X-Git-Url: http://developer.intra2net.com/git/?p=libftdi;a=blobdiff_plain;f=src%2Fftdi.c;h=a87d6537a1f700162360c78d631bb3ee50121270;hp=d2c4a1163008fe27cb46129a527d2c2aa705b7a2;hb=0c93de8177ee7310292ac7eab4c2e3ff993b4f2f;hpb=ef6f483889aa3d719a676f7f32303c4232941e57

diff --git a/src/ftdi.c b/src/ftdi.c
index d2c4a11..a87d653 100644
--- a/src/ftdi.c
+++ b/src/ftdi.c
@@ -98,6 +98,7 @@ int ftdi_init(struct ftdi_context *ftdi)
     ftdi->readbuffer_offset = 0;
     ftdi->readbuffer_remaining = 0;
     ftdi->writebuffer_chunksize = 4096;
+    ftdi->max_packet_size = 0;
 
     ftdi->interface = 0;
     ftdi->index = 0;
@@ -385,6 +386,45 @@ int ftdi_usb_get_strings(struct ftdi_context * ftdi, struct usb_device * dev,
 }
 
 /**
+ * Internal function to determine the maximum packet size.
+ * \param ftdi pointer to ftdi_context
+ * \param dev libusb usb_dev to use
+ * \retval Maximum packet size for this device
+ */
+static unsigned int _ftdi_determine_max_packet_size(struct ftdi_context *ftdi, struct usb_device *dev)
+{
+    unsigned int packet_size;
+
+    // Determine maximum packet size. Init with default value.
+    // New hi-speed devices from FTDI use a packet size of 512 bytes
+    // but could be connected to a normal speed USB hub -> 64 bytes packet size.
+    if (ftdi->type == TYPE_2232H || ftdi->type == TYPE_4232H)
+        packet_size = 512;
+    else
+        packet_size = 64;
+
+    if (dev->descriptor.bNumConfigurations > 0 && dev->config)
+    {
+        struct usb_config_descriptor config = dev->config[0];
+
+        if (ftdi->interface < config.bNumInterfaces)
+        {
+            struct usb_interface interface = config.interface[ftdi->interface];
+            if (interface.num_altsetting > 0)
+            {
+                struct usb_interface_descriptor descriptor = interface.altsetting[0];
+                if (descriptor.bNumEndpoints > 0)
+                {
+                    packet_size = descriptor.endpoint[0].wMaxPacketSize;
+                }
+            }
+        }
+    }
+
+    return packet_size;
+}
+
+/**
     Opens a ftdi device given by a usb_device.
 
     \param ftdi pointer to ftdi_context
@@ -400,6 +440,7 @@ int ftdi_usb_get_strings(struct ftdi_context * ftdi, struct usb_device * dev,
 int ftdi_usb_open_dev(struct ftdi_context *ftdi, struct usb_device *dev)
 {
     int detach_errno = 0;
+    int config_val = 1;
     if (!(ftdi->usb_dev = usb_open(dev)))
         ftdi_error_return(-4, "usb_open() failed");
 
@@ -419,18 +460,25 @@ int ftdi_usb_open_dev(struct ftdi_context *ftdi, struct usb_device *dev)
     // set configuration (needed especially for windows)
     // tolerate EBUSY: one device with one configuration, but two interfaces
     //    and libftdi sessions to both interfaces (e.g. FT2232)
-    if (dev->descriptor.bNumConfigurations > 0 &&
-            usb_set_configuration(ftdi->usb_dev, dev->config[0].bConfigurationValue) &&
-            errno != EBUSY)
+
+    if (dev->descriptor.bNumConfigurations > 0)
     {
-        ftdi_usb_close_internal (ftdi);
-        if (detach_errno == EPERM)
-        {
-            ftdi_error_return(-8, "inappropriate permissions on device!");
-        }
-        else
+        // libusb-win32 on Windows 64 can return a null pointer for a valid device
+        if (dev->config)
+            config_val = dev->config[0].bConfigurationValue;
+
+        if (usb_set_configuration(ftdi->usb_dev, config_val) &&
+            errno != EBUSY)
         {
-            ftdi_error_return(-3, "unable to set usb configuration. Make sure ftdi_sio is unloaded!");
+            ftdi_usb_close_internal (ftdi);
+            if (detach_errno == EPERM)
+            {
+                ftdi_error_return(-8, "inappropriate permissions on device!");
+            }
+            else
+            {
+                ftdi_error_return(-3, "unable to set usb configuration. Make sure ftdi_sio is unloaded!");
+            }
         }
     }
 #endif
@@ -483,6 +531,9 @@ int ftdi_usb_open_dev(struct ftdi_context *ftdi, struct usb_device *dev)
             break;
     }
 
+    // Determine maximum packet size
+    ftdi->max_packet_size = _ftdi_determine_max_packet_size(ftdi, dev);
+
     if (ftdi_set_baudrate (ftdi, 9600) != 0)
     {
         ftdi_usb_close_internal (ftdi);
@@ -822,7 +873,7 @@ static int ftdi_convert_baudrate(int baudrate, struct ftdi_context *ftdi,
     }
     // Split into "value" and "index" values
     *value = (unsigned short)(encoded_divisor & 0xFFFF);
-    if (ftdi->type == TYPE_2232C)
+    if (ftdi->type == TYPE_2232C || ftdi->type == TYPE_2232H || ftdi->type == TYPE_4232H)
     {
         *index = (unsigned short)(encoded_divisor >> 8);
         *index &= 0xFF00;
@@ -1258,13 +1309,11 @@ int ftdi_write_data_get_chunksize(struct ftdi_context *ftdi, unsigned int *chunk
 int ftdi_read_data(struct ftdi_context *ftdi, unsigned char *buf, int size)
 {
     int offset = 0, ret = 1, i, num_of_chunks, chunk_remains;
-    int packet_size;
+    int packet_size = ftdi->max_packet_size;
 
-    // New hi-speed devices from FTDI use a packet size of 512 bytes
-    if (ftdi->type == TYPE_2232H || ftdi->type == TYPE_4232H)
-        packet_size = 512;
-    else
-        packet_size = 64;
+    // Packet size sanity check (avoid division by zero)
+    if (packet_size == 0)
+        ftdi_error_return(-1, "max_packet_size is bogus (zero)");
 
     // everything we want is still in the readbuffer?
     if (size <= ftdi->readbuffer_remaining)