--==_Exmh_-17561433160
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The NCR 3416 (eagle) is a pure EISA (mpc type 2) box. It uses an external
82489DX for the local APIC (even for dual pentium machines)and it has a
strange type 0x1 IO-APIC. The changes occur in 4 parts:
1) detect the 82489 and handle it correctly (PICLK divisors don't work).
2) use the ELCR for level/edge interrupts on the EISA box. I've made this
happen only on type 2 boards to be conservative, but I believe it should
happen whenever the system sees it has an EISA bus.
3) set up pin 0 as ExtINT for type 2 boards (this has to be done because pin2
isn't connected to the timer).
4) detect the unusual IO-APIC. It doesn't seem to work correctly in logical
routing mode, so switch it to physical.
These changes are probably sufficient to get some i486-SMP boards running as
well, although I haven't tested this.
I'd like to see these changes go into the 2.2 kernel, but since they change
the handling of MPC default type 2 boards, I need people with these boards to
test the changes. The assumption I used was that type 2 boards never worked,
so if anyone has one of these currently working, I'll need to refine the
checks.
James Bottomley
NCR Columbia
As usual, NCR Corp will not warranty, support or endorse these changes.
--==_Exmh_-17561433160
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Content-Description: eagle.diff
Content-Disposition: attachment; filename="eagle.diff"
--- linux/arch/i386/kernel/smp.c.orig Thu Feb 18 11:59:29 1999
+++ linux/arch/i386/kernel/smp.c Thu Feb 18 12:37:50 1999
@@ -94,6 +94,8 @@
static void cache_APIC_registers (void);
static void stop_this_cpu (void);
+static unsigned int external_82489DX = 0; /* set if external local apic */
+
static int smp_b_stepping = 0; /* Set if we find a B stepping CPU */
static int max_cpus = -1; /* Setup configured maximum number of CPUs to activate */
@@ -1225,7 +1227,6 @@
printk(KERN_INFO "SMP mode deactivated, forcing use of dummy APIC emulation.\n");
}
-#ifdef SMP_DEBUG
{
int reg;
@@ -1237,6 +1238,17 @@
*/
reg = apic_read(APIC_VERSION);
+ /* James.Bottomley@ColumbiaSC.ncr.com:
+ *
+ * Support the NCR3416. However this should also work
+ * for almost all 486 SMP systems. */
+ external_82489DX = ((reg & 0xf0) == 0);
+
+ if(external_82489DX) {
+ printk("Local APIC is external 82489DX\n");
+ }
+
+#ifdef SMP_DEBUG
SMP_PRINTK(("Getting VERSION: %x\n", reg));
apic_write(APIC_VERSION, 0);
@@ -1260,8 +1272,8 @@
reg = apic_read(APIC_LVT1);
SMP_PRINTK(("Getting LVT1: %x\n", reg));
- }
#endif
+ }
enable_local_APIC();
@@ -1866,14 +1878,19 @@
apic_write(APIC_LVTT , lvtt1_value);
/*
- * Divide PICLK by 16
- */
+ * Divide PICLK by 16;
+ *
+ * James.Bottomley@ColumbiaSC.ncr.com: this won't work for
+ * external local APIC, so adjust the APIC_DIVISOR accordingly */
tmp_value = apic_read(APIC_TDCR);
apic_write(APIC_TDCR , (tmp_value & ~APIC_TDR_DIV_1 )
| APIC_TDR_DIV_16);
tmp_value = apic_read(APIC_TMICT);
- apic_write(APIC_TMICT, clocks/APIC_DIVISOR);
+ if(!external_82489DX) {
+ clocks /= APIC_DIVISOR;
+ }
+ apic_write(APIC_TMICT, clocks);
}
void __init wait_8254_wraparound(void)
@@ -1958,7 +1975,10 @@
* underflown to be exact, as the timer counts down ;)
*/
- calibration_result = (tt1-tt2)*APIC_DIVISOR/LOOPS;
+ calibration_result = (tt1-tt2)/LOOPS;
+ if(!external_82489DX) {
+ calibration_result *= APIC_DIVISOR;
+ }
SMP_PRINTK(("\n..... %ld CPU clocks in 1 timer chip tick.",
(unsigned long)(t2-t1)/LOOPS));
--- linux/arch/i386/kernel/io_apic.c.orig Thu Feb 18 11:59:29 1999
+++ linux/arch/i386/kernel/io_apic.c Thu Feb 18 12:00:10 1999
@@ -332,10 +332,11 @@
* It's part of the EISA specification, but maybe it should only be
* used if the interrupt is actually marked as EISA?
*
- * Oh, well. Don't do it until somebody tells us what the right thing
- * to do is..
+ * James.Bottomley@Columbiasc.ncr.com:
+ * The correct thing to do is to use this *if* the mpc type identifies
+ * the BUS as EISA. This code *only* works for mpc default types.
*/
-#undef USE_ELCR_TRIGGER_LEVEL
+#define USE_ELCR_TRIGGER_LEVEL
#ifdef USE_ELCR_TRIGGER_LEVEL
/*
@@ -344,8 +345,15 @@
static int __init EISA_ELCR(unsigned int irq)
{
if (irq < 16) {
- unsigned int port = 0x4d0 + (irq >> 3);
- return (inb(port) >> (irq & 7)) & 1;
+ unsigned int port;
+
+ switch(mpc_default_type) {
+ case 2:
+ port = 0x4d0 + (irq >> 3);
+ return (inb(port) >> (irq & 7)) & 1;
+ default:
+ return 0;
+ }
}
printk("Broken MPtable reports ISA irq %d\n", irq);
return 0;
@@ -577,7 +585,14 @@
{
struct IO_APIC_route_entry entry;
int pin, idx, bus, irq, first_notcon = 1;
+ struct IO_APIC_reg_01 reg_01;
+ int ioapic_physical_only;
+ /* James.Bottomley@ColumbiaSC.ncr.com: support for ancient
+ * IO-APIC in NCR3416. This doesn't route IRQs properly in
+ * logical mode */
+ *(int *)®_01 = io_apic_read(1);
+ ioapic_physical_only = (reg_01.version == 1);
printk("init IO_APIC IRQs\n");
for (pin = 0; pin < nr_ioapic_registers; pin++) {
@@ -588,9 +603,15 @@
memset(&entry,0,sizeof(entry));
entry.delivery_mode = dest_LowestPrio;
- entry.dest_mode = 1; /* logical delivery */
+ if(ioapic_physical_only) {
+ entry.dest_mode = 0; /* physical mode */
+ entry.dest.physical.physical_dest = 0;
+ }
+ else {
+ entry.dest_mode = 1; /* logical delivery */
+ entry.dest.logical.logical_dest = 0;/* but no route */
+ }
entry.mask = 0; /* enable IRQ */
- entry.dest.logical.logical_dest = 0; /* but no route */
idx = find_irq_entry(pin,mp_INT);
if (idx == -1) {
@@ -702,10 +723,17 @@
printk("....... [IO-APIC cannot route PCI PIRQ 0-3]\n");
printk("....... : IO APIC version: %04X\n", reg_01.version);
- if ( (reg_01.version != 0x10) && /* oldest IO-APICs */
+ if(reg_01.version == 1) {
+ /* ancient EISA eagle IO-APIC; doesn't support
+ * logical delivery mode correctly
+ */
+ printk("....... : NCR 3416 IO-APIC; physical delivery only mode\n");
+ }
+ else if ( (reg_01.version != 0x10) && /* oldest IO-APICs */
(reg_01.version != 0x11) && /* Pentium/Pro IO-APICs */
(reg_01.version != 0x13) /* Xeon IO-APICs */
)
+
UNEXPECTED_IO_APIC();
if (reg_01.__reserved_1 || reg_01.__reserved_2)
UNEXPECTED_IO_APIC();
@@ -929,6 +957,7 @@
switch (mpc_default_type)
{
case 2:
+ mp_irqs[0].mpc_irqtype = mp_ExtINT;
break;
default:
/*
--==_Exmh_-17561433160--
-
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