Subject: arm32 build failure after 992aa864dca068554802a65a467a2640985cc213

From: Nathan Chancellor <[email-masked]>
Date: Mon, 17 Jun 2019 18:46:04 -0700

Hi all,

A 32-bit ARM allyesconfig fails to link after commit 992aa864dca0
("mlxsw: spectrum_ptp: Add implementation for physical hardware clock
operations") because of 64-bit division:

arm-linux-gnueabi-ld:
drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.o: in function
`mlxsw_sp1_ptp_phc_settime':
spectrum_ptp.c:(.text+0x39c): undefined reference to `__aeabi_uldivmod'

The following diff fixes it but I have no idea if it is proper or not
(hence reaching out before sending it, in case one of you has a more
proper idea).

Cheers,
Nathan

---

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
index 2a9bbc90225e..65686f0b6834 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_ptp.c
@@ -87,7 +87,7 @@ mlxsw_sp1_ptp_phc_settime(struct mlxsw_sp_ptp_clock *clock, u64 nsec)
        u32 next_sec;
        int err;
 
-       next_sec = nsec / NSEC_PER_SEC + 1;
+       next_sec = (u32)div64_u64(nsec, NSEC_PER_SEC + 1);
        next_sec_in_nsec = next_sec * NSEC_PER_SEC;
 
        spin_lock(&clock->lock);