* [PATCH net] net: stmmac: propagate PTP addend and system time programming errors
@ 2026-09-20 13:00 Lorenzo Bianconi
2026-09-23 23:16 ` kernel test robot
0 siblings, 1 reply; 2+ messages in thread
From: Lorenzo Bianconi @ 2026-09-20 13:00 UTC (permalink / raw)
To: Maxime Chevallier, Andrew Lunn, David S. Miller, Eric Dumazet,
Jakub Kicinski, Paolo Abeni, Maxime Coquelin, Alexandre Torgue,
Richard Cochran, Jose Abreu
Cc: netdev, linux-stm32, linux-arm-kernel, Lorenzo Bianconi
stmmac_update_subsecond_increment() ignores the error returned by
stmmac_config_addend(), and stmmac_init_tstamp_counter() discards the
addend and system time programming errors, always returning success. A
failure to program the addend (PTP_TCR_TSADDREG) or to initialize the
system time counter (PTP_TCR_TSINIT) is therefore silently swallowed,
leaving the hardware timestamp counter in a non-running or partially
configured state while the driver keeps operating as if timestamping
were up. This matters for TAPRIO/EST offloading, which derives the gate
base time from the hardware timestamp counter.
Return error codes from stmmac_update_subsecond_increment(),
stmmac_init_tstamp_counter() and stmmac_dl_ts_coarse_set() instead of
silently returning success.
Fixes: cc4c9001ce31 ("net: stmmac: Switch stmmac_hwtimestamp to generic HW Interface Helpers")
Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
---
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 89 ++++++++++++++++++-----
1 file changed, 69 insertions(+), 20 deletions(-)
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 1fb5f804ea23..52587ecb1a54 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -601,31 +601,63 @@ static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p,
}
}
-static void stmmac_update_subsecond_increment(struct stmmac_priv *priv)
+static void stmmac_restore_subsecond_increment(struct stmmac_priv *priv,
+ u32 default_addend,
+ u32 systime_flags)
{
bool xmac = dwmac_is_xmac(priv->plat->core_type);
- u32 sec_inc = 0;
+ u32 sec_inc;
+
+ stmmac_config_addend(priv, priv->ptpaddr, default_addend);
+ stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
+ stmmac_config_sub_second_increment(priv, priv->ptpaddr,
+ priv->plat->clk_ptp_rate,
+ xmac, &sec_inc);
+ priv->default_addend = default_addend;
+ priv->sub_second_inc = sec_inc;
+}
+
+static int stmmac_update_subsecond_increment(struct stmmac_priv *priv,
+ u32 systime_flags)
+{
+ bool xmac = dwmac_is_xmac(priv->plat->core_type);
+ u32 sec_inc = 0, val;
u64 temp = 0;
+ int ret;
- stmmac_config_hw_tstamping(priv, priv->ptpaddr, priv->systime_flags);
+ stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
/* program Sub Second Increment reg */
stmmac_config_sub_second_increment(priv, priv->ptpaddr,
priv->plat->clk_ptp_rate,
xmac, &sec_inc);
- temp = div_u64(1000000000ULL, sec_inc);
-
- /* Store sub second increment for later use */
- priv->sub_second_inc = sec_inc;
+ if (!sec_inc) {
+ ret = -EINVAL;
+ goto error;
+ }
/* calculate default added value:
* formula is :
* addend = (2^32)/freq_div_ratio;
* where, freq_div_ratio = 1e9ns/sec_inc
*/
+ temp = div_u64(1000000000ULL, sec_inc);
temp = (u64)(temp << 32);
- priv->default_addend = div_u64(temp, priv->plat->clk_ptp_rate);
- stmmac_config_addend(priv, priv->ptpaddr, priv->default_addend);
+ val = div_u64(temp, priv->plat->clk_ptp_rate);
+
+ ret = stmmac_config_addend(priv, priv->ptpaddr, val);
+ if (ret)
+ goto error;
+
+ priv->sub_second_inc = sec_inc;
+ priv->default_addend = val;
+
+ return 0;
+error:
+ /* Restore previous configuration */
+ stmmac_restore_subsecond_increment(priv, priv->default_addend,
+ priv->systime_flags);
+ return ret;
}
/**
@@ -864,25 +896,37 @@ static int stmmac_hwtstamp_get(struct net_device *dev,
static int stmmac_init_tstamp_counter(struct stmmac_priv *priv,
u32 systime_flags)
{
+ u32 default_addend = priv->default_addend;
struct timespec64 now;
+ int ret;
if (!priv->plat->clk_ptp_rate) {
netdev_err(priv->dev, "Invalid PTP clock rate");
return -EINVAL;
}
- stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
- priv->systime_flags = systime_flags;
-
- stmmac_update_subsecond_increment(priv);
+ ret = stmmac_update_subsecond_increment(priv, systime_flags);
+ if (ret)
+ return ret;
/* initialize system time */
ktime_get_real_ts64(&now);
/* lower 32 bits of tv_sec are safe until y2106 */
- stmmac_init_systime(priv, priv->ptpaddr, (u32)now.tv_sec, now.tv_nsec);
+ ret = stmmac_init_systime(priv, priv->ptpaddr, (u32)now.tv_sec,
+ now.tv_nsec);
+ if (ret)
+ goto error;
+
+ priv->systime_flags = systime_flags;
return 0;
+error:
+ /* Restore previous configuration */
+ stmmac_restore_subsecond_increment(priv, default_addend,
+ priv->systime_flags);
+
+ return ret;
}
/**
@@ -7693,18 +7737,23 @@ static int stmmac_dl_ts_coarse_set(struct devlink *dl, u32 id,
{
struct stmmac_devlink_priv *dl_priv = devlink_priv(dl);
struct stmmac_priv *priv = dl_priv->stmmac_priv;
+ u32 systime_flags = priv->systime_flags;
+ int ret;
- priv->tsfupdt_coarse = ctx->val.vbool;
-
- if (priv->tsfupdt_coarse)
- priv->systime_flags &= ~PTP_TCR_TSCFUPDT;
+ if (ctx->val.vbool)
+ systime_flags &= ~PTP_TCR_TSCFUPDT;
else
- priv->systime_flags |= PTP_TCR_TSCFUPDT;
+ systime_flags |= PTP_TCR_TSCFUPDT;
/* In Coarse mode, we can use a smaller subsecond increment, let's
* reconfigure the systime, subsecond increment and addend.
*/
- stmmac_update_subsecond_increment(priv);
+ ret = stmmac_update_subsecond_increment(priv, systime_flags);
+ if (ret)
+ return ret;
+
+ priv->tsfupdt_coarse = ctx->val.vbool;
+ priv->systime_flags = systime_flags;
return 0;
}
---
base-commit: 1e24c4f2ee44be0eee94092b5d13cbdb4bdf0d60
change-id: 20260920-stmmac-ptp-added-systime-error-bc9566262f2f
Best regards,
--
Lorenzo Bianconi <lorenzo.bianconi@oss.qualcomm.com>
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] net: stmmac: propagate PTP addend and system time programming errors
2026-09-20 13:00 [PATCH net] net: stmmac: propagate PTP addend and system time programming errors Lorenzo Bianconi
@ 2026-09-23 23:16 ` kernel test robot
0 siblings, 0 replies; 2+ messages in thread
From: kernel test robot @ 2026-09-23 23:16 UTC (permalink / raw)
To: Lorenzo Bianconi, Maxime Chevallier, Andrew Lunn, David S. Miller,
Eric Dumazet, Jakub Kicinski, Paolo Abeni, Maxime Coquelin,
Alexandre Torgue, Richard Cochran, Jose Abreu
Cc: llvm, oe-kbuild-all, netdev, linux-stm32, linux-arm-kernel,
Lorenzo Bianconi
Hi Lorenzo,
kernel test robot noticed the following build warnings:
[auto build test WARNING on 1e24c4f2ee44be0eee94092b5d13cbdb4bdf0d60]
url: https://github.com/intel-lab-lkp/linux/commits/Lorenzo-Bianconi/net-stmmac-propagate-PTP-addend-and-system-time-programming-errors/20260920-150002
base: 1e24c4f2ee44be0eee94092b5d13cbdb4bdf0d60
patch link: https://lore.kernel.org/r/20260920-stmmac-ptp-added-systime-error-v1-1-8ac9e7a3fce2%40oss.qualcomm.com
patch subject: [PATCH net] net: stmmac: propagate PTP addend and system time programming errors
config: arm-defconfig (https://download.01.org/0day-ci/archive/20260924/202609240727.6U1AzUEr-lkp@intel.com/config)
compiler: clang version 24.0.0git (https://github.com/llvm/llvm-project 6e714c8d91116794cb699cdf80c26afe9cda3ef3)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260924/202609240727.6U1AzUEr-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202609240727.6U1AzUEr-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:613:2: warning: variable 'sec_inc' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
613 | stmmac_config_sub_second_increment(priv, priv->ptpaddr,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
614 | priv->plat->clk_ptp_rate,
| ~~~~~~~~~~~~~~~~~~~~~~~~~
615 | xmac, &sec_inc);
| ~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/hwif.h:517:2: note: expanded from macro 'stmmac_config_sub_second_increment'
517 | stmmac_do_void_callback(__priv, ptp, config_sub_second_increment, __args)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/hwif.h:15:6: note: expanded from macro 'stmmac_do_void_callback'
15 | if ((__priv)->hw->__module && (__priv)->hw->__module->__cname) { \
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:617:25: note: uninitialized use occurs here
617 | priv->sub_second_inc = sec_inc;
| ^~~~~~~
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:613:2: note: remove the 'if' if its condition is always true
613 | stmmac_config_sub_second_increment(priv, priv->ptpaddr,
| ^
drivers/net/ethernet/stmicro/stmmac/hwif.h:517:2: note: expanded from macro 'stmmac_config_sub_second_increment'
517 | stmmac_do_void_callback(__priv, ptp, config_sub_second_increment, __args)
| ^
drivers/net/ethernet/stmicro/stmmac/hwif.h:15:2: note: expanded from macro 'stmmac_do_void_callback'
15 | if ((__priv)->hw->__module && (__priv)->hw->__module->__cname) { \
| ^
>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:613:2: warning: variable 'sec_inc' is used uninitialized whenever '&&' condition is false [-Wsometimes-uninitialized]
613 | stmmac_config_sub_second_increment(priv, priv->ptpaddr,
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
614 | priv->plat->clk_ptp_rate,
| ~~~~~~~~~~~~~~~~~~~~~~~~~
615 | xmac, &sec_inc);
| ~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/hwif.h:517:2: note: expanded from macro 'stmmac_config_sub_second_increment'
517 | stmmac_do_void_callback(__priv, ptp, config_sub_second_increment, __args)
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/hwif.h:15:6: note: expanded from macro 'stmmac_do_void_callback'
15 | if ((__priv)->hw->__module && (__priv)->hw->__module->__cname) { \
| ^~~~~~~~~~~~~~~~~~~~~~
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:617:25: note: uninitialized use occurs here
617 | priv->sub_second_inc = sec_inc;
| ^~~~~~~
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:613:2: note: remove the '&&' if its condition is always true
613 | stmmac_config_sub_second_increment(priv, priv->ptpaddr,
| ^
drivers/net/ethernet/stmicro/stmmac/hwif.h:517:2: note: expanded from macro 'stmmac_config_sub_second_increment'
517 | stmmac_do_void_callback(__priv, ptp, config_sub_second_increment, __args)
| ^
drivers/net/ethernet/stmicro/stmmac/hwif.h:15:6: note: expanded from macro 'stmmac_do_void_callback'
15 | if ((__priv)->hw->__module && (__priv)->hw->__module->__cname) { \
| ^
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:609:13: note: initialize the variable 'sec_inc' to silence this warning
609 | u32 sec_inc;
| ^
| = 0
2 warnings generated.
vim +613 drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
603
604 static void stmmac_restore_subsecond_increment(struct stmmac_priv *priv,
605 u32 default_addend,
606 u32 systime_flags)
607 {
608 bool xmac = dwmac_is_xmac(priv->plat->core_type);
609 u32 sec_inc;
610
611 stmmac_config_addend(priv, priv->ptpaddr, default_addend);
612 stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
> 613 stmmac_config_sub_second_increment(priv, priv->ptpaddr,
614 priv->plat->clk_ptp_rate,
615 xmac, &sec_inc);
616 priv->default_addend = default_addend;
617 priv->sub_second_inc = sec_inc;
618 }
619
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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