[PATCH] ppc64: Get native PCI going on iSeries, from Paul Mackerras

From: Anton Blanchard <anton@samba.org>

Get native PCI going on iSeries, from Paul Mackerras

arch/ppc64/kernel/iSeries_IoMmTable.c

@@ -31,7 +31,6 @@
 #include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <asm/ppcdebug.h>
-#include <asm/flight_recorder.h>
 #include <asm/iSeries/HvCallPci.h>
 #include <asm/iSeries/iSeries_pci.h>
 

arch/ppc64/kernel/iSeries_VpdInfo.c

@@ -153,7 +153,7 @@ int device_Location(struct pci_dev *PciDev, char *BufPtr)
 	struct iSeries_Device_Node *DevNode =
 		(struct iSeries_Device_Node *)PciDev->sysdata;
 	return sprintf(BufPtr, "PCI: Bus%3d, AgentId%3d, Vendor %04X, Location %s",
-		       DevNode->DsaAddr.busNumber, DevNode->AgentId,
+		       DevNode->DsaAddr.Dsa.busNumber, DevNode->AgentId,
 		       DevNode->Vendor, DevNode->Location);
 }
 

arch/ppc64/kernel/iSeries_irq.c

@@ -55,45 +55,13 @@ static hw_irq_controller iSeries_IRQ_handler = {
 	.end = iSeries_end_IRQ
 };
 
-struct iSeries_irqEntry {
-	u32 dsa;
-	struct iSeries_irqEntry* next;
-};
-
-struct iSeries_irqAnchor {
-	u8  valid : 1;
-	u8  reserved : 7;
-	u16  entryCount;
-	struct iSeries_irqEntry* head;
-};
-
-static struct iSeries_irqAnchor iSeries_irqMap[NR_IRQS];
-
-#if 0
-static void iSeries_init_irqMap(int irq);
-#endif
-
 void iSeries_init_irq_desc(irq_desc_t *desc)
 {
-	desc->handler = &iSeries_IRQ_handler;
 }
 
 /* This is called by init_IRQ.  set in ppc_md.init_IRQ by iSeries_setup.c */
 void __init iSeries_init_IRQ(void)
 {
-#if 0
-	int i;
-	irq_desc_t *desc;
-
-	for (i = 0; i < NR_IRQS; i++) {
-		desc = get_irq_desc(i);
-		desc->handler = &iSeries_IRQ_handler;
-		desc->status = 0;
-		desc->status |= IRQ_DISABLED;
-		desc->depth = 1;
-		iSeries_init_irqMap(i);
-	}
-#endif
 	/* Register PCI event handler and open an event path */
 	PPCDBG(PPCDBG_BUSWALK,
 			"Register PCI event handler and open an event path\n");
@@ -101,35 +69,24 @@ void __init iSeries_init_IRQ(void)
 	return;
 }
 
-#if 0
-/*
- *  Called by iSeries_init_IRQ 
- * Prevent IRQs 0 and 255 from being used.  IRQ 0 appears in
- * uninitialized devices.  IRQ 255 appears in the PCI interrupt
- * line register if a PCI error occurs,
- */
-static void __init iSeries_init_irqMap(int irq)
-{
-	iSeries_irqMap[irq].valid = ((irq == 0) || (irq == 255)) ? 0 : 1;
-	iSeries_irqMap[irq].entryCount = 0;
-	iSeries_irqMap[irq].head = NULL;
-}
-#endif
-
 /*
  * This is called out of iSeries_scan_slot to allocate an IRQ for an EADS slot
  * It calculates the irq value for the slot.
+ * Note that subBusNumber is always 0 (at the moment at least).
  */
 int __init iSeries_allocate_IRQ(HvBusNumber busNumber,
 		HvSubBusNumber subBusNumber, HvAgentId deviceId)
 {
 	u8 idsel = (deviceId >> 4);
-	u8 function = deviceId & 0x0F;
+	u8 function = deviceId & 7;
 
-	return ((((busNumber - 1) * 16 + (idsel - 1) * 8
-					+ function) * 9 / 8) % 253) + 2;
+	return ((busNumber - 1) << 6) + ((idsel - 1) << 3) + function + 1;
 }
 
+#define IRQ_TO_BUS(irq)		(((((irq) - 1) >> 6) & 0xff) + 1)
+#define IRQ_TO_IDSEL(irq)	(((((irq) - 1) >> 3) & 7) + 1)
+#define IRQ_TO_FUNC(irq)	(((irq) - 1) & 7)
+
 /*
  * This is called out of iSeries_scan_slot to assign the EADS slot
  * to its IRQ number
@@ -137,66 +94,33 @@ int __init iSeries_allocate_IRQ(HvBusNumber busNumber,
 int __init iSeries_assign_IRQ(int irq, HvBusNumber busNumber,
 		HvSubBusNumber subBusNumber, HvAgentId deviceId)
 {
-	int rc;
-	u32 dsa = (busNumber << 16) | (subBusNumber << 8) | deviceId;
-	struct iSeries_irqEntry *newEntry;
-	unsigned long flags;
-	irq_desc_t *desc = get_irq_desc(irq);
+	irq_desc_t *desc = get_real_irq_desc(irq);
 
-	if ((irq < 0) || (irq >= NR_IRQS))
+	if (desc == NULL)
 		return -1;
-
-	newEntry = kmalloc(sizeof(*newEntry), GFP_KERNEL);
-	if (newEntry == NULL)
-		return -ENOMEM;
-
-	newEntry->dsa  = dsa;
-	newEntry->next = NULL;
-	/*
-	 * Probably not necessary to lock the irq since allocation is only 
-	 * done during buswalk, but it should not hurt anything except a 
-	 * little performance to be smp safe.
-	 */
-	spin_lock_irqsave(&desc->lock, flags);
-
-	if (iSeries_irqMap[irq].valid) {
-		/* Push the new element onto the irq stack */
-		newEntry->next = iSeries_irqMap[irq].head;
-		iSeries_irqMap[irq].head = newEntry;
-		++iSeries_irqMap[irq].entryCount;
-		rc = 0;
-		PPCDBG(PPCDBG_BUSWALK, "iSeries_assign_IRQ   0x%04X.%02X.%02X = 0x%04X\n",
-				busNumber, subBusNumber, deviceId, irq);
-	} else {
-		printk("PCI: Something is wrong with the iSeries_irqMap.\n");
-		kfree(newEntry);
-		rc = -1;
-	}
-	spin_unlock_irqrestore(&desc->lock, flags);
-	return rc;
+	desc->handler = &iSeries_IRQ_handler;
+	return 0;
 }
 
 
 /* This is called by iSeries_activate_IRQs */
 static unsigned int iSeries_startup_IRQ(unsigned int irq)
 {
-	struct iSeries_irqEntry *entry;
-	u32 bus, subBus, deviceId, function, mask;
+	u32 bus, deviceId, function, mask;
+	const u32 subBus = 0;
+
+	bus = IRQ_TO_BUS(irq);
+	function = IRQ_TO_FUNC(irq);
+	deviceId = (IRQ_TO_IDSEL(irq) << 4) + function;
 
-	for (entry = iSeries_irqMap[irq].head; entry != NULL;
-			entry = entry->next) {
-		bus = (entry->dsa >> 16) & 0xFFFF;
-		subBus = (entry->dsa >> 8) & 0xFF;
-		deviceId = entry->dsa & 0xFF;
-		function = deviceId & 0x0F;
 	/* Link the IRQ number to the bridge */
 	HvCallXm_connectBusUnit(bus, subBus, deviceId, irq);
+
 	/* Unmask bridge interrupts in the FISR */
 	mask = 0x01010000 << function;
 	HvCallPci_unmaskFisr(bus, subBus, deviceId, mask);
 	PPCDBG(PPCDBG_BUSWALK, "iSeries_activate_IRQ 0x%02X.%02X.%02X  Irq:0x%02X\n",
 				bus, subBus, deviceId, irq);
-	}
 	return 0;
 }
 
@@ -223,22 +147,20 @@ void __init iSeries_activate_IRQs()
 /*  this is not called anywhere currently */
 static void iSeries_shutdown_IRQ(unsigned int irq)
 {
-	struct iSeries_irqEntry *entry;
-	u32 bus, subBus, deviceId, function, mask;
+	u32 bus, deviceId, function, mask;
+	const u32 subBus = 0;
 
 	/* irq should be locked by the caller */
+	bus = IRQ_TO_BUS(irq);
+	function = IRQ_TO_FUNC(irq);
+	deviceId = (IRQ_TO_IDSEL(irq) << 4) + function;
 
-	for (entry = iSeries_irqMap[irq].head; entry; entry = entry->next) {
-		bus = (entry->dsa >> 16) & 0xFFFF;
-		subBus = (entry->dsa >> 8) & 0xFF;
-		deviceId = entry->dsa & 0xFF;
-		function = deviceId & 0x0F;
 	/* Invalidate the IRQ number in the bridge */
 	HvCallXm_connectBusUnit(bus, subBus, deviceId, 0);
+
 	/* Mask bridge interrupts in the FISR */
 	mask = 0x01010000 << function;
 	HvCallPci_maskFisr(bus, subBus, deviceId, mask);
-	}
 }
 
 /*
@@ -247,21 +169,19 @@ static void iSeries_shutdown_IRQ(unsigned int irq)
  */
 static void iSeries_disable_IRQ(unsigned int irq)
 {
-	struct iSeries_irqEntry *entry;
-	u32 bus, subBus, deviceId, mask;
+	u32 bus, deviceId, function, mask;
+	const u32 subBus = 0;
 
 	/* The IRQ has already been locked by the caller */
-	for (entry = iSeries_irqMap[irq].head; entry; entry = entry->next) {
-		bus = (entry->dsa >> 16) & 0xFFFF;
-		subBus = (entry->dsa >> 8) & 0xFF;
-		deviceId = entry->dsa & 0xFF;
+	bus = IRQ_TO_BUS(irq);
+	function = IRQ_TO_FUNC(irq);
+	deviceId = (IRQ_TO_IDSEL(irq) << 4) + function;
+
 	/* Mask secondary INTA   */
 	mask = 0x80000000;
 	HvCallPci_maskInterrupts(bus, subBus, deviceId, mask);
-		PPCDBG(PPCDBG_BUSWALK,
-				"iSeries_disable_IRQ 0x%02X.%02X.%02X 0x%04X\n",
+	PPCDBG(PPCDBG_BUSWALK, "iSeries_disable_IRQ 0x%02X.%02X.%02X 0x%04X\n",
 	       bus, subBus, deviceId, irq);
-    	}
 }
 
 /*
@@ -270,21 +190,19 @@ static void iSeries_disable_IRQ(unsigned int irq)
  */
 static void iSeries_enable_IRQ(unsigned int irq)
 {
-	struct iSeries_irqEntry *entry;
-	u32 bus, subBus, deviceId, mask;
+	u32 bus, deviceId, function, mask;
+	const u32 subBus = 0;
 
 	/* The IRQ has already been locked by the caller */
-	for (entry = iSeries_irqMap[irq].head; entry; entry = entry->next) {
-		bus = (entry->dsa >> 16) & 0xFFFF;
-		subBus = (entry->dsa >> 8) & 0xFF;
-		deviceId = entry->dsa & 0xFF;
+	bus = IRQ_TO_BUS(irq);
+	function = IRQ_TO_FUNC(irq);
+	deviceId = (IRQ_TO_IDSEL(irq) << 4) + function;
+
 	/* Unmask secondary INTA */
 	mask = 0x80000000;
 	HvCallPci_unmaskInterrupts(bus, subBus, deviceId, mask);
-		PPCDBG(PPCDBG_BUSWALK,
-				"iSeries_enable_IRQ 0x%02X.%02X.%02X 0x%04X\n",
+	PPCDBG(PPCDBG_BUSWALK, "iSeries_enable_IRQ 0x%02X.%02X.%02X 0x%04X\n",
 	       bus, subBus, deviceId, irq);
-	}
 }
 
 /*

arch/ppc64/kernel/iSeries_pci_reset.c

@@ -36,7 +36,6 @@
 #include <asm/iSeries/HvCallPci.h>
 #include <asm/iSeries/HvTypes.h>
 #include <asm/iSeries/mf.h>
-#include <asm/flight_recorder.h>
 #include <asm/pci.h>
 
 #include <asm/iSeries/iSeries_pci.h>

arch/ppc64/kernel/irq.c

@@ -589,7 +589,9 @@ int do_IRQ(struct pt_regs *regs)
 
 	return 1; /* lets ret_from_int know we can do checks */
 }
+
 #else	/* CONFIG_PPC_ISERIES */
+
 int do_IRQ(struct pt_regs *regs)
 {
 	int irq, first = 1;

arch/ppc64/kernel/pci.c

@@ -224,7 +224,11 @@ pci_alloc_pci_controller(enum phb_types controller_type)
         struct pci_controller *hose;
 	char *model;
 
+#ifdef CONFIG_PPC_ISERIES
+        hose = (struct pci_controller *)kmalloc(sizeof(struct pci_controller), GFP_KERNEL);
+#else
         hose = (struct pci_controller *)alloc_bootmem(sizeof(struct pci_controller));
+#endif
         if(hose == NULL) {
                 printk(KERN_ERR "PCI: Allocate pci_controller failed.\n");
                 return NULL;
@@ -232,6 +236,11 @@ pci_alloc_pci_controller(enum phb_types controller_type)
         memset(hose, 0, sizeof(struct pci_controller));
 
 	switch(controller_type) {
+#ifdef CONFIG_PPC_ISERIES
+	case phb_type_hypervisor:
+		model = "PHB HV";
+		break;
+#endif
 	case phb_type_python:
 		model = "PHB PY";
 		break;
@@ -311,6 +320,7 @@ static int __init pcibios_init(void)
 		hose->last_busno = bus->subordinate;
 	}
 
+#ifndef CONFIG_PPC_ISERIES
 	if (pci_probe_only)
 		pcibios_claim_of_setup();
 	else
@@ -318,6 +328,7 @@ static int __init pcibios_init(void)
 		   pci_assign_unassigned_resources() is able to work
 		   correctly with [partially] allocated PCI tree. */
 		pci_assign_unassigned_resources();
+#endif
 
 	/* Call machine dependent fixup */
 	pcibios_final_fixup();
@@ -375,9 +386,13 @@ int pcibios_enable_device(struct pci_dev *dev, int mask)
  */
 int pci_domain_nr(struct pci_bus *bus)
 {
+#ifdef CONFIG_PPC_ISERIES
+	return 0;
+#else
 	struct pci_controller *hose = PCI_GET_PHB_PTR(bus);
 
 	return hose->global_number;
+#endif
 }
 
 EXPORT_SYMBOL(pci_domain_nr);
@@ -385,11 +400,13 @@ EXPORT_SYMBOL(pci_domain_nr);
 /* Set the name of the bus as it appears in /proc/bus/pci */
 int pci_name_bus(char *name, struct pci_bus *bus)
 {
+#ifndef CONFIG_PPC_ISERIES
 	struct pci_controller *hose = PCI_GET_PHB_PTR(bus);
 
 	if (hose->buid)
 		sprintf(name, "%04x:%02x", pci_domain_nr(bus), bus->number);
 	else
+#endif
 		sprintf(name, "%02x", bus->number);
 
 	return 0;

include/asm-ppc64/iSeries/HvCallPci.h

 /************************************************************************/
 /* Provides the Hypervisor PCI calls for iSeries Linux Parition.        */
-/* Copyright (C) 20yy  <Wayne G Holm> <IBM Corporation>                 */
+/* Copyright (C) 2001  <Wayne G Holm> <IBM Corporation>                 */
 /*                                                                      */
 /* This program is free software; you can redistribute it and/or modify */
 /* it under the terms of the GNU General Public License as published by */
@@ -21,40 +21,25 @@
 /* Change Activity:                                                     */
 /*   Created, Jan 9, 2001                                               */
 /************************************************************************/
-//============================================================================
-//							 Header File Id
-// Name______________:	HvCallPci.H
-//
-// Description_______:
-//
-//	This file contains the "hypervisor call" interface which is used to
-//	drive the hypervisor from SLIC.
-//
-//============================================================================
+
 #ifndef _HVCALLPCI_H
 #define _HVCALLPCI_H
 
-//-------------------------------------------------------------------
-// Forward declarations 
-//-------------------------------------------------------------------
-
-//-------------------------------------------------------------------
-// Standard Includes
-//-------------------------------------------------------------------
 #include <asm/iSeries/HvCallSc.h>
 #include <asm/iSeries/HvTypes.h>
 
-//-----------------------------------------------------------------------------
-// Constants
-//-----------------------------------------------------------------------------
-
-struct HvCallPci_DsaAddr { // make sure this struct size is 64-bits total
-	u16		busNumber;
-	u8		subBusNumber; 
-	u8		deviceId;     
+/*
+ * DSA == Direct Select Address
+ * this struct must be 64 bits in total
+ */
+struct HvCallPci_DsaAddr {
+	u16		busNumber;		/* PHB index? */
+	u8		subBusNumber; 		/* PCI bus number? */
+	u8		deviceId;     		/* device and function? */
 	u8		barNumber;
 	u8		reserved[3];
 };
+
 union HvDsaMap {
 	u64	DsaAddr;
 	struct HvCallPci_DsaAddr Dsa;
@@ -65,7 +50,8 @@ struct HvCallPci_LoadReturn {
 	u64		value;
 };
 
-enum HvCallPci_DeviceType {HvCallPci_NodeDevice	= 1,
+enum HvCallPci_DeviceType {
+	HvCallPci_NodeDevice	= 1,
 	HvCallPci_SpDevice	= 2,	
 	HvCallPci_IopDevice     = 3,	
 	HvCallPci_BridgeDevice	= 4,	

include/asm-ppc64/iSeries/iSeries_pci.h

 #ifndef _ISERIES_64_PCI_H
 #define _ISERIES_64_PCI_H
+
 /************************************************************************/
 /* File iSeries_pci.h created by Allan Trautman on Tue Feb 20, 2001.    */
 /************************************************************************/
 /* Define some useful macros for the iSeries pci routines.              */
-/* Copyright (C) 20yy  Allan H Trautman, IBM Corporation                */
+/* Copyright (C) 2001  Allan H Trautman, IBM Corporation                */
 /*                                                                      */
 /* This program is free software; you can redistribute it and/or modify */
 /* it under the terms of the GNU General Public License as published by */
@@ -28,56 +29,58 @@
 /*   Ported to ppc64, May 25, 2001                                      */
 /* End Change Activity                                                  */
 /************************************************************************/
+
 #include <asm/iSeries/HvCallPci.h>
 
 struct pci_dev;				/* For Forward Reference        */
 struct iSeries_Device_Node;
+
 /************************************************************************/
-/* Gets iSeries Bus, SubBus, of DevFn using pci_dev* structure          */
+/* Gets iSeries Bus, SubBus, DevFn using iSeries_Device_Node structure */
 /************************************************************************/
-#define ISERIES_BUS(DevPtr)    DevPtr->DsaAddr.busNumber
-#define ISERIES_SUBBUS(DevPtr) DevPtr->DsaAddr.subBusNumber
-#define ISERIES_DEVICE(DevPtr) DevPtr->DsaAddr.deviceId
+
+#define ISERIES_BUS(DevPtr)	DevPtr->DsaAddr.Dsa.busNumber
+#define ISERIES_SUBBUS(DevPtr)	DevPtr->DsaAddr.Dsa.subBusNumber
+#define ISERIES_DEVICE(DevPtr)	DevPtr->DsaAddr.Dsa.deviceId
+#define ISERIES_DSA(DevPtr)	DevPtr->DsaAddr.DsaAddr
 #define ISERIES_DEVFUN(DevPtr)	DevPtr->DevFn
-#define ISERIES_DSA(DevPtr)   (*(u64*)&DevPtr->DsaAddr)
 #define ISERIES_DEVNODE(PciDev) ((struct iSeries_Device_Node*)PciDev->sysdata)
 
 #define EADsMaxAgents 7
-/************************************************************************************/
+
+/************************************************************************/
 /* Decodes Linux DevFn to iSeries DevFn, bridge device, or function.    */
 /* For Linux, see PCI_SLOT and PCI_FUNC in include/linux/pci.h          */
-/************************************************************************************/
-#define ISERIES_DECODE_DEVFN(linuxdevfn)  (((linuxdevfn & 0x71) << 1) | (linuxdevfn & 0x07))
-#define ISERIES_DECODE_DEVICE(linuxdevfn) (((linuxdevfn & 0x38) >> 3) |(((linuxdevfn & 0x40) >> 2) + 0x10))
-#define ISERIES_DECODE_FUNCTION(linuxdevfn) (linuxdevfn & 0x07)
+/************************************************************************/
+
 #define ISERIES_PCI_AGENTID(idsel,func)	((idsel & 0x0F) << 4) | (func  & 0x07)
+#define ISERIES_ENCODE_DEVICE(agentid)	((0x10) | ((agentid&0x20)>>2) | (agentid&07))
 
 #define ISERIES_GET_DEVICE_FROM_SUBBUS(subbus)   ((subbus >> 5) & 0x7)
 #define ISERIES_GET_FUNCTION_FROM_SUBBUS(subbus) ((subbus >> 2) & 0x7)
 
-#define ISERIES_ENCODE_DEVICE(agentid)	((0x10) | ((agentid&0x20)>>2) | (agentid&07))
-/************************************************************************************/
+/*
+ * N.B. the ISERIES_DECODE_* macros are not used anywhere, and I think
+ * the 0x71 (at least) must be wrong - 0x78 maybe?  -- paulus.
+ */
+#define ISERIES_DECODE_DEVFN(linuxdevfn)  (((linuxdevfn & 0x71) << 1) | (linuxdevfn & 0x07))
+#define ISERIES_DECODE_DEVICE(linuxdevfn) (((linuxdevfn & 0x38) >> 3) |(((linuxdevfn & 0x40) >> 2) + 0x10))
+#define ISERIES_DECODE_FUNCTION(linuxdevfn) (linuxdevfn & 0x07)
+
+/************************************************************************/
 /* Converts Virtual Address to Real Address for Hypervisor calls        */
-/************************************************************************************/
-#define REALADDR(virtaddr)  (0x8000000000000000 | (virt_to_absolute((u64)virtaddr) ))
+/************************************************************************/
 
-/************************************************************************************/
-/* Define TRUE and FALSE Values for Al                                              */
-/************************************************************************************/
-#ifndef TRUE
-#define TRUE 1
-#endif
-#ifndef FALSE
-#define FALSE 0
-#endif
+#define REALADDR(virtaddr)  (0x8000000000000000 | (virt_to_absolute((u64)virtaddr) ))
 
 /************************************************************************/
 /* iSeries Device Information                                           */
 /************************************************************************/
+
 struct iSeries_Device_Node {
-	struct list_head Device_List;    /* Must be first for cast to wo*/
+	struct list_head Device_List;
 	struct pci_dev* PciDev;         /* Pointer to pci_dev structure*/
-        struct HvCallPci_DsaAddr DsaAddr;/* Direct Select Address       */
+        union HvDsaMap	DsaAddr;	/* Direct Select Address       */
                                         /* busNumber,subBusNumber,     */ 
 	                                /* deviceId, barNumber         */
 	HvAgentId       AgentId;	/* Hypervisor DevFn            */
@@ -96,9 +99,11 @@ struct iSeries_Device_Node {
 	char            CardLocation[4];/* Char format of planar vpd   */
 	char            Location[20];   /* Frame  1, Card C10          */
 };
+
 /************************************************************************/
 /* Location Data extracted from the VPD list and device info.           */
 /************************************************************************/
+
 struct LocationDataStruct { 	/* Location data structure for device  */
 	u16  Bus;               /* iSeries Bus Number              0x00*/
 	u16  Board;             /* iSeries Board                   0x02*/
@@ -108,17 +113,14 @@ struct LocationDataStruct { 	/* Location data structure for device  */
 	u8   Card;
 	char CardLocation[4];      
 };
+
 typedef struct LocationDataStruct  LocationData;
 #define LOCATION_DATA_SIZE      48
-/************************************************************************/
-/* Flight Recorder tracing                                              */
-/************************************************************************/
-extern int  iSeries_Set_PciTraceFlag(int TraceFlag);
-extern int  iSeries_Get_PciTraceFlag(void);
 
 /************************************************************************/
 /* Functions                                                            */
 /************************************************************************/
+
 extern LocationData* iSeries_GetLocationData(struct pci_dev* PciDev);
 extern int           iSeries_Device_Information(struct pci_dev*,char*, int);
 extern void          iSeries_Get_Location_Code(struct iSeries_Device_Node*);

include/asm-ppc64/irq.h

@@ -41,11 +41,6 @@ static inline unsigned long virt_irq_to_real(unsigned long virt_irq) {
 	return virt_irq_to_real_map[virt_irq];
 }
 
-/*
- * This gets called from serial.c, which is now used on
- * powermacs as well as prep/chrp boxes.
- * Prep and chrp both have cascaded 8259 PICs.
- */
 static __inline__ int irq_canonicalize(int irq)
 {
 	return irq;