Cosmetic fixes and comment additions in acpi.c.

 - Fix whitespace, coding style, and indentation in some places.

 - Add comments for less obvious entries and hardcoded numbers (e.g. 'type').

 - Add comments for all/most 'revision' fields, mention in which version
   of the ACPI spec which revision number is to be used.

 - Add URLs to a few external documents which describe tables that are
   not mentioned in the ACPI spec (or where the external document may
   provide further info), e.g. SRAT, SLIT, HPET, MCFG, etc.

 - Use the ASLC #define instead of hardcoding "CORE" in one instance
   (ASLC is already used everywhere else).

 - Add some TODOs for additional stuff which is in the spec but not yet
   handled by our code / #defines.

Abuild-tested.

Signed-off-by: Uwe Hermann <uwe@hermann-uwe.de>
Acked-by: Uwe Hermann <uwe@hermann-uwe.de>



git-svn-id: svn://svn.coreboot.org/coreboot/trunk@6098 2b7e53f0-3cfb-0310-b3e9-8179ed1497e1

1 files changed, 218 insertions, 210 deletions

diff --git a/src/arch/i386/boot/acpi.c b/src/arch/i386/boot/acpi.c
index e5169eaf43..5264e13e0d 100644
--- a/src/arch/i386/boot/acpi.c
+++ b/src/arch/i386/boot/acpi.c
@@ -34,7 +34,7 @@
 
 u8 acpi_checksum(u8 *table, u32 length)
 {
-	u8 ret=0;
+	u8 ret = 0;
 	while (length--) {
 		ret += *table;
 		table++;
@@ -43,88 +43,89 @@ u8 acpi_checksum(u8 *table, u32 length)
 }
 
 /**
- * Add an ACPI table to the RSDT (and XSDT) structure, recalculate length and checksum
+ * Add an ACPI table to the RSDT (and XSDT) structure, recalculate length
+ * and checksum.
  */
-
 void acpi_add_table(acpi_rsdp_t *rsdp, void *table)
 {
 	int i, entries_num;
 	acpi_rsdt_t *rsdt;
 	acpi_xsdt_t *xsdt = NULL;
 
-	/* The RSDT is mandatory ... */
+	/* The RSDT is mandatory... */
 	rsdt = (acpi_rsdt_t *)rsdp->rsdt_address;
 
-	/* ... while the XSDT is not */
-	if (rsdp->xsdt_address) {
+	/* ...while the XSDT is not. */
+	if (rsdp->xsdt_address)
 		xsdt = (acpi_xsdt_t *)((u32)rsdp->xsdt_address);
-	}
 
-	/* This should always be MAX_ACPI_TABLES */
+	/* This should always be MAX_ACPI_TABLES. */
 	entries_num = ARRAY_SIZE(rsdt->entry);
 
 	for (i = 0; i < entries_num; i++) {
-		if(rsdt->entry[i] == 0)
+		if (rsdt->entry[i] == 0)
 			break;
 	}
 
 	if (i >= entries_num) {
-		printk(BIOS_ERR, "ACPI: Error: Could not add ACPI table, too many tables.\n");
+		printk(BIOS_ERR, "ACPI: Error: Could not add ACPI table, "
+		       "too many tables.\n");
 		return;
 	}
 
-	/* Add table to the RSDT */
+	/* Add table to the RSDT. */
 	rsdt->entry[i] = (u32)table;
 
-	/* Fix RSDT length or the kernel will assume invalid entries */
-	rsdt->header.length = sizeof(acpi_header_t) + (sizeof(u32) * (i+1));
+	/* Fix RSDT length or the kernel will assume invalid entries. */
+	rsdt->header.length = sizeof(acpi_header_t) + (sizeof(u32) * (i + 1));
 
-	/* Re-calculate checksum */
+	/* Re-calculate checksum. */
 	rsdt->header.checksum = 0; /* Hope this won't get optimized away */
-	rsdt->header.checksum = acpi_checksum((u8 *)rsdt,
-			rsdt->header.length);
+	rsdt->header.checksum = acpi_checksum((u8 *)rsdt, rsdt->header.length);
 
-	/* And now the same thing for the XSDT. We use the same index as for
+	/*
+	 * And now the same thing for the XSDT. We use the same index as for
 	 * now we want the XSDT and RSDT to always be in sync in coreboot.
 	 */
 	if (xsdt) {
-		/* Add table to the XSDT */
-		xsdt->entry[i]=(u64)(u32)table;
+		/* Add table to the XSDT. */
+		xsdt->entry[i] = (u64)(u32)table;
 
-		/* Fix XSDT length */
+		/* Fix XSDT length. */
 		xsdt->header.length = sizeof(acpi_header_t) +
-			(sizeof(u64) * (i+1));
+				      (sizeof(u64) * (i + 1));
 
-		/* Re-calculate checksum */
-		xsdt->header.checksum=0;
-		xsdt->header.checksum=acpi_checksum((u8 *)xsdt,
-				xsdt->header.length);
+		/* Re-calculate checksum. */
+		xsdt->header.checksum = 0;
+		xsdt->header.checksum = acpi_checksum((u8 *)xsdt,
+						      xsdt->header.length);
 	}
 
-	printk(BIOS_DEBUG, "ACPI: added table %d/%d Length now %d\n",
-			i+1, entries_num, rsdt->header.length);
+	printk(BIOS_DEBUG, "ACPI: added table %d/%d, length now %d\n",
+	       i + 1, entries_num, rsdt->header.length);
 }
 
-int acpi_create_mcfg_mmconfig(acpi_mcfg_mmconfig_t *mmconfig, u32 base, u16 seg_nr, u8 start, u8 end)
+int acpi_create_mcfg_mmconfig(acpi_mcfg_mmconfig_t *mmconfig, u32 base,
+			      u16 seg_nr, u8 start, u8 end)
 {
 	mmconfig->base_address = base;
 	mmconfig->base_reserved = 0;
 	mmconfig->pci_segment_group_number = seg_nr;
 	mmconfig->start_bus_number = start;
 	mmconfig->end_bus_number = end;
-	return (sizeof(acpi_mcfg_mmconfig_t));
+
+	return sizeof(acpi_mcfg_mmconfig_t);
 }
 
 int acpi_create_madt_lapic(acpi_madt_lapic_t *lapic, u8 cpu, u8 apic)
 {
-	lapic->type=0;
-	lapic->length=sizeof(acpi_madt_lapic_t);
-	lapic->flags=1;
+	lapic->type = 0; /* Local APIC structure */
+	lapic->length = sizeof(acpi_madt_lapic_t);
+	lapic->flags = (1 << 0); /* Processor/LAPIC enabled */
+	lapic->processor_id = cpu;
+	lapic->apic_id = apic;
 
-	lapic->processor_id=cpu;
-	lapic->apic_id=apic;
-
-	return(lapic->length);
+	return lapic->length;
 }
 
 unsigned long acpi_create_madt_lapics(unsigned long current)
@@ -132,97 +133,97 @@ unsigned long acpi_create_madt_lapics(unsigned long current)
 	device_t cpu;
 	int cpu_index = 0;
 
-	for(cpu = all_devices; cpu; cpu = cpu->next) {
+	for (cpu = all_devices; cpu; cpu = cpu->next) {
 		if ((cpu->path.type != DEVICE_PATH_APIC) ||
 		   (cpu->bus->dev->path.type != DEVICE_PATH_APIC_CLUSTER)) {
 			continue;
 		}
-		if (!cpu->enabled) {
+		if (!cpu->enabled)
 			continue;
-		}
-		current += acpi_create_madt_lapic((acpi_madt_lapic_t *)current, cpu_index, cpu->path.apic.apic_id);
+		current += acpi_create_madt_lapic((acpi_madt_lapic_t *)current,
+				cpu_index, cpu->path.apic.apic_id);
 		cpu_index++;
 	}
+
 	return current;
 }
 
-int acpi_create_madt_ioapic(acpi_madt_ioapic_t *ioapic, u8 id, u32 addr,u32 gsi_base)
+int acpi_create_madt_ioapic(acpi_madt_ioapic_t *ioapic, u8 id, u32 addr,
+			    u32 gsi_base)
 {
-	ioapic->type=1;
-	ioapic->length=sizeof(acpi_madt_ioapic_t);
-	ioapic->reserved=0x00;
-	ioapic->gsi_base=gsi_base;
-
-	ioapic->ioapic_id=id;
-	ioapic->ioapic_addr=addr;
-
-	return(ioapic->length);
+	ioapic->type = 1; /* I/O APIC structure */
+	ioapic->length = sizeof(acpi_madt_ioapic_t);
+	ioapic->reserved = 0x00;
+	ioapic->gsi_base = gsi_base;
+	ioapic->ioapic_id = id;
+	ioapic->ioapic_addr = addr;
+
+	return ioapic->length;
 }
 
 int acpi_create_madt_irqoverride(acpi_madt_irqoverride_t *irqoverride,
 		u8 bus, u8 source, u32 gsirq, u16 flags)
 {
-	irqoverride->type=2;
-	irqoverride->length=sizeof(acpi_madt_irqoverride_t);
-	irqoverride->bus=bus;
-	irqoverride->source=source;
-	irqoverride->gsirq=gsirq;
-	irqoverride->flags=flags;
-
-	return(irqoverride->length);
+	irqoverride->type = 2; /* Interrupt source override */
+	irqoverride->length = sizeof(acpi_madt_irqoverride_t);
+	irqoverride->bus = bus;
+	irqoverride->source = source;
+	irqoverride->gsirq = gsirq;
+	irqoverride->flags = flags;
+
+	return irqoverride->length;
 }
 
 int acpi_create_madt_lapic_nmi(acpi_madt_lapic_nmi_t *lapic_nmi, u8 cpu,
-		u16 flags, u8 lint)
+			       u16 flags, u8 lint)
 {
-	lapic_nmi->type=4;
-	lapic_nmi->length=sizeof(acpi_madt_lapic_nmi_t);
-
-	lapic_nmi->flags=flags;
-	lapic_nmi->processor_id=cpu;
-	lapic_nmi->lint=lint;
+	lapic_nmi->type = 4; /* Local APIC NMI structure */
+	lapic_nmi->length = sizeof(acpi_madt_lapic_nmi_t);
+	lapic_nmi->flags = flags;
+	lapic_nmi->processor_id = cpu;
+	lapic_nmi->lint = lint;
 
-	return(lapic_nmi->length);
+	return lapic_nmi->length;
 }
 
 void acpi_create_madt(acpi_madt_t *madt)
 {
 #define LOCAL_APIC_ADDR	0xfee00000ULL
 
-	acpi_header_t *header=&(madt->header);
-	unsigned long current=(unsigned long)madt+sizeof(acpi_madt_t);
+	acpi_header_t *header = &(madt->header);
+	unsigned long current = (unsigned long)madt + sizeof(acpi_madt_t);
 
 	memset((void *)madt, 0, sizeof(acpi_madt_t));
 
-	/* fill out header fields */
+	/* Fill out header fields. */
 	memcpy(header->signature, "APIC", 4);
 	memcpy(header->oem_id, OEM_ID, 6);
 	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
 	memcpy(header->asl_compiler_id, ASLC, 4);
 
 	header->length = sizeof(acpi_madt_t);
-	header->revision = 1;
+	header->revision = 1; /* ACPI 1.0/2.0: 1, ACPI 3.0: 2, ACPI 4.0: 3 */
 
-	madt->lapic_addr= LOCAL_APIC_ADDR;
-	madt->flags	= 0x1; /* PCAT_COMPAT */
+	madt->lapic_addr = LOCAL_APIC_ADDR;
+	madt->flags = 0x1; /* PCAT_COMPAT */
 
 	current = acpi_fill_madt(current);
 
-	/* recalculate length */
-	header->length= current - (unsigned long)madt;
+	/* (Re)calculate length and checksum. */
+	header->length = current - (unsigned long)madt;
 
-	header->checksum	= acpi_checksum((void *)madt, header->length);
+	header->checksum = acpi_checksum((void *)madt, header->length);
 }
 
+/* MCFG is defined in the PCI Firmware Specification 3.0. */
 void acpi_create_mcfg(acpi_mcfg_t *mcfg)
 {
-
-	acpi_header_t *header=&(mcfg->header);
-	unsigned long current=(unsigned long)mcfg+sizeof(acpi_mcfg_t);
+	acpi_header_t *header = &(mcfg->header);
+	unsigned long current = (unsigned long)mcfg + sizeof(acpi_mcfg_t);
 
 	memset((void *)mcfg, 0, sizeof(acpi_mcfg_t));
 
-	/* fill out header fields */
+	/* Fill out header fields. */
 	memcpy(header->signature, "MCFG", 4);
 	memcpy(header->oem_id, OEM_ID, 6);
 	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
@@ -233,37 +234,40 @@ void acpi_create_mcfg(acpi_mcfg_t *mcfg)
 
 	current = acpi_fill_mcfg(current);
 
-	/* recalculate length */
-	header->length= current - (unsigned long)mcfg;
-
-	header->checksum	= acpi_checksum((void *)mcfg, header->length);
+	/* (Re)calculate length and checksum. */
+	header->length = current - (unsigned long)mcfg;
+	header->checksum = acpi_checksum((void *)mcfg, header->length);
 }
 
-/* this can be overriden by platform ACPI setup code,
- * if it calls acpi_create_ssdt_generator
+/*
+ * This can be overriden by platform ACPI setup code, if it calls
+ * acpi_create_ssdt_generator().
  */
-unsigned long __attribute__((weak)) acpi_fill_ssdt_generator(unsigned long current,
-						    const char *oem_table_id) {
+unsigned long __attribute__((weak)) acpi_fill_ssdt_generator(
+			unsigned long current, const char *oem_table_id)
+{
 	return current;
 }
 
 void acpi_create_ssdt_generator(acpi_header_t *ssdt, const char *oem_table_id)
 {
-	unsigned long current=(unsigned long)ssdt+sizeof(acpi_header_t);
+	unsigned long current = (unsigned long)ssdt + sizeof(acpi_header_t);
+
 	memset((void *)ssdt, 0, sizeof(acpi_header_t));
+
 	memcpy(&ssdt->signature, "SSDT", 4);
-	ssdt->revision = 2;
+	ssdt->revision = 2; /* ACPI 1.0/2.0: ?, ACPI 3.0/4.0: 2 */
 	memcpy(&ssdt->oem_id, OEM_ID, 6);
 	memcpy(&ssdt->oem_table_id, oem_table_id, 8);
 	ssdt->oem_revision = 42;
-	memcpy(&ssdt->asl_compiler_id, "CORE", 4);
+	memcpy(&ssdt->asl_compiler_id, ASLC, 4);
 	ssdt->asl_compiler_revision = 42;
 	ssdt->length = sizeof(acpi_header_t);
 
 	acpigen_set_current((char *) current);
 	current = acpi_fill_ssdt_generator(current, oem_table_id);
 
-	/* recalculate length */
+	/* (Re)calculate length and checksum. */
 	ssdt->length = current - (unsigned long)ssdt;
 	ssdt->checksum = acpi_checksum((void *)ssdt, ssdt->length);
 }
@@ -271,120 +275,117 @@ void acpi_create_ssdt_generator(acpi_header_t *ssdt, const char *oem_table_id)
 int acpi_create_srat_lapic(acpi_srat_lapic_t *lapic, u8 node, u8 apic)
 {
 	memset((void *)lapic, 0, sizeof(acpi_srat_lapic_t));
-        lapic->type=0;
-        lapic->length=sizeof(acpi_srat_lapic_t);
-        lapic->flags=1;
 
-        lapic->proximity_domain_7_0 = node;
-        lapic->apic_id=apic;
+	lapic->type = 0; /* Processor local APIC/SAPIC affinity structure */
+	lapic->length = sizeof(acpi_srat_lapic_t);
+	lapic->flags = (1 << 0); /* Enabled (the use of this structure). */
+	lapic->proximity_domain_7_0 = node;
+	/* TODO: proximity_domain_31_8, local SAPIC EID, clock domain. */
+	lapic->apic_id = apic;
 
-        return(lapic->length);
+	return lapic->length;
 }
 
-int acpi_create_srat_mem(acpi_srat_mem_t *mem, u8 node, u32 basek,u32 sizek, u32 flags)
+int acpi_create_srat_mem(acpi_srat_mem_t *mem, u8 node, u32 basek, u32 sizek,
+			 u32 flags)
 {
-        mem->type=1;
-        mem->length=sizeof(acpi_srat_mem_t);
-
-        mem->base_address_low = (basek<<10);
-	mem->base_address_high = (basek>>(32-10));
-
-        mem->length_low = (sizek<<10);
-        mem->length_high = (sizek>>(32-10));
-
-        mem->proximity_domain = node;
-
+	mem->type = 1; /* Memory affinity structure */
+	mem->length = sizeof(acpi_srat_mem_t);
+	mem->base_address_low = (basek << 10);
+	mem->base_address_high = (basek >> (32 - 10));
+	mem->length_low = (sizek << 10);
+	mem->length_high = (sizek >> (32 - 10));
+	mem->proximity_domain = node;
 	mem->flags = flags;
 
-        return(mem->length);
+	return mem->length;
 }
 
+/* http://www.microsoft.com/whdc/system/sysinternals/sratdwn.mspx */
 void acpi_create_srat(acpi_srat_t *srat)
 {
+	acpi_header_t *header = &(srat->header);
+	unsigned long current = (unsigned long)srat + sizeof(acpi_srat_t);
 
-        acpi_header_t *header=&(srat->header);
-        unsigned long current=(unsigned long)srat+sizeof(acpi_srat_t);
-
-        memset((void *)srat, 0, sizeof(acpi_srat_t));
+	memset((void *)srat, 0, sizeof(acpi_srat_t));
 
-        /* fill out header fields */
-        memcpy(header->signature, "SRAT", 4);
-        memcpy(header->oem_id, OEM_ID, 6);
-        memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
-        memcpy(header->asl_compiler_id, ASLC, 4);
-
-        header->length = sizeof(acpi_srat_t);
-        header->revision = 1;
+	/* Fill out header fields. */
+	memcpy(header->signature, "SRAT", 4);
+	memcpy(header->oem_id, OEM_ID, 6);
+	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
+	memcpy(header->asl_compiler_id, ASLC, 4);
 
-        srat->resv     = 0x1; /* BACK COMP */
+	header->length = sizeof(acpi_srat_t);
+	header->revision = 1; /* ACPI 1.0: N/A, 2.0: 1, 3.0: 2, 4.0: 3 */
 
-        current = acpi_fill_srat(current);
+	srat->resv = 1; /* Spec: Reserved to 1 for backwards compatibility. */
 
-        /* recalculate length */
-        header->length= current - (unsigned long)srat;
+	current = acpi_fill_srat(current);
 
-        header->checksum        = acpi_checksum((void *)srat, header->length);
+	/* (Re)calculate length and checksum. */
+	header->length = current - (unsigned long)srat;
+	header->checksum = acpi_checksum((void *)srat, header->length);
 }
 
+/* http://h21007.www2.hp.com/portal/download/files/unprot/Itanium/slit.pdf */
 void acpi_create_slit(acpi_slit_t *slit)
 {
+	acpi_header_t *header = &(slit->header);
+	unsigned long current = (unsigned long)slit + sizeof(acpi_slit_t);
 
-        acpi_header_t *header=&(slit->header);
-        unsigned long current=(unsigned long)slit+sizeof(acpi_slit_t);
-
-        memset((void *)slit, 0, sizeof(acpi_slit_t));
-
-        /* fill out header fields */
-        memcpy(header->signature, "SLIT", 4);
-        memcpy(header->oem_id, OEM_ID, 6);
-        memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
-        memcpy(header->asl_compiler_id, ASLC, 4);
+	memset((void *)slit, 0, sizeof(acpi_slit_t));
 
-        header->length = sizeof(acpi_slit_t);
-        header->revision = 1;
+	/* Fill out header fields. */
+	memcpy(header->signature, "SLIT", 4);
+	memcpy(header->oem_id, OEM_ID, 6);
+	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
+	memcpy(header->asl_compiler_id, ASLC, 4);
 
-        current = acpi_fill_slit(current);
+	header->length = sizeof(acpi_slit_t);
+	header->revision = 1; /* ACPI 1.0: N/A, ACPI 2.0/3.0/4.0: 1 */
 
-        /* recalculate length */
-        header->length= current - (unsigned long)slit;
+	current = acpi_fill_slit(current);
 
-        header->checksum        = acpi_checksum((void *)slit, header->length);
+	/* (Re)calculate length and checksum. */
+	header->length = current - (unsigned long)slit;
+	header->checksum = acpi_checksum((void *)slit, header->length);
 }
 
+/* http://www.intel.com/hardwaredesign/hpetspec_1.pdf */
 void acpi_create_hpet(acpi_hpet_t *hpet)
 {
-#define HPET_ADDR  0xfed00000ULL
-	acpi_header_t *header=&(hpet->header);
-	acpi_addr_t *addr=&(hpet->addr);
+#define HPET_ADDR 0xfed00000ULL
+	acpi_header_t *header = &(hpet->header);
+	acpi_addr_t *addr = &(hpet->addr);
 
 	memset((void *)hpet, 0, sizeof(acpi_hpet_t));
 
-	/* fill out header fields */
+	/* Fill out header fields. */
 	memcpy(header->signature, "HPET", 4);
 	memcpy(header->oem_id, OEM_ID, 6);
 	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
 	memcpy(header->asl_compiler_id, ASLC, 4);
 
 	header->length = sizeof(acpi_hpet_t);
-	header->revision = 1;
+	header->revision = 1; /* Currently 1. Table added in ACPI 2.0. */
 
-	/* fill out HPET address */
-	addr->space_id		= 0; /* Memory */
-	addr->bit_width		= 64;
-	addr->bit_offset	= 0;
-	addr->addrl		= HPET_ADDR & 0xffffffff;
-	addr->addrh		= HPET_ADDR >> 32;
+	/* Fill out HPET address. */
+	addr->space_id = 0; /* Memory */
+	addr->bit_width = 64;
+	addr->bit_offset = 0;
+	addr->addrl = HPET_ADDR & 0xffffffff;
+	addr->addrh = HPET_ADDR >> 32;
 
-	hpet->id	= 0x102282a0; /* AMD ? */
-	hpet->number	= 0;
-	hpet->min_tick  = 4096;
+	hpet->id = 0x102282a0; /* AMD! FIXME */
+	hpet->number = 0;
+	hpet->min_tick = 4096;
 
-	header->checksum	= acpi_checksum((void *)hpet, sizeof(acpi_hpet_t));
+	header->checksum = acpi_checksum((void *)hpet, sizeof(acpi_hpet_t));
 }
+
 void acpi_create_facs(acpi_facs_t *facs)
 {
-
-	memset( (void *)facs,0, sizeof(acpi_facs_t));
+	memset((void *)facs, 0, sizeof(acpi_facs_t));
 
 	memcpy(facs->signature, "FACS", 4);
 	facs->length = sizeof(acpi_facs_t);
@@ -394,72 +395,74 @@ void acpi_create_facs(acpi_facs_t *facs)
 	facs->flags = 0;
 	facs->x_firmware_waking_vector_l = 0;
 	facs->x_firmware_waking_vector_h = 0;
-	facs->version = 1;
+	facs->version = 1; /* ACPI 1.0: 0, ACPI 2.0/3.0: 1, ACPI 4.0: 2 */
 }
 
 void acpi_write_rsdt(acpi_rsdt_t *rsdt)
 {
-	acpi_header_t *header=&(rsdt->header);
+	acpi_header_t *header = &(rsdt->header);
 
-	/* fill out header fields */
+	/* Fill out header fields. */
 	memcpy(header->signature, "RSDT", 4);
 	memcpy(header->oem_id, OEM_ID, 6);
 	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
 	memcpy(header->asl_compiler_id, ASLC, 4);
 
 	header->length = sizeof(acpi_rsdt_t);
-	header->revision = 1;
-
-	/* fill out entries */
-
-	// entries are filled in later, we come with an empty set.
+	header->revision = 1; /* ACPI 1.0/2.0/3.0/4.0: 1 */
 
-	/* fix checksum */
+	/* Entries are filled in later, we come with an empty set. */
 
+	/* Fix checksum. */
 	header->checksum = acpi_checksum((void *)rsdt, sizeof(acpi_rsdt_t));
 }
 
 void acpi_write_xsdt(acpi_xsdt_t *xsdt)
 {
-	acpi_header_t *header=&(xsdt->header);
+	acpi_header_t *header = &(xsdt->header);
 
-	/* fill out header fields */
+	/* Fill out header fields. */
 	memcpy(header->signature, "XSDT", 4);
 	memcpy(header->oem_id, OEM_ID, 6);
 	memcpy(header->oem_table_id, ACPI_TABLE_CREATOR, 8);
 	memcpy(header->asl_compiler_id, ASLC, 4);
 
 	header->length = sizeof(acpi_xsdt_t);
-	header->revision = 1;
-
-	/* fill out entries */
-
-	// entries are filled in later, we come with an empty set.
+	header->revision = 1; /* ACPI 1.0: N/A, 2.0/3.0/4.0: 1 */
 
-	/* fix checksum */
+	/* Entries are filled in later, we come with an empty set. */
 
+	/* Fix checksum. */
 	header->checksum = acpi_checksum((void *)xsdt, sizeof(acpi_xsdt_t));
 }
 
 void acpi_write_rsdp(acpi_rsdp_t *rsdp, acpi_rsdt_t *rsdt, acpi_xsdt_t *xsdt)
 {
 	memset(rsdp, 0, sizeof(acpi_rsdp_t));
+
 	memcpy(rsdp->signature, RSDP_SIG, 8);
 	memcpy(rsdp->oem_id, OEM_ID, 6);
-	rsdp->length		= sizeof(acpi_rsdp_t);
-	rsdp->rsdt_address	= (u32)rsdt;
-	/* Some OSes expect an XSDT to be present for RSD PTR
-	 * revisions >= 2. If we don't have an ACPI XSDT, force
-	 * ACPI 1.0 (and thus RSD PTR revision 0)
+
+	rsdp->length = sizeof(acpi_rsdp_t);
+	rsdp->rsdt_address = (u32)rsdt;
+
+	/*
+	 * Revision: ACPI 1.0: 0, ACPI 2.0/3.0/4.0: 2.
+	 *
+	 * Some OSes expect an XSDT to be present for RSD PTR revisions >= 2.
+	 * If we don't have an ACPI XSDT, force ACPI 1.0 (and thus RSD PTR
+	 * revision 0).
 	 */
 	if (xsdt == NULL) {
-		rsdp->revision		= 0;
+		rsdp->revision = 0;
 	} else {
-		rsdp->xsdt_address	= (u64)(u32)xsdt;
-		rsdp->revision		= 2;
+		rsdp->xsdt_address = (u64)(u32)xsdt;
+		rsdp->revision = 2;
 	}
-	rsdp->checksum		= acpi_checksum((void *)rsdp, 20);
-	rsdp->ext_checksum	= acpi_checksum((void *)rsdp, sizeof(acpi_rsdp_t));
+
+	/* Calculate checksums. */
+	rsdp->checksum = acpi_checksum((void *)rsdp, 20);
+	rsdp->ext_checksum = acpi_checksum((void *)rsdp, sizeof(acpi_rsdp_t));
 }
 
 #if CONFIG_HAVE_ACPI_RESUME == 1
@@ -478,13 +481,13 @@ void suspend_resume(void)
 	#error "And coreboot memory reserved in mainboard.c"
 #endif
 #endif
-	/* if we happen to be resuming find wakeup vector and jump to OS */
+	/* If we happen to be resuming find wakeup vector and jump to OS. */
 	wake_vec = acpi_find_wakeup_vector();
 	if (wake_vec)
 		acpi_jump_to_wakeup(wake_vec);
 }
 
-/* this is to be filled by SB code - startup value what was found */
+/* This is to be filled by SB code - startup value what was found. */
 u8 acpi_slp_type = 0;
 
 static int acpi_is_wakeup(void)
@@ -506,7 +509,6 @@ static acpi_rsdp_t *valid_rsdp(acpi_rsdp_t *rsdp)
 	if ((rsdp->revision > 1) && (acpi_checksum((void *)rsdp,
 						rsdp->length) != 0))
 		return NULL;
-
 	printk(BIOS_DEBUG, "Checksum 2 passed all OK\n");
 
 	return rsdp;
@@ -522,11 +524,10 @@ void *acpi_get_wakeup_rsdp(void)
 void *acpi_find_wakeup_vector(void)
 {
 	char *p, *end;
-
 	acpi_rsdt_t *rsdt;
 	acpi_facs_t *facs;
 	acpi_fadt_t *fadt;
-	void  *wake_vec;
+	void *wake_vec;
 	int i;
 
 	rsdp = NULL;
@@ -534,11 +535,11 @@ void *acpi_find_wakeup_vector(void)
 	if (!acpi_is_wakeup())
 		return NULL;
 
-	printk(BIOS_DEBUG, "Trying to find the wakeup vector ...\n");
+	printk(BIOS_DEBUG, "Trying to find the wakeup vector...\n");
 
-	/* find RSDP */
-	for (p = (char *) 0xe0000; p <  (char *) 0xfffff; p+=16) {
-		if ((rsdp = valid_rsdp((acpi_rsdp_t *) p)))
+	/* Find RSDP. */
+	for (p = (char *)0xe0000; p < (char *)0xfffff; p += 16) {
+		if ((rsdp = valid_rsdp((acpi_rsdp_t *)p)))
 			break;
 	}
 
@@ -548,11 +549,11 @@ void *acpi_find_wakeup_vector(void)
 	printk(BIOS_DEBUG, "RSDP found at %p\n", rsdp);
 	rsdt = (acpi_rsdt_t *) rsdp->rsdt_address;
 
-	end = (char *) rsdt + rsdt->header.length;
+	end = (char *)rsdt + rsdt->header.length;
 	printk(BIOS_DEBUG, "RSDT found at %p ends at %p\n", rsdt, end);
 
-	for (i = 0; ((char *) &rsdt->entry[i]) < end; i++) {
-		fadt = (acpi_fadt_t *) rsdt->entry[i];
+	for (i = 0; ((char *)&rsdt->entry[i]) < end; i++) {
+		fadt = (acpi_fadt_t *)rsdt->entry[i];
 		if (strncmp((char *)fadt, "FACP", 4) == 0)
 			break;
 		fadt = NULL;
@@ -565,13 +566,15 @@ void *acpi_find_wakeup_vector(void)
 	facs = (acpi_facs_t *)fadt->firmware_ctrl;
 
 	if (facs == NULL) {
-		printk(BIOS_DEBUG, "No FACS found, wake up from S3 not possible.\n");
+		printk(BIOS_DEBUG, "No FACS found, wake up from S3 not "
+		       "possible.\n");
 		return NULL;
 	}
 
 	printk(BIOS_DEBUG, "FACS found at %p\n", facs);
-	wake_vec = (void *) facs->firmware_waking_vector;
+	wake_vec = (void *)facs->firmware_waking_vector;
 	printk(BIOS_DEBUG, "OS waking vector is %p\n", wake_vec);
+
 	return wake_vec;
 }
 
@@ -579,29 +582,34 @@ extern char *lowmem_backup;
 extern char *lowmem_backup_ptr;
 extern int lowmem_backup_size;
 
-#define WAKEUP_BASE		0x600
+#define WAKEUP_BASE 0x600
 
-void (*acpi_do_wakeup)(u32 vector, u32 backup_source, u32 backup_target, u32
-		backup_size) __attribute__((regparm(0))) = (void *)WAKEUP_BASE;
+void (*acpi_do_wakeup)(u32 vector, u32 backup_source, u32 backup_target,
+       u32 backup_size) __attribute__((regparm(0))) = (void *)WAKEUP_BASE;
 
 extern unsigned char __wakeup, __wakeup_size;
 
 void acpi_jump_to_wakeup(void *vector)
 {
-	u32 acpi_backup_memory = (u32) cbmem_find(CBMEM_ID_RESUME);
+	u32 acpi_backup_memory = (u32)cbmem_find(CBMEM_ID_RESUME);
 
 	if (!acpi_backup_memory) {
-		printk(BIOS_WARNING, "ACPI: Backup memory missing. No S3 Resume.\n");
+		printk(BIOS_WARNING, "ACPI: Backup memory missing. "
+		       "No S3 resume.\n");
 		return;
 	}
 
-	// FIXME this should go into the ACPI backup memory, too. No pork saussages.
-	/* just restore the SMP trampoline and continue with wakeup on assembly level */
+	// FIXME: This should go into the ACPI backup memory, too. No pork saussages.
+	/*
+	 * Just restore the SMP trampoline and continue with wakeup on
+	 * assembly level.
+	 */
 	memcpy(lowmem_backup_ptr, lowmem_backup, lowmem_backup_size);
 
-	/* copy wakeup trampoline in place */
+	/* Copy wakeup trampoline in place. */
 	memcpy((void *)WAKEUP_BASE, &__wakeup, (size_t)&__wakeup_size);
 
-	acpi_do_wakeup((u32)vector, acpi_backup_memory, CONFIG_RAMBASE, HIGH_MEMORY_SAVE);
+	acpi_do_wakeup((u32)vector, acpi_backup_memory, CONFIG_RAMBASE,
+		       HIGH_MEMORY_SAVE);
 }
 #endif