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
|
/*
* reset.c - logic for resetting the cpu
*
* Copyright (c) 2005-2008 Analog Devices Inc.
*
* Licensed under the GPL-2 or later.
*/
#include <common.h>
#include <command.h>
#include <asm/blackfin.h>
#include "cpu.h"
/* A system soft reset makes external memory unusable so force
* this function into L1. We use the compiler ssync here rather
* than SSYNC() because it's safe (no interrupts and such) and
* we save some L1. We do not need to force sanity in the SYSCR
* register as the BMODE selection bit is cleared by the soft
* reset while the Core B bit (on dual core parts) is cleared by
* the core reset.
*/
__attribute__ ((__l1_text__, __noreturn__))
void bfin_reset(void)
{
/* Wait for completion of "system" events such as cache line
* line fills so that we avoid infinite stalls later on as
* much as possible. This code is in L1, so it won't trigger
* any such event after this point in time.
*/
__builtin_bfin_ssync();
while (1) {
/* Initiate System software reset. */
bfin_write_SWRST(0x7);
/* Due to the way reset is handled in the hardware, we need
* to delay for 7 SCLKS. The only reliable way to do this is
* to calculate the CCLK/SCLK ratio and multiply 7. For now,
* we'll assume worse case which is a 1:15 ratio.
*/
asm(
"LSETUP (1f, 1f) LC0 = %0\n"
"1: nop;"
:
: "a" (15 * 7)
: "LC0", "LB0", "LT0"
);
/* Clear System software reset */
bfin_write_SWRST(0);
/* Wait for the SWRST write to complete. Cannot rely on SSYNC
* though as the System state is all reset now.
*/
asm(
"LSETUP (1f, 1f) LC1 = %0\n"
"1: nop;"
:
: "a" (15 * 1)
: "LC1", "LB1", "LT1"
);
/* Issue core reset */
asm("raise 1");
}
}
/* We need to trampoline ourselves up into L1 since our linker
* does not have relaxtion support and will only generate a
* PC relative call with a 25 bit immediate. This is not enough
* to get us from the top of SDRAM into L1.
*/
__attribute__ ((__noreturn__))
static inline void bfin_reset_trampoline(void)
{
if (board_reset)
board_reset();
while (1)
asm("jump (%0);" : : "a" (bfin_reset));
}
__attribute__ ((__noreturn__))
void bfin_reset_or_hang(void)
{
#ifdef CONFIG_PANIC_HANG
hang();
#else
bfin_reset_trampoline();
#endif
}
int do_reset(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
bfin_reset_trampoline();
return 0;
}
|
