blob: 0dac49773065f862a2c1c9d281ae620a23b5133e (
plain)
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
|
#include <symbols.h>
/* mailbox message buffer */
volatile unsigned int __attribute__((aligned(16))) mbox[36];
#define VIDEOCORE_MBOX (MMIO_BASE+0x0000B880)
#define MBOX_READ ((volatile unsigned int*)(VIDEOCORE_MBOX+0x0))
#define MBOX_POLL ((volatile unsigned int*)(VIDEOCORE_MBOX+0x10))
#define MBOX_SENDER ((volatile unsigned int*)(VIDEOCORE_MBOX+0x14))
#define MBOX_STATUS ((volatile unsigned int*)(VIDEOCORE_MBOX+0x18))
#define MBOX_CONFIG ((volatile unsigned int*)(VIDEOCORE_MBOX+0x1C))
#define MBOX_WRITE ((volatile unsigned int*)(VIDEOCORE_MBOX+0x20))
#define MBOX_RESPONSE 0x80000000
#define MBOX_FULL 0x80000000
#define MBOX_EMPTY 0x40000000
/**
* Make a mailbox call. Returns 0 on failure, non-zero on success
*/
int mbox_call(unsigned char ch)
{
unsigned int r = (((unsigned int)((unsigned long)&mbox)&~0xF) | (ch&0xF));
/* wait until we can write to the mailbox */
do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_FULL);
/* write the address of our message to the mailbox with channel identifier */
*MBOX_WRITE = r;
/* now wait for the response */
while(1) {
/* is there a response? */
do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_EMPTY);
/* is it a response to our message? */
if(r == *MBOX_READ)
/* is it a valid successful response? */
return mbox[1]==MBOX_RESPONSE;
}
return 0;
}
|
