diff options
| author | Cristian Marussi <cristian.marussi@arm.com> | 2022-06-16 18:03:47 +0100 |
|---|---|---|
| committer | Sudeep Holla <sudeep.holla@arm.com> | 2022-06-20 10:17:33 +0100 |
| commit | 754f04cac362417b157e30d5dc4046b5ec92060c (patch) | |
| tree | c0f1f79fdfbc15fadc335bce1b11a12c1f74987c /drivers/firmware/arm_scmi/clock.c | |
| parent | 44dbdf3bb3f44bf08897ed5f22eb262edcf3d926 (diff) | |
firmware: arm_scmi: Relax CLOCK_DESCRIBE_RATES out-of-spec checks
A reply to CLOCK_DESCRIBE_RATES issued against a non rate-discrete clock
should be composed of a triplet of rates descriptors (min/max/step)
returned all in one reply message.
This is not always the case when dealing with some SCMI server deployed in
the wild: relax such constraint while maintaining memory safety by checking
carefully the returned payload size.
While at that cleanup a stale debug printout.
Link: https://lore.kernel.org/r/20220616170347.2800771-1-cristian.marussi@arm.com
Fixes: 7bc7caafe6b1 ("firmware: arm_scmi: Use common iterators in the clock protocol")
Tested-by: Robin Murphy <robin.murphy@arm.com>
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Diffstat (limited to 'drivers/firmware/arm_scmi/clock.c')
| -rw-r--r-- | drivers/firmware/arm_scmi/clock.c | 26 |
1 files changed, 25 insertions, 1 deletions
diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c index c7a83f6e38e5..3ed7ae0d6781 100644 --- a/drivers/firmware/arm_scmi/clock.c +++ b/drivers/firmware/arm_scmi/clock.c @@ -194,6 +194,7 @@ static int rate_cmp_func(const void *_r1, const void *_r2) } struct scmi_clk_ipriv { + struct device *dev; u32 clk_id; struct scmi_clock_info *clk; }; @@ -223,6 +224,29 @@ iter_clk_describe_update_state(struct scmi_iterator_state *st, st->num_returned = NUM_RETURNED(flags); p->clk->rate_discrete = RATE_DISCRETE(flags); + /* Warn about out of spec replies ... */ + if (!p->clk->rate_discrete && + (st->num_returned != 3 || st->num_remaining != 0)) { + dev_warn(p->dev, + "Out-of-spec CLOCK_DESCRIBE_RATES reply for %s - returned:%d remaining:%d rx_len:%zd\n", + p->clk->name, st->num_returned, st->num_remaining, + st->rx_len); + + /* + * A known quirk: a triplet is returned but num_returned != 3 + * Check for a safe payload size and fix. + */ + if (st->num_returned != 3 && st->num_remaining == 0 && + st->rx_len == sizeof(*r) + sizeof(__le32) * 2 * 3) { + st->num_returned = 3; + st->num_remaining = 0; + } else { + dev_err(p->dev, + "Cannot fix out-of-spec reply !\n"); + return -EPROTO; + } + } + return 0; } @@ -255,7 +279,6 @@ iter_clk_describe_process_response(const struct scmi_protocol_handle *ph, *rate = RATE_TO_U64(r->rate[st->loop_idx]); p->clk->list.num_rates++; - //XXX dev_dbg(ph->dev, "Rate %llu Hz\n", *rate); } return ret; @@ -275,6 +298,7 @@ scmi_clock_describe_rates_get(const struct scmi_protocol_handle *ph, u32 clk_id, struct scmi_clk_ipriv cpriv = { .clk_id = clk_id, .clk = clk, + .dev = ph->dev, }; iter = ph->hops->iter_response_init(ph, &ops, SCMI_MAX_NUM_RATES, |