1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2016 Stefan Roese <sr@denx.de>
4  */
5 
6 #include <common.h>
7 #include <asm/io.h>
8 #include <asm/pnp_def.h>
9 
10 #define WINBOND_ENTRY_KEY	0x87
11 #define WINBOND_EXIT_KEY	0xaa
12 
13 /* Enable configuration: pass entry key '0x87' into index port dev twice */
14 static void pnp_enter_conf_state(u16 dev)
15 {
16 	u16 port = dev >> 8;
17 
18 	outb(WINBOND_ENTRY_KEY, port);
19 	outb(WINBOND_ENTRY_KEY, port);
20 }
21 
22 /* Disable configuration: pass exit key '0xAA' into index port dev */
23 static void pnp_exit_conf_state(u16 dev)
24 {
25 	u16 port = dev >> 8;
26 
27 	outb(WINBOND_EXIT_KEY, port);
28 }
29 
30 /* Bring up early serial debugging output before the RAM is initialized */
31 void winbond_enable_serial(uint dev, uint iobase, uint irq)
32 {
33 	pnp_enter_conf_state(dev);
34 	pnp_set_logical_device(dev);
35 	pnp_set_enable(dev, 0);
36 	pnp_set_iobase(dev, PNP_IDX_IO0, iobase);
37 	pnp_set_irq(dev, PNP_IDX_IRQ0, irq);
38 	pnp_set_enable(dev, 1);
39 	pnp_exit_conf_state(dev);
40 }
41