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 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 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 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 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 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 } 115 116 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 } 140 141 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 } 160 161 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