------------
* Implementation of functions defined in portable.h for the RISC-V port.
*----------------------------------------------------------*/
/* Scheduler includes. */
#include "FreeRTOS.h"
#include "task.h"
#include "portmacro.h"
#include "riscv_hal.h"
#ifdef __riscv64
# define STORE sd
# define LOAD ld
# define REGBYTES 8
#else
# define STORE sw
# define LOAD lw
# define REGBYTES 4
#endif
/* A variable is used to keep track of the critical section nesting. This
variable has to be stored as part of the task context and must be initialized to
a non zero value to ensure interrupts don't inadvertently become unmasked before
the scheduler starts. As it is stored as part of the task context it will
automatically be set to 0 when the first task is started. */
static UBaseType_t uxCriticalNesting = 0xaaaaaaaa;
/* Contains context when starting scheduler, save all 31 registers */
#ifdef __gracefulExit
BaseType_t xStartContext[31] = {0};
#endif
typedef struct
{
uint32_t val_low;
uint32_t val_high;
}riscv_machine_timer_t;
static volatile riscv_machine_timer_t *mtime = (riscv_machine_timer_t *)0x4400BFF8;
static volatile riscv_machine_timer_t *mtimecmp = (riscv_machine_timer_t *)0x44004000;
/*
* Setup the timer to generate the tick interrupts.
*/
void vPortSetupTimer( void );
/*
* Set the next interval for the timer
*/
static void prvSetNextTimerInterrupt( void );
/*
* Used to catch tasks that attempt to return from their implementing function.
*/
static void prvTaskExitError( void );
void vPortEnterCritical( void )
{
portDISABLE_INTERRUPTS();
uxCriticalNesting++;
}
/*-----------------------------------------------------------*/
void vPortExitCritical( void )
{
uxCriticalNesting--;
if( uxCriticalNesting == 0 )
{
portENABLE_INTERRUPTS();
}
}
/*-----------------------------------------------------------*/
/* Sets the next timer interrupt
* Reads previous timer compare register, and adds tickrate */
static void prvSetNextTimerInterrupt(void)
{
uint64_t time;
time = mtime->val_low;
time |= ((uint64_t)mtime->val_high << 32);
time += (configCPU_CLOCK_HZ / configTICK_RATE_HZ);
mtimecmp->val_low = (uint32_t)(time & 0xFFFFFFFF);
mtimecmp->val_high = (uint32_t)((time >> 32) & 0xFFFFFFFF);
/* Enable timer interrupt */
__asm volatile("csrs mie,%0"::"r"(0x80));
}
/*-----------------------------------------------------------*/
/* Sets and enable the timer interrupt */
void vPortSetupTimer(void)
{
uint64_t time;
time = mtime->val_low;
time |= ((uint64_t)mtime->val_high << 32);
time += (configCPU_CLOCK_HZ / configTICK_RATE_HZ);
mtimecmp->val_low = (uint32_t)(time & 0xFFFFFFFF);
mtimecmp->val_high = (uint32_t)((time >> 32) & 0xFFFFFFFF);
/* Enable timer interrupt */
__asm volatile("csrs mie,%0"::"r"(0x80));
}
/*-----------------------------------------------------------*/
void prvTaskExitError( void )
{
/* A function that implements a task must not exit or attempt to return to
its caller as there is nothing to return to. If a task wants to exit it
should instead call vTaskDelete( NULL ).
Artificially force an assert() to be triggered if configASSERT() is
defined, then stop here so application writers can catch the error. */
configASSERT( uxCriticalNesting == ~0UL );
portDISABLE_INTERRUPTS();
for( ;; );
}
/*-----------------------------------------------------------*/
/* Clear current interrupt mask and set given mask */
void vPortClearInterruptMask(int mask)
{
__asm volatile("csrw mie, %0"::"r"(mask));
}
/*-----------------------------------------------------------*/
/* Set interrupt mask and return current interrupt enable register */
int vPortSetInterruptMask(void)
{
int ret;
__asm volatile("csrr %0,mie":"=r"(ret));
__asm volatile("csrc mie,%0"::"i"(7));
return ret;
}
/*
* See header file for description.
*/
StackType_t *pxPortInitialiseStack( StackType_t *pxTopOfStack, TaskFunction_t pxCode, void *pvParameters )
{
/* Simulate the stack frame as it would be created by a context switch
interrupt. */
register int *tp asm("x3");
pxTopOfStack--;
*pxTopOfStack = (portSTACK_TYPE)pxCode; /* Start address */
pxTopOfStack -= 22;
*pxTopOfStack = (portSTACK_TYPE)pvParameters; /* Register a0 */
pxTopOfStack -= 6;
*pxTopOfStack = (portSTACK_TYPE)tp; /* Register thread pointer */
pxTopOfStack -= 3;
*pxTopOfStack = (portSTACK_TYPE)prvTaskExitError; /* Register ra */
return pxTopOfStack;
}
/*-----------------------------------------------------------*/
void vPortSysTickHandler( void )
{
/*Save Context*/
{
__asm volatile("lw t0, pxCurrentTCB");
__asm volatile("sw a2, 0x0(t0)");
}
/* Increment the RTOS tick. */
prvSetNextTimerInterrupt();
/*Switch task */
if( xTaskIncrementTick() != pdFALSE )
{
vTaskSwitchContext();
}
/*Restore Context*/
{
__asm volatile("lw sp, pxCurrentTCB");
__asm volatile("lw sp, 0x0(sp)");
__asm volatile("lw t0, 31 * 4(sp)");
__asm volatile("csrw mepc, t0");
__asm volatile("lw x1, 0x0(sp)");
__asm volatile("lw x4, 3 * 4(sp)");
__asm volatile("lw x5, 4 * 4(sp)");
__asm volatile("lw x6, 5 * 4(sp)");
__asm volatile("lw x7, 6 * 4(sp)");
__asm volatile("lw x8, 7 * 4(sp)");
__asm volatile("lw x9, 8 * 4(sp)");
__asm volatile("lw x10, 9 * 4(sp)");
__asm volatile("lw x11, 10 * 4(sp)");
__asm volatile("lw x12, 11 * 4(sp)");
__asm volatile("lw x13, 12 * 4(sp)");
__asm volatile("lw x14, 13 * 4(sp)");
__asm volatile("lw x15, 14 * 4(sp)");
__asm volatile("lw x16, 15 * 4(sp)");
__asm volatile("lw x17, 16 * 4(sp)");
__asm volatile("lw x18, 17 * 4(sp)");
__asm volatile("lw x19, 18 * 4(sp)");
__asm volatile("lw x20, 19 * 4(sp)");
__asm volatile("lw x21, 20 * 4(sp)");
__asm volatile("lw x22, 21 * 4(sp)");
__asm volatile("lw x23, 22 * 4(sp)");
__asm volatile("lw x24, 23 * 4(sp)");
__asm volatile("lw x25, 24 * 4(sp)");
__asm volatile("lw x26, 25 * 4(sp)");
__asm volatile("lw x27, 26 * 4(sp)");
__asm volatile("lw x28, 27 * 4(sp)");
__asm volatile("lw x29, 28 * 4(sp)");
__asm volatile("lw x30, 29 * 4(sp)");
__asm volatile("lw x31, 30 * 4(sp)");
__asm volatile("addi sp, sp, 4 * 32");
__asm volatile("mret");
}
}
uint32_t g_startscheduler = 0;
BaseType_t xPortStartScheduler( void )
{
vPortSetupTimer();
uxCriticalNesting = 0;
g_startscheduler = 1;
__enable_irq();
raise_soft_interrupt();
/*Should not get here*/
return pdFALSE;
}
void Software_IRQHandler(void)
{
if(1 == g_startscheduler)
{
g_startscheduler = 2; //skip the save n switch context first time when scheduler is starting.
}
else
{
/*Save Context*/
{
__asm volatile("lw t0, pxCurrentTCB");
__asm volatile("sw a2, 0x0(t0)");
}
vTaskSwitchContext();
}
/*Restore Context*/
{
__asm volatile("lw sp, pxCurrentTCB");
__asm volatile("lw sp, 0x0(sp)");
__asm volatile("lw t0, 31 * 4(sp)");
__asm volatile("csrw mepc, t0");
__asm volatile("lw x1, 0x0(sp)");
__asm volatile("lw x4, 3 * 4(sp)");
__asm volatile("lw x5, 4 * 4(sp)");
__asm volatile("lw x6, 5 * 4(sp)");
__asm volatile("lw x7, 6 * 4(sp)");
__asm volatile("lw x8, 7 * 4(sp)");
__asm volatile("lw x9, 8 * 4(sp)");
__asm volatile("lw x10, 9 * 4(sp)");
__asm volatile("lw x11, 10 * 4(sp)");
__asm volatile("lw x12, 11 * 4(sp)");
__asm volatile("lw x13, 12 * 4(sp)");
__asm volatile("lw x14, 13 * 4(sp)");
__asm volatile("lw x15, 14 * 4(sp)");
__asm volatile("lw x16, 15 * 4(sp)");
__asm volatile("lw x17, 16 * 4(sp)");
__asm volatile("lw x18, 17 * 4(sp)");
__asm volatile("lw x19, 18 * 4(sp)");
__asm volatile("lw x20, 19 * 4(sp)");
__asm volatile("lw x21, 20 * 4(sp)");
__asm volatile("lw x22, 21 * 4(sp)");
__asm volatile("lw x23, 22 * 4(sp)");
__asm volatile("lw x24, 23 * 4(sp)");
__asm volatile("lw x25, 24 * 4(sp)");
__asm volatile("lw x26, 25 * 4(sp)");
__asm volatile("lw x27, 26 * 4(sp)");
__asm volatile("lw x28, 27 * 4(sp)");
__asm volatile("lw x29, 28 * 4(sp)");
__asm volatile("lw x30, 29 * 4(sp)");
__asm volatile("lw x31, 30 * 4(sp)");
__asm volatile("addi sp, sp, 4 * 32");
//PRCI->MSIP[0] = 0x00;
__asm volatile("addi sp, sp, -1*4");
__asm volatile("sw t0, 0(sp)");
__asm volatile("li t0, 0x44000000"); // address of PRCI->MSIP[0]
__asm volatile("sw zero,0(t0)");
__asm volatile("lw t0, 0(sp)");
__asm volatile("addi sp, sp, 1*4");
__asm volatile("mret");
}
}
void vPortYield( void )
{
raise_soft_interrupt();
}
|
