Untangle the code in this file to improve understandability. Both

ia64_count_cpus() and ia64_probe_sapics() called a single function
to do the the actual work. The difference in behaviour was handled
in that function and was further complicated by adding bootverbose
related code. As such, even the simplest of changes was hard to
comprehend.

Untangling has been done by increasing code duplication and using
a more naive style of coding. FWIW, the object file is slightly
smaller than before, so things aren't as bad as it may seem.

Triggered by: a simple fix on the P4 branch that never got merged.

1 files changed, 155 insertions, 159 deletions

diff --git a/sys/ia64/acpica/madt.c b/sys/ia64/acpica/madt.c
index ac281d3..1e53e8b 100644
--- a/sys/ia64/acpica/madt.c
+++ b/sys/ia64/acpica/madt.c
@@ -97,212 +97,208 @@ typedef struct  /* PLATFORM INTERRUPT SOURCE */
 #pragma pack()
 
 static void
-parse_interrupt_override(INTERRUPT_SOURCE_OVERRIDE *override)
+print_entry(APIC_HEADER *entry)
 {
-	if (bootverbose)
-		printf("\t\tBus=%d, Source=%d, Irq=0x%x\n", override->Bus,
-		    override->Source, override->GlobalSystemInterrupt);
-}
 
-static void
-parse_io_sapic(IO_SAPIC *sapic)
-{
-	if (bootverbose)
+	switch (entry->Type) {
+	case APIC_INTERRUPT_SOURCE_OVERRIDE: {
+		INTERRUPT_SOURCE_OVERRIDE *iso =
+		    (INTERRUPT_SOURCE_OVERRIDE *)entry;
+		printf("\tInterrupt source override entry\n");
+		printf("\t\tBus=%d, Source=%d, Irq=0x%x\n", iso->Bus,
+		    iso->Source, iso->GlobalSystemInterrupt);
+		break;
+	}
+
+	case APIC_IO:
+		printf("\tI/O APIC entry\n");
+		break;
+
+	case APIC_IO_SAPIC: {
+		IO_SAPIC *sapic = (IO_SAPIC *)entry;
+		printf("\tI/O SAPIC entry\n");
 		printf("\t\tId=0x%x, Vector=0x%x, Address=0x%lx\n",
 		    sapic->IoSapicId, sapic->Vector, sapic->IoSapicAddress);
-	sapic_create(sapic->IoSapicId, sapic->Vector, sapic->IoSapicAddress);
-}
+		break;
+	}
 
-static void
-parse_local_sapic(LOCAL_SAPIC *sapic)
-{
-	if (bootverbose) {
+	case APIC_LOCAL_APIC_NMI:
+		printf("\tLocal APIC NMI entry\n");
+		break;
+
+	case APIC_LOCAL_APIC_OVERRIDE: {
+		LAPIC_OVERRIDE *lapic = (LAPIC_OVERRIDE *)entry;
+		printf("\tLocal APIC override entry\n");
+		printf("\t\tLocal APIC address=0x%lx\n",
+		    lapic->LocalApicAddress);
+		break;
+	}
+
+	case APIC_LOCAL_SAPIC: {
+		LOCAL_SAPIC *sapic = (LOCAL_SAPIC *)entry;
+		printf("\tLocal SAPIC entry\n");
 		printf("\t\tProcessorId=0x%x, Id=0x%x, Eid=0x%x",
 		    sapic->ProcessorId, sapic->LocalSapicId,
 		    sapic->LocalSapicEid);
 		if (!sapic->ProcessorEnabled)
 			printf(" (disabled)");
 		printf("\n");
+		break;
 	}
-#ifdef SMP
-	if (sapic->ProcessorEnabled)
-		cpu_mp_add(sapic->ProcessorId, sapic->LocalSapicId,
-		    sapic->LocalSapicEid);
-#endif
-}
 
-static void
-parse_lapic_override(LAPIC_OVERRIDE *lapic)
-{
-	if (bootverbose)
-		printf("\t\tLocal APIC address=0x%lx\n",
-		    lapic->LocalApicAddress);
-	ia64_lapic_address = lapic->LocalApicAddress;
-}
+	case APIC_NMI:
+		printf("\tNMI entry\n");
+		break;
 
-static void
-parse_platform_interrupt(PLATFORM_INTERRUPT_SOURCE *source)
-{
-	if (bootverbose)
+	case APIC_PLATFORM_INTERRUPT: {
+		PLATFORM_INTERRUPT_SOURCE *pis =
+		    (PLATFORM_INTERRUPT_SOURCE *)entry;
+		printf("\tPlatform interrupt entry\n");
 		printf("\t\tPolarity=%d, TriggerMode=%d, Id=0x%x, "
-		    "Eid=0x%x, Vector=0x%x, Irq=%d\n", source->Polarity,
-		    source->TriggerMode, source->ProcessorId,
-		    source->ProcessorEid, source->IoSapicVector,
-		    source->GlobalSystemInterrupt);
+		    "Eid=0x%x, Vector=0x%x, Irq=%d\n",
+		    pis->Polarity, pis->TriggerMode, pis->ProcessorId,
+		    pis->ProcessorEid, pis->IoSapicVector,
+		    pis->GlobalSystemInterrupt);
+		break;
+	}
+
+	case APIC_PROC:
+		printf("\tLocal APIC entry\n");
+		break;
+
+	default:
+		printf("\tUnknown type %d entry\n", entry->Type);
+		break;
+	}
 }
 
-static int
-parse_madt(APIC_TABLE *madt, int countcpus)
+void
+ia64_probe_sapics(void)
 {
+	ACPI_POINTER rsdp_ptr;
+	APIC_HEADER *entry;
+	APIC_TABLE *table;
+	RSDP_DESCRIPTOR *rsdp;
+	XSDT_DESCRIPTOR *xsdt;
 	char *end, *p;
-	int cpus;
-
-	end = (char *)madt + madt->Header.Length;
-
-	/*
-	 * MADT header is followed by a number of variable length
-	 * structures.
-	 */
+	int t, tables;
 
-	if (countcpus) {
-		cpus = 0;
-
-		for (p = (char *)(madt + 1); p < end; ) {
-			APIC_HEADER *head = (APIC_HEADER *)p;
-
-			if (head->Type == APIC_LOCAL_SAPIC) {
-				LOCAL_SAPIC *sapic = (LOCAL_SAPIC *) head;
-				if (sapic->ProcessorEnabled)
-					cpus++;
-			}
-			p = p + head->Length;
-		}
+	if (AcpiOsGetRootPointer(ACPI_LOGICAL_ADDRESSING, &rsdp_ptr) != AE_OK)
+		return;
 
-		return (cpus);
-	}
+	rsdp = (RSDP_DESCRIPTOR *)IA64_PHYS_TO_RR7(rsdp_ptr.Pointer.Physical);
+	xsdt = (XSDT_DESCRIPTOR *)IA64_PHYS_TO_RR7(rsdp->XsdtPhysicalAddress);
 
-	/* Save the address of the processor interrupt block. */
-	if (bootverbose)
-		printf("\tLocal APIC address=0x%x\n",
-		    madt->LocalApicAddress);
-	ia64_lapic_address = madt->LocalApicAddress;
+	tables = (UINT64 *)((char *)xsdt + xsdt->Header.Length) -
+	    xsdt->TableOffsetEntry;
 
-	for (p = (char *)(madt + 1); p < end; ) {
-		APIC_HEADER *head = (APIC_HEADER *)p;
+	for (t = 0; t < tables; t++) {
+		table = (APIC_TABLE *)
+		    IA64_PHYS_TO_RR7(xsdt->TableOffsetEntry[t]);
 
 		if (bootverbose)
-			printf("\t");
-
-		switch (head->Type) {
-		case APIC_PROC:
-			if (bootverbose)
-				printf("Local APIC entry\n");
-			break;
+			printf("Table '%c%c%c%c' at %p\n",
+			    table->Header.Signature[0],
+			    table->Header.Signature[1],
+			    table->Header.Signature[2],
+			    table->Header.Signature[3], table);
 
-		case APIC_IO:
-			if (bootverbose)
-				printf("I/O APIC entry\n");
-			break;
-
-		case APIC_INTERRUPT_SOURCE_OVERRIDE:
-			if (bootverbose)
-				printf("Interrupt source override entry\n");
-			parse_interrupt_override
-				((INTERRUPT_SOURCE_OVERRIDE *) head);
-			break;
+		if (strncmp(table->Header.Signature, APIC_SIG, 4) != 0)
+			continue;
 
-		case APIC_NMI:
-			if (bootverbose)
-				printf("NMI entry\n");
-			break;
-
-		case APIC_LOCAL_APIC_NMI:
-			if (bootverbose)
-				printf("Local APIC NMI entry\n");
-			break;
+		/* Save the address of the processor interrupt block. */
+		if (bootverbose)
+			printf("\tLocal APIC address=0x%x\n",
+			    table->LocalApicAddress);
+		ia64_lapic_address = table->LocalApicAddress;
 
+		end = (char *)table + table->Header.Length;
+		p = (char *)(table + 1);
+		while (p < end) {
+			entry = (APIC_HEADER *)p;
 
-		case APIC_LOCAL_APIC_OVERRIDE:
 			if (bootverbose)
-				printf("Local APIC override entry\n");
-			parse_lapic_override((LAPIC_OVERRIDE*)head);
-			break;
+				print_entry(entry);
+
+			switch (entry->Type) {
+			case APIC_IO_SAPIC: {
+				IO_SAPIC *sapic = (IO_SAPIC *)entry;
+				sapic_create(sapic->IoSapicId, sapic->Vector,
+				    sapic->IoSapicAddress);
+				break;
+			}
 
-		case APIC_IO_SAPIC:
-			if (bootverbose)
-				printf("I/O SAPIC entry\n");
-			parse_io_sapic((IO_SAPIC *) head);
-			break;
+			case APIC_LOCAL_APIC_OVERRIDE: {
+				LAPIC_OVERRIDE *lapic = (LAPIC_OVERRIDE*)entry;
+				ia64_lapic_address = lapic->LocalApicAddress;
+				break;
+			}
 
-		case APIC_LOCAL_SAPIC:
-			if (bootverbose)
-				printf("Local SAPIC entry\n");
-			parse_local_sapic((LOCAL_SAPIC *) head);
-			break;
+#ifdef SMP
+			case APIC_LOCAL_SAPIC: {
+				LOCAL_SAPIC *sapic = (LOCAL_SAPIC *)entry;
+				if (sapic->ProcessorEnabled)
+					cpu_mp_add(sapic->ProcessorId,
+					    sapic->LocalSapicId,
+					    sapic->LocalSapicEid);
+				break;
+			}
+#endif
 
-		case APIC_PLATFORM_INTERRUPT:
-			if (bootverbose)
-				printf("Platform interrupt entry\n");
-			parse_platform_interrupt
-				((PLATFORM_INTERRUPT_SOURCE *) head);
-			break;
+			default:
+				break;
+			}
 
-		default:
-			if (bootverbose)
-				printf("Unknown type %d entry\n", head->Type);
-			break;
+			p += entry->Length;
 		}
-
-		p = p + head->Length;
 	}
-
-	return (0);
 }
 
-static int
-parse_table(int countcpus)
+/*
+ * Count the number of local SAPIC entries in the APIC table. Every enabled
+ * entry corresponds to a processor.
+ */
+int
+ia64_count_cpus(void)
 {
-	ACPI_POINTER		rsdp_ptr;
-	RSDP_DESCRIPTOR		*rsdp;
-	XSDT_DESCRIPTOR		*xsdt;
-	ACPI_TABLE_HEADER	*table;
-	int			i, count;
+	ACPI_POINTER rsdp_ptr;
+	APIC_TABLE *table;
+	LOCAL_SAPIC *entry;
+	RSDP_DESCRIPTOR *rsdp;
+	XSDT_DESCRIPTOR *xsdt;
+	char *end, *p;
+	int cpus, t, tables;
 
 	if (AcpiOsGetRootPointer(ACPI_LOGICAL_ADDRESSING, &rsdp_ptr) != AE_OK)
-		return 0;
+		return (0);
 
 	rsdp = (RSDP_DESCRIPTOR *)IA64_PHYS_TO_RR7(rsdp_ptr.Pointer.Physical);
 	xsdt = (XSDT_DESCRIPTOR *)IA64_PHYS_TO_RR7(rsdp->XsdtPhysicalAddress);
 
-	count = (UINT64 *)((char *)xsdt + xsdt->Header.Length)
-	    - xsdt->TableOffsetEntry;
-	for (i = 0; i < count; i++) {
-		table = (ACPI_TABLE_HEADER *)
-			IA64_PHYS_TO_RR7(xsdt->TableOffsetEntry[i]);
+	tables = (UINT64 *)((char *)xsdt + xsdt->Header.Length) -
+	    xsdt->TableOffsetEntry;
 
-		if (bootverbose && !countcpus)
-			printf("Table '%c%c%c%c' at %p\n", table->Signature[0],
-			    table->Signature[1], table->Signature[2],
-			    table->Signature[3], table);
+	cpus = 0;
 
-		if (!strncmp(table->Signature, APIC_SIG, 4))
-			return (parse_madt((APIC_TABLE *) table, countcpus));
-	}
-	return (0);
-}
+	for (t = 0; t < tables; t++) {
+		table = (APIC_TABLE *)
+		    IA64_PHYS_TO_RR7(xsdt->TableOffsetEntry[t]);
 
-void
-ia64_probe_sapics(void)
-{
-	parse_table(0);
-}
+		if (strncmp(table->Header.Signature, APIC_SIG, 4) != 0)
+			continue;
 
-/*
- * Count the number of local SAPIC entries in the APIC table. Every enabled
- * entry corresponds to a processor.
- */
-int
-ia64_count_cpus(void)
-{
-	return (parse_table(1));
+		end = (char *)table + table->Header.Length;
+		p = (char *)(table + 1);
+		while (p < end) {
+			entry = (LOCAL_SAPIC *)p;
+
+			if (entry->Header.Type == APIC_LOCAL_SAPIC &&
+			    entry->ProcessorEnabled)
+				cpus++;
+
+			p += entry->Header.Length;
+		}
+	}
+
+	return (cpus);
 }