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 #include <asm/setup.h>
17
18 #include "pic32mzda.h"
19 #include "early_pin.h"
20
21 /* Default early console parameters */
22 #define EARLY_CONSOLE_PORT 1
23 #define EARLY_CONSOLE_BAUDRATE 115200
24
25 #define UART_ENABLE BIT(15)
26 #define UART_ENABLE_RX BIT(12)
27 #define UART_ENABLE_TX BIT(10)
28 #define UART_TX_FULL BIT(9)
29
30 /* UART1(x == 0) - UART6(x == 5) */
31 #define UART_BASE(x) ((x) * 0x0200)
32 #define U_MODE(x) UART_BASE(x)
33 #define U_STA(x) (UART_BASE(x) + 0x10)
34 #define U_TXR(x) (UART_BASE(x) + 0x20)
35 #define U_BRG(x) (UART_BASE(x) + 0x40)
36
37 static void __iomem *uart_base;
38 static char console_port = -1;
39
configure_uart_pins(int port)40 static int __init configure_uart_pins(int port)
41 {
42 switch (port) {
43 case 1:
44 pic32_pps_input(IN_FUNC_U2RX, IN_RPB0);
45 pic32_pps_output(OUT_FUNC_U2TX, OUT_RPG9);
46 break;
47 case 5:
48 pic32_pps_input(IN_FUNC_U6RX, IN_RPD0);
49 pic32_pps_output(OUT_FUNC_U6TX, OUT_RPB8);
50 break;
51 default:
52 return -1;
53 }
54
55 return 0;
56 }
57
configure_uart(char port,int baud)58 static void __init configure_uart(char port, int baud)
59 {
60 u32 pbclk;
61
62 pbclk = pic32_get_pbclk(2);
63
64 __raw_writel(0, uart_base + U_MODE(port));
65 __raw_writel(((pbclk / baud) / 16) - 1, uart_base + U_BRG(port));
66 __raw_writel(UART_ENABLE, uart_base + U_MODE(port));
67 __raw_writel(UART_ENABLE_TX | UART_ENABLE_RX,
68 uart_base + PIC32_SET(U_STA(port)));
69 }
70
setup_early_console(char port,int baud)71 static void __init setup_early_console(char port, int baud)
72 {
73 if (configure_uart_pins(port))
74 return;
75
76 console_port = port;
77 configure_uart(console_port, baud);
78 }
79
pic32_getcmdline(void)80 static char * __init pic32_getcmdline(void)
81 {
82 /*
83 * arch_mem_init() has not been called yet, so we don't have a real
84 * command line setup if using CONFIG_CMDLINE_BOOL.
85 */
86 #ifdef CONFIG_CMDLINE_OVERRIDE
87 return CONFIG_CMDLINE;
88 #else
89 return fw_getcmdline();
90 #endif
91 }
92
get_port_from_cmdline(char * arch_cmdline)93 static int __init get_port_from_cmdline(char *arch_cmdline)
94 {
95 char *s;
96 int port = -1;
97
98 if (!arch_cmdline || *arch_cmdline == '\0')
99 goto _out;
100
101 s = strstr(arch_cmdline, "earlyprintk=");
102 if (s) {
103 s = strstr(s, "ttyS");
104 if (s)
105 s += 4;
106 else
107 goto _out;
108
109 port = (*s) - '0';
110 }
111
112 _out:
113 return port;
114 }
115
get_baud_from_cmdline(char * arch_cmdline)116 static int __init get_baud_from_cmdline(char *arch_cmdline)
117 {
118 char *s;
119 int baud = -1;
120
121 if (!arch_cmdline || *arch_cmdline == '\0')
122 goto _out;
123
124 s = strstr(arch_cmdline, "earlyprintk=");
125 if (s) {
126 s = strstr(s, "ttyS");
127 if (s)
128 s += 6;
129 else
130 goto _out;
131
132 baud = 0;
133 while (*s >= '0' && *s <= '9')
134 baud = baud * 10 + *s++ - '0';
135 }
136
137 _out:
138 return baud;
139 }
140
fw_init_early_console(char port)141 void __init fw_init_early_console(char port)
142 {
143 char *arch_cmdline = pic32_getcmdline();
144 int baud = -1;
145
146 uart_base = ioremap_nocache(PIC32_BASE_UART, 0xc00);
147
148 baud = get_baud_from_cmdline(arch_cmdline);
149 if (port == -1)
150 port = get_port_from_cmdline(arch_cmdline);
151
152 if (port == -1)
153 port = EARLY_CONSOLE_PORT;
154
155 if (baud == -1)
156 baud = EARLY_CONSOLE_BAUDRATE;
157
158 setup_early_console(port, baud);
159 }
160
prom_putchar(char c)161 void prom_putchar(char c)
162 {
163 if (console_port >= 0) {
164 while (__raw_readl(
165 uart_base + U_STA(console_port)) & UART_TX_FULL)
166 ;
167
168 __raw_writel(c, uart_base + U_TXR(console_port));
169 }
170 }
171
