freebsd-nq/sys/powerpc/powernv/opal_async.c
Justin Hibbits dac618a648 powerpc/powernv: Add asynchronous token management for powernv
The OPAL firmware only supports a finite number of in-flight asynchronous
operations.  Rather than have each subsystem try to manage its own, use a
central management service to hand out tokens.

More work can be done to improve asynchronous behavior, such as funneling
things through a future OPAL heartbeat handler, but capabilities will be
added as needed.

Augment the existing consumers (i2c and sensors) to use this new API.

MFC after:	4 weeks
2019-03-01 02:49:47 +00:00

95 lines
2.6 KiB
C

/*-
* Copyright (C) 2019 Justin Hibbits
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/types.h>
#include <sys/malloc.h>
#include <sys/proc.h>
#include <sys/vmem.h>
#include <vm/vm.h>
#include <vm/pmap.h>
#include "opal.h"
/*
* Manage asynchronous tokens for the OPAL abstraction layer.
*
* Only a finite number of in-flight tokens are supported by OPAL, so we must be
* careful managing this. The basic design uses the vmem subsystem as a general
* purpose allocator, with wrappers to manage expected behaviors and
* requirements.
*/
static vmem_t *async_token_pool;
/* Setup the token pool. */
int
opal_init_async_tokens(int count)
{
/* Only allow one initialization */
if (async_token_pool != NULL)
return (EINVAL);
async_token_pool = vmem_create("OPAL Async", 0, count, 1, 1,
M_WAITOK | M_FIRSTFIT);
return (0);
}
int
opal_alloc_async_token(void)
{
vmem_addr_t token;
vmem_alloc(async_token_pool, 1, M_FIRSTFIT | M_WAITOK, &token);
return (token);
}
void
opal_free_async_token(int token)
{
vmem_free(async_token_pool, token, 1);
}
/*
* Wait for the operation watched by the token to complete. Return the result
* of the operation, error if it returns early.
*/
int
opal_wait_completion(void *buf, uint64_t size, uint64_t token)
{
int err;
do {
err = opal_call(OPAL_CHECK_ASYNC_COMPLETION,
vtophys(buf), size, token);
} while (err == OPAL_BUSY);
return (err);
}