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// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
/* Copyright (C) 2016-2019 Netronome Systems, Inc. */
#include <linux/bitops.h>
#include "ccm.h"
#include "nfp_app.h"
#include "nfp_net.h"
#define ccm_warn(app, msg...) nn_dp_warn(&(app)->ctrl->dp, msg)
#define NFP_CCM_TAG_ALLOC_SPAN (U16_MAX / 4)
static bool nfp_ccm_all_tags_busy(struct nfp_ccm *ccm)
{
u16 used_tags;
used_tags = ccm->tag_alloc_next - ccm->tag_alloc_last;
return used_tags > NFP_CCM_TAG_ALLOC_SPAN;
}
static int nfp_ccm_alloc_tag(struct nfp_ccm *ccm)
{
/* CCM is for FW communication which is request-reply. To make sure
* we don't reuse the message ID too early after timeout - limit the
* number of requests in flight.
*/
if (unlikely(nfp_ccm_all_tags_busy(ccm))) {
ccm_warn(ccm->app, "all FW request contexts busy!\n");
return -EAGAIN;
}
WARN_ON(__test_and_set_bit(ccm->tag_alloc_next, ccm->tag_allocator));
return ccm->tag_alloc_next++;
}
static void nfp_ccm_free_tag(struct nfp_ccm *ccm, u16 tag)
{
WARN_ON(!__test_and_clear_bit(tag, ccm->tag_allocator));
while (!test_bit(ccm->tag_alloc_last, ccm->tag_allocator) &&
ccm->tag_alloc_last != ccm->tag_alloc_next)
ccm->tag_alloc_last++;
}
static struct sk_buff *__nfp_ccm_reply(struct nfp_ccm *ccm, u16 tag)
{
unsigned int msg_tag;
struct sk_buff *skb;
skb_queue_walk(&ccm->replies, skb) {
msg_tag = nfp_ccm_get_tag(skb);
if (msg_tag == tag) {
nfp_ccm_free_tag(ccm, tag);
__skb_unlink(skb, &ccm->replies);
return skb;
}
}
return NULL;
}
static struct sk_buff *
nfp_ccm_reply(struct nfp_ccm *ccm, struct nfp_app *app, u16 tag)
{
struct sk_buff *skb;
nfp_ctrl_lock(app->ctrl);
skb = __nfp_ccm_reply(ccm, tag);
nfp_ctrl_unlock(app->ctrl);
return skb;
}
static struct sk_buff *
nfp_ccm_reply_drop_tag(struct nfp_ccm *ccm, struct nfp_app *app, u16 tag)
{
struct sk_buff *skb;
nfp_ctrl_lock(app->ctrl);
skb = __nfp_ccm_reply(ccm, tag);
if (!skb)
nfp_ccm_free_tag(ccm, tag);
nfp_ctrl_unlock(app->ctrl);
return skb;
}
static struct sk_buff *
nfp_ccm_wait_reply(struct nfp_ccm *ccm, struct nfp_app *app,
enum nfp_ccm_type type, int tag)
{
struct sk_buff *skb;
int i, err;
for (i = 0; i < 50; i++) {
udelay(4);
skb = nfp_ccm_reply(ccm, app, tag);
if (skb)
return skb;
}
err = wait_event_interruptible_timeout(ccm->wq,
skb = nfp_ccm_reply(ccm, app,
tag),
msecs_to_jiffies(5000));
/* We didn't get a response - try last time and atomically drop
* the tag even if no response is matched.
*/
if (!skb)
skb = nfp_ccm_reply_drop_tag(ccm, app, tag);
if (err < 0) {
ccm_warn(app, "%s waiting for response to 0x%02x: %d\n",
err == ERESTARTSYS ? "interrupted" : "error",
type, err);
return ERR_PTR(err);
}
if (!skb) {
ccm_warn(app, "timeout waiting for response to 0x%02x\n", type);
return ERR_PTR(-ETIMEDOUT);
}
return skb;
}
struct sk_buff *
nfp_ccm_communicate(struct nfp_ccm *ccm, struct sk_buff *skb,
enum nfp_ccm_type type, unsigned int reply_size)
{
struct nfp_app *app = ccm->app;
struct nfp_ccm_hdr *hdr;
int reply_type, tag;
nfp_ctrl_lock(app->ctrl);
tag = nfp_ccm_alloc_tag(ccm);
if (tag < 0) {
nfp_ctrl_unlock(app->ctrl);
dev_kfree_skb_any(skb);
return ERR_PTR(tag);
}
hdr = (void *)skb->data;
hdr->ver = NFP_CCM_ABI_VERSION;
hdr->type = type;
hdr->tag = cpu_to_be16(tag);
__nfp_app_ctrl_tx(app, skb);
nfp_ctrl_unlock(app->ctrl);
skb = nfp_ccm_wait_reply(ccm, app, type, tag);
if (IS_ERR(skb))
return skb;
reply_type = nfp_ccm_get_type(skb);
if (reply_type != __NFP_CCM_REPLY(type)) {
ccm_warn(app, "cmsg drop - wrong type 0x%02x != 0x%02lx!\n",
reply_type, __NFP_CCM_REPLY(type));
goto err_free;
}
/* 0 reply_size means caller will do the validation */
if (reply_size && skb->len != reply_size) {
ccm_warn(app, "cmsg drop - type 0x%02x wrong size %d != %d!\n",
type, skb->len, reply_size);
goto err_free;
}
return skb;
err_free:
dev_kfree_skb_any(skb);
return ERR_PTR(-EIO);
}
void nfp_ccm_rx(struct nfp_ccm *ccm, struct sk_buff *skb)
{
struct nfp_app *app = ccm->app;
unsigned int tag;
if (unlikely(skb->len < sizeof(struct nfp_ccm_hdr))) {
ccm_warn(app, "cmsg drop - too short %d!\n", skb->len);
goto err_free;
}
nfp_ctrl_lock(app->ctrl);
tag = nfp_ccm_get_tag(skb);
if (unlikely(!test_bit(tag, ccm->tag_allocator))) {
ccm_warn(app, "cmsg drop - no one is waiting for tag %u!\n",
tag);
goto err_unlock;
}
__skb_queue_tail(&ccm->replies, skb);
wake_up_interruptible_all(&ccm->wq);
nfp_ctrl_unlock(app->ctrl);
return;
err_unlock:
nfp_ctrl_unlock(app->ctrl);
err_free:
dev_kfree_skb_any(skb);
}
int nfp_ccm_init(struct nfp_ccm *ccm, struct nfp_app *app)
{
ccm->app = app;
skb_queue_head_init(&ccm->replies);
init_waitqueue_head(&ccm->wq);
return 0;
}
void nfp_ccm_clean(struct nfp_ccm *ccm)
{
WARN_ON(!skb_queue_empty(&ccm->replies));
}
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