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(UCLASS_PINCTRL, &dev) || !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_ofdata_to_platdata(struct udevice * dev)36 static int bcm283x_pl011_serial_ofdata_to_platdata(struct udevice *dev)
37 {
38 struct pl01x_serial_platdata *plat = dev_get_platdata(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 ret = pl01x_serial_ofdata_to_platdata(dev);
46 if (ret)
47 return ret;
48
49 /*
50 * TODO: Reinitialization doesn't always work for now, just skip
51 * init always - we know we're already initialized
52 */
53 plat->skip_init = true;
54
55 return 0;
56 }
57
bcm283x_pl011_serial_setbrg(struct udevice * dev,int baudrate)58 static int bcm283x_pl011_serial_setbrg(struct udevice *dev, int baudrate)
59 {
60 int r;
61
62 r = pl01x_serial_setbrg(dev, baudrate);
63
64 /*
65 * We may have been muxed to a bogus line before. Drain the RX
66 * queue so we start at a clean slate.
67 */
68 while (pl01x_serial_getc(dev) != -EAGAIN) ;
69
70 return r;
71 }
72
73 static const struct dm_serial_ops bcm283x_pl011_serial_ops = {
74 .putc = pl01x_serial_putc,
75 .pending = pl01x_serial_pending,
76 .getc = pl01x_serial_getc,
77 .setbrg = bcm283x_pl011_serial_setbrg,
78 };
79
80 static const struct udevice_id bcm283x_pl011_serial_id[] = {
81 {.compatible = "brcm,bcm2835-pl011", .data = TYPE_PL011},
82 {}
83 };
84
85 U_BOOT_DRIVER(bcm283x_pl011_uart) = {
86 .name = "bcm283x_pl011",
87 .id = UCLASS_SERIAL,
88 .of_match = of_match_ptr(bcm283x_pl011_serial_id),
89 .ofdata_to_platdata = of_match_ptr(bcm283x_pl011_serial_ofdata_to_platdata),
90 .platdata_auto_alloc_size = sizeof(struct pl01x_serial_platdata),
91 .probe = pl01x_serial_probe,
92 .ops = &bcm283x_pl011_serial_ops,
93 #if !CONFIG_IS_ENABLED(OF_CONTROL)
94 .flags = DM_FLAG_PRE_RELOC,
95 #endif
96 .priv_auto_alloc_size = sizeof(struct pl01x_priv),
97 };
98