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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* (C) Copyright 2016 Stephen Warren <swarren@wwwdotorg.org>
*
* Derived from pl01x code:
*
* (C) Copyright 2000
* Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
*
* (C) Copyright 2004
* ARM Ltd.
* Philippe Robin, <philippe.robin@arm.com>
*/
/* Simple U-Boot driver for the BCM283x mini UART */
#include <common.h>
#include <dm.h>
#include <errno.h>
#include <watchdog.h>
#include <asm/gpio.h>
#include <asm/io.h>
#include <serial.h>
#include <dm/platform_data/serial_bcm283x_mu.h>
#include <dm/pinctrl.h>
#include <linux/compiler.h>
struct bcm283x_mu_regs {
u32 io;
u32 iir;
u32 ier;
u32 lcr;
u32 mcr;
u32 lsr;
u32 msr;
u32 scratch;
u32 cntl;
u32 stat;
u32 baud;
};
#define BCM283X_MU_LCR_DATA_SIZE_8 3
#define BCM283X_MU_LSR_TX_IDLE BIT(6)
/* This actually means not full, but is named not empty in the docs */
#define BCM283X_MU_LSR_TX_EMPTY BIT(5)
#define BCM283X_MU_LSR_RX_READY BIT(0)
struct bcm283x_mu_priv {
struct bcm283x_mu_regs *regs;
};
static int bcm283x_mu_serial_getc(struct udevice *dev);
static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
{
struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
struct bcm283x_mu_priv *priv = dev_get_priv(dev);
struct bcm283x_mu_regs *regs = priv->regs;
u32 divider;
if (plat->skip_init)
goto out;
divider = plat->clock / (baudrate * 8);
writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);
writel(divider - 1, ®s->baud);
out:
/* Flush the RX queue - all data in there is bogus */
while (bcm283x_mu_serial_getc(dev) != -EAGAIN) ;
return 0;
}
static int bcm283x_mu_serial_probe(struct udevice *dev)
{
struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
struct bcm283x_mu_priv *priv = dev_get_priv(dev);
priv->regs = (struct bcm283x_mu_regs *)plat->base;
return 0;
}
static int bcm283x_mu_serial_getc(struct udevice *dev)
{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);
struct bcm283x_mu_regs *regs = priv->regs;
u32 data;
/* Wait until there is data in the FIFO */
if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))
return -EAGAIN;
data = readl(®s->io);
return (int)data;
}
static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);
struct bcm283x_mu_regs *regs = priv->regs;
/* Wait until there is space in the FIFO */
if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))
return -EAGAIN;
/* Send the character */
writel(data, ®s->io);
return 0;
}
static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
{
struct bcm283x_mu_priv *priv = dev_get_priv(dev);
struct bcm283x_mu_regs *regs = priv->regs;
unsigned int lsr;
lsr = readl(®s->lsr);
if (input) {
WATCHDOG_RESET();
return (lsr & BCM283X_MU_LSR_RX_READY) ? 1 : 0;
} else {
return (lsr & BCM283X_MU_LSR_TX_IDLE) ? 0 : 1;
}
}
static const struct dm_serial_ops bcm283x_mu_serial_ops = {
.putc = bcm283x_mu_serial_putc,
.pending = bcm283x_mu_serial_pending,
.getc = bcm283x_mu_serial_getc,
.setbrg = bcm283x_mu_serial_setbrg,
};
#if CONFIG_IS_ENABLED(OF_CONTROL)
static const struct udevice_id bcm283x_mu_serial_id[] = {
{.compatible = "brcm,bcm2835-aux-uart"},
{}
};
/*
* Check if this serial device is muxed
*
* The serial device will only work properly if it has been muxed to the serial
* pins by firmware. Check whether that happened here.
*
* @return true if serial device is muxed, false if not
*/
static bool bcm283x_is_serial_muxed(void)
{
int serial_gpio = 15;
struct udevice *dev;
if (uclass_first_device(UCLASS_PINCTRL, &dev) || !dev)
return false;
if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT5)
return false;
return true;
}
static int bcm283x_mu_serial_ofdata_to_platdata(struct udevice *dev)
{
struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
fdt_addr_t addr;
/* Don't spawn the device if it's not muxed */
if (!bcm283x_is_serial_muxed())
return -ENODEV;
addr = devfdt_get_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
plat->base = addr;
plat->clock = dev_read_u32_default(dev, "clock", 1);
/*
* TODO: Reinitialization doesn't always work for now, just skip
* init always - we know we're already initialized
*/
plat->skip_init = true;
return 0;
}
#endif
U_BOOT_DRIVER(serial_bcm283x_mu) = {
.name = "serial_bcm283x_mu",
.id = UCLASS_SERIAL,
.of_match = of_match_ptr(bcm283x_mu_serial_id),
.ofdata_to_platdata = of_match_ptr(bcm283x_mu_serial_ofdata_to_platdata),
.platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
.probe = bcm283x_mu_serial_probe,
.ops = &bcm283x_mu_serial_ops,
.flags = DM_FLAG_PRE_RELOC,
.priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),
};
|
