[PATCH v4 1/5] ata: ahci_st: Assert the power down reset in the probe() error path

[Niklas Cassel <cassel@kernel.org>]

st_ahci_probe_resets() deasserts the "pwr-dwn" reset, but the probe()
error path of st_ahci_probe() only releases the host resources, so the
SATA IP is left powered up when probe() fails after
st_ahci_probe_resets() has succeeded, e.g. when
ahci_platform_enable_resources() fails.

The reset is asserted by st_ahci_host_stop(), however ->host_stop() is
only called through the ata_host_stop() devres action registered by
ata_host_start(), so it does not cover any failure happening before the
host has been started.

Factor the assert out into st_ahci_assert_pwrdwn() and call it from both
probe() error paths. The "pwr-dwn" reset control is an exclusive one, so
asserting it once more from st_ahci_host_stop() is harmless.

No functional change intended for ->host_stop() and st_ahci_suspend().

Fixes: 76884cb2f7da ("ahci: st: Add support for ST's SATA IP")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/ahci_st.c | 51 +++++++++++++++++++++++++------------------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
index 4336c8a6e208..39ebedf93344 100644
--- a/drivers/ata/ahci_st.c
+++ b/drivers/ata/ahci_st.c
@@ -83,18 +83,27 @@ static int st_ahci_deassert_resets(struct ahci_host_priv *hpriv,
 	return 0;
 }
 
-static void st_ahci_host_stop(struct ata_host *host)
+static int st_ahci_assert_pwrdwn(struct ahci_host_priv *hpriv,
+				 struct device *dev)
 {
-	struct ahci_host_priv *hpriv = host->private_data;
 	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
-	struct device *dev = host->dev;
 	int err;
 
-	if (drv_data->pwr) {
-		err = reset_control_assert(drv_data->pwr);
-		if (err)
-			dev_err(dev, "unable to pwrdwn\n");
-	}
+	if (!drv_data->pwr)
+		return 0;
+
+	err = reset_control_assert(drv_data->pwr);
+	if (err)
+		dev_err(dev, "unable to pwrdwn\n");
+
+	return err;
+}
+
+static void st_ahci_host_stop(struct ata_host *host)
+{
+	struct ahci_host_priv *hpriv = host->private_data;
+
+	st_ahci_assert_pwrdwn(hpriv, host->dev);
 
 	ahci_platform_disable_resources(hpriv);
 }
@@ -162,38 +171,38 @@ static int st_ahci_probe(struct platform_device *pdev)
 
 	err = ahci_platform_enable_resources(hpriv);
 	if (err)
-		return err;
+		goto assert_pwrdwn;
 
 	st_ahci_configure_oob(hpriv->mmio);
 
 	err = ahci_platform_init_host(pdev, hpriv, &st_ahci_port_info,
 				      &ahci_platform_sht);
-	if (err) {
-		ahci_platform_disable_resources(hpriv);
-		return err;
-	}
+	if (err)
+		goto disable_resources;
 
 	return 0;
+
+disable_resources:
+	ahci_platform_disable_resources(hpriv);
+assert_pwrdwn:
+	st_ahci_assert_pwrdwn(hpriv, &pdev->dev);
+
+	return err;
 }
 
 static int st_ahci_suspend(struct device *dev)
 {
 	struct ata_host *host = dev_get_drvdata(dev);
 	struct ahci_host_priv *hpriv = host->private_data;
-	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
 	int err;
 
 	err = ahci_platform_suspend_host(dev);
 	if (err)
 		return err;
 
-	if (drv_data->pwr) {
-		err = reset_control_assert(drv_data->pwr);
-		if (err) {
-			dev_err(dev, "unable to pwrdwn");
-			return err;
-		}
-	}
+	err = st_ahci_assert_pwrdwn(hpriv, dev);
+	if (err)
+		return err;
 
 	ahci_platform_disable_resources(hpriv);
 
-- 
2.55.0