1 files changed, 220 insertions, 0 deletions
diff --git a/drivers/net/ethernet/netronome/nfp/ccm.c b/drivers/net/ethernet/netronome/nfp/ccm.c
new file mode 100644
index 000000000000..94476e41e261
--- /dev/null
+++ b/drivers/net/ethernet/netronome/nfp/ccm.c
@@ -0,0 +1,220 @@
+// 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 NFP_CCM_TYPE_REPLY_BIT		7
+#define __NFP_CCM_REPLY(req)		(BIT(NFP_CCM_TYPE_REPLY_BIT) | (req))
+
+#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));
+}