diff options
| author |   Christophe Leroy <christophe.leroy@c-s.fr> | 2012-09-24 08:39:44 +0200 |
|---|---|---|
| committer |   Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-09-26 13:39:39 -0700 |
| commit | 6e62bdc07e1b397704354cf3bd58950943ecaaf1 (patch) | |
| tree | 71f6170d74ffa166ad1e70a22c066eda76412788 /drivers/tty | |
| parent | Powerpc 8xx CPM_UART maxidl should not depend on fifo size (diff) | |
| download | linux-dev-6e62bdc07e1b397704354cf3bd58950943ecaaf1.tar.xz linux-dev-6e62bdc07e1b397704354cf3bd58950943ecaaf1.zip | |
Powerpc 8xx CPM_UART setting MAXIDL register proportionaly to baud rate
MAXIDL is the timeout after which a receive buffer is closed when not full if
no more characters are received. We calculate it from the baudrate so that the
duration is always the same at standard rates: about 4ms. At 9600 bauds it gives
a timeout of 4 characters, which is the timeout on the 8250 UART.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
| -rw-r--r-- | drivers/tty/serial/cpm_uart/cpm_uart_core.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/tty/serial/cpm_uart/cpm_uart_core.c b/drivers/tty/serial/cpm_uart/cpm_uart_core.c index 7f6a1c7cb3de..d0dd9194cecc 100644 --- a/drivers/tty/serial/cpm_uart/cpm_uart_core.c +++ b/drivers/tty/serial/cpm_uart/cpm_uart_core.c @@ -501,6 +501,7 @@ static void cpm_uart_set_termios(struct uart_port *port, struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port; smc_t __iomem *smcp = pinfo->smcp; scc_t __iomem *sccp = pinfo->sccp; + int maxidl; pr_debug("CPM uart[%d]:set_termios\n", port->line); @@ -511,6 +512,17 @@ static void cpm_uart_set_termios(struct uart_port *port, else pinfo->rx_fifosize = RX_BUF_SIZE; + /* MAXIDL is the timeout after which a receive buffer is closed + * when not full if no more characters are received. + * We calculate it from the baudrate so that the duration is + * always the same at standard rates: about 4ms. + */ + maxidl = baud / 2400; + if (maxidl < 1) + maxidl = 1; + if (maxidl > 0x10) + maxidl = 0x10; + /* Character length programmed into the mode register is the * sum of: 1 start bit, number of data bits, 0 or 1 parity bit, * 1 or 2 stop bits, minus 1. @@ -611,6 +623,7 @@ static void cpm_uart_set_termios(struct uart_port *port, * SMC/SCC receiver is disabled. */ out_be16(&pinfo->smcup->smc_mrblr, pinfo->rx_fifosize); + out_be16(&pinfo->smcup->smc_maxidl, maxidl); /* Set the mode register. We want to keep a copy of the * enables, because we want to put them back if they were @@ -623,6 +636,7 @@ static void cpm_uart_set_termios(struct uart_port *port, SMCMR_SM_UART | prev_mode); } else { out_be16(&pinfo->sccup->scc_genscc.scc_mrblr, pinfo->rx_fifosize); + out_be16(&pinfo->sccup->scc_maxidl, maxidl); out_be16(&sccp->scc_psmr, (sbits << 12) | scval); } |