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
|
/*
* Copyright (C) 2010 NVIDIA Corporation.
* Copyright (C) 2010 Google, Inc.
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program 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. See the
* GNU General Public License for more details.
*
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/sched.h>
#include <linux/mutex.h>
#include "apbio.h"
#include "iomap.h"
#if defined(CONFIG_TEGRA20_APB_DMA)
static DEFINE_MUTEX(tegra_apb_dma_lock);
static u32 *tegra_apb_bb;
static dma_addr_t tegra_apb_bb_phys;
static DECLARE_COMPLETION(tegra_apb_wait);
static u32 tegra_apb_readl_direct(unsigned long offset);
static void tegra_apb_writel_direct(u32 value, unsigned long offset);
static struct dma_chan *tegra_apb_dma_chan;
static struct dma_slave_config dma_sconfig;
bool tegra_apb_dma_init(void)
{
dma_cap_mask_t mask;
mutex_lock(&tegra_apb_dma_lock);
/* Check to see if we raced to setup */
if (tegra_apb_dma_chan)
goto skip_init;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
tegra_apb_dma_chan = dma_request_channel(mask, NULL, NULL);
if (!tegra_apb_dma_chan) {
/*
* This is common until the device is probed, so don't
* shout about it.
*/
pr_debug("%s: can not allocate dma channel\n", __func__);
goto err_dma_alloc;
}
tegra_apb_bb = dma_alloc_coherent(NULL, sizeof(u32),
&tegra_apb_bb_phys, GFP_KERNEL);
if (!tegra_apb_bb) {
pr_err("%s: can not allocate bounce buffer\n", __func__);
goto err_buff_alloc;
}
dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
dma_sconfig.src_maxburst = 1;
dma_sconfig.dst_maxburst = 1;
skip_init:
mutex_unlock(&tegra_apb_dma_lock);
return true;
err_buff_alloc:
dma_release_channel(tegra_apb_dma_chan);
tegra_apb_dma_chan = NULL;
err_dma_alloc:
mutex_unlock(&tegra_apb_dma_lock);
return false;
}
static void apb_dma_complete(void *args)
{
complete(&tegra_apb_wait);
}
static int do_dma_transfer(unsigned long apb_add,
enum dma_transfer_direction dir)
{
struct dma_async_tx_descriptor *dma_desc;
int ret;
if (dir == DMA_DEV_TO_MEM)
dma_sconfig.src_addr = apb_add;
else
dma_sconfig.dst_addr = apb_add;
ret = dmaengine_slave_config(tegra_apb_dma_chan, &dma_sconfig);
if (ret)
return ret;
dma_desc = dmaengine_prep_slave_single(tegra_apb_dma_chan,
tegra_apb_bb_phys, sizeof(u32), dir,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!dma_desc)
return -EINVAL;
dma_desc->callback = apb_dma_complete;
dma_desc->callback_param = NULL;
INIT_COMPLETION(tegra_apb_wait);
dmaengine_submit(dma_desc);
dma_async_issue_pending(tegra_apb_dma_chan);
ret = wait_for_completion_timeout(&tegra_apb_wait,
msecs_to_jiffies(50));
if (WARN(ret == 0, "apb read dma timed out")) {
dmaengine_terminate_all(tegra_apb_dma_chan);
return -EFAULT;
}
return 0;
}
static u32 tegra_apb_readl_using_dma(unsigned long offset)
{
int ret;
if (!tegra_apb_dma_chan && !tegra_apb_dma_init())
return tegra_apb_readl_direct(offset);
mutex_lock(&tegra_apb_dma_lock);
ret = do_dma_transfer(offset, DMA_DEV_TO_MEM);
if (ret < 0) {
pr_err("error in reading offset 0x%08lx using dma\n", offset);
*(u32 *)tegra_apb_bb = 0;
}
mutex_unlock(&tegra_apb_dma_lock);
return *((u32 *)tegra_apb_bb);
}
static void tegra_apb_writel_using_dma(u32 value, unsigned long offset)
{
int ret;
if (!tegra_apb_dma_chan && !tegra_apb_dma_init()) {
tegra_apb_writel_direct(value, offset);
return;
}
mutex_lock(&tegra_apb_dma_lock);
*((u32 *)tegra_apb_bb) = value;
ret = do_dma_transfer(offset, DMA_MEM_TO_DEV);
if (ret < 0)
pr_err("error in writing offset 0x%08lx using dma\n", offset);
mutex_unlock(&tegra_apb_dma_lock);
}
#else
#define tegra_apb_readl_using_dma tegra_apb_readl_direct
#define tegra_apb_writel_using_dma tegra_apb_writel_direct
#endif
typedef u32 (*apbio_read_fptr)(unsigned long offset);
typedef void (*apbio_write_fptr)(u32 value, unsigned long offset);
static apbio_read_fptr apbio_read;
static apbio_write_fptr apbio_write;
static u32 tegra_apb_readl_direct(unsigned long offset)
{
return readl(IO_ADDRESS(offset));
}
static void tegra_apb_writel_direct(u32 value, unsigned long offset)
{
writel(value, IO_ADDRESS(offset));
}
void tegra_apb_io_init(void)
{
/* Need to use dma only when it is Tegra20 based platform */
if (of_machine_is_compatible("nvidia,tegra20") ||
!of_have_populated_dt()) {
apbio_read = tegra_apb_readl_using_dma;
apbio_write = tegra_apb_writel_using_dma;
} else {
apbio_read = tegra_apb_readl_direct;
apbio_write = tegra_apb_writel_direct;
}
}
u32 tegra_apb_readl(unsigned long offset)
{
return apbio_read(offset);
}
void tegra_apb_writel(u32 value, unsigned long offset)
{
apbio_write(value, offset);
}
|
