--- /dev/null
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+/* Copyright (C) 2019 Netronome Systems, Inc. */
+
+#include <linux/bitfield.h>
+#include <linux/io.h>
+#include <linux/skbuff.h>
+
+#include "ccm.h"
+#include "nfp_net.h"
+
+/* CCM messages via the mailbox. CMSGs get wrapped into simple TLVs
+ * and copied into the mailbox. Multiple messages can be copied to
+ * form a batch. Threads come in with CMSG formed in an skb, then
+ * enqueue that skb onto the request queue. If threads skb is first
+ * in queue this thread will handle the mailbox operation. It copies
+ * up to 16 messages into the mailbox (making sure that both requests
+ * and replies will fit. After FW is done processing the batch it
+ * copies the data out and wakes waiting threads.
+ * If a thread is waiting it either gets its the message completed
+ * (response is copied into the same skb as the request, overwriting
+ * it), or becomes the first in queue.
+ * Completions and next-to-run are signaled via the control buffer
+ * to limit potential cache line bounces.
+ */
+
+#define NFP_CCM_MBOX_BATCH_LIMIT 16
+#define NFP_CCM_TIMEOUT (NFP_NET_POLL_TIMEOUT * 1000)
+#define NFP_CCM_MAX_QLEN 256
+
+enum nfp_net_mbox_cmsg_state {
+ NFP_NET_MBOX_CMSG_STATE_QUEUED,
+ NFP_NET_MBOX_CMSG_STATE_NEXT,
+ NFP_NET_MBOX_CMSG_STATE_BUSY,
+ NFP_NET_MBOX_CMSG_STATE_REPLY_FOUND,
+ NFP_NET_MBOX_CMSG_STATE_DONE,
+};
+
+/**
+ * struct nfp_ccm_mbox_skb_cb - CCM mailbox specific info
+ * @state: processing state (/stage) of the message
+ * @err: error encountered during processing if any
+ * @max_len: max(request_len, reply_len)
+ * @exp_reply: expected reply length (0 means don't validate)
+ */
+struct nfp_ccm_mbox_cmsg_cb {
+ enum nfp_net_mbox_cmsg_state state;
+ int err;
+ unsigned int max_len;
+ unsigned int exp_reply;
+};
+
+static u32 nfp_ccm_mbox_max_msg(struct nfp_net *nn)
+{
+ return round_down(nn->tlv_caps.mbox_len, 4) -
+ NFP_NET_CFG_MBOX_SIMPLE_VAL - /* common mbox command header */
+ 4 * 2; /* Msg TLV plus End TLV headers */
+}
+
+static void
+nfp_ccm_mbox_msg_init(struct sk_buff *skb, unsigned int exp_reply, int max_len)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ cb->state = NFP_NET_MBOX_CMSG_STATE_QUEUED;
+ cb->err = 0;
+ cb->max_len = max_len;
+ cb->exp_reply = exp_reply;
+}
+
+static int nfp_ccm_mbox_maxlen(const struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ return cb->max_len;
+}
+
+static bool nfp_ccm_mbox_done(struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ return cb->state == NFP_NET_MBOX_CMSG_STATE_DONE;
+}
+
+static bool nfp_ccm_mbox_in_progress(struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ return cb->state != NFP_NET_MBOX_CMSG_STATE_QUEUED &&
+ cb->state != NFP_NET_MBOX_CMSG_STATE_NEXT;
+}
+
+static void nfp_ccm_mbox_set_busy(struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ cb->state = NFP_NET_MBOX_CMSG_STATE_BUSY;
+}
+
+static bool nfp_ccm_mbox_is_first(struct nfp_net *nn, struct sk_buff *skb)
+{
+ return skb_queue_is_first(&nn->mbox_cmsg.queue, skb);
+}
+
+static bool nfp_ccm_mbox_should_run(struct nfp_net *nn, struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ return cb->state == NFP_NET_MBOX_CMSG_STATE_NEXT;
+}
+
+static void nfp_ccm_mbox_mark_next_runner(struct nfp_net *nn)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb;
+ struct sk_buff *skb;
+
+ skb = skb_peek(&nn->mbox_cmsg.queue);
+ if (!skb)
+ return;
+
+ cb = (void *)skb->cb;
+ cb->state = NFP_NET_MBOX_CMSG_STATE_NEXT;
+}
+
+static void
+nfp_ccm_mbox_write_tlv(struct nfp_net *nn, u32 off, u32 type, u32 len)
+{
+ nn_writel(nn, off,
+ FIELD_PREP(NFP_NET_MBOX_TLV_TYPE, type) |
+ FIELD_PREP(NFP_NET_MBOX_TLV_LEN, len));
+}
+
+static void nfp_ccm_mbox_copy_in(struct nfp_net *nn, struct sk_buff *last)
+{
+ struct sk_buff *skb;
+ int reserve, i, cnt;
+ __be32 *data;
+ u32 off, len;
+
+ off = nn->tlv_caps.mbox_off + NFP_NET_CFG_MBOX_SIMPLE_VAL;
+ skb = __skb_peek(&nn->mbox_cmsg.queue);
+ while (true) {
+ nfp_ccm_mbox_write_tlv(nn, off, NFP_NET_MBOX_TLV_TYPE_MSG,
+ skb->len);
+ off += 4;
+
+ /* Write data word by word, skb->data should be aligned */
+ data = (__be32 *)skb->data;
+ cnt = skb->len / 4;
+ for (i = 0 ; i < cnt; i++) {
+ nn_writel(nn, off, be32_to_cpu(data[i]));
+ off += 4;
+ }
+ if (skb->len & 3) {
+ __be32 tmp = 0;
+
+ memcpy(&tmp, &data[i], skb->len & 3);
+ nn_writel(nn, off, be32_to_cpu(tmp));
+ off += 4;
+ }
+
+ /* Reserve space if reply is bigger */
+ len = round_up(skb->len, 4);
+ reserve = nfp_ccm_mbox_maxlen(skb) - len;
+ if (reserve > 0) {
+ nfp_ccm_mbox_write_tlv(nn, off,
+ NFP_NET_MBOX_TLV_TYPE_RESV,
+ reserve);
+ off += 4 + reserve;
+ }
+
+ if (skb == last)
+ break;
+ skb = skb_queue_next(&nn->mbox_cmsg.queue, skb);
+ }
+
+ nfp_ccm_mbox_write_tlv(nn, off, NFP_NET_MBOX_TLV_TYPE_END, 0);
+}
+
+static struct sk_buff *
+nfp_ccm_mbox_find_req(struct nfp_net *nn, __be16 tag, struct sk_buff *last)
+{
+ struct sk_buff *skb;
+
+ skb = __skb_peek(&nn->mbox_cmsg.queue);
+ while (true) {
+ if (__nfp_ccm_get_tag(skb) == tag)
+ return skb;
+
+ if (skb == last)
+ return NULL;
+ skb = skb_queue_next(&nn->mbox_cmsg.queue, skb);
+ }
+}
+
+static void nfp_ccm_mbox_copy_out(struct nfp_net *nn, struct sk_buff *last)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb;
+ u8 __iomem *data, *end;
+ struct sk_buff *skb;
+
+ data = nn->dp.ctrl_bar + nn->tlv_caps.mbox_off +
+ NFP_NET_CFG_MBOX_SIMPLE_VAL;
+ end = data + nn->tlv_caps.mbox_len;
+
+ while (true) {
+ unsigned int length, offset, type;
+ struct nfp_ccm_hdr hdr;
+ __be32 *skb_data;
+ u32 tlv_hdr;
+ int i, cnt;
+
+ tlv_hdr = readl(data);
+ type = FIELD_GET(NFP_NET_MBOX_TLV_TYPE, tlv_hdr);
+ length = FIELD_GET(NFP_NET_MBOX_TLV_LEN, tlv_hdr);
+ offset = data - nn->dp.ctrl_bar;
+
+ /* Advance past the header */
+ data += 4;
+
+ if (data + length > end) {
+ nn_dp_warn(&nn->dp, "mailbox oversized TLV type:%d offset:%u len:%u\n",
+ type, offset, length);
+ break;
+ }
+
+ if (type == NFP_NET_MBOX_TLV_TYPE_END)
+ break;
+ if (type == NFP_NET_MBOX_TLV_TYPE_RESV)
+ goto next_tlv;
+ if (type != NFP_NET_MBOX_TLV_TYPE_MSG &&
+ type != NFP_NET_MBOX_TLV_TYPE_MSG_NOSUP) {
+ nn_dp_warn(&nn->dp, "mailbox unknown TLV type:%d offset:%u len:%u\n",
+ type, offset, length);
+ break;
+ }
+
+ if (length < 4) {
+ nn_dp_warn(&nn->dp, "mailbox msg too short to contain header TLV type:%d offset:%u len:%u\n",
+ type, offset, length);
+ break;
+ }
+
+ hdr.raw = cpu_to_be32(readl(data));
+
+ skb = nfp_ccm_mbox_find_req(nn, hdr.tag, last);
+ if (!skb) {
+ nn_dp_warn(&nn->dp, "mailbox request not found:%u\n",
+ be16_to_cpu(hdr.tag));
+ break;
+ }
+ cb = (void *)skb->cb;
+
+ if (type == NFP_NET_MBOX_TLV_TYPE_MSG_NOSUP) {
+ nn_dp_warn(&nn->dp,
+ "mailbox msg not supported type:%d\n",
+ nfp_ccm_get_type(skb));
+ cb->err = -EIO;
+ goto next_tlv;
+ }
+
+ if (hdr.type != __NFP_CCM_REPLY(nfp_ccm_get_type(skb))) {
+ nn_dp_warn(&nn->dp, "mailbox msg reply wrong type:%u expected:%lu\n",
+ hdr.type,
+ __NFP_CCM_REPLY(nfp_ccm_get_type(skb)));
+ cb->err = -EIO;
+ goto next_tlv;
+ }
+ if (cb->exp_reply && length != cb->exp_reply) {
+ nn_dp_warn(&nn->dp, "mailbox msg reply wrong size type:%u expected:%u have:%u\n",
+ hdr.type, length, cb->exp_reply);
+ cb->err = -EIO;
+ goto next_tlv;
+ }
+ if (length > cb->max_len) {
+ nn_dp_warn(&nn->dp, "mailbox msg oversized reply type:%u max:%u have:%u\n",
+ hdr.type, cb->max_len, length);
+ cb->err = -EIO;
+ goto next_tlv;
+ }
+
+ if (length <= skb->len)
+ __skb_trim(skb, length);
+ else
+ skb_put(skb, length - skb->len);
+
+ /* We overcopy here slightly, but that's okay, the skb is large
+ * enough, and the garbage will be ignored (beyond skb->len).
+ */
+ skb_data = (__be32 *)skb->data;
+ memcpy(skb_data, &hdr, 4);
+
+ cnt = DIV_ROUND_UP(length, 4);
+ for (i = 1 ; i < cnt; i++)
+ skb_data[i] = cpu_to_be32(readl(data + i * 4));
+
+ cb->state = NFP_NET_MBOX_CMSG_STATE_REPLY_FOUND;
+next_tlv:
+ data += round_up(length, 4);
+ if (data + 4 > end) {
+ nn_dp_warn(&nn->dp,
+ "reached end of MBOX without END TLV\n");
+ break;
+ }
+ }
+
+ smp_wmb(); /* order the skb->data vs. cb->state */
+ spin_lock_bh(&nn->mbox_cmsg.queue.lock);
+ do {
+ skb = __skb_dequeue(&nn->mbox_cmsg.queue);
+ cb = (void *)skb->cb;
+
+ if (cb->state != NFP_NET_MBOX_CMSG_STATE_REPLY_FOUND) {
+ cb->err = -ENOENT;
+ smp_wmb(); /* order the cb->err vs. cb->state */
+ }
+ cb->state = NFP_NET_MBOX_CMSG_STATE_DONE;
+ } while (skb != last);
+
+ nfp_ccm_mbox_mark_next_runner(nn);
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+}
+
+static void
+nfp_ccm_mbox_mark_all_err(struct nfp_net *nn, struct sk_buff *last, int err)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb;
+ struct sk_buff *skb;
+
+ spin_lock_bh(&nn->mbox_cmsg.queue.lock);
+ do {
+ skb = __skb_dequeue(&nn->mbox_cmsg.queue);
+ cb = (void *)skb->cb;
+
+ cb->err = err;
+ smp_wmb(); /* order the cb->err vs. cb->state */
+ cb->state = NFP_NET_MBOX_CMSG_STATE_DONE;
+ } while (skb != last);
+
+ nfp_ccm_mbox_mark_next_runner(nn);
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+}
+
+static void nfp_ccm_mbox_run_queue_unlock(struct nfp_net *nn)
+ __releases(&nn->mbox_cmsg.queue.lock)
+{
+ int space = nn->tlv_caps.mbox_len - NFP_NET_CFG_MBOX_SIMPLE_VAL;
+ struct sk_buff *skb, *last;
+ int cnt, err;
+
+ space -= 4; /* for End TLV */
+
+ /* First skb must fit, because it's ours and we checked it fits */
+ cnt = 1;
+ last = skb = __skb_peek(&nn->mbox_cmsg.queue);
+ space -= 4 + nfp_ccm_mbox_maxlen(skb);
+
+ while (!skb_queue_is_last(&nn->mbox_cmsg.queue, last)) {
+ skb = skb_queue_next(&nn->mbox_cmsg.queue, last);
+ space -= 4 + nfp_ccm_mbox_maxlen(skb);
+ if (space < 0)
+ break;
+ last = skb;
+ nfp_ccm_mbox_set_busy(skb);
+ cnt++;
+ if (cnt == NFP_CCM_MBOX_BATCH_LIMIT)
+ break;
+ }
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+
+ /* Now we own all skb's marked in progress, new requests may arrive
+ * at the end of the queue.
+ */
+
+ nn_ctrl_bar_lock(nn);
+
+ nfp_ccm_mbox_copy_in(nn, last);
+
+ err = nfp_net_mbox_reconfig(nn, NFP_NET_CFG_MBOX_CMD_TLV_CMSG);
+ if (!err)
+ nfp_ccm_mbox_copy_out(nn, last);
+ else
+ nfp_ccm_mbox_mark_all_err(nn, last, -EIO);
+
+ nn_ctrl_bar_unlock(nn);
+
+ wake_up_all(&nn->mbox_cmsg.wq);
+}
+
+static int nfp_ccm_mbox_skb_return(struct sk_buff *skb)
+{
+ struct nfp_ccm_mbox_cmsg_cb *cb = (void *)skb->cb;
+
+ if (cb->err)
+ dev_kfree_skb_any(skb);
+ return cb->err;
+}
+
+/* If wait timed out but the command is already in progress we have
+ * to wait until it finishes. Runners has ownership of the skbs marked
+ * as busy.
+ */
+static int
+nfp_ccm_mbox_unlink_unlock(struct nfp_net *nn, struct sk_buff *skb,
+ enum nfp_ccm_type type)
+ __releases(&nn->mbox_cmsg.queue.lock)
+{
+ bool was_first;
+
+ if (nfp_ccm_mbox_in_progress(skb)) {
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+
+ wait_event(nn->mbox_cmsg.wq, nfp_ccm_mbox_done(skb));
+ smp_rmb(); /* pairs with smp_wmb() after data is written */
+ return nfp_ccm_mbox_skb_return(skb);
+ }
+
+ was_first = nfp_ccm_mbox_should_run(nn, skb);
+ __skb_unlink(skb, &nn->mbox_cmsg.queue);
+ if (was_first)
+ nfp_ccm_mbox_mark_next_runner(nn);
+
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+
+ if (was_first)
+ wake_up_all(&nn->mbox_cmsg.wq);
+
+ nn_dp_warn(&nn->dp, "time out waiting for mbox response to 0x%02x\n",
+ type);
+ return -ETIMEDOUT;
+}
+
+static int
+nfp_ccm_mbox_msg_prepare(struct nfp_net *nn, struct sk_buff *skb,
+ enum nfp_ccm_type type,
+ unsigned int reply_size, unsigned int max_reply_size,
+ gfp_t flags)
+{
+ const unsigned int mbox_max = nfp_ccm_mbox_max_msg(nn);
+ unsigned int max_len;
+ ssize_t undersize;
+ int err;
+
+ if (unlikely(!(nn->tlv_caps.mbox_cmsg_types & BIT(type)))) {
+ nn_dp_warn(&nn->dp,
+ "message type %d not supported by mailbox\n", type);
+ return -EINVAL;
+ }
+
+ /* If the reply size is unknown assume it will take the entire
+ * mailbox, the callers should do their best for this to never
+ * happen.
+ */
+ if (!max_reply_size)
+ max_reply_size = mbox_max;
+ max_reply_size = round_up(max_reply_size, 4);
+
+ /* Make sure we can fit the entire reply into the skb,
+ * and that we don't have to slow down the mbox handler
+ * with allocations.
+ */
+ undersize = max_reply_size - (skb_end_pointer(skb) - skb->data);
+ if (undersize > 0) {
+ err = pskb_expand_head(skb, 0, undersize, flags);
+ if (err) {
+ nn_dp_warn(&nn->dp,
+ "can't allocate reply buffer for mailbox\n");
+ return err;
+ }
+ }
+
+ /* Make sure that request and response both fit into the mailbox */
+ max_len = max(max_reply_size, round_up(skb->len, 4));
+ if (max_len > mbox_max) {
+ nn_dp_warn(&nn->dp,
+ "message too big for tha mailbox: %u/%u vs %u\n",
+ skb->len, max_reply_size, mbox_max);
+ return -EMSGSIZE;
+ }
+
+ nfp_ccm_mbox_msg_init(skb, reply_size, max_len);
+
+ return 0;
+}
+
+static int
+nfp_ccm_mbox_msg_enqueue(struct nfp_net *nn, struct sk_buff *skb,
+ enum nfp_ccm_type type)
+{
+ struct nfp_ccm_hdr *hdr;
+
+ assert_spin_locked(&nn->mbox_cmsg.queue.lock);
+
+ if (nn->mbox_cmsg.queue.qlen >= NFP_CCM_MAX_QLEN) {
+ nn_dp_warn(&nn->dp, "mailbox request queue too long\n");
+ return -EBUSY;
+ }
+
+ hdr = (void *)skb->data;
+ hdr->ver = NFP_CCM_ABI_VERSION;
+ hdr->type = type;
+ hdr->tag = cpu_to_be16(nn->mbox_cmsg.tag++);
+
+ __skb_queue_tail(&nn->mbox_cmsg.queue, skb);
+
+ return 0;
+}
+
+int nfp_ccm_mbox_communicate(struct nfp_net *nn, struct sk_buff *skb,
+ enum nfp_ccm_type type,
+ unsigned int reply_size,
+ unsigned int max_reply_size)
+{
+ int err;
+
+ err = nfp_ccm_mbox_msg_prepare(nn, skb, type, reply_size,
+ max_reply_size, GFP_KERNEL);
+ if (err)
+ goto err_free_skb;
+
+ spin_lock_bh(&nn->mbox_cmsg.queue.lock);
+
+ err = nfp_ccm_mbox_msg_enqueue(nn, skb, type);
+ if (err)
+ goto err_unlock;
+
+ /* First in queue takes the mailbox lock and processes the batch */
+ if (!nfp_ccm_mbox_is_first(nn, skb)) {
+ bool to;
+
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+
+ to = !wait_event_timeout(nn->mbox_cmsg.wq,
+ nfp_ccm_mbox_done(skb) ||
+ nfp_ccm_mbox_should_run(nn, skb),
+ msecs_to_jiffies(NFP_CCM_TIMEOUT));
+
+ /* fast path for those completed by another thread */
+ if (nfp_ccm_mbox_done(skb)) {
+ smp_rmb(); /* pairs with wmb after data is written */
+ return nfp_ccm_mbox_skb_return(skb);
+ }
+
+ spin_lock_bh(&nn->mbox_cmsg.queue.lock);
+
+ if (!nfp_ccm_mbox_is_first(nn, skb)) {
+ WARN_ON(!to);
+
+ err = nfp_ccm_mbox_unlink_unlock(nn, skb, type);
+ if (err)
+ goto err_free_skb;
+ return 0;
+ }
+ }
+
+ /* run queue expects the lock held */
+ nfp_ccm_mbox_run_queue_unlock(nn);
+ return nfp_ccm_mbox_skb_return(skb);
+
+err_unlock:
+ spin_unlock_bh(&nn->mbox_cmsg.queue.lock);
+err_free_skb:
+ dev_kfree_skb_any(skb);
+ return err;
+}
+
+struct sk_buff *
+nfp_ccm_mbox_alloc(struct nfp_net *nn, unsigned int req_size,
+ unsigned int reply_size, gfp_t flags)
+{
+ unsigned int max_size;
+ struct sk_buff *skb;
+
+ if (!reply_size)
+ max_size = nfp_ccm_mbox_max_msg(nn);
+ else
+ max_size = max(req_size, reply_size);
+ max_size = round_up(max_size, 4);
+
+ skb = alloc_skb(max_size, flags);
+ if (!skb)
+ return NULL;
+
+ skb_put(skb, req_size);
+
+ return skb;
+}
+
+bool nfp_ccm_mbox_fits(struct nfp_net *nn, unsigned int size)
+{
+ return nfp_ccm_mbox_max_msg(nn) >= size;
+}
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