[PATCH 5.15 070/201] net: stmmac: fix unbalanced ptp clock issue in suspend/resume flow

Greg Kroah-Hartman
2022-07-27T17:08:36Z

From: Biao Huang <biao.huang@mediatek.com>

[ Upstream commit f4c7d8948e866918d61493264dbbd67e45ef2bda ]

Current stmmac driver will prepare/enable ptp_ref clock in
stmmac_init_tstamp_counter().

The stmmac_pltfr_noirq_suspend will disable it once in suspend flow.

But in resume flow,
stmmac_pltfr_noirq_resume --> stmmac_init_tstamp_counter
stmmac_resume --> stmmac_hw_setup --> stmmac_init_ptp --> stmmac_init_tstamp_counter
ptp_ref clock reference counter increases twice, which leads to unbalance
ptp clock when resume back.

Move ptp_ref clock prepare/enable out of stmmac_init_tstamp_counter to fix it.

Fixes: 0735e639f129d ("net: stmmac: skip only stmmac_ptp_register when resume from suspend")
Signed-off-by: Biao Huang <biao.huang@mediatek.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../net/ethernet/stmicro/stmmac/stmmac_main.c | 17 ++++++++---------
.../ethernet/stmicro/stmmac/stmmac_platform.c | 8 +++++++-
2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
index 95e1307cfda2..b4f83c865568 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
@@ -844,19 +844,10 @@ int stmmac_init_tstamp_counter(struct stmmac_priv *priv, u32 systime_flags)
struct timespec64 now;
u32 sec_inc = 0;
u64 temp = 0;
- int ret;

if (!(priv->dma_cap.time_stamp || priv->dma_cap.atime_stamp))
return -EOPNOTSUPP;

- ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
- if (ret < 0) {
- netdev_warn(priv->dev,
- "failed to enable PTP reference clock: %pe\n",
- ERR_PTR(ret));
- return ret;
- }
-
stmmac_config_hw_tstamping(priv, priv->ptpaddr, systime_flags);
priv->systime_flags = systime_flags;

@@ -3325,6 +3316,14 @@ static int stmmac_hw_setup(struct net_device *dev, bool ptp_register)

stmmac_mmc_setup(priv);

+ if (ptp_register) {
+ ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
+ if (ret < 0)
+ netdev_warn(priv->dev,
+ "failed to enable PTP reference clock: %pe\n",
+ ERR_PTR(ret));
+ }
+
ret = stmmac_init_ptp(priv);
if (ret == -EOPNOTSUPP)
netdev_warn(priv->dev, "PTP not supported by HW\n");
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
index 11e1055e8260..9f5cac4000da 100644
--- a/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
+++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_platform.c
@@ -815,7 +815,13 @@ static int __maybe_unused stmmac_pltfr_noirq_resume(struct device *dev)
if (ret)
return ret;

- stmmac_init_tstamp_counter(priv, priv->systime_flags);
+ ret = clk_prepare_enable(priv->plat->clk_ptp_ref);
+ if (ret < 0) {
+ netdev_warn(priv->dev,
+ "failed to enable PTP reference clock: %pe\n",
+ ERR_PTR(ret));
+ return ret;
+ }
}

return 0;
--
2.35.1