fix some races for recording

diff --git a/main.c b/main.c
index 0cae7e6..0a52e57 100644 (file)
--- a/main.c
+++ b/main.c
@@ -22,11 +22,16 @@ static struct {
                uint8_t fixed_state[4];
                uint32_t fixed_state32;
        };
+       union {
+               uint8_t pending_state[4];
+               uint32_t pending_state32;
+       };
        uint32_t stream_enable_to:1;
        uint32_t stream_enable_from:1;
        uint32_t stream_started:1;
        uint32_t stream_ended:1;
        uint32_t use_readinc:1;
+       uint32_t use_pending:1;
        uint32_t frame_cnt;
        uint32_t edge_cnt;
        uint32_t t_i;
@@ -53,6 +58,7 @@ void yield(void)
 {
 }
 
+/* portb handles TH */
 static void portb_isr_fixed(void)
 {
        uint32_t isfr, th;
@@ -128,6 +134,7 @@ static noinline void do_from_step(void)
 
        // should hopefully give atomic fixed_state read..
        s = g.fixed_state32;
+       g.fixed_state32 = g.pending_state32;
        g.stream_from[g.f_i][0] = s;
        g.stream_from[g.f_i][1] = s >> 8;
        g.f_i = (g.f_i + 1) & STREAM_BUF_MASK;
@@ -252,6 +259,7 @@ static void do_start_seq(void)
                }
        }
        else if (g.stream_enable_from) {
+               g.use_pending = 1;
                if (g.use_readinc) {
                        attachInterruptVector(IRQ_PORTB,
                                                portb_isr_fixed_do_from);
@@ -262,9 +270,6 @@ static void do_start_seq(void)
                        attachInterruptVector(IRQ_PORTC,
                                              portc_isr_frameinc_do_from);
                }
-
-               // prep first frame already
-               do_from_step();
        }
        __enable_irq();
 }
@@ -274,9 +279,10 @@ static void clear_state(void)
 {
        g.stream_enable_to = 0;
        g.stream_enable_from = 0;
-       g.use_readinc = 0;
        g.stream_started = 0;
        g.stream_ended = 0;
+       g.use_readinc = 0;
+       g.use_pending = 0;
        g.t_i = g.t_o = 0;
        g.f_i = g.f_o = 0;
        g.frame_cnt = 0;
@@ -302,7 +308,11 @@ static void do_usb(void *buf)
 
        switch (pkt->type) {
        case PKT_FIXED_STATE:
-               memcpy(g.fixed_state, pkt->data, sizeof(g.fixed_state));
+               memcpy(&i, pkt->data, sizeof(i));
+               if (g.use_pending)
+                       g.pending_state32 = i;
+               else
+                       g.fixed_state32 = i;
                break;
        case PKT_STREAM_ENABLE:
                __disable_irq();