diff options
Diffstat (limited to 'drivers/tty/serial/sh-sci.c')
| -rw-r--r-- | drivers/tty/serial/sh-sci.c | 94 |
1 files changed, 64 insertions, 30 deletions
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 88236da0ddf7..3081e46085ce 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -1560,13 +1560,6 @@ static void sci_stop_rx(struct uart_port *port) serial_port_out(port, SCSCR, ctrl); } -static void sci_enable_ms(struct uart_port *port) -{ - /* - * Not supported by hardware, always a nop. - */ -} - static void sci_break_ctl(struct uart_port *port, int break_state) { struct sci_port *s = to_sci_port(port); @@ -1783,30 +1776,71 @@ static unsigned int sci_scbrr_calc(struct sci_port *s, unsigned int bps, return ((freq + 16 * bps) / (32 * bps) - 1); } +/* calculate frame length from SMR */ +static int sci_baud_calc_frame_len(unsigned int smr_val) +{ + int len = 10; + + if (smr_val & SCSMR_CHR) + len--; + if (smr_val & SCSMR_PE) + len++; + if (smr_val & SCSMR_STOP) + len++; + + return len; +} + + /* calculate sample rate, BRR, and clock select for HSCIF */ static void sci_baud_calc_hscif(unsigned int bps, unsigned long freq, int *brr, unsigned int *srr, - unsigned int *cks) + unsigned int *cks, int frame_len) { - int sr, c, br, err; + int sr, c, br, err, recv_margin; int min_err = 1000; /* 100% */ + int recv_max_margin = 0; /* Find the combination of sample rate and clock select with the smallest deviation from the desired baud rate. */ for (sr = 8; sr <= 32; sr++) { for (c = 0; c <= 3; c++) { /* integerized formulas from HSCIF documentation */ - br = freq / (sr * (1 << (2 * c + 1)) * bps) - 1; - if (br < 0 || br > 255) + br = DIV_ROUND_CLOSEST(freq, (sr * + (1 << (2 * c + 1)) * bps)) - 1; + br = clamp(br, 0, 255); + err = DIV_ROUND_CLOSEST(freq, ((br + 1) * bps * sr * + (1 << (2 * c + 1)) / 1000)) - + 1000; + if (err < 0) continue; - err = freq / ((br + 1) * bps * sr * - (1 << (2 * c + 1)) / 1000) - 1000; + + /* Calc recv margin + * M: Receive margin (%) + * N: Ratio of bit rate to clock (N = sampling rate) + * D: Clock duty (D = 0 to 1.0) + * L: Frame length (L = 9 to 12) + * F: Absolute value of clock frequency deviation + * + * M = |(0.5 - 1 / 2 * N) - ((L - 0.5) * F) - + * (|D - 0.5| / N * (1 + F))| + * NOTE: Usually, treat D for 0.5, F is 0 by this + * calculation. + */ + recv_margin = abs((500 - + DIV_ROUND_CLOSEST(1000, sr << 1)) / 10); if (min_err > err) { min_err = err; - *brr = br; - *srr = sr - 1; - *cks = c; - } + recv_max_margin = recv_margin; + } else if ((min_err == err) && + (recv_margin > recv_max_margin)) + recv_max_margin = recv_margin; + else + continue; + + *brr = br; + *srr = sr - 1; + *cks = c; } } @@ -1840,10 +1874,19 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, { struct sci_port *s = to_sci_port(port); struct plat_sci_reg *reg; - unsigned int baud, smr_val, max_baud, cks = 0; + unsigned int baud, smr_val = 0, max_baud, cks = 0; int t = -1; unsigned int srr = 15; + if ((termios->c_cflag & CSIZE) == CS7) + smr_val |= SCSMR_CHR; + if (termios->c_cflag & PARENB) + smr_val |= SCSMR_PE; + if (termios->c_cflag & PARODD) + smr_val |= SCSMR_PE | SCSMR_ODD; + if (termios->c_cflag & CSTOPB) + smr_val |= SCSMR_STOP; + /* * earlyprintk comes here early on with port->uartclk set to zero. * the clock framework is not up and running at this point so here @@ -1857,8 +1900,9 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, baud = uart_get_baud_rate(port, termios, old, 0, max_baud); if (likely(baud && port->uartclk)) { if (s->cfg->type == PORT_HSCIF) { + int frame_len = sci_baud_calc_frame_len(smr_val); sci_baud_calc_hscif(baud, port->uartclk, &t, &srr, - &cks); + &cks, frame_len); } else { t = sci_scbrr_calc(s, baud, port->uartclk); for (cks = 0; t >= 256 && cks <= 3; cks++) @@ -1870,16 +1914,7 @@ static void sci_set_termios(struct uart_port *port, struct ktermios *termios, sci_reset(port); - smr_val = serial_port_in(port, SCSMR) & 3; - - if ((termios->c_cflag & CSIZE) == CS7) - smr_val |= SCSMR_CHR; - if (termios->c_cflag & PARENB) - smr_val |= SCSMR_PE; - if (termios->c_cflag & PARODD) - smr_val |= SCSMR_PE | SCSMR_ODD; - if (termios->c_cflag & CSTOPB) - smr_val |= SCSMR_STOP; + smr_val |= serial_port_in(port, SCSMR) & 3; uart_update_timeout(port, termios->c_cflag, baud); @@ -2080,7 +2115,6 @@ static struct uart_ops sci_uart_ops = { .start_tx = sci_start_tx, .stop_tx = sci_stop_tx, .stop_rx = sci_stop_rx, - .enable_ms = sci_enable_ms, .break_ctl = sci_break_ctl, .startup = sci_startup, .shutdown = sci_shutdown, |