1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (c) 2018 Alexander Graf <agraf@suse.de>
4 */
5
6 #include <common.h>
7 #include <dm.h>
8 #include <asm/gpio.h>
9 #include <dm/pinctrl.h>
10 #include <dm/platform_data/serial_pl01x.h>
11 #include <serial.h>
12 #include "serial_pl01x_internal.h"
13
14 /*
15 * Check if this serial device is muxed
16 *
17 * The serial device will only work properly if it has been muxed to the serial
18 * pins by firmware. Check whether that happened here.
19 *
20 * Return: true if serial device is muxed, false if not
21 */
bcm283x_is_serial_muxed(void)22 static bool bcm283x_is_serial_muxed(void)
23 {
24 int serial_gpio = 15;
25 struct udevice *dev;
26
27 if (uclass_first_device_err(UCLASS_PINCTRL, &dev))
28 return false;
29
30 if (pinctrl_get_gpio_mux(dev, 0, serial_gpio) != BCM2835_GPIO_ALT0)
31 return false;
32
33 return true;
34 }
35
bcm283x_pl011_serial_probe(struct udevice * dev)36 static int bcm283x_pl011_serial_probe(struct udevice *dev)
37 {
38 struct pl01x_serial_plat *plat = dev_get_plat(dev);
39 int ret;
40
41 /* Don't spawn the device if it's not muxed */
42 if (!bcm283x_is_serial_muxed())
43 return -ENODEV;
44
45 /*
46 * Read the ofdata here rather than in an of_to_plat() method
47 * since we need the soc simple-bus to be probed so that the 'ranges'
48 * property is used.
49 */
50 ret = pl01x_serial_of_to_plat(dev);
51 if (ret)
52 return ret;
53
54 /*
55 * TODO: Reinitialization doesn't always work for now, just skip
56 * init always - we know we're already initialized
57 */
58 plat->skip_init = true;
59
60 return pl01x_serial_probe(dev);
61 }
62
bcm283x_pl011_serial_setbrg(struct udevice * dev,int baudrate)63 static int bcm283x_pl011_serial_setbrg(struct udevice *dev, int baudrate)
64 {
65 int r;
66
67 r = pl01x_serial_setbrg(dev, baudrate);
68
69 /*
70 * We may have been muxed to a bogus line before. Drain the RX
71 * queue so we start at a clean slate.
72 */
73 while (pl01x_serial_getc(dev) != -EAGAIN) ;
74
75 return r;
76 }
77
78 static const struct dm_serial_ops bcm283x_pl011_serial_ops = {
79 .putc = pl01x_serial_putc,
80 .pending = pl01x_serial_pending,
81 .getc = pl01x_serial_getc,
82 .setbrg = bcm283x_pl011_serial_setbrg,
83 };
84
85 static const struct udevice_id bcm283x_pl011_serial_id[] = {
86 {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
87 {}
88 };
89
90 U_BOOT_DRIVER(bcm283x_pl011_uart) = {
91 .name = "bcm283x_pl011",
92 .id = UCLASS_SERIAL,
93 .of_match = of_match_ptr(bcm283x_pl011_serial_id),
94 .probe = bcm283x_pl011_serial_probe,
95 .plat_auto = sizeof(struct pl01x_serial_plat),
96 .ops = &bcm283x_pl011_serial_ops,
97 #if !CONFIG_IS_ENABLED(OF_CONTROL) || IS_ENABLED(CONFIG_OF_BOARD)
98 .flags = DM_FLAG_PRE_RELOC,
99 #endif
100 .priv_auto = sizeof(struct pl01x_priv),
101 };
102