linux/include/asm-ppc64/iSeries/ItLpQueue.h
Michael Ellerman 719d1cd867 [PATCH] ppc64: Replace custom locking code with a spinlock
The hvlpevent_queue (formally ItLpQueue) has a member called xInUseWord
which is used for serialising access to the queue. Because it's a word
(ie. 32 bit) there's a custom 32-bit version of test_and_set_bit() or
thereabouts in ItLpQueue.c.

The xInUseWord is not shared with they hypervisor, so we can replace it
with a spinlock and remove the custom code.

There is also another locking mechanism (ItLpQueueInProcess). This is
redundant because it's only manipulated while the lock's held. Remove it.

Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-06-30 15:17:02 +10:00

82 lines
2.8 KiB
C

/*
* ItLpQueue.h
* Copyright (C) 2001 Mike Corrigan 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
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _ITLPQUEUE_H
#define _ITLPQUEUE_H
/*
* This control block defines the simple LP queue structure that is
* shared between the hypervisor (PLIC) and the OS in order to send
* events to an LP.
*/
#include <asm/types.h>
#include <asm/ptrace.h>
struct HvLpEvent;
#define ITMaxLpQueues 8
#define NotUsed 0 // Queue will not be used by PLIC
#define DedicatedIo 1 // Queue dedicated to IO processor specified
#define DedicatedLp 2 // Queue dedicated to LP specified
#define Shared 3 // Queue shared for both IO and LP
#define LpEventStackSize 4096
#define LpEventMaxSize 256
#define LpEventAlign 64
struct hvlpevent_queue {
/*
* The xSlicCurEventPtr is the pointer to the next event stack entry
* that will become valid. The OS must peek at this entry to determine
* if it is valid. PLIC will set the valid indicator as the very last
* store into that entry.
*
* When the OS has completed processing of the event then it will mark
* the event as invalid so that PLIC knows it can store into that event
* location again.
*
* If the event stack fills and there are overflow events, then PLIC
* will set the xPlicOverflowIntPending flag in which case the OS will
* have to fetch the additional LP events once they have drained the
* event stack.
*
* The first 16-bytes are known by both the OS and PLIC. The remainder
* of the cache line is for use by the OS.
*/
u8 xPlicOverflowIntPending;// 0x00 Overflow events are pending
u8 xPlicStatus; // 0x01 DedicatedIo or DedicatedLp or NotUsed
u16 xSlicLogicalProcIndex; // 0x02 Logical Proc Index for correlation
u8 xPlicRsvd[12]; // 0x04
char *xSlicCurEventPtr; // 0x10
char *xSlicLastValidEventPtr; // 0x18
char *xSlicEventStackPtr; // 0x20
u8 xIndex; // 0x28 unique sequential index.
u8 xSlicRsvd[3]; // 0x29-2b
spinlock_t lock;
};
extern struct hvlpevent_queue hvlpevent_queue;
extern int hvlpevent_is_pending(void);
extern void process_hvlpevents(struct pt_regs *);
extern void setup_hvlpevent_queue(void);
#endif /* _ITLPQUEUE_H */