1 /* 2 * udbg for for zilog scc ports as found on Apple PowerMacs 3 * 4 * Copyright (C) 2001-2005 PPC 64 Team, IBM Corp 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 #include <linux/config.h> 12 #include <linux/types.h> 13 #include <asm/udbg.h> 14 #include <asm/processor.h> 15 #include <asm/io.h> 16 #include <asm/prom.h> 17 #include <asm/pmac_feature.h> 18 19 extern u8 real_readb(volatile u8 __iomem *addr); 20 extern void real_writeb(u8 data, volatile u8 __iomem *addr); 21 22 #define SCC_TXRDY 4 23 #define SCC_RXRDY 1 24 25 static volatile u8 __iomem *sccc; 26 static volatile u8 __iomem *sccd; 27 28 static void udbg_scc_putc(char c) 29 { 30 if (sccc) { 31 while ((in_8(sccc) & SCC_TXRDY) == 0) 32 ; 33 out_8(sccd, c); 34 if (c == '\n') 35 udbg_scc_putc('\r'); 36 } 37 } 38 39 static int udbg_scc_getc_poll(void) 40 { 41 if (sccc) { 42 if ((in_8(sccc) & SCC_RXRDY) != 0) 43 return in_8(sccd); 44 else 45 return -1; 46 } 47 return -1; 48 } 49 50 static int udbg_scc_getc(void) 51 { 52 if (sccc) { 53 while ((in_8(sccc) & SCC_RXRDY) == 0) 54 ; 55 return in_8(sccd); 56 } 57 return -1; 58 } 59 60 static unsigned char scc_inittab[] = { 61 13, 0, /* set baud rate divisor */ 62 12, 0, 63 14, 1, /* baud rate gen enable, src=rtxc */ 64 11, 0x50, /* clocks = br gen */ 65 5, 0xea, /* tx 8 bits, assert DTR & RTS */ 66 4, 0x46, /* x16 clock, 1 stop */ 67 3, 0xc1, /* rx enable, 8 bits */ 68 }; 69 70 void udbg_scc_init(int force_scc) 71 { 72 u32 *reg; 73 unsigned long addr; 74 struct device_node *stdout = NULL, *escc = NULL, *macio = NULL; 75 struct device_node *ch, *ch_def = NULL, *ch_a = NULL; 76 char *path; 77 int i, x; 78 79 escc = of_find_node_by_name(NULL, "escc"); 80 if (escc == NULL) 81 goto bail; 82 macio = of_get_parent(escc); 83 if (macio == NULL) 84 goto bail; 85 path = (char *)get_property(of_chosen, "linux,stdout-path", NULL); 86 if (path != NULL) 87 stdout = of_find_node_by_path(path); 88 for (ch = NULL; (ch = of_get_next_child(escc, ch)) != NULL;) { 89 if (ch == stdout) 90 ch_def = of_node_get(ch); 91 if (strcmp(ch->name, "ch-a") == 0) 92 ch_a = of_node_get(ch); 93 } 94 if (ch_def == NULL && !force_scc) 95 goto bail; 96 97 ch = ch_def ? ch_def : ch_a; 98 99 /* Get address within mac-io ASIC */ 100 reg = (u32 *)get_property(escc, "reg", NULL); 101 if (reg == NULL) 102 goto bail; 103 addr = reg[0]; 104 105 /* Get address of mac-io PCI itself */ 106 reg = (u32 *)get_property(macio, "assigned-addresses", NULL); 107 if (reg == NULL) 108 goto bail; 109 addr += reg[2]; 110 111 /* Lock the serial port */ 112 pmac_call_feature(PMAC_FTR_SCC_ENABLE, ch, 113 PMAC_SCC_ASYNC | PMAC_SCC_FLAG_XMON, 1); 114 115 116 /* Setup for 57600 8N1 */ 117 if (ch == ch_a) 118 addr += 0x20; 119 sccc = ioremap(addr & PAGE_MASK, PAGE_SIZE) ; 120 sccc += addr & ~PAGE_MASK; 121 sccd = sccc + 0x10; 122 123 mb(); 124 125 for (i = 20000; i != 0; --i) 126 x = in_8(sccc); 127 out_8(sccc, 0x09); /* reset A or B side */ 128 out_8(sccc, 0xc0); 129 for (i = 0; i < sizeof(scc_inittab); ++i) 130 out_8(sccc, scc_inittab[i]); 131 132 udbg_putc = udbg_scc_putc; 133 udbg_getc = udbg_scc_getc; 134 udbg_getc_poll = udbg_scc_getc_poll; 135 136 udbg_puts("Hello World !\n"); 137 138 bail: 139 of_node_put(macio); 140 of_node_put(escc); 141 of_node_put(stdout); 142 of_node_put(ch_def); 143 of_node_put(ch_a); 144 } 145 146 #ifdef CONFIG_PPC64 147 static void udbg_real_scc_putc(char c) 148 { 149 while ((real_readb(sccc) & SCC_TXRDY) == 0) 150 ; 151 real_writeb(c, sccd); 152 if (c == '\n') 153 udbg_real_scc_putc('\r'); 154 } 155 156 void __init udbg_init_pmac_realmode(void) 157 { 158 sccc = (volatile u8 __iomem *)0x80013020ul; 159 sccd = (volatile u8 __iomem *)0x80013030ul; 160 161 udbg_putc = udbg_real_scc_putc; 162 udbg_getc = NULL; 163 udbg_getc_poll = NULL; 164 } 165 #endif /* CONFIG_PPC64 */ 166