From e917ba01d69ad705a4cd6a6c77538f55d84f5907 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Frank=20Sch=C3=A4fer?= Date: Tue, 6 Aug 2013 19:26:26 +0200 Subject: [PATCH] usb: pl2303: move the two baud rate encoding methods to separate functions MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Signed-off-by: Frank Schäfer Signed-off-by: Greg Kroah-Hartman --- drivers/usb/serial/pl2303.c | 215 +++++++++++++++++++----------------- 1 file changed, 114 insertions(+), 101 deletions(-) diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c index a0ea92ed35c6..693ed7e4871a 100644 --- a/drivers/usb/serial/pl2303.c +++ b/drivers/usb/serial/pl2303.c @@ -269,115 +269,128 @@ static int pl2303_set_control_lines(struct usb_serial_port *port, u8 value) return retval; } +static int pl2303_baudrate_encode_direct(int baud, enum pl2303_type type, + u8 buf[4]) +{ + /* + * NOTE: Only the values defined in baud_sup are supported ! + * => if unsupported values are set, the PL2303 seems to + * use 9600 baud (at least my PL2303X always does) + */ + const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, 3600, + 4800, 7200, 9600, 14400, 19200, 28800, 38400, + 57600, 115200, 230400, 460800, 614400, 921600, + 1228800, 2457600, 3000000, 6000000 }; + int i; + + /* Set baudrate to nearest supported value */ + for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) { + if (baud_sup[i] > baud) + break; + } + if (i == ARRAY_SIZE(baud_sup)) + baud = baud_sup[i - 1]; + else if (i > 0 && (baud_sup[i] - baud) > (baud - baud_sup[i - 1])) + baud = baud_sup[i - 1]; + else + baud = baud_sup[i]; + /* type_0, type_1 only support up to 1228800 baud */ + if (type != HX) + baud = min_t(int, baud, 1228800); + /* Direct (standard) baud rate encoding method */ + put_unaligned_le32(baud, buf); + + return baud; +} + +static int pl2303_baudrate_encode_divisor(int baud, enum pl2303_type type, + u8 buf[4]) +{ + /* + * Divisor based baud rate encoding method + * + * NOTE: it's not clear if the type_0/1 chips support this method + * + * divisor = 12MHz * 32 / baudrate = 2^A * B + * + * with + * + * A = buf[1] & 0x0e + * B = buf[0] + (buf[1] & 0x01) << 8 + * + * Special cases: + * => 8 < B < 16: device seems to work not properly + * => B <= 8: device uses the max. value B = 512 instead + */ + unsigned int A, B; + + /* Respect the specified baud rate limits */ + baud = max_t(int, baud, 75); + if (type == HX) + baud = min_t(int, baud, 6000000); + else + baud = min_t(int, baud, 1228800); + /* Determine factors A and B */ + A = 0; + B = 12000000 * 32 / baud; /* 12MHz */ + B <<= 1; /* Add one bit for rounding */ + while (B > (512 << 1) && A <= 14) { + A += 2; + B >>= 2; + } + if (A > 14) { /* max. divisor = min. baudrate reached */ + A = 14; + B = 512; + /* => ~45.78 baud */ + } else { + B = (B + 1) >> 1; /* Round the last bit */ + } + /* Handle special cases */ + if (B == 512) + B = 0; /* also: 1 to 8 */ + else if (B < 16) + /* + * NOTE: With the current algorithm this happens + * only for A=0 and means that the min. divisor + * (respectively: the max. baudrate) is reached. + */ + B = 16; /* => 24 MBaud */ + /* Encode the baud rate */ + buf[3] = 0x80; /* Select divisor encoding method */ + buf[2] = 0; + buf[1] = (A & 0x0e); /* A */ + buf[1] |= ((B & 0x100) >> 8); /* MSB of B */ + buf[0] = B & 0xff; /* 8 LSBs of B */ + /* Calculate the actual/resulting baud rate */ + if (B <= 8) + B = 512; + baud = 12000000 * 32 / ((1 << A) * B); + + return baud; +} + static void pl2303_encode_baudrate(struct tty_struct *tty, struct usb_serial_port *port, + enum pl2303_type type, u8 buf[4]) { - struct usb_serial *serial = port->serial; - struct pl2303_serial_private *spriv = usb_get_serial_data(serial); int baud; baud = tty_get_baud_rate(tty); dev_dbg(&port->dev, "baud requested = %d\n", baud); if (!baud) return; - - if (spriv->type != HX || baud <= 115200) { - /* - * NOTE: Only the values defined in baud_sup are supported ! - * => if unsupported values are set, the PL2303 seems to - * use 9600 baud (at least my PL2303X always does) - */ - const int baud_sup[] = { 75, 150, 300, 600, 1200, 1800, 2400, - 3600, 4800, 7200, 9600, 14400, 19200, - 28800, 38400, 57600, 115200, 230400, - 460800, 614400, 921600, 1228800, - 2457600, 3000000, 6000000 }; - int i; - - /* Set baudrate to nearest supported value */ - for (i = 0; i < ARRAY_SIZE(baud_sup); ++i) { - if (baud_sup[i] > baud) - break; - } - - if (i == ARRAY_SIZE(baud_sup)) - baud = baud_sup[i - 1]; - else if (i > 0 - && (baud_sup[i] - baud) > (baud - baud_sup[i - 1])) - baud = baud_sup[i - 1]; - else - baud = baud_sup[i]; - - /* type_0, type_1 only support up to 1228800 baud */ - if (spriv->type != HX) - baud = min_t(int, baud, 1228800); - - /* Direct (standard) baud rate encoding method */ - put_unaligned_le32(baud, buf); - } else { - /* - * Divisor based baud rate encoding method - * - * NOTE: it's not clear if the type_0/1 chips - * support this method - * - * divisor = 12MHz * 32 / baudrate = 2^A * B - * - * with - * - * A = buf[1] & 0x0e - * B = buf[0] + (buf[1] & 0x01) << 8 - * - * Special cases: - * => 8 < B < 16: device seems to work not properly - * => B <= 8: device uses the max. value B = 512 instead - */ - unsigned int A, B; - - /* Respect the specified baud rate limits */ - baud = max_t(int, baud, 75); - if (spriv->type == HX) - baud = min_t(int, baud, 6000000); - else - baud = min_t(int, baud, 1228800); - /* Determine factors A and B */ - A = 0; - B = 12000000 * 32 / baud; /* 12MHz */ - B <<= 1; /* Add one bit for rounding */ - while (B > (512 << 1) && A <= 14) { - A += 2; - B >>= 2; - } - if (A > 14) { /* max. divisor = min. baudrate reached */ - A = 14; - B = 512; - /* => ~45.78 baud */ - } else { - B = (B + 1) >> 1; /* Round the last bit */ - } - /* Handle special cases */ - if (B == 512) - B = 0; /* also: 1 to 8 */ - else if (B < 16) - /* - * NOTE: With the current algorithm this happens - * only for A=0 and means that the min. divisor - * (respectively: the max. baudrate) is reached. - */ - B = 16; /* => 24 MBaud */ - /* Encode the baud rate */ - buf[3] = 0x80; /* Select divisor encoding method */ - buf[2] = 0; - buf[1] = (A & 0x0e); /* A */ - buf[1] |= ((B & 0x100) >> 8); /* MSB of B */ - buf[0] = B & 0xff; /* 8 LSBs of B */ - /* Calculate the actual/resulting baud rate */ - if (B <= 8) - B = 512; - baud = 12000000 * 32 / ((1 << A) * B); - } - + /* + * There are two methods for setting/encoding the baud rate + * 1) Direct method: encodes the baud rate value directly + * => supported by all chip types + * 2) Divisor based method: encodes a divisor to a base value (12MHz*32) + * => supported by HX chips (and likely not by type_0/1 chips) + */ + if (type != HX || baud <= 115200) + baud = pl2303_baudrate_encode_direct(baud, type, buf); + else + baud = pl2303_baudrate_encode_divisor(baud, type, buf); /* Save resulting baud rate */ tty_encode_baud_rate(tty, baud, baud); dev_dbg(&port->dev, "baud set = %d\n", baud); @@ -434,8 +447,8 @@ static void pl2303_set_termios(struct tty_struct *tty, dev_dbg(&port->dev, "data bits = %d\n", buf[6]); } - /* For reference buf[0]:buf[3] baud rate value */ - pl2303_encode_baudrate(tty, port, &buf[0]); + /* For reference: buf[0]:buf[3] baud rate value */ + pl2303_encode_baudrate(tty, port, spriv->type, buf); /* For reference buf[4]=0 is 1 stop bits */ /* For reference buf[4]=1 is 1.5 stop bits */ -- 2.20.1