apps/system/zmodem: Allow stack size and priority to be configured.

system/zmodem/Kconfig

@@ -16,6 +16,14 @@ menuconfig SYSTEM_ZMODEM
 
 if SYSTEM_ZMODEM
 
+config SYSTEM_ZMODEM_PRIORITY
+	int "rz/sz task priority"
+	default 100
+
+config SYSTEM_ZMODEM_STACKSIZE
+	int "rz/ez stack size"
+	default 2048
+
 config SYSTEM_ZMODEM_DEVNAME
 	string "Default Zmodem device"
 	default "/dev/console"

system/zmodem/Makefile

@@ -39,8 +39,19 @@ include $(APPDIR)/Make.defs
 
 # Zmodem sz and rz commands
 
-PRIORITY = SCHED_PRIORITY_DEFAULT
+CONFIG_SYSTEM_SZPROGNAME ?= sz$(EXEEXT)
-STACKSIZE = 1536
+SZ_PROGNAME = $(CONFIG_SYSTEM_SZPROGNAME)
+
+CONFIG_SYSTEM_RZPROGNAME ?= rz$(EXEEXT)
+RZ_PROGNAME = $(CONFIG_SYSTEM_RZPROGNAME)
+
+CONFIG_SYSTEM_ZMODEM_PRIORITY ?= 100
+CONFIG_SYSTEM_ZMODEM_STACKSIZE ?= 2048
+
+PRIORITY = $(CONFIG_SYSTEM_ZMODEM_PRIORITY)
+STACKSIZE = $(CONFIG_SYSTEM_ZMODEM_STACKSIZE)
+
+# Source/object files
 
 ASRCS  =
 
@@ -77,12 +88,6 @@ else
   INSTALL_DIR = $(BIN_DIR)
 endif
 
-CONFIG_SYSTEM_SZPROGNAME ?= sz$(EXEEXT)
-SZ_PROGNAME = $(CONFIG_SYSTEM_SZPROGNAME)
-
-CONFIG_SYSTEM_RZPROGNAME ?= rz$(EXEEXT)
-RZ_PROGNAME = $(CONFIG_SYSTEM_RZPROGNAME)
-
 ROOTDEPPATH = --dep-path .
 
 # Common build

system/zmodem/README.txt

@@ -142,9 +142,12 @@ Using NuttX Zmodem with a Linux Host
 
     Then use the sz command on Linux to send the file to the target:
 
-      $ sudo sz <filename> </dev/ttyS0 >/dev/ttyS0
+      $ sudo sz <filename> [-l nnnn] </dev/ttyS0 >/dev/ttyS0
 
-    Where <filename> is the file that you want to send.
+    Where <filename> is the file that you want to send. If -l nnnn is not
+    specified, then there will likely be packet buffer overflow errors.
+    nnnn should be set to a value less than or equal to
+    CONFIG_SYSTEM_ZMODEM_PKTBUFSIZE
 
     The resulting file will be found where you have configured the Zmodem
     "sandbox" via CONFIG_SYSTEM_ZMODEM_MOUNTPOINT.