From 2b56a5ce50807c0c4197f17f42b23f069dab02ba Mon Sep 17 00:00:00 2001 From: ian Date: Sun, 31 Mar 2013 23:24:04 +0000 Subject: Accommodate uart devices with large FIFOs (or DMA buffers which amount to the same thing) by allocating the uart(4) rx buffer based on the device's rxfifosz rather than using a hard-coded size of 384 bytes. The historical 384 byte size is 3 times the largest hard-coded fifo size in the tree, so use that ratio as a guide and allocate the buffer as three times rxfifosz, but never smaller than the historical size. --- sys/dev/uart/uart_core.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/sys/dev/uart/uart_core.c b/sys/dev/uart/uart_core.c index f5a9a1c..b264e5b 100644 --- a/sys/dev/uart/uart_core.c +++ b/sys/dev/uart/uart_core.c @@ -457,7 +457,13 @@ uart_bus_attach(device_t dev) callout_init(&sc->sc_timer, 1); } - sc->sc_rxbufsz = 384; + /* + * Ensure there is room for at least three full FIFOs of data in the + * receive buffer (handles the case of low-level drivers with huge + * FIFOs), and also ensure that there is no less than the historical + * size of 384 bytes (handles the typical small-FIFO case). + */ + sc->sc_rxbufsz = MAX(384, sc->sc_rxfifosz * 3); sc->sc_rxbuf = malloc(sc->sc_rxbufsz * sizeof(*sc->sc_rxbuf), M_UART, M_WAITOK); sc->sc_txbuf = malloc(sc->sc_txfifosz * sizeof(*sc->sc_txbuf), -- cgit v1.1