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
|
// SPDX-License-Identifier: GPL-2.0+
/*
* Support for Serial I/O using STMicroelectronics' on-chip ASC.
*
* Copyright (C) 2017, STMicroelectronics - All Rights Reserved
* Author(s): Patrice Chotard, <patrice.chotard@st.com> for STMicroelectronics.
*/
#include <common.h>
#include <dm.h>
#include <serial.h>
#include <asm/io.h>
DECLARE_GLOBAL_DATA_PTR;
#define BAUDMODE 0x00001000
#define RXENABLE 0x00000100
#define RUN 0x00000080
#define MODE 0x00000001
#define MODE_8BIT 0x0001
#define STOP_1BIT 0x0008
#define PARITYODD 0x0020
#define STA_TF BIT(9)
#define STA_RBF BIT(0)
struct sti_asc_uart {
u32 baudrate;
u32 txbuf;
u32 rxbuf;
u32 control;
u32 inten;
u32 status;
u32 guardtime;
u32 timeout;
u32 txreset;
u32 rxreset;
};
struct sti_asc_serial {
/* address of registers in physical memory */
struct sti_asc_uart *regs;
};
/* Values for the BAUDRATE Register */
#define PCLK (200ul * 1000000ul)
#define BAUDRATE_VAL_M0(bps) (PCLK / (16 * (bps)))
#define BAUDRATE_VAL_M1(bps) ((bps * (1 << 14)) + (1<<13)) / (PCLK/(1 << 6))
/*
* MODE 0
* ICCLK
* ASCBaudRate = ----------------
* baudrate * 16
*
* MODE 1
* baudrate * 16 * 2^16
* ASCBaudRate = ------------------------
* ICCLK
*
* NOTE:
* Mode 1 should be used for baudrates of 19200, and above, as it
* has a lower deviation error than Mode 0 for higher frequencies.
* Mode 0 should be used for all baudrates below 19200.
*/
static int sti_asc_pending(struct udevice *dev, bool input)
{
struct sti_asc_serial *priv = dev_get_priv(dev);
struct sti_asc_uart *const uart = priv->regs;
unsigned long status;
status = readl(&uart->status);
if (input)
return status & STA_RBF;
else
return status & STA_TF;
}
static int _sti_asc_serial_setbrg(struct sti_asc_uart *uart, int baudrate)
{
unsigned long val;
int t, mode = 1;
switch (baudrate) {
case 9600:
t = BAUDRATE_VAL_M0(9600);
mode = 0;
break;
case 19200:
t = BAUDRATE_VAL_M1(19200);
break;
case 38400:
t = BAUDRATE_VAL_M1(38400);
break;
case 57600:
t = BAUDRATE_VAL_M1(57600);
break;
default:
debug("ASC: unsupported baud rate: %d, using 115200 instead.\n",
baudrate);
case 115200:
t = BAUDRATE_VAL_M1(115200);
break;
}
/* disable the baudrate generator */
val = readl(&uart->control);
writel(val & ~RUN, &uart->control);
/* set baud generator reload value */
writel(t, &uart->baudrate);
/* reset the RX & TX buffers */
writel(1, &uart->txreset);
writel(1, &uart->rxreset);
/* set baud generator mode */
if (mode)
val |= BAUDMODE;
/* finally, write value and enable ASC */
writel(val, &uart->control);
return 0;
}
/* called to adjust baud-rate */
static int sti_asc_serial_setbrg(struct udevice *dev, int baudrate)
{
struct sti_asc_serial *priv = dev_get_priv(dev);
struct sti_asc_uart *const uart = priv->regs;
return _sti_asc_serial_setbrg(uart, baudrate);
}
/* blocking function, that returns next char */
static int sti_asc_serial_getc(struct udevice *dev)
{
struct sti_asc_serial *priv = dev_get_priv(dev);
struct sti_asc_uart *const uart = priv->regs;
/* polling wait: for a char to be read */
if (!sti_asc_pending(dev, true))
return -EAGAIN;
return readl(&uart->rxbuf);
}
/* write write out a single char */
static int sti_asc_serial_putc(struct udevice *dev, const char c)
{
struct sti_asc_serial *priv = dev_get_priv(dev);
struct sti_asc_uart *const uart = priv->regs;
/* wait till safe to write next char */
if (sti_asc_pending(dev, false))
return -EAGAIN;
/* finally, write next char */
writel(c, &uart->txbuf);
return 0;
}
/* initialize the ASC */
static int sti_asc_serial_probe(struct udevice *dev)
{
struct sti_asc_serial *priv = dev_get_priv(dev);
unsigned long val;
fdt_addr_t base;
base = devfdt_get_addr(dev);
if (base == FDT_ADDR_T_NONE)
return -EINVAL;
priv->regs = (struct sti_asc_uart *)base;
sti_asc_serial_setbrg(dev, gd->baudrate);
/*
* build up the value to be written to CONTROL
* set character length, bit stop number, odd parity
*/
val = RXENABLE | RUN | MODE_8BIT | STOP_1BIT | PARITYODD;
writel(val, &priv->regs->control);
return 0;
}
static const struct dm_serial_ops sti_asc_serial_ops = {
.putc = sti_asc_serial_putc,
.pending = sti_asc_pending,
.getc = sti_asc_serial_getc,
.setbrg = sti_asc_serial_setbrg,
};
static const struct udevice_id sti_serial_of_match[] = {
{ .compatible = "st,asc" },
{ }
};
U_BOOT_DRIVER(serial_sti_asc) = {
.name = "serial_sti_asc",
.id = UCLASS_SERIAL,
.of_match = sti_serial_of_match,
.ops = &sti_asc_serial_ops,
.probe = sti_asc_serial_probe,
.priv_auto_alloc_size = sizeof(struct sti_asc_serial),
.flags = DM_FLAG_PRE_RELOC,
};
|
