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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: Christophe Leroy <christophe.leroy@c-s.fr> Acked-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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@ -501,6 +501,7 @@ static void cpm_uart_set_termios(struct uart_port *port,
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struct uart_cpm_port *pinfo = (struct uart_cpm_port *)port;
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smc_t __iomem *smcp = pinfo->smcp;
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scc_t __iomem *sccp = pinfo->sccp;
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int maxidl;
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pr_debug("CPM uart[%d]:set_termios\n", port->line);
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@ -511,6 +512,17 @@ static void cpm_uart_set_termios(struct uart_port *port,
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else
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pinfo->rx_fifosize = RX_BUF_SIZE;
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/* MAXIDL is the timeout after which a receive buffer is closed
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* when not full if no more characters are received.
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* We calculate it from the baudrate so that the duration is
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* always the same at standard rates: about 4ms.
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*/
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maxidl = baud / 2400;
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if (maxidl < 1)
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maxidl = 1;
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if (maxidl > 0x10)
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maxidl = 0x10;
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/* Character length programmed into the mode register is the
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* sum of: 1 start bit, number of data bits, 0 or 1 parity bit,
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* 1 or 2 stop bits, minus 1.
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@ -611,6 +623,7 @@ static void cpm_uart_set_termios(struct uart_port *port,
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* SMC/SCC receiver is disabled.
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*/
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out_be16(&pinfo->smcup->smc_mrblr, pinfo->rx_fifosize);
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out_be16(&pinfo->smcup->smc_maxidl, maxidl);
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/* Set the mode register. We want to keep a copy of the
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* enables, because we want to put them back if they were
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@ -623,6 +636,7 @@ static void cpm_uart_set_termios(struct uart_port *port,
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SMCMR_SM_UART | prev_mode);
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} else {
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out_be16(&pinfo->sccup->scc_genscc.scc_mrblr, pinfo->rx_fifosize);
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out_be16(&pinfo->sccup->scc_maxidl, maxidl);
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out_be16(&sccp->scc_psmr, (sbits << 12) | scval);
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}
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