[lvc-project] [PATCH net] stmmac: dwmac-intel-plat: fix call balance of tx_clk handling routines

[Vitalii Mordan]

If the clock dwmac->tx_clk was not enabled in intel_eth_plat_probe,
it should not be disabled in any path.

Conversely, if it was enabled in intel_eth_plat_probe, it must be disabled
in all error paths to ensure proper cleanup.

Found by Linux Verification Center (linuxtesting.org) with Klever.

Fixes: 9efc9b2b04c7 ("net: stmmac: Add dwmac-intel-plat for GBE driver")
Signed-off-by: Vitalii Mordan <mordan at ispras.ru>
---
 .../ethernet/stmicro/stmmac/dwmac-intel-plat.c   | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c
index d68f0c4e7835..2a2893f2f2a8 100644
--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-intel-plat.c
@@ -108,7 +108,12 @@ static int intel_eth_plat_probe(struct platform_device *pdev)
 			if (IS_ERR(dwmac->tx_clk))
 				return PTR_ERR(dwmac->tx_clk);
 
-			clk_prepare_enable(dwmac->tx_clk);
+			ret = clk_prepare_enable(dwmac->tx_clk);
+			if (ret) {
+				dev_err(&pdev->dev,
+					"Failed to enable tx_clk\n");
+				return ret;
+			}
 
 			/* Check and configure TX clock rate */
 			rate = clk_get_rate(dwmac->tx_clk);
@@ -117,6 +122,7 @@ static int intel_eth_plat_probe(struct platform_device *pdev)
 				rate = dwmac->data->tx_clk_rate;
 				ret = clk_set_rate(dwmac->tx_clk, rate);
 				if (ret) {
+					clk_disable_unprepare(dwmac->tx_clk);
 					dev_err(&pdev->dev,
 						"Failed to set tx_clk\n");
 					return ret;
@@ -131,6 +137,8 @@ static int intel_eth_plat_probe(struct platform_device *pdev)
 			rate = dwmac->data->ptp_ref_clk_rate;
 			ret = clk_set_rate(plat_dat->clk_ptp_ref, rate);
 			if (ret) {
+				if (dwmac->data->tx_clk_en)
+					clk_disable_unprepare(dwmac->tx_clk);
 				dev_err(&pdev->dev,
 					"Failed to set clk_ptp_ref\n");
 				return ret;
@@ -150,7 +158,8 @@ static int intel_eth_plat_probe(struct platform_device *pdev)
 
 	ret = stmmac_dvr_probe(&pdev->dev, plat_dat, &stmmac_res);
 	if (ret) {
-		clk_disable_unprepare(dwmac->tx_clk);
+		if (dwmac->data->tx_clk_en)
+			clk_disable_unprepare(dwmac->tx_clk);
 		return ret;
 	}
 
@@ -162,7 +171,8 @@ static void intel_eth_plat_remove(struct platform_device *pdev)
 	struct intel_dwmac *dwmac = get_stmmac_bsp_priv(&pdev->dev);
 
 	stmmac_pltfr_remove(pdev);
-	clk_disable_unprepare(dwmac->tx_clk);
+	if (dwmac->data->tx_clk_en)
+		clk_disable_unprepare(dwmac->tx_clk);
 }
 
 static struct platform_driver intel_eth_plat_driver = {
-- 
2.25.1