The branch main has been updated by andrew:
URL:
https://cgit.FreeBSD.org/src/commit/?id=c508841dfc5923ef81ed8ea61da364fb20616bbf
commit c508841dfc5923ef81ed8ea61da364fb20616bbf
Author: Cristian Marussi <cristian.maru...@arm.com>
AuthorDate: 2025-01-23 13:24:06 +0000
Commit: Andrew Turner <and...@freebsd.org>
CommitDate: 2025-01-23 17:26:27 +0000
scmi: Add scmi_token_reserve helper
During normal operation, the SCMI stack, upon each transmission attempt,
takes care to automatically pick an appropriate, monotonically increasing,
sequence number to fill-in the token field in the egressing message.
This does not cope well with the alternative scenario in which, instead,
a complete and fully formed message is provided upfront: in such a case the
SCMI stack will have to use the already provided sequence number, embedded
in the message, to track such transaction.
Add a method to attempt to reserve a specific sequence number to be used
when a fully firmed (raw) message is handled.
Tested on: Arm Morello Board
Reviewed by: andrew
Sponsored by: Arm Ltd
Pull Request: https://reviews.freebsd.org/D47424
Signed-off-by: Cristian Marussi <cristian.maru...@arm.com>
---
sys/dev/firmware/arm/scmi.c | 48 ++++++++++++++++++++++++++++++++++++---------
1 file changed, 39 insertions(+), 9 deletions(-)
diff --git a/sys/dev/firmware/arm/scmi.c b/sys/dev/firmware/arm/scmi.c
index 8104f4e10429..c24768a5668a 100644
--- a/sys/dev/firmware/arm/scmi.c
+++ b/sys/dev/firmware/arm/scmi.c
@@ -93,6 +93,7 @@ struct scmi_req {
bool timed_out;
bool use_polling;
bool done;
+ bool is_raw;
struct mtx mtx;
LIST_ENTRY(scmi_req) next;
int protocol_id;
@@ -139,6 +140,7 @@ static void scmi_req_free_unlocked(struct
scmi_softc *,
static void scmi_req_get(struct scmi_softc *, struct scmi_req *);
static void scmi_req_put(struct scmi_softc *, struct scmi_req *);
static int scmi_token_pick(struct scmi_softc *);
+static int scmi_token_reserve(struct scmi_softc *, uint16_t);
static void scmi_token_release_unlocked(struct scmi_softc *, int);
static int scmi_req_track_inflight(struct scmi_softc *,
struct scmi_req *);
@@ -376,6 +378,7 @@ scmi_req_free_unlocked(struct scmi_softc *sc, enum
scmi_chan ch_idx,
mtx_lock_spin(&rp->mtx);
req->timed_out = false;
req->done = false;
+ req->is_raw = false;
refcount_init(&req->cnt, 0);
LIST_INSERT_HEAD(&rp->head, req, next);
mtx_unlock_spin(&rp->mtx);
@@ -424,7 +427,6 @@ scmi_token_pick(struct scmi_softc *sc)
*/
next_msg_id = sc->trs->next_id++ & SCMI_HDR_TOKEN_BF;
token = BIT_FFS_AT(SCMI_MAX_TOKEN, &sc->trs->avail_tokens, next_msg_id);
- /* TODO Account for wrap-arounds and holes */
if (token != 0)
BIT_CLR(SCMI_MAX_TOKEN, token - 1, &sc->trs->avail_tokens);
mtx_unlock_spin(&sc->trs->mtx);
@@ -440,6 +442,28 @@ scmi_token_pick(struct scmi_softc *sc)
return ((int)(token - 1));
}
+static int
+scmi_token_reserve(struct scmi_softc *sc, uint16_t candidate)
+{
+ int token = -EBUSY, retries = 3;
+
+ do {
+ mtx_lock_spin(&sc->trs->mtx);
+ if (BIT_ISSET(SCMI_MAX_TOKEN, candidate,
&sc->trs->avail_tokens)) {
+ BIT_CLR(SCMI_MAX_TOKEN, candidate,
&sc->trs->avail_tokens);
+ token = candidate;
+ sc->trs->next_id++;
+ }
+ mtx_unlock_spin(&sc->trs->mtx);
+ if (token == candidate || retries-- == 0)
+ break;
+
+ pause("scmi_tk_reserve", hz);
+ } while (1);
+
+ return (token);
+}
+
static void
scmi_token_release_unlocked(struct scmi_softc *sc, int token)
{
@@ -450,19 +474,23 @@ scmi_token_release_unlocked(struct scmi_softc *sc, int
token)
static int
scmi_finalize_req(struct scmi_softc *sc, struct scmi_req *req)
{
- uint32_t header = 0;
+ if (!req->is_raw)
+ req->token = scmi_token_pick(sc);
+ else
+ req->token = scmi_token_reserve(sc,
SCMI_MSG_TOKEN(req->msg.hdr));
- req->token = scmi_token_pick(sc);
if (req->token < 0)
return (EBUSY);
- header = req->message_id;
- header |= SCMI_MSG_TYPE_CMD << SCMI_HDR_MESSAGE_TYPE_S;
- header |= req->protocol_id << SCMI_HDR_PROTOCOL_ID_S;
- header |= req->token << SCMI_HDR_TOKEN_S;
+ if (!req->is_raw) {
+ req->msg.hdr = req->message_id;
+ req->msg.hdr |= SCMI_MSG_TYPE_CMD << SCMI_HDR_MESSAGE_TYPE_S;
+ req->msg.hdr |= req->protocol_id << SCMI_HDR_PROTOCOL_ID_S;
+ req->msg.hdr |= req->token << SCMI_HDR_TOKEN_S;
+ }
- req->header = htole32(header);
- req->msg.hdr = htole32(header);
+ /* Save requested header */
+ req->header = req->msg.hdr;
return (0);
}
@@ -670,6 +698,8 @@ scmi_msg_get(device_t dev, int tx_payld_sz, int rx_payld_sz)
if (req == NULL)
return (NULL);
+ req->is_raw = true;
+
return (&req->msg);
}
