Revert "usb: pl2303: move the two baud rate encoding methods to separate functions"

This reverts commit e917ba01d69ad705a4cd6a6c77538f55d84f5907.

Revert all of the pl2303 changes that went into 3.12-rc1 and -rc2 as
they cause regressions on some versions of the chip.  This will all be
revisited for later kernel versions when we can figure out how to handle
this in a way that does not break working devices.

Reported-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Cc: Frank Schäfer <fschaefer.oss@googlemail.com>
Acked-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 101 insertions, 114 deletions

diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 693ed7e4871a..a0ea92ed35c6 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -269,128 +269,115 @@ 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;
-        /*
-         * 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);
+
+        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);
+        }
+
         /* Save resulting baud rate */
         tty_encode_baud_rate(tty, baud, baud);
         dev_dbg(&port->dev, "baud set = %d\n", baud);
@@ -447,8 +434,8 @@ 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, spriv->type, buf);
+        /* For reference buf[0]:buf[3] baud rate value */
+        pl2303_encode_baudrate(tty, port, &buf[0]);
 
         /* For reference buf[4]=0 is 1 stop bits */
         /* For reference buf[4]=1 is 1.5 stop bits */