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 <asm/io.h> 18#include <asm/prom.h> 19#include <asm/termbits.h> 20 21#include "mpc10x.h" 22 23static void __iomem *avr_addr; 24static unsigned long avr_clock; 25 26static struct work_struct wd_work; 27 28static void wd_stop(struct work_struct *unused) 29{ 30 const char string[] = "AAAAFFFFJJJJ>>>>VVVV>>>>ZZZZVVVVKKKK"; 31 int i = 0, rescue = 8; 32 int len = strlen(string); 33 34 while (rescue--) { 35 int j; 36 char lsr = in_8(avr_addr + UART_LSR); 37 38 if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) { 39 for (j = 0; j < 16 && i < len; j++, i++) 40 out_8(avr_addr + UART_TX, string[i]); 41 if (i == len) { 42 /* Read "OK" back: 4ms for the last "KKKK" 43 plus a couple bytes back */ 44 msleep(7); 45 printk("linkstation: disarming the AVR watchdog: "); 46 while (in_8(avr_addr + UART_LSR) & UART_LSR_DR) 47 printk("%c", in_8(avr_addr + UART_RX)); 48 break; 49 } 50 } 51 msleep(17); 52 } 53 printk("\n"); 54} 55 56#define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600) 57 58void avr_uart_configure(void) 59{ 60 unsigned char cval = UART_LCR_WLEN8; 61 unsigned int quot = AVR_QUOT(avr_clock); 62 63 if (!avr_addr || !avr_clock) 64 return; 65 66 out_8(avr_addr + UART_LCR, cval); /* initialise UART */ 67 out_8(avr_addr + UART_MCR, 0); 68 out_8(avr_addr + UART_IER, 0); 69 70 cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR; 71 72 out_8(avr_addr + UART_LCR, cval); /* Set character format */ 73 74 out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB); /* set DLAB */ 75 out_8(avr_addr + UART_DLL, quot & 0xff); /* LS of divisor */ 76 out_8(avr_addr + UART_DLM, quot >> 8); /* MS of divisor */ 77 out_8(avr_addr + UART_LCR, cval); /* reset DLAB */ 78 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */ 79} 80 81void avr_uart_send(const char c) 82{ 83 if (!avr_addr || !avr_clock) 84 return; 85 86 out_8(avr_addr + UART_TX, c); 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} 91 92static void __init ls_uart_init(void) 93{ 94 local_irq_disable(); 95 96#ifndef CONFIG_SERIAL_8250 97 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO); /* enable FIFO */ 98 out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO | 99 UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT); /* clear FIFOs */ 100 out_8(avr_addr + UART_FCR, 0); 101 out_8(avr_addr + UART_IER, 0); 102 103 /* Clear up interrupts */ 104 (void) in_8(avr_addr + UART_LSR); 105 (void) in_8(avr_addr + UART_RX); 106 (void) in_8(avr_addr + UART_IIR); 107 (void) in_8(avr_addr + UART_MSR); 108#endif 109 avr_uart_configure(); 110 111 local_irq_enable(); 112} 113 114static int __init ls_uarts_init(void) 115{ 116 struct device_node *avr; 117 phys_addr_t phys_addr; 118 int len; 119 120 avr = of_find_node_by_path("/soc10x/serial@80004500"); 121 if (!avr) 122 return -EINVAL; 123 124 avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len); 125 phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0]; 126 127 if (!avr_clock || !phys_addr) 128 return -EINVAL; 129 130 avr_addr = ioremap(phys_addr, 32); 131 if (!avr_addr) 132 return -EFAULT; 133 134 ls_uart_init(); 135 136 INIT_WORK(&wd_work, wd_stop); 137 schedule_work(&wd_work); 138 139 return 0; 140} 141 142machine_late_initcall(linkstation, ls_uarts_init); 143