1 /*
2  * Copyright (C) 2015 Google, Inc
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <errno.h>
9 #include <asm/io.h>
10 
11 #define PCI_DEV_CONFIG(segbus, dev, fn) ( \
12 		(((segbus) & 0xfff) << 20) | \
13 		(((dev) & 0x1f) << 15) | \
14 		(((fn)  & 0x07) << 12))
15 
16 /* Platform Controller Unit */
17 #define LPC_DEV			0x1f
18 #define LPC_FUNC		0
19 
20 /* Enable UART */
21 #define UART_CONT		0x80
22 
23 /* SCORE Pad definitions */
24 #define UART_RXD_PAD			82
25 #define UART_TXD_PAD			83
26 
27 /* Pad base: PAD_CONF0[n]= PAD_BASE + 16 * n */
28 #define GPSCORE_PAD_BASE	(IO_BASE_ADDRESS + IO_BASE_OFFSET_GPSCORE)
29 
30 /* IO Memory */
31 #define IO_BASE_ADDRESS			0xfed0c000
32 #define  IO_BASE_OFFSET_GPSCORE		0x0000
33 #define  IO_BASE_OFFSET_GPNCORE		0x1000
34 #define  IO_BASE_OFFSET_GPSSUS		0x2000
35 #define IO_BASE_SIZE			0x4000
36 
37 static inline unsigned int score_pconf0(int pad_num)
38 {
39 	return GPSCORE_PAD_BASE + pad_num * 16;
40 }
41 
42 static void score_select_func(int pad, int func)
43 {
44 	uint32_t reg;
45 	uint32_t pconf0_addr = score_pconf0(pad);
46 
47 	reg = readl(pconf0_addr);
48 	reg &= ~0x7;
49 	reg |= func & 0x7;
50 	writel(reg, pconf0_addr);
51 }
52 
53 static void pci_write_config32(int dev, unsigned int where, u32 value)
54 {
55 	unsigned long addr;
56 
57 	addr = CONFIG_PCIE_ECAM_BASE | dev | (where & ~3);
58 	writel(value, addr);
59 }
60 
61 /* This can be called after memory-mapped PCI is working */
62 int setup_early_uart(void)
63 {
64 	/* Enable the legacy UART hardware. */
65 	pci_write_config32(PCI_DEV_CONFIG(0, LPC_DEV, LPC_FUNC), UART_CONT, 1);
66 
67 	/*
68 	 * Set up the pads to the UART function. This allows the signals to
69 	 * leave the chip
70 	 */
71 	score_select_func(UART_RXD_PAD, 1);
72 	score_select_func(UART_TXD_PAD, 1);
73 
74 	/* TODO(sjg@chromium.org): Call debug_uart_init() */
75 
76 	return 0;
77 }
78