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