arm ssp_isr: disable interrupt when no buffer

Count the occurences of DMA buffer unavailable.
Disable ssp interrupts when no dma buffer is available.  The irq
condition will persist, probably reentering the isr at high rate.

altera.c

@@ -1048,6 +1048,7 @@ const struct keywords altera_variable_names[] = {
 	{"ssp_block_size",    {.par=&ssp_block_size}},
 	{"ssp_write_ptr",     {.par=&ssp_injection_write_ptr}},
 	{"ssp_read_ptr",      {.par=&ssp_injection_read_ptr}},
+	{"ssp_nobuffer_count",{.par=&ssp_nobuffer_count}},
 	{"alterastatus",      {.par=&alterastatus}},
 	{"altera2status",     {.par=&altera2status}},
 	{"psconfig2",         {.par=&psconfig2}},

flash_NMAHEPAM/DESCENT.SPY

@@ -1,3 +1,3 @@
 @s/if pres<8000 or pres>11000 or temp > 3432 or temp < 2432: s/exit
 s/exec "SAFE.RC" 3
-@e not reached, spy file is closed
+@e not reached after three hits

flash_NMAHEPAM/MEASURE.RC

@@ -1,16 +1,16 @@
 @alt/stream/off
 @s/exe "PRESSURE.RC"
-var/set spi_min_qtime = 665
-@var/set udp_reset = 1000000
+var spi_min_qtime = 665
+@var udp_reset = 1000000
 @al/fifo/clear 1
 @al/fifo/set 10
 @al/fifo/reset 0x1f0
-@var/set sd_write_size = 0
-@v/set sd_write_count = 0
-@v/set udp_count = 0
-@v/set udp_size = 0
-@V W=600
-@v/set R=-1
+@var sd_write_size = 0
+@var sd_write_count = 0
+@var udp_count = 0
+@var udp_size = 0
+@var W=600
+@var R=-1
 @script/cron/none
 @var/cache ssp_dma spy_return second time hk_count hk_mes
 @var/cache sd_status udp_rx_cmd udp_size enc altera

flash_NMAHEPAM/PRESSURE.RC

@@ -1,9 +1,9 @@
 @var/cache pressure temp
 @var F=4
-@pres/read/verify
+pres/read/verify
 @s/if errno >= 500: s/exit
 @pressure/spy/on
-script/spy "ASCENT.SPY"
+s/spy "ASCENT.SPY"
 @var F=1
 @var N=0
 @var script_cron_prio=3

nmahepam.py

@@ -8,7 +8,7 @@ def HK():
     Vss   = hk2mvolt("adc_Vmcsa")*(-0.002)
     Icc   = hk2mvolt("adc_Ipcsa")*0.1
     Iss   = hk2mvolt("adc_Imcsa")*(-0.1)
-    Vprim = hk2mvolt("adc_Vprim")*(0.011)
+    Vprim = hk2mvolt("adc_Vprim")*(0.0163)
     Vbias = hk2mvolt("adc_Vbias")*(-0.05)
     Ibias = hk2mvolt("adc_Ibias")*0.0955
     Ibiasp = hk2mvolt("adc_dac")*0.0955

ssp.c

@@ -29,6 +29,7 @@ unsigned int ssp_dma_size;
 unsigned int ssp_min_size = 1;
 unsigned int ssp_block_idle = 256;
 unsigned int ssp_block_size = 3;
+unsigned int ssp_nobuffer_count;
 
 unsigned int ssp_get_status(void)
 {
@@ -139,6 +140,8 @@ static void ssp_isr(void)
 	// Try again.
 	if (!j->buf_count) {
 		if (get_new_buffer(j->buf_start)) {
+			SSPIMSC = 0;
+			ssp_nobuffer_count++;
 			VICVectAddr = 0;
 			return;
 		}

ssp.h

@@ -21,6 +21,7 @@ extern unsigned int ssp_lastword;
 extern unsigned int ssp_dma_size;
 extern unsigned int ssp_block_idle;
 extern unsigned int ssp_block_size;
+extern unsigned int ssp_nobuffer_count;
 
 enum ssp_flags {
 	ssp_compress = 1,

udp.c

@@ -161,6 +161,8 @@ int udp_write_stream(void *buf)
 			return 0;
 		case 1:
 			break;
+		case 3:
+			return 1;
 		default:
 			if (udp_stream_reset 
 			    && dropped_tick