This series implements flow control for the ASPEED VUART driver. This hardware is slightly unusual in that the RX data rate can quickly overwhelm the flip buffer code, so the ldisc-driven throttle/unthrottle mechanisms don't entirely solve the problem. To do this, we have a couple of minor changes to the tty core, as well as an update to the tty proc interface to display buffer overrun metrics (entirely optional, but does allow us to see the problem). Then, we implement the standard throttle mechanism, and augment it with a fast-path to throttle if we overrun the flip buffers before the ldisc has had a chance to run. Questions and comments most welcome; I'm fairly new to the tty layer. Cheers, Jeremy --- Jeremy Kerr (5): serial: Introduce UPSTAT_SYNC_FIFO for synchronised FIFOs serial: expose buf_overrun count through proc interface serial/8250: export serial8250_read_char serial/aspeed-vuart: Implement rx throttling serial/aspeed-vuart: Implement quick throttle mechanism drivers/tty/serial/8250/8250_aspeed_vuart.c | 122 ++++++++++++++++++++++++++++ drivers/tty/serial/8250/8250_port.c | 3 +- drivers/tty/serial/serial_core.c | 6 +- include/linux/serial_8250.h | 1 + include/linux/serial_core.h | 1 + 5 files changed, 130 insertions(+), 3 deletions(-) -- 2.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
