1 files changed, 66 insertions, 45 deletions

diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index 155b82a25d18..c42d3bdbe98c 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -122,6 +122,11 @@ static struct usb_driver cypress_driver = {
         .no_dynamic_id =        1,
 };
 
+enum packet_format {
+        packet_format_1,  /* b0:status, b1:payload count */
+        packet_format_2   /* b0[7:3]:status, b0[2:0]:payload count */
+};
+
 struct cypress_private {
         spinlock_t lock;                   /* private lock */
         int chiptype;                      /* identifier of device, for quirks/etc */
@@ -139,6 +144,7 @@ struct cypress_private {
         __u8 current_status;               /* received from last read - info on dsr,cts,cd,ri,etc */
         __u8 current_config;               /* stores the current configuration byte */
         __u8 rx_flags;                     /* throttling - used from whiteheat/ftdi_sio */
+        enum packet_format pkt_fmt;        /* format to use for packet send / receive */
         int baud_rate;                     /* stores current baud rate in integer form */
         int cbr_mask;                      /* stores current baud rate in masked form */
         int isthrottled;                   /* if throttled, discard reads */
@@ -532,6 +538,17 @@ static int generic_startup (struct usb_serial *serial)
         priv->termios_initialized = 0;
         priv->rx_flags = 0;
         priv->cbr_mask = B300;
+        /* Default packet format setting is determined by packet size.
+           Anything with a size larger then 9 must have a separate
+           count field since the 3 bit count field is otherwise too
+           small.  Otherwise we can use the slightly more compact
+           format.  This is in accordance with the cypress_m8 serial
+           converter app note. */
+        if (port->interrupt_out_size > 9) {
+                priv->pkt_fmt = packet_format_1;
+        } else {
+                priv->pkt_fmt = packet_format_2;
+        }
         if (interval > 0) {
                 priv->write_urb_interval = interval;
                 priv->read_urb_interval = interval;
@@ -564,6 +581,9 @@ static int cypress_earthmate_startup (struct usb_serial *serial)
 
         priv = usb_get_serial_port_data(serial->port[0]);
         priv->chiptype = CT_EARTHMATE;
+        /* All Earthmate devices use the separated-count packet
+           format!  Idiotic. */
+        priv->pkt_fmt = packet_format_1;
 
         return 0;
 } /* cypress_earthmate_startup */
@@ -811,21 +831,18 @@ static void cypress_send(struct usb_serial_port *port)
         memset(port->interrupt_out_urb->transfer_buffer, 0, port->interrupt_out_size);
 
         spin_lock_irqsave(&priv->lock, flags);
-        switch (port->interrupt_out_size) {
-                case 32:
-                        /* this is for the CY7C64013... */
-                        offset = 2;
-                        port->interrupt_out_buffer[0] = priv->line_control;
-                        break;
-                case 8:
-                        /* this is for the CY7C63743... */
-                        offset = 1;
-                        port->interrupt_out_buffer[0] = priv->line_control;
-                        break;
-                default:
-                        dbg("%s - wrong packet size", __FUNCTION__);
-                        spin_unlock_irqrestore(&priv->lock, flags);
-                        return;
+        switch (priv->pkt_fmt) {
+        default:
+        case packet_format_1:
+                /* this is for the CY7C64013... */
+                offset = 2;
+                port->interrupt_out_buffer[0] = priv->line_control;
+                break;
+        case packet_format_2:
+                /* this is for the CY7C63743... */
+                offset = 1;
+                port->interrupt_out_buffer[0] = priv->line_control;
+                break;
         }
 
         if (priv->line_control & CONTROL_RESET)
@@ -846,12 +863,13 @@ static void cypress_send(struct usb_serial_port *port)
                 return;
         }
 
-        switch (port->interrupt_out_size) {
-                case 32:
-                        port->interrupt_out_buffer[1] = count;
-                        break;
-                case 8:
-                        port->interrupt_out_buffer[0] |= count;
+        switch (priv->pkt_fmt) {
+        default:
+        case packet_format_1:
+                port->interrupt_out_buffer[1] = count;
+                break;
+        case packet_format_2:
+                port->interrupt_out_buffer[0] |= count;
         }
 
         dbg("%s - count is %d", __FUNCTION__, count);
@@ -864,8 +882,9 @@ send:
         if (priv->cmd_ctrl)
                 actual_size = 1;
         else
-                actual_size = count + (port->interrupt_out_size == 32 ? 2 : 1);
-        
+                actual_size = count +
+                              (priv->pkt_fmt == packet_format_1 ? 2 : 1);
+
         usb_serial_debug_data(debug, &port->dev, __FUNCTION__, port->interrupt_out_size,
                               port->interrupt_out_urb->transfer_buffer);
 
@@ -1331,30 +1350,32 @@ static void cypress_read_int_callback(struct urb *urb)
         }
 
         spin_lock_irqsave(&priv->lock, flags);
-        switch(urb->actual_length) {
-                case 32:
-                        /* This is for the CY7C64013... */
-                        priv->current_status = data[0] & 0xF8;
-                        bytes = data[1] + 2;
-                        i = 2;
-                        if (bytes > 2)
-                                havedata = 1;
-                        break;
-                case 8:
-                        /* This is for the CY7C63743... */
-                        priv->current_status = data[0] & 0xF8;
-                        bytes = (data[0] & 0x07) + 1;
-                        i = 1;
-                        if (bytes > 1)
-                                havedata = 1;
-                        break;
-                default:
-                        dbg("%s - wrong packet size - received %d bytes",
-                                        __FUNCTION__, urb->actual_length);
-                        spin_unlock_irqrestore(&priv->lock, flags);
-                        goto continue_read;
+        result = urb->actual_length;
+        switch (priv->pkt_fmt) {
+        default:
+        case packet_format_1:
+                /* This is for the CY7C64013... */
+                priv->current_status = data[0] & 0xF8;
+                bytes = data[1] + 2;
+                i = 2;
+                if (bytes > 2)
+                        havedata = 1;
+                break;
+        case packet_format_2:
+                /* This is for the CY7C63743... */
+                priv->current_status = data[0] & 0xF8;
+                bytes = (data[0] & 0x07) + 1;
+                i = 1;
+                if (bytes > 1)
+                        havedata = 1;
+                break;
         }
         spin_unlock_irqrestore(&priv->lock, flags);
+        if (result < bytes) {
+                dbg("%s - wrong packet size - received %d bytes but packet "
+                    "said %d bytes", __func__, result, bytes);
+                goto continue_read;
+        }
 
         usb_serial_debug_data (debug, &port->dev, __FUNCTION__,
                         urb->actual_length, data);