drivers/serial/ns16550.c

   1 /*
   2  * COM1 NS16550 support
   3  * originally from linux source (arch/powerpc/boot/ns16550.c)
   4  * modified to use CONFIG_SYS_ISA_MEM and new defines
   5  */
   6
   7 #include <config.h>
   8 #include <ns16550.h>
   9 #include <watchdog.h>
  10 #include <linux/types.h>
  11 #include <asm/io.h>
  12
  13 #define UART_LCRVAL UART_LCR_8N1                /* 8 data, 1 stop, no parity */
  14 #define UART_MCRVAL (UART_MCR_DTR | \
  15                      UART_MCR_RTS)              /* RTS/DTR */
  16 #define UART_FCRVAL (UART_FCR_FIFO_EN | \
  17                      UART_FCR_RXSR |    \
  18                      UART_FCR_TXSR)             /* Clear & enable FIFOs */
  19 #ifdef CONFIG_SYS_NS16550_PORT_MAPPED
  20 #define serial_out(x, y)        outb(x, (ulong)y)
  21 #define serial_in(y)            inb((ulong)y)
  22 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE > 0)
  23 #define serial_out(x, y)        out_be32(y, x)
  24 #define serial_in(y)            in_be32(y)
  25 #elif defined(CONFIG_SYS_NS16550_MEM32) && (CONFIG_SYS_NS16550_REG_SIZE < 0)
  26 #define serial_out(x, y)        out_le32(y, x)
  27 #define serial_in(y)            in_le32(y)
  28 #else
  29 #define serial_out(x, y)        writeb(x, y)
  30 #define serial_in(y)            readb(y)
  31 #endif
  32
  33 #ifndef CONFIG_SYS_NS16550_IER
  34 #define CONFIG_SYS_NS16550_IER  0x00
  35 #endif /* CONFIG_SYS_NS16550_IER */
  36
  37 void NS16550_init(NS16550_t com_port, int baud_divisor)
  38 {
  39 #if (defined(CONFIG_SPL_BUILD) && defined(CONFIG_OMAP34XX))
  40         /*
  41          * On some OMAP3 devices when UART3 is configured for boot mode before
  42          * SPL starts only THRE bit is set. We have to empty the transmitter
  43          * before initialization starts.
  44          */
  45         if ((serial_in(&com_port->lsr) & (UART_LSR_TEMT | UART_LSR_THRE))
  46              == UART_LSR_THRE) {
  47                 serial_out(UART_LCR_DLAB, &com_port->lcr);
  48                 serial_out(baud_divisor & 0xff, &com_port->dll);
  49                 serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
  50                 serial_out(UART_LCRVAL, &com_port->lcr);
  51                 serial_out(0, &com_port->mdr1);
  52         }
  53 #endif
  54
  55         while (!(serial_in(&com_port->lsr) & UART_LSR_TEMT))
  56                 ;
  57
  58         serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
  59 #if defined(CONFIG_OMAP) || defined(CONFIG_AM33XX) || \
  60                         defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
  61         serial_out(0x7, &com_port->mdr1);       /* mode select reset TL16C750*/
  62 #endif
  63         serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
  64         serial_out(0, &com_port->dll);
  65         serial_out(0, &com_port->dlm);
  66         serial_out(UART_LCRVAL, &com_port->lcr);
  67         serial_out(UART_MCRVAL, &com_port->mcr);
  68         serial_out(UART_FCRVAL, &com_port->fcr);
  69         serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
  70         serial_out(baud_divisor & 0xff, &com_port->dll);
  71         serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
  72         serial_out(UART_LCRVAL, &com_port->lcr);
  73 #if (defined(CONFIG_OMAP) && !defined(CONFIG_OMAP3_ZOOM2)) || \
  74         defined(CONFIG_AM33XX) || defined(CONFIG_SOC_DA8XX) || \
  75         defined(CONFIG_TI81XX) || defined(CONFIG_AM43XX)
  76
  77         /* /16 is proper to hit 115200 with 48MHz */
  78         serial_out(0, &com_port->mdr1);
  79 #endif /* CONFIG_OMAP */
  80 }
  81
  82 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
  83 void NS16550_reinit(NS16550_t com_port, int baud_divisor)
  84 {
  85         serial_out(CONFIG_SYS_NS16550_IER, &com_port->ier);
  86         serial_out(UART_LCR_BKSE | UART_LCRVAL, &com_port->lcr);
  87         serial_out(0, &com_port->dll);
  88         serial_out(0, &com_port->dlm);
  89         serial_out(UART_LCRVAL, &com_port->lcr);
  90         serial_out(UART_MCRVAL, &com_port->mcr);
  91         serial_out(UART_FCRVAL, &com_port->fcr);
  92         serial_out(UART_LCR_BKSE, &com_port->lcr);
  93         serial_out(baud_divisor & 0xff, &com_port->dll);
  94         serial_out((baud_divisor >> 8) & 0xff, &com_port->dlm);
  95         serial_out(UART_LCRVAL, &com_port->lcr);
  96 }
  97 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */
  98
  99 void NS16550_putc(NS16550_t com_port, char c)
 100 {
 101         while ((serial_in(&com_port->lsr) & UART_LSR_THRE) == 0)
 102                 ;
 103         serial_out(c, &com_port->thr);
 104
 105         /*
 106          * Call watchdog_reset() upon newline. This is done here in putc
 107          * since the environment code uses a single puts() to print the complete
 108          * environment upon "printenv". So we can't put this watchdog call
 109          * in puts().
 110          */
 111         if (c == '\n')
 112                 WATCHDOG_RESET();
 113 }
 114
 115 #ifndef CONFIG_NS16550_MIN_FUNCTIONS
 116 char NS16550_getc(NS16550_t com_port)
 117 {
 118         while ((serial_in(&com_port->lsr) & UART_LSR_DR) == 0) {
 119 #if !defined(CONFIG_SPL_BUILD) && defined(CONFIG_USB_TTY)
 120                 extern void usbtty_poll(void);
 121                 usbtty_poll();
 122 #endif
 123                 WATCHDOG_RESET();
 124         }
 125         return serial_in(&com_port->rbr);
 126 }
 127
 128 int NS16550_tstc(NS16550_t com_port)
 129 {
 130         return (serial_in(&com_port->lsr) & UART_LSR_DR) != 0;
 131 }
 132
 133 #endif /* CONFIG_NS16550_MIN_FUNCTIONS */