Changeset 540 for trunk/hal

Timestamp:

Sep 21, 2018, 10:22:02 PM (6 years ago)

Author:

nicolas.van.phan@…

Message:

TTY MUX 5/5 : Multiplex TTY character receiving

The multiplexing for receving chars is done by redirecting
the IRQs (when a char is received) to the right chdev (so the right
server DEV thread). When the user types an uppercase letter,
it is treated as a special char used to change the active tty
by redirecting the IRQs to the chdev corresponding to the appropriate
channel.

Add some documentation and example in the code.

Add mfences calls in spinlock_unlock_busy fix a bug on letty physical
hardware.

File:

• trunk/hal/tsar_mips32/drivers/soclib_mtty.c (modified) (3 diffs)

trunk/hal/tsar_mips32/drivers/soclib_mtty.c

@@ -322 +322 @@
             byte = (char)hal_remote_lb( read_xp );
 
+            // Ignore Carriage Returns
+            if( byte == 0xD )
+            {
+                continue;
+            }
+
+            // This is the MTTY multiplexing
+            // When a extended ASCII char are received (typing Ctrl-Shift-U then 100+n for example on the terminal)
+            // Two characters are received : 0xFFFFFFc4 then 0xFFFFFF80 + n
+            // When this second char is received, it is considered a metachar that determines the tty dest number
+            // Thus, if you want to make tty 5 the new target, type Ctrl+Shift+U then 105
+            // Now all keystrokes IRQs will be handled by the server DEV thread
+            // associated to RX channel number 5
+            if( (byte & 0xFF) > 0x80 && (byte & 0xFF) <= 0x89 )
+            {
+                // Disable MTTY IRQ for the core owning
+                // the current channel's server DEV thread
+                dev_pic_disable_irq( server_lid, XPTR( local_cxy , chdev ) );
+                
+                int         tty_destnb  = (int)(byte & 0xFF) - 0x80;
+                chdev_t *   new_chdev   = chdev_dir.txt_rx[tty_destnb];
+                lid_t       new_lid     = new_chdev->server->core->lid;
+
+                // Bind MTTY IRQ to the core owning the new channel's server DEV thread
+                dev_pic_bind_irq( new_lid , new_chdev );                
+
+                // Enable MTTY IRQ for the core owning
+                // the new channel's server DEV thread
+                dev_pic_enable_irq( new_lid , XPTR( local_cxy , new_chdev ) );
+
+                channel    = new_chdev->channel;
+                is_rx      = new_chdev->is_rx;
+                server     = new_chdev->server;
+                server_lid = new_lid;
+                fifo = &mtty_rx_fifo[channel];
+                continue;
+            }
+
             // filter special character ^Z  => block TXT owner process
             if( byte == 0x1A ) 
@@ -533 +571 @@
 void __attribute__ ((noinline)) soclib_mtty_aux( void * args )
 {
-    uint32_t   status;
-    bool_t     empty;
-    uint32_t   i;
-
     xptr_t     dev_xp = ((txt_sync_args_t *)args)->dev_xp;
     char     * buffer = ((txt_sync_args_t *)args)->buffer;
@@ -557 +591 @@
     xptr_t status_xp = XPTR( tty_cxy , tty_ptr + MTTY_STATUS );
 
-    reg_t  save_sr;
-
     // loop on characters (busy waiting policy)
+    uint32_t   i;
     for( i = 0 ; i < count ; i++ )
     {
         // This is the MTTY multiplexing
-        // Before each character, we send the destination TTY number for this char.
+        // Before each character, we send the destination (RX) TTY number for this char.
         // The two bytes (dest number + char) must be sent consecutively,
         // so to guarantee this atomicity, we use a lock to prevent other
         // concurrent server DEV threads to write a byte in between our two bytes
 
-        // Get the lock
-        spinlock_lock_busy( &txt0_lock, &save_sr );
-
         // Send the destination TTY number
-        do
-        {
+        // HACK: Remove this on the Lety physical prototype.
+        // This 'if' is here so that the kernel messages in simulation are readable
+        bool_t empty = false;
+        if (channel > 0) {
+            // For examples, "Hello" would appear "0H0e0l0l0o" on the simulation terminal
+            do {
+                // get MTTY_STATUS
+                uint32_t status = hal_remote_lw( status_xp );
+                empty  = ( (status & MTTY_STATUS_TX_FULL) == 0 );
+
+                // transfer one byte if TX buffer empty
+                if ( empty ) {
+                    hal_remote_sb( write_xp , channel + '0' );
+                }
+            } while ( empty == false );
+        }
+
+        // Send the character
+        do {
             // get MTTY_STATUS
-            status = hal_remote_lw( status_xp );
+            uint32_t status = hal_remote_lw( status_xp );
             empty  = ( (status & MTTY_STATUS_TX_FULL) == 0 );
 
             // transfer one byte if TX buffer empty
-            if ( empty )  hal_remote_sb( write_xp , channel + '0' );
-            
-        }
-        while ( empty == false );
-
-        // Send the character
-        do
-        {
-            // get MTTY_STATUS
-            status = hal_remote_lw( status_xp );
-            empty  = ( (status & MTTY_STATUS_TX_FULL) == 0 );
-
-            // transfer one byte if TX buffer empty
-            if ( empty )  hal_remote_sb( write_xp , buffer[i] );
-        }
-        while ( empty == false );
-
-        // Release the lock
-        spinlock_unlock_busy( &txt0_lock, save_sr );
+            if ( empty ) {
+                hal_remote_sb( write_xp , buffer[i] );
+            }
+        } while ( empty == false );
     }
 }  // end soclib_mtty_aux()