LXR linux/arch/powerpc/platforms/embedded6xx/ls

   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