pru: Use a pointer when working with send_data array items

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/pru/internal.h

@@ -22,15 +22,16 @@
 #define ALT_PRU_PTR(ptr) ((typeof(ptr))((uint32_t)(ptr) ^ 0x2000))
 
 // Layout of shared memory
+struct shared_response_buffer {
+    uint32_t count;
+    char data[64];
+};
 struct shared_mem {
     uint32_t signal;
     const struct command_parser *next_command;
     uint32_t next_command_args[16];
     uint32_t send_push_pos, send_pop_pos;
-    struct {
-        uint32_t count;
-        char data[64];
-    } send_data[4];
+    struct shared_response_buffer send_data[4];
     const struct command_parser *command_index;
     uint32_t command_index_size;
     const struct command_parser *shutdown_handler;

src/pru/main.c

@@ -125,19 +125,16 @@ console_sendf(const struct command_encoder *ce, va_list args)
 {
     // Verify space for message
     uint32_t max_size = ce->max_size;
-    if (max_size > sizeof(SHARED_MEM->send_data[0].data))
-        return;
     uint32_t send_push_pos = SHARED_MEM->send_push_pos;
-    if (readl(&SHARED_MEM->send_data[send_push_pos].count))
-        // Queue full
+    struct shared_response_buffer *s = &SHARED_MEM->send_data[send_push_pos];
+    if (max_size > sizeof(s->data) || readl(&s->count))
         return;
 
     // Generate message
-    char *buf = SHARED_MEM->send_data[send_push_pos].data;
-    uint32_t msglen = command_encodef(buf, max_size, ce, args);
+    uint32_t msglen = command_encodef(s->data, max_size, ce, args);
 
     // Signal PRU0 to transmit message
-    writel(&SHARED_MEM->send_data[send_push_pos].count, msglen);
+    writel(&s->count, msglen);
     write_r31(R31_WRITE_IRQ_SELECT | (KICK_PRU0_EVENT - R31_WRITE_IRQ_OFFSET));
     SHARED_MEM->send_push_pos = (
         (send_push_pos + 1) % ARRAY_SIZE(SHARED_MEM->send_data));

src/pru/pru0.c

@@ -38,15 +38,14 @@ check_can_send(void)
 {
     for (;;) {
         uint32_t send_pop_pos = SHARED_MEM->send_pop_pos;
-        uint32_t count = readl(&SHARED_MEM->send_data[send_pop_pos].count);
+        struct shared_response_buffer *s = &SHARED_MEM->send_data[send_pop_pos];
+        uint32_t count = readl(&s->count);
         if (!count)
             // Queue empty
             break;
-        command_add_frame(SHARED_MEM->send_data[send_pop_pos].data, count);
-        pru_rpmsg_send(
-            &transport, CHAN_PORT, transport_dst
-            , &SHARED_MEM->send_data[send_pop_pos].data, count);
-        writel(&SHARED_MEM->send_data[send_pop_pos].count, 0);
+        command_add_frame(s->data, count);
+        pru_rpmsg_send(&transport, CHAN_PORT, transport_dst, &s->data, count);
+        writel(&s->count, 0);
         SHARED_MEM->send_pop_pos = (
             (send_pop_pos + 1) % ARRAY_SIZE(SHARED_MEM->send_data));
     }