Make size of LPC1766 EMAC RAM configurable

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@3142 42af7a65-404d-4744-a932-0658087f49c3

17 files changed, 130 insertions, 29 deletions

diff --git a/nuttx/arch/arm/src/lpc17xx/lpc17_allocateheap.c b/nuttx/arch/arm/src/lpc17xx/lpc17_allocateheap.c
index 46d5d9e7a..5bf482799 100755
--- a/nuttx/arch/arm/src/lpc17xx/lpc17_allocateheap.c
+++ b/nuttx/arch/arm/src/lpc17xx/lpc17_allocateheap.c
@@ -57,6 +57,7 @@
  ****************************************************************************/
 
 /* Configuration ************************************************************/
+/* The configured RAM start address must be the beginning of CPU SRAM */
 
 #if CONFIG_DRAM_START != LPC17_SRAM_BASE
 #  warning "CONFIG_DRAM_START is not at LPC17_SRAM_BASE"
@@ -66,6 +67,8 @@
 #  define CONFIG_DRAM_END  (LPC17_SRAM_BASE+LPC17_CPUSRAM_SIZE)
 #endif
 
+/* The configured RAM size must be less then or equal to the CPU SRAM size */
+
 #if CONFIG_DRAM_SIZE > LPC17_CPUSRAM_SIZE
 #  warning "CONFIG_DRAM_SIZE is larger than the size of CPU SRAM"
 #  undef CONFIG_DRAM_SIZE
@@ -76,13 +79,25 @@
 #  warning "CONFIG_DRAM_END is before end of CPU SRAM... not all of CPU SRAM used"
 #endif
 
+/* Sanity checking */
+
 #ifdef LPC17_HAVE_BANK0
-#  if CONFIG_MM_REGIONS < 2
-#    warning "CONFIG_MM_REGIONS < 2: AHB SRAM Bank(s) not included in HEAP"
+#  if defined(LPC17_BANK0_HEAPSIZE) || defined(LPC17_HAVE_BANK1)
+#    if CONFIG_MM_REGIONS < 2
+#      warning "CONFIG_MM_REGIONS < 2: AHB SRAM Bank(s) not included in HEAP"
+#    endif
+#    if CONFIG_MM_REGIONS > 2
+#      warning "CONFIG_MM_REGIONS > 2: Additional regions handled by application?"
+#    endif
+#  else
+#    if CONFIG_MM_REGIONS > 1
+#      warning "CONFIG_MM_REGIONS > 1: This MCU has no available AHB SRAM Bank0/1"
+#    endif
 #  endif
 #else
 #  if CONFIG_MM_REGIONS > 1
 #    warning "CONFIG_MM_REGIONS > 1: This MCU has no AHB SRAM Bank0/1"
+#    warning "                       Other memory regions handled by application?"
 #  endif
 #endif
 
@@ -131,22 +146,44 @@ void up_addregion(void)
   /* Banks 0 and 1 are each 16Kb.  If both are present, they occupy a
    * contiguous 32Kb memory region.
    *
-   * If Ethernet is enabled, it will take all of bank 0 for packet
+   * If Ethernet is enabled, it will take some or all of bank 0 for packet
    * buffering and descriptor tables.
    */
 
 #ifdef LPC17_HAVE_BANK0
-#  if defined(CONFIG_NET) && defined(CONFIG_LPC17_ETHERNET) && defined(LPC17_NETHCONTROLLERS)
-#    ifdef LPC17_HAVE_BANK1
-       mm_addregion((FAR void*)LPC17_SRAM_BANK1, LPC17_BANK1_SIZE);
-#    endif
+
+  /* We have BANK0 (and, hence, possibly Bank1).  Is Bank0 all used for
+   * Ethernet packet buffering?  Or is there any part of Bank0 available for
+   * the heap.
+   */
+
+# ifdef LPC17_BANK0_HEAPSIZE
+
+  /* Some or all of Bank0 is available for the heap.  Is Bank1 present? */
+
+#  ifdef LPC17_HAVE_BANK1
+
+  /* Yes... the heap space available is the unused memory at the end of
+   * Bank0 plus all of Bank1.
+   */
+
+   mm_addregion((FAR void*)LPC17_BANK0_HEAPBASE, LPC17_BANK0_HEAPSIZE+LPC17_BANK1_SIZE);
 #  else
-#    ifdef LPC17_HAVE_BANK1
-       mm_addregion((FAR void*)LPC17_SRAM_BANK0, LPC17_BANK0_SIZE+LPC17_BANK1_SIZE);
-#    else
-       mm_addregion((FAR void*)LPC17_SRAM_BANK0, LPC17_BANK0_SIZE);
-#    endif
+
+   /* No... only the unused memory at the end of Bank0 is available for the
+    * heap/
+    */
+
+   mm_addregion((FAR void*)LPC17_BANK0_HEAPBASE, LPC17_BANK0_HEAPSIZE);
+#  endif
+# else
+
+  /* Nothing is available in Bank0.  Is Bank1 available? */
+
+#  ifdef LPC17_HAVE_BANK1
+   mm_addregion((FAR void*)LPC17_SRAM_BANK1, LPC17_BANK1_SIZE);
 #  endif
+# endif
 #endif
 }
 #endif
diff --git a/nuttx/arch/arm/src/lpc17xx/lpc17_emacram.h b/nuttx/arch/arm/src/lpc17xx/lpc17_emacram.h
index 75137084e..3759ccb9e 100755
--- a/nuttx/arch/arm/src/lpc17xx/lpc17_emacram.h
+++ b/nuttx/arch/arm/src/lpc17xx/lpc17_emacram.h
@@ -41,20 +41,36 @@
  ************************************************************************************/

 

 #include <nuttx/config.h>

-#if defined(CONFIG_NET) && defined(CONFIG_LPC17_ETHERNET)

-

 #include "chip.h"

 #include "lpc17_memorymap.h"

 

-/* Does this chip have and ethernet controller? */

-

-#if LPC17_NETHCONTROLLERS > 0

-

 /************************************************************************************

  * Pre-processor Definitions

  ************************************************************************************/

+/* Default, no-EMAC Case ************************************************************/

+/* Assume that all of AHB SRAM will be available for heap. If this is not true, then

+ * LPC17_BANK0_HEAPSIZE will be undefined and redefined below.

+ */

+

+#undef LPC17_BANK0_HEAPBASE

+#undef LPC17_BANK0_HEAPSIZE

+#ifdef LPC17_HAVE_BANK0

+#  define LPC17_BANK0_HEAPBASE LPC17_SRAM_BANK0

+#  define LPC17_BANK0_HEAPSIZE LPC17_BANK0_SIZE

+#endif

 

-/* Configuration ********************************************************************/

+/* Is networking enabled?  Is the LPC17xx Ethernet device enabled? Does this chip have

+ * and Ethernet controlloer?  Yes... then we will replace the above default definitions.

+ */

+

+#if defined(CONFIG_NET) && defined(CONFIG_LPC17_ETHERNET) && LPC17_NETHCONTROLLERS > 0

+

+/* EMAC RAM Configuration ***********************************************************/

+/* Is AHB SRAM available? */

+

+#ifndef LPC17_HAVE_BANK0

+#  error "AHB SRAM Bank0 is not available for EMAC RAM"

+#endif

 

 /* Number of Tx descriptors */

 

@@ -68,12 +84,43 @@
 #  define CONFIG_NET_NRXDESC 18

 #endif

 

-/* All of AHB SRAM, Bank 0 is set aside for EMAC Tx and Rx descriptors. */

+/* Size of the region at the beginning of AHB SRAM 0 set set aside for the EMAC.

+ * This size must fit within AHB SRAM Bank 0 and also be a multiple of 32-bit

+ * words.

+ */

+

+#ifndef CONFIG_NET_EMACRAM_SIZE

+#  define CONFIG_NET_EMACRAM_SIZE LPC17_BANK0_SIZE

+#endif

+

+#if CONFIG_NET_EMACRAM_SIZE > LPC17_BANK0_SIZE

+#  error "EMAC RAM size cannot exceed the size of AHB SRAM Bank 0"

+#endif

+

+#if (CONFIG_NET_EMACRAM_SIZE & 3) != 0

+#  error "EMAC RAM size must be in multiples of 32-bit words"

+#endif

+

+/* Determine is there is any meaning space left at the end of AHB Bank 0 that

+ * could be added to the heap.

+ */

+

+#undef LPC17_BANK0_HEAPBASE

+#undef LPC17_BANK0_HEAPSIZE

+#if CONFIG_NET_EMACRAM_SIZE < (LPC17_BANK0_SIZE-128)

+#  define LPC17_BANK0_HEAPBASE (LPC17_SRAM_BANK0 + CONFIG_NET_EMACRAM_SIZE)

+#  define LPC17_BANK0_HEAPSIZE (LPC17_BANK0_SIZE - CONFIG_NET_EMACRAM_SIZE)

+#endif

+

+/* Memory at the beginning of AHB SRAM, Bank 0 is set aside for EMAC Tx and Rx

+ * descriptors.  The position is not controllable, only the size of the region

+ * is controllable.

+ */

 

 #define LPC17_EMACRAM_BASE   LPC17_SRAM_BANK0

-#define LPC17_EMACRAM_SIZE   LPC17_BANK0_SIZE

+#define LPC17_EMACRAM_SIZE   CONFIG_NET_EMACRAM_SIZE

 

-/* Descriptors Memory Layout ********************************************************/

+/* Descriptor Memory Layout *********************************************************/

 /* EMAC DMA RAM and descriptor definitions.  The configured number of descriptors

  * will determine the organization and the size of the descriptor and status tables.

  * There is a complex interaction between the maximum packet size (CONFIG_NET_BUFSIZE)

@@ -90,7 +137,7 @@
  *

  * An example with all of the details:

  *

- * NTXDESC=18 NRXDESC=18 CONFIG_NET_BUFSIZE=420:

+ * NTXDESC=18 NRXDESC=18 CONFIG_NET_EMACRAM_SIZE=16Kb CONFIG_NET_BUFSIZE=420:

  *   LPC17_TXDESCTAB_SIZE = 18*8 = 144

  *   LPC17_TXSTATTAB_SIZE = 18*4 =  72

  *   LPC17_TXTAB_SIZE     = 216

@@ -191,6 +238,5 @@
  * Public Functions

  ************************************************************************************/

 

-#endif /* LPC17_NETHCONTROLLERS > 0 */

-#endif /* CONFIG_NET && CONFIG_LPC17_ETHERNET */

+#endif /* CONFIG_NET && CONFIG_LPC17_ETHERNET && LPC17_NETHCONTROLLERS > 0*/

 #endif /* __ARCH_ARM_SRC_LPC17XX_LPC17_EMACRAM_H */

diff --git a/nuttx/configs/mbed/README.txt b/nuttx/configs/mbed/README.txt
index 01becd3df..6098fc88b 100755
--- a/nuttx/configs/mbed/README.txt
+++ b/nuttx/configs/mbed/README.txt
@@ -291,6 +291,7 @@ mbed Configuration Options
 	CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.

 	CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex

 

+    CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb

 	CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18

 	CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18

 	CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is

diff --git a/nuttx/configs/mbed/nsh/defconfig b/nuttx/configs/mbed/nsh/defconfig
index d8f559062..1cddaa924 100755
--- a/nuttx/configs/mbed/nsh/defconfig
+++ b/nuttx/configs/mbed/nsh/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/nucleus2g/README.txt b/nuttx/configs/nucleus2g/README.txt
index 229c69a9b..654fd9089 100755
--- a/nuttx/configs/nucleus2g/README.txt
+++ b/nuttx/configs/nucleus2g/README.txt
@@ -403,6 +403,7 @@ Nucleus 2G Configuration Options
 	CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.

 	CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex

 

+    CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb

 	CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18

 	CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18

 	CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is

diff --git a/nuttx/configs/nucleus2g/nsh/defconfig b/nuttx/configs/nucleus2g/nsh/defconfig
index 0ae8f76a9..447df77ba 100755
--- a/nuttx/configs/nucleus2g/nsh/defconfig
+++ b/nuttx/configs/nucleus2g/nsh/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/nucleus2g/ostest/defconfig b/nuttx/configs/nucleus2g/ostest/defconfig
index f55fc07f0..4f5321289 100755
--- a/nuttx/configs/nucleus2g/ostest/defconfig
+++ b/nuttx/configs/nucleus2g/ostest/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/nucleus2g/usbserial/defconfig b/nuttx/configs/nucleus2g/usbserial/defconfig
index 1b3d0fdfb..aaed805b1 100755
--- a/nuttx/configs/nucleus2g/usbserial/defconfig
+++ b/nuttx/configs/nucleus2g/usbserial/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/nucleus2g/usbstorage/defconfig b/nuttx/configs/nucleus2g/usbstorage/defconfig
index 8b21405a2..fc0aa5f96 100755
--- a/nuttx/configs/nucleus2g/usbstorage/defconfig
+++ b/nuttx/configs/nucleus2g/usbstorage/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/README.txt b/nuttx/configs/olimex-lpc1766stk/README.txt
index 7aebf16ee..65264b770 100755
--- a/nuttx/configs/olimex-lpc1766stk/README.txt
+++ b/nuttx/configs/olimex-lpc1766stk/README.txt
@@ -609,6 +609,7 @@ Olimex LPC1766-STK Configuration Options
 	CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.

 	CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex

 

+    CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb

 	CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18

 	CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18

 	CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is

diff --git a/nuttx/configs/olimex-lpc1766stk/nettest/defconfig b/nuttx/configs/olimex-lpc1766stk/nettest/defconfig
index 2d36172c1..be6fb9960 100755
--- a/nuttx/configs/olimex-lpc1766stk/nettest/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/nettest/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/nsh/defconfig b/nuttx/configs/olimex-lpc1766stk/nsh/defconfig
index 783070df6..d8dcf573a 100755
--- a/nuttx/configs/olimex-lpc1766stk/nsh/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/nsh/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/ostest/defconfig b/nuttx/configs/olimex-lpc1766stk/ostest/defconfig
index d0dc7385d..3b9eb5384 100755
--- a/nuttx/configs/olimex-lpc1766stk/ostest/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/ostest/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/thttpd/defconfig b/nuttx/configs/olimex-lpc1766stk/thttpd/defconfig
index 4b2b5345e..f8eebba35 100755
--- a/nuttx/configs/olimex-lpc1766stk/thttpd/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/thttpd/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/usbserial/defconfig b/nuttx/configs/olimex-lpc1766stk/usbserial/defconfig
index acef97a79..29b78e72b 100755
--- a/nuttx/configs/olimex-lpc1766stk/usbserial/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/usbserial/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/configs/olimex-lpc1766stk/usbstorage/defconfig b/nuttx/configs/olimex-lpc1766stk/usbstorage/defconfig
index 033d42c56..99619b98a 100755
--- a/nuttx/configs/olimex-lpc1766stk/usbstorage/defconfig
+++ b/nuttx/configs/olimex-lpc1766stk/usbstorage/defconfig
@@ -188,6 +188,7 @@ CONFIG_UART3_2STOP=0
 # CONFIG_PHY_AUTONEG - Enable auto-negotion
 # CONFIG_PHY_SPEED100 - Select 100Mbit vs. 10Mbit speed.
 # CONFIG_PHY_FDUPLEX - Select full (vs. half) duplex
+# CONFIG_NET_EMACRAM_SIZE - Size of EMAC RAM.  Default: 16Kb
 # CONFIG_NET_NTXDESC - Configured number of Tx descriptors. Default: 18
 # CONFIG_NET_NRXDESC - Configured number of Rx descriptors. Default: 18
 # CONFIG_NET_PRIORITY - Ethernet interrupt priority.  The is default is
diff --git a/nuttx/net/send.c b/nuttx/net/send.c
index 14b9cea99..b3f137376 100644
--- a/nuttx/net/send.c
+++ b/nuttx/net/send.c
@@ -268,13 +268,17 @@ static uint16_t send_interrupt(struct uip_driver_s *dev, void *pvconn,
        * then the send won't actually make it out... it will be replaced with
        * an ARP request.
        *
-       * NOTE: If we are actually harvesting IP addresses on incomming IP
-       * packets, then this check should be necessary; the MAC mapping should
-       * already be in the ARP table.
+       * NOTE 1: This could an expensive check if there are a lot of entries
+       * in the ARP table.  Hence, we only check on the first packet -- when
+       * snd_sent is zero.
+       *
+       * NOTE 2: If we are actually harvesting IP addresses on incomming IP
+       * packets, then this check should not be necessary; the MAC mapping
+       * should already be in the ARP table.
        */
 
 #ifndef CONFIG_NET_ARP_IPIN
-      if (uip_arp_find(conn->ripaddr) != NULL)
+      if (pstate->snd_sent != 0 || uip_arp_find(conn->ripaddr) != NULL)
 #endif
         {
           /* Update the amount of data sent (but not necessarily ACKed) */