1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2015 Google, Inc
4  */
5 
6 #include <common.h>
7 #include <errno.h>
8 #include <asm/io.h>
9 
10 #define PCI_DEV_CONFIG(segbus, dev, fn) ( \
11 		(((segbus) & 0xfff) << 20) | \
12 		(((dev) & 0x1f) << 15) | \
13 		(((fn)  & 0x07) << 12))
14 
15 /* Platform Controller Unit */
16 #define LPC_DEV			0x1f
17 #define LPC_FUNC		0
18 
19 /* Enable UART */
20 #define UART_CONT		0x80
21 
22 /* SCORE Pad definitions */
23 #define UART_RXD_PAD			82
24 #define UART_TXD_PAD			83
25 
26 /* Pad base: PAD_CONF0[n]= PAD_BASE + 16 * n */
27 #define GPSCORE_PAD_BASE	(IO_BASE_ADDRESS + IO_BASE_OFFSET_GPSCORE)
28 
29 /* IO Memory */
30 #define IO_BASE_ADDRESS			0xfed0c000
31 #define  IO_BASE_OFFSET_GPSCORE		0x0000
32 #define  IO_BASE_OFFSET_GPNCORE		0x1000
33 #define  IO_BASE_OFFSET_GPSSUS		0x2000
34 #define IO_BASE_SIZE			0x4000
35 
36 static inline unsigned int score_pconf0(int pad_num)
37 {
38 	return GPSCORE_PAD_BASE + pad_num * 16;
39 }
40 
41 static void score_select_func(int pad, int func)
42 {
43 	uint32_t reg;
44 	uint32_t pconf0_addr = score_pconf0(pad);
45 
46 	reg = readl(pconf0_addr);
47 	reg &= ~0x7;
48 	reg |= func & 0x7;
49 	writel(reg, pconf0_addr);
50 }
51 
52 static void x86_pci_write_config32(int dev, unsigned int where, u32 value)
53 {
54 	unsigned long addr;
55 
56 	addr = CONFIG_PCIE_ECAM_BASE | dev | (where & ~3);
57 	writel(value, addr);
58 }
59 
60 /* This can be called after memory-mapped PCI is working */
61 int setup_internal_uart(int enable)
62 {
63 	/* Enable or disable the legacy UART hardware */
64 	x86_pci_write_config32(PCI_DEV_CONFIG(0, LPC_DEV, LPC_FUNC), UART_CONT,
65 			       enable);
66 
67 	/* All done for the disable part, so just return */
68 	if (!enable)
69 		return 0;
70 
71 	/*
72 	 * Set up the pads to the UART function. This allows the signals to
73 	 * leave the chip
74 	 */
75 	score_select_func(UART_RXD_PAD, 1);
76 	score_select_func(UART_TXD_PAD, 1);
77 
78 	/* TODO(sjg@chromium.org): Call debug_uart_init() */
79 
80 	return 0;
81 }
82 
83 void board_debug_uart_init(void)
84 {
85 	setup_internal_uart(1);
86 }
87