cvs commit: src/sys/arm/at91 uart_dev_at91usart.c

[Warner Losh]

imp         2006-07-02 03:45:33 UTC

  FreeBSD src repository

  Modified files:
    sys/arm/at91         uart_dev_at91usart.c 
  Log:
  MFp4:
  
  Make serial ports more robust and reliable.  Make non-console ports
  work.  This might have broken skyeye stuff.
  
  o Introduce ping-pong receive buffers.
  o Use DMA to copy characters directly into memory.
  o Support baud rates other than 115200
  o Use 1 stop bit when 1 stop bit is requested (otherwise 2 were used,
    which caused dropped characters when received in bursts).
  o Use 1.5 stop bits for 5-bit bytes, and 2 stop bits otherwise when 2
    stop bits were requested.
  o Actually update line parameters.
  o Fix comments
  o Move init into attach
  o Tweaks to TX interrupt registers to get them reliable and non-storming.
  o harvest data in ipend since the latency between it and the callback
    was too long.  This likely is how it should be, I don't know why I deferred
    things to the callback before.
  o disable all interrupts in console init.  We don't want interrupts until
    we turn on an ISR.
  o cosmetic tweaks
  o Automatically detect of the TIMEOUT interrupt is supported.  If so, use
    it so we get better CPU utilization.  Otherwise do a character at a time
    RX.  Good news here is that it seems we have enough CPU and low enough
    fast interrupt latency to do this reliably.
  o Don't read USART_CR.  It is a write-only register.
  o start to implement bus_ioctl.  Do BAUD now...
  
  Revision  Changes    Path
  1.7       +208 -53   src/sys/arm/at91/uart_dev_at91usart.c