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https://github.com/riscv-software-src/opensbi.git
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f700216cb5
Currently, there is no provision for tracking multiple IPIs sent to a single hart at the same time by different harts. Use a fifo manage the outstanding requests. While dequeueing, read all the entries once, because we have only 1 bit to track the type of IPI. Once the queue is full, busy wait until the there is space available in queue. This is not the most elegant approach. It should be changed in favor of a wakeup event once available in opensbi. Signed-off-by: Atish Patra <atish.patra@wdc.com>
84 lines
1.6 KiB
C
84 lines
1.6 KiB
C
/*
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2019 Western Digital Corporation or its affiliates.
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*
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* Authors:
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* Atish Patra<atish.patra@wdc.com>
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*
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*/
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#include <sbi/riscv_locks.h>
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#include <sbi/sbi_fifo.h>
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#include <plat/string.h>
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void sbi_fifo_init(struct sbi_fifo *fifo, unsigned long entries,
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unsigned long size)
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{
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fifo->head = -1;
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fifo->tail = -1;
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fifo->num_entries = entries;
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fifo->entrysize = size;
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SPIN_LOCK_INIT(&fifo->qlock);
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memset(fifo->queue, 0, entries * size);
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}
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bool sbi_fifo_is_full(struct sbi_fifo *fifo)
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{
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if (((fifo->head == fifo->num_entries-1) && fifo->tail == 0) ||
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(fifo->tail == fifo->head + 1)) {
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return TRUE;
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}
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return FALSE;
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}
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bool sbi_fifo_is_empty(struct sbi_fifo *fifo)
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{
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if (fifo->head == -1)
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return TRUE;
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return FALSE;
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}
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int sbi_fifo_enqueue(struct sbi_fifo *fifo, void *data)
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{
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if (!fifo || !data)
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return -1;
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spin_lock(&fifo->qlock);
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if (sbi_fifo_is_full(fifo)) {
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spin_unlock(&fifo->qlock);
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return -1;
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}
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if (fifo->tail == -1)
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fifo->tail = 0;
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fifo->head = (fifo->head + 1) % fifo->num_entries;
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memcpy(fifo->queue + fifo->head * fifo->entrysize, data,
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fifo->entrysize);
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spin_unlock(&fifo->qlock);
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return 0;
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}
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int sbi_fifo_dequeue(struct sbi_fifo *fifo, void *data)
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{
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if (!fifo || !data)
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return -1;
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spin_lock(&fifo->qlock);
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if (sbi_fifo_is_empty(fifo)) {
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spin_unlock(&fifo->qlock);
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return -1;
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}
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memcpy(data, fifo->queue + fifo->tail * fifo->entrysize,
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fifo->entrysize);
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if (fifo->tail == fifo->head) {
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fifo->tail = -1;
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fifo->head = -1;
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} else {
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fifo->tail = (fifo->tail + 1) % fifo->num_entries;
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}
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spin_unlock(&fifo->qlock);
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return 0;
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}
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