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Commit 6e62bdc0 authored by Christophe Leroy's avatar Christophe Leroy Committed by Greg Kroah-Hartman
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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: default avatarChristophe Leroy <christophe.leroy@c-s.fr>
Acked-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent fbbb9d96

drivers/tty/serial/cpm_uart/cpm_uart_core.c

+14 −0
Original line number Diff line number Diff line
@@ -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);

	}