1 /*
2 * Joshua Henderson <joshua.henderson@microchip.com>
3 * Copyright (C) 2015 Microchip Technology Inc. All rights reserved.
4 *
5 * This program is free software; you can distribute it and/or modify it
6 * under the terms of the GNU General Public License (Version 2) as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * for more details.
13 */
14 #include <asm/mach-pic32/pic32.h>
15 #include <asm/fw/fw.h>
16
17 #include "pic32mzda.h"
18 #include "early_pin.h"
19
20 /* Default early console parameters */
21 #define EARLY_CONSOLE_PORT 1
22 #define EARLY_CONSOLE_BAUDRATE 115200
23
24 #define UART_ENABLE BIT(15)
25 #define UART_ENABLE_RX BIT(12)
26 #define UART_ENABLE_TX BIT(10)
27 #define UART_TX_FULL BIT(9)
28
29 /* UART1(x == 0) - UART6(x == 5) */
30 #define UART_BASE(x) ((x) * 0x0200)
31 #define U_MODE(x) UART_BASE(x)
32 #define U_STA(x) (UART_BASE(x) + 0x10)
33 #define U_TXR(x) (UART_BASE(x) + 0x20)
34 #define U_BRG(x) (UART_BASE(x) + 0x40)
35
36 static void __iomem *uart_base;
37 static char console_port = -1;
38
configure_uart_pins(int port)39 static int __init configure_uart_pins(int port)
40 {
41 switch (port) {
42 case 1:
43 pic32_pps_input(IN_FUNC_U2RX, IN_RPB0);
44 pic32_pps_output(OUT_FUNC_U2TX, OUT_RPG9);
45 break;
46 case 5:
47 pic32_pps_input(IN_FUNC_U6RX, IN_RPD0);
48 pic32_pps_output(OUT_FUNC_U6TX, OUT_RPB8);
49 break;
50 default:
51 return -1;
52 }
53
54 return 0;
55 }
56
configure_uart(char port,int baud)57 static void __init configure_uart(char port, int baud)
58 {
59 u32 pbclk;
60
61 pbclk = pic32_get_pbclk(2);
62
63 __raw_writel(0, uart_base + U_MODE(port));
64 __raw_writel(((pbclk / baud) / 16) - 1, uart_base + U_BRG(port));
65 __raw_writel(UART_ENABLE, uart_base + U_MODE(port));
66 __raw_writel(UART_ENABLE_TX | UART_ENABLE_RX,
67 uart_base + PIC32_SET(U_STA(port)));
68 }
69
setup_early_console(char port,int baud)70 static void __init setup_early_console(char port, int baud)
71 {
72 if (configure_uart_pins(port))
73 return;
74
75 console_port = port;
76 configure_uart(console_port, baud);
77 }
78
pic32_getcmdline(void)79 static char * __init pic32_getcmdline(void)
80 {
81 /*
82 * arch_mem_init() has not been called yet, so we don't have a real
83 * command line setup if using CONFIG_CMDLINE_BOOL.
84 */
85 #ifdef CONFIG_CMDLINE_OVERRIDE
86 return CONFIG_CMDLINE;
87 #else
88 return fw_getcmdline();
89 #endif
90 }
91
get_port_from_cmdline(char * arch_cmdline)92 static int __init get_port_from_cmdline(char *arch_cmdline)
93 {
94 char *s;
95 int port = -1;
96
97 if (!arch_cmdline || *arch_cmdline == '\0')
98 goto _out;
99
100 s = strstr(arch_cmdline, "earlyprintk=");
101 if (s) {
102 s = strstr(s, "ttyS");
103 if (s)
104 s += 4;
105 else
106 goto _out;
107
108 port = (*s) - '0';
109 }
110
111 _out:
112 return port;
113 }
114
get_baud_from_cmdline(char * arch_cmdline)115 static int __init get_baud_from_cmdline(char *arch_cmdline)
116 {
117 char *s;
118 int baud = -1;
119
120 if (!arch_cmdline || *arch_cmdline == '\0')
121 goto _out;
122
123 s = strstr(arch_cmdline, "earlyprintk=");
124 if (s) {
125 s = strstr(s, "ttyS");
126 if (s)
127 s += 6;
128 else
129 goto _out;
130
131 baud = 0;
132 while (*s >= '0' && *s <= '9')
133 baud = baud * 10 + *s++ - '0';
134 }
135
136 _out:
137 return baud;
138 }
139
fw_init_early_console(char port)140 void __init fw_init_early_console(char port)
141 {
142 char *arch_cmdline = pic32_getcmdline();
143 int baud = -1;
144
145 uart_base = ioremap_nocache(PIC32_BASE_UART, 0xc00);
146
147 baud = get_baud_from_cmdline(arch_cmdline);
148 if (port == -1)
149 port = get_port_from_cmdline(arch_cmdline);
150
151 if (port == -1)
152 port = EARLY_CONSOLE_PORT;
153
154 if (baud == -1)
155 baud = EARLY_CONSOLE_BAUDRATE;
156
157 setup_early_console(port, baud);
158 }
159
prom_putchar(char c)160 int prom_putchar(char c)
161 {
162 if (console_port >= 0) {
163 while (__raw_readl(
164 uart_base + U_STA(console_port)) & UART_TX_FULL)
165 ;
166
167 __raw_writel(c, uart_base + U_TXR(console_port));
168 }
169
170 return 1;
171 }
172