arch/powerpc/platforms/embedded6xx/ls_uart.c

   1 #include <linux/workqueue.h>
   2 #include <linux/string.h>
   3 #include <linux/delay.h>
   4 #include <linux/serial_reg.h>
   5 #include <linux/serial_8250.h>
   6 #include <asm/io.h>
   7 #include <asm/mpc10x.h>
   8 #include <asm/prom.h>
   9 #include <asm/termbits.h>
  10
  11 static void __iomem *avr_addr;
  12 static unsigned long avr_clock;
  13
  14 static struct work_struct wd_work;
  15
  16 static void wd_stop(struct work_struct *unused)
  17 {
  18         const char string[] = "AAAAFFFFJJJJ>>>>VVVV>>>>ZZZZVVVVKKKK";
  19         int i = 0, rescue = 8;
  20         int len = strlen(string);
  21
  22         while (rescue--) {
  23                 int j;
  24                 char lsr = in_8(avr_addr + UART_LSR);
  25
  26                 if (lsr & (UART_LSR_THRE | UART_LSR_TEMT)) {
  27                         for (j = 0; j < 16 && i < len; j++, i++)
  28                                 out_8(avr_addr + UART_TX, string[i]);
  29                         if (i == len) {
  30                                 /* Read "OK" back: 4ms for the last "KKKK"
  31                                    plus a couple bytes back */
  32                                 msleep(7);
  33                                 printk("linkstation: disarming the AVR watchdog: ");
  34                                 while (in_8(avr_addr + UART_LSR) & UART_LSR_DR)
  35                                         printk("%c", in_8(avr_addr + UART_RX));
  36                                 break;
  37                         }
  38                 }
  39                 msleep(17);
  40         }
  41         printk("\n");
  42 }
  43
  44 #define AVR_QUOT(clock) ((clock) + 8 * 9600) / (16 * 9600)
  45
  46 void avr_uart_configure(void)
  47 {
  48         unsigned char cval = UART_LCR_WLEN8;
  49         unsigned int quot = AVR_QUOT(avr_clock);
  50
  51         if (!avr_addr || !avr_clock)
  52                 return;
  53
  54         out_8(avr_addr + UART_LCR, cval);                       /* initialise UART */
  55         out_8(avr_addr + UART_MCR, 0);
  56         out_8(avr_addr + UART_IER, 0);
  57
  58         cval |= UART_LCR_STOP | UART_LCR_PARITY | UART_LCR_EPAR;
  59
  60         out_8(avr_addr + UART_LCR, cval);                       /* Set character format */
  61
  62         out_8(avr_addr + UART_LCR, cval | UART_LCR_DLAB);       /* set DLAB */
  63         out_8(avr_addr + UART_DLL, quot & 0xff);                /* LS of divisor */
  64         out_8(avr_addr + UART_DLM, quot >> 8);                  /* MS of divisor */
  65         out_8(avr_addr + UART_LCR, cval);                       /* reset DLAB */
  66         out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);       /* enable FIFO */
  67 }
  68
  69 void avr_uart_send(const char c)
  70 {
  71         if (!avr_addr || !avr_clock)
  72                 return;
  73
  74         out_8(avr_addr + UART_TX, c);
  75         out_8(avr_addr + UART_TX, c);
  76         out_8(avr_addr + UART_TX, c);
  77         out_8(avr_addr + UART_TX, c);
  78 }
  79
  80 static void __init ls_uart_init(void)
  81 {
  82         local_irq_disable();
  83
  84 #ifndef CONFIG_SERIAL_8250
  85         out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO);       /* enable FIFO */
  86         out_8(avr_addr + UART_FCR, UART_FCR_ENABLE_FIFO |
  87               UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);       /* clear FIFOs */
  88         out_8(avr_addr + UART_FCR, 0);
  89         out_8(avr_addr + UART_IER, 0);
  90
  91         /* Clear up interrupts */
  92         (void) in_8(avr_addr + UART_LSR);
  93         (void) in_8(avr_addr + UART_RX);
  94         (void) in_8(avr_addr + UART_IIR);
  95         (void) in_8(avr_addr + UART_MSR);
  96 #endif
  97         avr_uart_configure();
  98
  99         local_irq_enable();
 100 }
 101
 102 static int __init ls_uarts_init(void)
 103 {
 104         struct device_node *avr;
 105         phys_addr_t phys_addr;
 106         int len;
 107
 108         avr = of_find_node_by_path("/soc10x/serial@80004500");
 109         if (!avr)
 110                 return -EINVAL;
 111
 112         avr_clock = *(u32*)of_get_property(avr, "clock-frequency", &len);
 113         phys_addr = ((u32*)of_get_property(avr, "reg", &len))[0];
 114
 115         if (!avr_clock || !phys_addr)
 116                 return -EINVAL;
 117
 118         avr_addr = ioremap(phys_addr, 32);
 119         if (!avr_addr)
 120                 return -EFAULT;
 121
 122         ls_uart_init();
 123
 124         INIT_WORK(&wd_work, wd_stop);
 125         schedule_work(&wd_work);
 126
 127         return 0;
 128 }
 129
 130 late_initcall(ls_uarts_init);