1 /* 2 * AVR power-management chip interface for the Buffalo Linkstation / 3 * Kurobox Platform. 4 * 5 * Author: 2006 (c) G. Liakhovetski 6 * g.liakhovetski@gmx.de 7 * 8 * This file is licensed under the terms of the GNU General Public License 9 * version 2. This program is licensed "as is" without any warranty of 10 * any kind, whether express or implied. 11 */ 12 #include <linux/workqueue.h> 13 #include <linux/string.h> 14 #include <linux/delay.h> 15 #include <linux/serial_reg.h> 16 #include <linux/serial_8250.h> 17 #include <linux/of.h> 18 #include <linux/of_address.h> 19 #include <asm/io.h> 20 #include <asm/termbits.h> 21 22 #include "mpc10x.h" 23 24 static void __iomem *avr_addr; 25 static unsigned long avr_clock; 26 27 static struct work_struct wd_work; 28 29 static void wd_stop(struct work_struct *unused) 30 { 31 const char string[] = "AAAAFFFFJJJJ>>>>VVVV>>>>ZZZZVVVVKKKK"; 32 int i = 0, rescue = 8; 33 int len = strlen(string); 34 35 while (rescue--) { 36 int j; 37 char lsr = in_8(avr_addr + UART_LSR); 38 39 if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) { 40 for (j = 0; j < 16 && i < len; j++, i++) 41 out_8(avr_addr + UART_TX, string[i]); 42 if (i == len) { 43 /* Read "OK" back: 4ms for the last "KKKK" 44 plus a couple bytes back */ 45 msleep(7); 46 printk("linkstation: disarming the AVR watchdog: "); 47 while (in_8(avr_addr + UART_LSR) & UART_LSR_DR) 48 printk("%c", in_8(avr_addr + UART_RX)); 49 break; 50 } 51 } 52 msleep(17); 53 } 54 printk("\n"); 55 } 56 57 #define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600) 58 59 void avr_uart_configure(void) 60 { 61 unsigned char cval = UART_LCR_WLEN8; 62 unsigned int quot = AVR_QUOT(avr_clock); 63 64 if (!avr_addr || !avr_clock) 65 return; 66 67 out_8(avr_addr + UART_LCR, cval); /* initialise UART */ 68 out_8(avr_addr + UART_MCR, 0); 69 out_8(avr_addr + UART_IER, 0); 70 71 cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR; 72 73 out_8(avr_addr + UART_LCR, cval); /* Set character format */ 74 75 out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB); /* set DLAB */ 76 out_8(avr_addr + UART_DLL, quot & 0xff); /* LS of divisor */ 77 out_8(avr_addr + UART_DLM, quot >> 8); /* MS of divisor */ 78 out_8(avr_addr + UART_LCR, cval); /* reset DLAB */ 79 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */ 80 } 81 82 void avr_uart_send(const char c) 83 { 84 if (!avr_addr || !avr_clock) 85 return; 86 87 out_8(avr_addr + UART_TX, c); 88 out_8(avr_addr + UART_TX, c); 89 out_8(avr_addr + UART_TX, c); 90 out_8(avr_addr + UART_TX, c); 91 } 92 93 static void __init ls_uart_init(void) 94 { 95 local_irq_disable(); 96 97 #ifndef CONFIG_SERIAL_8250 98 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */ 99 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO | 100 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); /* clear FIFOs */ 101 out_8(avr_addr + UART_FCR, 0); 102 out_8(avr_addr + UART_IER, 0); 103 104 /* Clear up interrupts */ 105 (void) in_8(avr_addr + UART_LSR); 106 (void) in_8(avr_addr + UART_RX); 107 (void) in_8(avr_addr + UART_IIR); 108 (void) in_8(avr_addr + UART_MSR); 109 #endif 110 avr_uart_configure(); 111 112 local_irq_enable(); 113 } 114 115 static int __init ls_uarts_init(void) 116 { 117 struct device_node *avr; 118 struct resource res; 119 int len, ret; 120 121 avr = of_find_node_by_path("/soc10x/serial@80004500"); 122 if (!avr) 123 return -EINVAL; 124 125 avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len); 126 if (!avr_clock) 127 return -EINVAL; 128 129 ret = of_address_to_resource(avr, 0, &res); 130 if (ret) 131 return ret; 132 133 of_node_put(avr); 134 135 avr_addr = ioremap(res.start, 32); 136 if (!avr_addr) 137 return -EFAULT; 138 139 ls_uart_init(); 140 141 INIT_WORK(&wd_work, wd_stop); 142 schedule_work(&wd_work); 143 144 return 0; 145 } 146 147 machine_late_initcall(linkstation, ls_uarts_init); 148