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);
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 */
projects / kernel.git / commitdiff