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
|
/*
* BCM2835 SDHCI
* Copyright (C) 2012 Stephen Warren
* Based on U-Boot's MMC driver for the BCM2835 by Oleksandr Tymoshenko & me
* Portions of the code there were obviously based on the Linux kernel at:
* git://github.com/raspberrypi/linux.git rpi-3.6.y
* commit f5b930b "Main bcm2708 linux port" signed-off-by Dom Cobley.
*
* 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/>.
*/
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/mmc/host.h>
#include "sdhci-pltfm.h"
/*
* 400KHz is max freq for card ID etc. Use that as min card clock. We need to
* know the min to enable static calculation of max BCM2835_SDHCI_WRITE_DELAY.
*/
#define MIN_FREQ 400000
/*
* The Arasan has a bugette whereby it may lose the content of successive
* writes to registers that are within two SD-card clock cycles of each other
* (a clock domain crossing problem). It seems, however, that the data
* register does not have this problem, which is just as well - otherwise we'd
* have to nobble the DMA engine too.
*
* This should probably be dynamically calculated based on the actual card
* frequency. However, this is the longest we'll have to wait, and doesn't
* seem to slow access down too much, so the added complexity doesn't seem
* worth it for now.
*
* 1/MIN_FREQ is (max) time per tick of eMMC clock.
* 2/MIN_FREQ is time for two ticks.
* Multiply by 1000000 to get uS per two ticks.
* *1000000 for uSecs.
* +1 for hack rounding.
*/
#define BCM2835_SDHCI_WRITE_DELAY (((2 * 1000000) / MIN_FREQ) + 1)
struct bcm2835_sdhci {
u32 shadow;
};
static void bcm2835_sdhci_writel(struct sdhci_host *host, u32 val, int reg)
{
writel(val, host->ioaddr + reg);
udelay(BCM2835_SDHCI_WRITE_DELAY);
}
static inline u32 bcm2835_sdhci_readl(struct sdhci_host *host, int reg)
{
u32 val = readl(host->ioaddr + reg);
if (reg == SDHCI_CAPABILITIES)
val |= SDHCI_CAN_VDD_330;
return val;
}
static void bcm2835_sdhci_writew(struct sdhci_host *host, u16 val, int reg)
{
struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
struct bcm2835_sdhci *bcm2835_host = pltfm_host->priv;
u32 oldval = (reg == SDHCI_COMMAND) ? bcm2835_host->shadow :
bcm2835_sdhci_readl(host, reg & ~3);
u32 word_num = (reg >> 1) & 1;
u32 word_shift = word_num * 16;
u32 mask = 0xffff << word_shift;
u32 newval = (oldval & ~mask) | (val << word_shift);
if (reg == SDHCI_TRANSFER_MODE)
bcm2835_host->shadow = newval;
else
bcm2835_sdhci_writel(host, newval, reg & ~3);
}
static u16 bcm2835_sdhci_readw(struct sdhci_host *host, int reg)
{
u32 val = bcm2835_sdhci_readl(host, (reg & ~3));
u32 word_num = (reg >> 1) & 1;
u32 word_shift = word_num * 16;
u32 word = (val >> word_shift) & 0xffff;
return word;
}
static void bcm2835_sdhci_writeb(struct sdhci_host *host, u8 val, int reg)
{
u32 oldval = bcm2835_sdhci_readl(host, reg & ~3);
u32 byte_num = reg & 3;
u32 byte_shift = byte_num * 8;
u32 mask = 0xff << byte_shift;
u32 newval = (oldval & ~mask) | (val << byte_shift);
bcm2835_sdhci_writel(host, newval, reg & ~3);
}
static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg)
{
u32 val = bcm2835_sdhci_readl(host, (reg & ~3));
u32 byte_num = reg & 3;
u32 byte_shift = byte_num * 8;
u32 byte = (val >> byte_shift) & 0xff;
return byte;
}
unsigned int bcm2835_sdhci_get_min_clock(struct sdhci_host *host)
{
return MIN_FREQ;
}
static const struct sdhci_ops bcm2835_sdhci_ops = {
.write_l = bcm2835_sdhci_writel,
.write_w = bcm2835_sdhci_writew,
.write_b = bcm2835_sdhci_writeb,
.read_l = bcm2835_sdhci_readl,
.read_w = bcm2835_sdhci_readw,
.read_b = bcm2835_sdhci_readb,
.get_max_clock = sdhci_pltfm_clk_get_max_clock,
.get_min_clock = bcm2835_sdhci_get_min_clock,
};
static const struct sdhci_pltfm_data bcm2835_sdhci_pdata = {
.quirks = SDHCI_QUIRK_BROKEN_CARD_DETECTION |
SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK,
.ops = &bcm2835_sdhci_ops,
};
static int bcm2835_sdhci_probe(struct platform_device *pdev)
{
struct sdhci_host *host;
struct bcm2835_sdhci *bcm2835_host;
struct sdhci_pltfm_host *pltfm_host;
int ret;
host = sdhci_pltfm_init(pdev, &bcm2835_sdhci_pdata);
if (IS_ERR(host))
return PTR_ERR(host);
bcm2835_host = devm_kzalloc(&pdev->dev, sizeof(*bcm2835_host),
GFP_KERNEL);
if (!bcm2835_host) {
dev_err(mmc_dev(host->mmc),
"failed to allocate bcm2835_sdhci\n");
return -ENOMEM;
}
pltfm_host = sdhci_priv(host);
pltfm_host->priv = bcm2835_host;
pltfm_host->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(pltfm_host->clk)) {
ret = PTR_ERR(pltfm_host->clk);
goto err;
}
return sdhci_add_host(host);
err:
sdhci_pltfm_free(pdev);
return ret;
}
static int bcm2835_sdhci_remove(struct platform_device *pdev)
{
struct sdhci_host *host = platform_get_drvdata(pdev);
int dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff);
sdhci_remove_host(host, dead);
sdhci_pltfm_free(pdev);
return 0;
}
static const struct of_device_id bcm2835_sdhci_of_match[] = {
{ .compatible = "brcm,bcm2835-sdhci" },
{ }
};
MODULE_DEVICE_TABLE(of, bcm2835_sdhci_of_match);
static struct platform_driver bcm2835_sdhci_driver = {
.driver = {
.name = "sdhci-bcm2835",
.owner = THIS_MODULE,
.of_match_table = bcm2835_sdhci_of_match,
.pm = SDHCI_PLTFM_PMOPS,
},
.probe = bcm2835_sdhci_probe,
.remove = bcm2835_sdhci_remove,
};
module_platform_driver(bcm2835_sdhci_driver);
MODULE_DESCRIPTION("BCM2835 SDHCI driver");
MODULE_AUTHOR("Stephen Warren");
MODULE_LICENSE("GPL v2");
|
