pru: Rework command processing so that most of it is done on pru0

Change the command dispatch and response generation so that most of
the work is done on pru0 instead of pru1.  This allows more code to
fit into the limited space on pru1.

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

1 files changed, 45 insertions, 47 deletions

diff --git a/src/pru/main.c b/src/pru/main.c
index d906b1ad..ea0ec602 100644
--- a/src/pru/main.c
+++ b/src/pru/main.c
@@ -99,73 +99,68 @@ DECL_INIT(timer_init);
  * Console IO
  ****************************************************************/
 
-// Return a buffer (and length) containing any incoming messages
-static char *
-console_get_input(uint8_t *plen)
-{
-    uint32_t read_count = readl(&SHARED_MEM->read_count);
-    if (read_count > 64)
-        read_count = 64;
-    *plen = read_count;
-    return SHARED_MEM->read_data;
-}
-
-// Remove from the receive buffer the given number of bytes
-static void
-console_pop_input(uint8_t len)
-{
-    writel(&SHARED_MEM->read_count, 0);
-}
-
 // Process any incoming commands
 void
 console_task(void)
 {
-    uint8_t buf_len, pop_count;
-    char *buf = console_get_input(&buf_len);
-    int8_t ret = command_find_block(buf, buf_len, &pop_count);
-    if (ret)
-        command_dispatch(buf, pop_count);
-    console_pop_input(pop_count);
+    const struct command_parser *cp = SHARED_MEM->next_command;
+    if (!cp)
+        return;
+    barrier();
+
+    if (sched_is_shutdown() && !(cp->flags & HF_IN_SHUTDOWN)) {
+        sched_report_shutdown();
+    } else {
+        void (*func)(uint32_t*) = cp->func;
+        func(SHARED_MEM->next_command_args);
+    }
+
+    writel(&SHARED_MEM->next_command, 0);
 }
 DECL_TASK(console_task);
 
-// Return an output buffer that the caller may fill with transmit messages
-static char *
-console_get_output(uint8_t len)
+// Encode and transmit a "response" message
+void
+console_sendf(const struct command_encoder *ce, va_list args)
 {
-    if (len > sizeof(SHARED_MEM->send_data[0].data))
-        return NULL;
+    // 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
-        return NULL;
-    return SHARED_MEM->send_data[send_push_pos].data;
-}
+        return;
 
-// Accept the given number of bytes added to the transmit buffer
-static void
-console_push_output(uint8_t len)
-{
-    uint32_t send_push_pos = SHARED_MEM->send_push_pos;
-    writel(&SHARED_MEM->send_data[send_push_pos].count, len);
+    // Generate message
+    char *buf = SHARED_MEM->send_data[send_push_pos].data;
+    uint32_t msglen = command_encodef(buf, max_size, ce, args);
+
+    // Signal PRU0 to transmit message
+    writel(&SHARED_MEM->send_data[send_push_pos].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));
 }
 
-// Encode and transmit a "response" message
 void
-console_sendf(const struct command_encoder *ce, va_list args)
+console_shutdown(void)
 {
-    uint8_t buf_len = ce->max_size;
-    char *buf = console_get_output(buf_len);
-    if (!buf)
-        return;
-    uint8_t msglen = command_encodef(buf, buf_len, ce, args);
-    command_add_frame(buf, msglen);
-    console_push_output(msglen);
+    writel(&SHARED_MEM->next_command, 0);
 }
+DECL_SHUTDOWN(console_shutdown);
+
+// Handle shutdown request from PRU0
+static void
+shutdown_handler(uint32_t *args)
+{
+    shutdown("Request from PRU0");
+}
+
+// Empty message (for ack/nak transmission)
+const struct command_parser shutdown_request = {
+    .func = shutdown_handler,
+};
 
 
 /****************************************************************
@@ -234,6 +229,9 @@ main(void)
     // Wait for PRU0 to initialize
     while (readl(&SHARED_MEM->signal) != SIGNAL_PRU0_WAITING)
         ;
+    SHARED_MEM->command_index = command_index;
+    SHARED_MEM->command_index_size = command_index_size;
+    SHARED_MEM->shutdown_handler = &shutdown_request;
     writel(&SHARED_MEM->signal, SIGNAL_PRU1_READY);
 
     sched_main();