[PATCH net-next 1/3] net: stmmac: Move subsecond increment configuration in dedicated helper

Maxime Chevallier
2025-10-15T10:28:01Z

In preparation for fine/coarse support, let's move the subsecond increment
and addend configuration in a dedicated helper.

Signed-off-by: Maxime Chevallier <maxime.chevallier@bootlin.com>
---
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 48 +++++++++++--------
1 file changed, 28 insertions(+), 20 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 650d75b73e0b..3f79b61d64b9 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -463,6 +463,33 @@ static void stmmac_get_rx_hwtstamp(struct stmmac_priv *priv, struct dma_desc *p,
}
}

+static void stmmac_update_subsecond_increment(struct stmmac_priv *priv)
+{
+ bool xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;
+ u32 sec_inc = 0;
+ u64 temp = 0;
+
+ stmmac_config_hw_tstamping(priv, priv->ptpaddr, priv->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;
+
+ /* calculate default added value:
+ * formula is :
+ * addend = (2^32)/freq_div_ratio;
+ * where, freq_div_ratio = 1e9ns/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);
+}
+
/**
* stmmac_hwtstamp_set - control hardware timestamping.
* @dev: device pointer.
@@ -696,10 +723,7 @@ static int stmmac_hwtstamp_get(struct net_device *dev,
static int stmmac_init_tstamp_counter(struct stmmac_priv *priv,
u32 systime_flags)
{
- bool xmac = priv->plat->has_gmac4 || priv->plat->has_xgmac;
struct timespec64 now;
- u32 sec_inc = 0;
- u64 temp = 0;

if (!priv->plat->clk_ptp_rate) {
netdev_err(priv->dev, "Invalid PTP clock rate");
@@ -709,23 +733,7 @@ static int stmmac_init_tstamp_counter(struct stmmac_priv *priv,
stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
priv->systime_flags = 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;
-
- /* calculate default added value:
- * formula is :
- * addend = (2^32)/freq_div_ratio;
- * where, freq_div_ratio = 1e9ns/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);
+ stmmac_update_subsecond_increment(priv);

/* initialize system time */
ktime_get_real_ts64(&now);
--
2.49.0