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
|
/* SPDX-License-Identifier: GPL-2.0-only */
/*
* Copyright (C) 2009 Sascha Hauer <s.hauer@pengutronix.de>
*/
#include <linux/linkage.h>
#include <asm/assembler.h>
/*
* r8 = bit 0-15: tx offset, bit 16-31: tx buffer size
* r9 = bit 0-15: rx offset, bit 16-31: rx buffer size
*/
#define SSI_STX0 0x00
#define SSI_SRX0 0x08
#define SSI_SISR 0x14
#define SSI_SIER 0x18
#define SSI_SACNT 0x38
#define SSI_SACNT_AC97EN (1 << 0)
#define SSI_SIER_TFE0_EN (1 << 0)
#define SSI_SISR_TFE0 (1 << 0)
#define SSI_SISR_RFF0 (1 << 2)
#define SSI_SIER_RFF0_EN (1 << 2)
.text
.global imx_ssi_fiq_start
.global imx_ssi_fiq_end
.global imx_ssi_fiq_base
.global imx_ssi_fiq_rx_buffer
.global imx_ssi_fiq_tx_buffer
/*
* imx_ssi_fiq_start is _intentionally_ not marked as a function symbol
* using ENDPROC(). imx_ssi_fiq_start and imx_ssi_fiq_end are used to
* mark the function body so that it can be copied to the FIQ vector in
* the vectors page. imx_ssi_fiq_start should only be called as the result
* of an FIQ: calling it directly will not work.
*/
imx_ssi_fiq_start:
ldr r12, .L_imx_ssi_fiq_base
/* TX */
ldr r13, .L_imx_ssi_fiq_tx_buffer
/* shall we send? */
ldr r11, [r12, #SSI_SIER]
tst r11, #SSI_SIER_TFE0_EN
beq 1f
/* TX FIFO empty? */
ldr r11, [r12, #SSI_SISR]
tst r11, #SSI_SISR_TFE0
beq 1f
mov r10, #0x10000
sub r10, #1
and r10, r10, r8 /* r10: current buffer offset */
add r13, r13, r10
ldrh r11, [r13]
strh r11, [r12, #SSI_STX0]
ldrh r11, [r13, #2]
strh r11, [r12, #SSI_STX0]
ldrh r11, [r13, #4]
strh r11, [r12, #SSI_STX0]
ldrh r11, [r13, #6]
strh r11, [r12, #SSI_STX0]
add r10, #8
lsr r11, r8, #16 /* r11: buffer size */
cmp r10, r11
lslgt r8, r11, #16
addle r8, #8
1:
/* RX */
/* shall we receive? */
ldr r11, [r12, #SSI_SIER]
tst r11, #SSI_SIER_RFF0_EN
beq 1f
/* RX FIFO full? */
ldr r11, [r12, #SSI_SISR]
tst r11, #SSI_SISR_RFF0
beq 1f
ldr r13, .L_imx_ssi_fiq_rx_buffer
mov r10, #0x10000
sub r10, #1
and r10, r10, r9 /* r10: current buffer offset */
add r13, r13, r10
ldr r11, [r12, #SSI_SACNT]
tst r11, #SSI_SACNT_AC97EN
ldr r11, [r12, #SSI_SRX0]
strh r11, [r13]
ldr r11, [r12, #SSI_SRX0]
strh r11, [r13, #2]
/* dummy read to skip slot 12 */
ldrne r11, [r12, #SSI_SRX0]
ldr r11, [r12, #SSI_SRX0]
strh r11, [r13, #4]
ldr r11, [r12, #SSI_SRX0]
strh r11, [r13, #6]
/* dummy read to skip slot 12 */
ldrne r11, [r12, #SSI_SRX0]
add r10, #8
lsr r11, r9, #16 /* r11: buffer size */
cmp r10, r11
lslgt r9, r11, #16
addle r9, #8
1:
@ return from FIQ
subs pc, lr, #4
.align
.L_imx_ssi_fiq_base:
imx_ssi_fiq_base:
.word 0x0
.L_imx_ssi_fiq_rx_buffer:
imx_ssi_fiq_rx_buffer:
.word 0x0
.L_imx_ssi_fiq_tx_buffer:
imx_ssi_fiq_tx_buffer:
.word 0x0
.L_imx_ssi_fiq_end:
imx_ssi_fiq_end:
|
