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
|
/*
* Copyright (c) 2013-2014, NVIDIA CORPORATION. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope 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.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* Based on drivers/misc/eeprom/sunxi_sid.c
*/
#include <linux/device.h>
#include <linux/clk.h>
#include <linux/completion.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/kobject.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/random.h>
#include <soc/tegra/fuse.h>
#include "fuse.h"
#define FUSE_BEGIN 0x100
#define FUSE_SIZE 0x1f8
#define FUSE_UID_LOW 0x08
#define FUSE_UID_HIGH 0x0c
static phys_addr_t fuse_phys;
static struct clk *fuse_clk;
static void __iomem __initdata *fuse_base;
static DEFINE_MUTEX(apb_dma_lock);
static DECLARE_COMPLETION(apb_dma_wait);
static struct dma_chan *apb_dma_chan;
static struct dma_slave_config dma_sconfig;
static u32 *apb_buffer;
static dma_addr_t apb_buffer_phys;
static void apb_dma_complete(void *args)
{
complete(&apb_dma_wait);
}
static u32 tegra20_fuse_readl(const unsigned int offset)
{
int ret;
u32 val = 0;
struct dma_async_tx_descriptor *dma_desc;
mutex_lock(&apb_dma_lock);
dma_sconfig.src_addr = fuse_phys + FUSE_BEGIN + offset;
ret = dmaengine_slave_config(apb_dma_chan, &dma_sconfig);
if (ret)
goto out;
dma_desc = dmaengine_prep_slave_single(apb_dma_chan, apb_buffer_phys,
sizeof(u32), DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!dma_desc)
goto out;
dma_desc->callback = apb_dma_complete;
dma_desc->callback_param = NULL;
reinit_completion(&apb_dma_wait);
clk_prepare_enable(fuse_clk);
dmaengine_submit(dma_desc);
dma_async_issue_pending(apb_dma_chan);
ret = wait_for_completion_timeout(&apb_dma_wait, msecs_to_jiffies(50));
if (WARN(ret == 0, "apb read dma timed out"))
dmaengine_terminate_all(apb_dma_chan);
else
val = *apb_buffer;
clk_disable_unprepare(fuse_clk);
out:
mutex_unlock(&apb_dma_lock);
return val;
}
static const struct of_device_id tegra20_fuse_of_match[] = {
{ .compatible = "nvidia,tegra20-efuse" },
{},
};
static int apb_dma_init(void)
{
dma_cap_mask_t mask;
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
apb_dma_chan = dma_request_channel(mask, NULL, NULL);
if (!apb_dma_chan)
return -EPROBE_DEFER;
apb_buffer = dma_alloc_coherent(NULL, sizeof(u32), &apb_buffer_phys,
GFP_KERNEL);
if (!apb_buffer) {
dma_release_channel(apb_dma_chan);
return -ENOMEM;
}
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;
return 0;
}
static int tegra20_fuse_probe(struct platform_device *pdev)
{
struct resource *res;
int err;
fuse_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(fuse_clk)) {
dev_err(&pdev->dev, "missing clock");
return PTR_ERR(fuse_clk);
}
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res)
return -EINVAL;
fuse_phys = res->start;
err = apb_dma_init();
if (err)
return err;
if (tegra_fuse_create_sysfs(&pdev->dev, FUSE_SIZE, tegra20_fuse_readl))
return -ENODEV;
dev_dbg(&pdev->dev, "loaded\n");
return 0;
}
static struct platform_driver tegra20_fuse_driver = {
.probe = tegra20_fuse_probe,
.driver = {
.name = "tegra20_fuse",
.of_match_table = tegra20_fuse_of_match,
}
};
static int __init tegra20_fuse_init(void)
{
return platform_driver_register(&tegra20_fuse_driver);
}
postcore_initcall(tegra20_fuse_init);
/* Early boot code. This code is called before the devices are created */
u32 __init tegra20_fuse_early(const unsigned int offset)
{
return readl_relaxed(fuse_base + FUSE_BEGIN + offset);
}
bool __init tegra20_spare_fuse_early(int spare_bit)
{
u32 offset = spare_bit * 4;
bool value;
value = tegra20_fuse_early(offset + 0x100);
return value;
}
static void __init tegra20_fuse_add_randomness(void)
{
u32 randomness[7];
randomness[0] = tegra_sku_info.sku_id;
randomness[1] = tegra_read_straps();
randomness[2] = tegra_read_chipid();
randomness[3] = tegra_sku_info.cpu_process_id << 16;
randomness[3] |= tegra_sku_info.core_process_id;
randomness[4] = tegra_sku_info.cpu_speedo_id << 16;
randomness[4] |= tegra_sku_info.soc_speedo_id;
randomness[5] = tegra20_fuse_early(FUSE_UID_LOW);
randomness[6] = tegra20_fuse_early(FUSE_UID_HIGH);
add_device_randomness(randomness, sizeof(randomness));
}
void __init tegra20_init_fuse_early(void)
{
fuse_base = ioremap(TEGRA_FUSE_BASE, TEGRA_FUSE_SIZE);
tegra_init_revision();
tegra20_init_speedo_data(&tegra_sku_info);
tegra20_fuse_add_randomness();
iounmap(fuse_base);
}
|
