arch/powerpc/platforms/cell/spufs/backing_ops.c

Source file repositories/reference/linux-study-clean/arch/powerpc/platforms/cell/spufs/backing_ops.c

File Facts

System
Linux kernel
Corpus path
arch/powerpc/platforms/cell/spufs/backing_ops.c
Extension
.c
Size
10492 bytes
Lines
401
Domain
Architecture Layer
Bucket
arch/powerpc
Inferred role
Architecture Layer: implementation source
Status
source implementation candidate

Why This File Exists

CPU and platform-specific kernel glue: boot entry, traps, syscall entry, interrupts, page tables, context switch, and low-level barriers.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-2.0-or-later
/* backing_ops.c - query/set operations on saved SPU context.
 *
 * Copyright (C) IBM 2005
 * Author: Mark Nutter <mnutter@us.ibm.com>
 *
 * These register operations allow SPUFS to operate on saved
 * SPU contexts rather than hardware.
 */

#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/poll.h>

#include <asm/io.h>
#include <asm/spu.h>
#include <asm/spu_csa.h>
#include <asm/spu_info.h>
#include <asm/mmu_context.h>
#include "spufs.h"

/*
 * Reads/writes to various problem and priv2 registers require
 * state changes, i.e.  generate SPU events, modify channel
 * counts, etc.
 */

static void gen_spu_event(struct spu_context *ctx, u32 event)
{
	u64 ch0_cnt;
	u64 ch0_data;
	u64 ch1_data;

	ch0_cnt = ctx->csa.spu_chnlcnt_RW[0];
	ch0_data = ctx->csa.spu_chnldata_RW[0];
	ch1_data = ctx->csa.spu_chnldata_RW[1];
	ctx->csa.spu_chnldata_RW[0] |= event;
	if ((ch0_cnt == 0) && !(ch0_data & event) && (ch1_data & event)) {
		ctx->csa.spu_chnlcnt_RW[0] = 1;
	}
}

static int spu_backing_mbox_read(struct spu_context *ctx, u32 * data)
{
	u32 mbox_stat;
	int ret = 0;

	spin_lock(&ctx->csa.register_lock);
	mbox_stat = ctx->csa.prob.mb_stat_R;
	if (mbox_stat & 0x0000ff) {
		/* Read the first available word.
		 * Implementation note: the depth
		 * of pu_mb_R is currently 1.
		 */
		*data = ctx->csa.prob.pu_mb_R;
		ctx->csa.prob.mb_stat_R &= ~(0x0000ff);
		ctx->csa.spu_chnlcnt_RW[28] = 1;
		gen_spu_event(ctx, MFC_PU_MAILBOX_AVAILABLE_EVENT);
		ret = 4;
	}
	spin_unlock(&ctx->csa.register_lock);
	return ret;
}

static u32 spu_backing_mbox_stat_read(struct spu_context *ctx)
{
	return ctx->csa.prob.mb_stat_R;
}

static __poll_t spu_backing_mbox_stat_poll(struct spu_context *ctx,
					  __poll_t events)
{
	__poll_t ret;
	u32 stat;

	ret = 0;
	spin_lock_irq(&ctx->csa.register_lock);
	stat = ctx->csa.prob.mb_stat_R;

	/* if the requested event is there, return the poll
	   mask, otherwise enable the interrupt to get notified,
	   but first mark any pending interrupts as done so
	   we don't get woken up unnecessarily */

Annotation

Implementation Notes