[PATCH] net: dwc_eth_qos: Fix needless phy auto-negotiation restarts

[Daniil Stas]

Disabling clk_ck clock leads to link up status loss in phy, which
leads to auto-negotiation restart before each network command
execution.

This issue is especially big for PXE boot protocol because of
auto-negotiation restarts before each configuration filename trial.

To avoid this issue don't disable clk_ck clock after it was enabled.

Signed-off-by: Daniil Stas <daniil.stas at posteo.net>
Cc: Ramon Fried <rfried.dev at gmail.com>
Cc: Joe Hershberger <joe.hershberger at ni.com>
Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
Cc: Patrice Chotard <patrice.chotard at foss.st.com>
---
 drivers/net/dwc_eth_qos.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/net/dwc_eth_qos.c b/drivers/net/dwc_eth_qos.c
index e8242ca4e1..2f088c758f 100644
--- a/drivers/net/dwc_eth_qos.c
+++ b/drivers/net/dwc_eth_qos.c
@@ -321,6 +321,7 @@ struct eqos_priv {
 	void *rx_pkt;
 	bool started;
 	bool reg_access_ok;
+	bool clk_ck_enabled;
 };
 
 /*
@@ -591,12 +592,13 @@ static int eqos_start_clks_stm32(struct udevice *dev)
 		goto err_disable_clk_rx;
 	}
 
-	if (clk_valid(&eqos->clk_ck)) {
+	if (clk_valid(&eqos->clk_ck) && !eqos->clk_ck_enabled) {
 		ret = clk_enable(&eqos->clk_ck);
 		if (ret < 0) {
 			pr_err("clk_enable(clk_ck) failed: %d", ret);
 			goto err_disable_clk_tx;
 		}
+		eqos->clk_ck_enabled = true;
 	}
 #endif
 
@@ -648,8 +650,6 @@ static void eqos_stop_clks_stm32(struct udevice *dev)
 	clk_disable(&eqos->clk_tx);
 	clk_disable(&eqos->clk_rx);
 	clk_disable(&eqos->clk_master_bus);
-	if (clk_valid(&eqos->clk_ck))
-		clk_disable(&eqos->clk_ck);
 #endif
 
 	debug("%s: OK\n", __func__);
-- 
2.31.0