Protect ISR against failure to unhook.

[people/lynusvaz/gpxe.git] / src / arch / i386 / drivers / net / undinet.c

diff --git a/src/arch/i386/drivers/net/undinet.c b/src/arch/i386/drivers/net/undinet.c
index c9a610a..d985f90 100644 (file)
--- a/src/arch/i386/drivers/net/undinet.c
+++ b/src/arch/i386/drivers/net/undinet.c
@@ -39,8 +39,6 @@
 
 /** An UNDI NIC */
 struct undi_nic {
-       /** Entry point */
-       SEGOFF16_t entry;
        /** Assigned IRQ number */
        unsigned int irq;
        /** Currently processing ISR */
@@ -167,7 +165,6 @@ static int undinet_call ( struct undi_nic *undinic, unsigned int function,
        /* Copy parameter block and entry point */
        assert ( params_len <= sizeof ( undinet_params ) );
        memcpy ( &undinet_params, params, params_len );
-       undinet_entry_point = undinic->entry;
 
        /* Call real-mode entry point.  This calling convention will
         * work with both the !PXE and the PXENV+ entry points.
@@ -222,7 +219,8 @@ static int undinet_call ( struct undi_nic *undinic, unsigned int function,
                DBGC ( undinic, "UNDINIC %p parameters at %04x:%04x length "
                       "%#02x, entry point at %04x:%04x\n", undinic,
                       rm_params.segment, rm_params.offset, params_len,
-                      undinic->entry.segment, undinic->entry.offset );
+                      undinet_entry_point.segment,
+                      undinet_entry_point.offset );
                DBGC ( undinic, "UNDINIC %p parameters provided:\n", undinic );
                DBGC_HDA ( undinic, rm_params, params, params_len );
                DBGC ( undinic, "UNDINIC %p parameters returned:\n", undinic );
@@ -268,13 +266,6 @@ static unsigned int last_trigger_count = 0;
  * Hook UNDI interrupt service routine
  *
  * @v irq              IRQ number
- *
- * The UNDI ISR specifically does @b not chain to the previous
- * interrupt handler.  BIOSes seem to install somewhat perverse
- * default interrupt handlers; some do nothing other than an iret (and
- * so will cause a screaming interrupt if there really is another
- * interrupting device) and some disable the interrupt at the PIC (and
- * so will bring our own interrupts to a shuddering halt).
  */
 static void undinet_hook_isr ( unsigned int irq ) {
 
@@ -411,6 +402,15 @@ static int undinet_transmit ( struct net_device *netdev,
  * so instead of doing it the easy way we have to go to all the hassle
  * of installing a genuine interrupt service routine and dealing with
  * the wonderful 8259 Programmable Interrupt Controller.  Joy.
+ *
+ * Addendum (10/07/07).  When doing things such as iSCSI boot, in
+ * which we have to co-operate with a running OS, we can't get away
+ * with the "ISR-just-increments-a-counter-and-returns" trick at all,
+ * because it involves tying up the PIC for far too long, and other
+ * interrupt-dependent components (e.g. local disks) start breaking.
+ * We therefore implement a "proper" ISR which calls PXENV_UNDI_ISR
+ * from within interrupt context in order to deassert the device
+ * interrupt, and sends EOI if applicable.
  */
 static void undinet_poll ( struct net_device *netdev ) {
        struct undi_nic *undinic = netdev->priv;
@@ -425,28 +425,6 @@ static void undinet_poll ( struct net_device *netdev ) {
                if ( ! undinet_isr_triggered() )
                        return;
 
-#if 0
-               /* See if this was our interrupt */
-               memset ( &undi_isr, 0, sizeof ( undi_isr ) );
-               undi_isr.FuncFlag = PXENV_UNDI_ISR_IN_START;
-               if ( ( rc = undinet_call ( undinic, PXENV_UNDI_ISR, &undi_isr,
-                                          sizeof ( undi_isr ) ) ) != 0 )
-                       return;
-
-               /* Send EOI to the PIC.  In an ideal world, we'd do
-                * this only for interrupts which the UNDI stack
-                * reports as "ours".  However, since we don't (can't)
-                * chain to the previous interrupt handler, we have to
-                * acknowledge all interrupts.  See undinet_hook_isr()
-                * for more background.
-                */
-               send_eoi ( undinic->irq );
-
-               /* If this wasn't our interrupt, exit now */
-               if ( undi_isr.FuncFlag != PXENV_UNDI_ISR_OUT_OURS )
-                       return;
-#endif
-               
                /* Start ISR processing */
                undinic->isr_processing = 1;
                undi_isr.FuncFlag = PXENV_UNDI_ISR_IN_PROCESS;
@@ -651,7 +629,7 @@ int undinet_probe ( struct undi_device *undi ) {
        undi_set_drvdata ( undi, netdev );
        netdev->dev = &undi->dev;
        memset ( undinic, 0, sizeof ( *undinic ) );
-       undinic->entry = undi->entry;
+       undinet_entry_point = undi->entry;
        DBGC ( undinic, "UNDINIC %p using UNDI %p\n", undinic, undi );
 
        /* Hook in UNDI stack */
@@ -770,6 +748,9 @@ void undinet_remove ( struct undi_device *undi ) {
                       sizeof ( stop_undi ) );
        undi->flags &= ~UNDI_FL_STARTED;
 
+       /* Clear entry point */
+       memset ( &undinet_entry_point, 0, sizeof ( undinet_entry_point ) );
+
        /* Free network device */
        netdev_nullify ( netdev );
        netdev_put ( netdev );