[PATCH v2] ata: ahci_st: fixup layering violations / drvdata errors

[PATCH v2] ata: ahci_st: fixup layering violations / drvdata errors

[Peter Griffin]

Hi Tejun / Brian,

I tested the initial version of this patch (see http://patchwork.ozlabs.org/patch/459422/)
on stih410 hardware, however it introduced a NULL ptr dereference, as plat_data
isn't set until ahci_platform_init_host() but plat_data was being used before
this in the st_ahci_probe_resets and st_ahci_deassert_resets() functions.

Also the original patch had a conflict with a patch which Tejun has already
taken of mine 
(see here http://lists.infradead.org/pipermail/linux-arm-kernel/2015-March/326900.html).

So this V2 fixes the conflict, and re-works st_ahci_probe_resets and 
st_ahci_deassert_resets functions to take struct ahci_host_priv *hpriv as
a parameter.

Brian - I'm not sure of the correct patch etiquette here. Currently I have
taken authorship of the patch and added a "Suggested-by" tag on the V2.
Maybe I should have also kept your "Signed-off-by" or done something else?
Please let me know if this is OK or if you would like something changed.

regards,

Peter. 

Changes since v1:
 - Rework st_ahci_deassert_resets and st_ahci_probe_resets
 - Fix conflict with "st_configure_oob must be called after IP is clocked." patch

Peter Griffin (1):
  ata: ahci_st: fixup layering violations / drvdata errors

 drivers/ata/ahci_st.c | 49 ++++++++++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

-- 
1.9.1

[PATCH v2] ata: ahci_st: fixup layering violations / drvdata errors

[Peter Griffin]

Brian noticed while working on another SATA driver that uses libahci_platform,
an error in this driver; it tries to the the driver data for its
device, while libata also thinks it can set the driver data. See:

  ahci_platform_init_host()
  -> ata_host_alloc_pinfo()
     -> ata_host_alloc()
        -> dev_set_drvdata()

So instead of sticking the IP-specific platform data into drvdata, let's
use the plat_data variable that is reserved for this use.

Addtionally plat_data isn't set until ahci_platform_init_host() has been
called further down in probe(). So re-work the st_ahci_probe_resets and
st_ahci_deassert_resets functions to take ahci_host_priv *hpriv as a
parameter.

Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
Suggested-by: Brian Norris <computersforpeace@gmail.com>
Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com>
Cc: Maxime Coquelin <maxime.coquelin@st.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
---
 drivers/ata/ahci_st.c | 49 ++++++++++++++++++++++++-------------------------
 1 file changed, 24 insertions(+), 25 deletions(-)

diff --git a/drivers/ata/ahci_st.c b/drivers/ata/ahci_st.c
index ea0ff00..8ff428f 100644
--- a/drivers/ata/ahci_st.c
+++ b/drivers/ata/ahci_st.c
@@ -37,7 +37,6 @@ struct st_ahci_drv_data {
 	struct reset_control *pwr;
 	struct reset_control *sw_rst;
 	struct reset_control *pwr_rst;
-	struct ahci_host_priv *hpriv;
 };
 
 static void st_ahci_configure_oob(void __iomem *mmio)
@@ -55,9 +54,10 @@ static void st_ahci_configure_oob(void __iomem *mmio)
 	writel(new_val, mmio + ST_AHCI_OOBR);
 }
 
-static int st_ahci_deassert_resets(struct device *dev)
+static int st_ahci_deassert_resets(struct ahci_host_priv *hpriv,
+				struct device *dev)
 {
-	struct st_ahci_drv_data *drv_data = dev_get_drvdata(dev);
+	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
 	int err;
 
 	if (drv_data->pwr) {
@@ -90,8 +90,8 @@ static int st_ahci_deassert_resets(struct device *dev)
 static void st_ahci_host_stop(struct ata_host *host)
 {
 	struct ahci_host_priv *hpriv = host->private_data;
+	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
 	struct device *dev = host->dev;
-	struct st_ahci_drv_data *drv_data = dev_get_drvdata(dev);
 	int err;
 
 	if (drv_data->pwr) {
@@ -103,29 +103,30 @@ static void st_ahci_host_stop(struct ata_host *host)
 	ahci_platform_disable_resources(hpriv);
 }
 
-static int st_ahci_probe_resets(struct platform_device *pdev)
+static int st_ahci_probe_resets(struct ahci_host_priv *hpriv,
+				struct device *dev)
 {
-	struct st_ahci_drv_data *drv_data = platform_get_drvdata(pdev);
+	struct st_ahci_drv_data *drv_data = hpriv->plat_data;
 
-	drv_data->pwr = devm_reset_control_get(&pdev->dev, "pwr-dwn");
+	drv_data->pwr = devm_reset_control_get(dev, "pwr-dwn");
 	if (IS_ERR(drv_data->pwr)) {
-		dev_info(&pdev->dev, "power reset control not defined\n");
+		dev_info(dev, "power reset control not defined\n");
 		drv_data->pwr = NULL;
 	}
 
-	drv_data->sw_rst = devm_reset_control_get(&pdev->dev, "sw-rst");
+	drv_data->sw_rst = devm_reset_control_get(dev, "sw-rst");
 	if (IS_ERR(drv_data->sw_rst)) {
-		dev_info(&pdev->dev, "soft reset control not defined\n");
+		dev_info(dev, "soft reset control not defined\n");
 		drv_data->sw_rst = NULL;
 	}
 
-	drv_data->pwr_rst = devm_reset_control_get(&pdev->dev, "pwr-rst");
+	drv_data->pwr_rst = devm_reset_control_get(dev, "pwr-rst");
 	if (IS_ERR(drv_data->pwr_rst)) {
-		dev_dbg(&pdev->dev, "power soft reset control not defined\n");
+		dev_dbg(dev, "power soft reset control not defined\n");
 		drv_data->pwr_rst = NULL;
 	}
 
-	return st_ahci_deassert_resets(&pdev->dev);
+	return st_ahci_deassert_resets(hpriv, dev);
 }
 
 static struct ata_port_operations st_ahci_port_ops = {
@@ -154,15 +155,12 @@ static int st_ahci_probe(struct platform_device *pdev)
 	if (!drv_data)
 		return -ENOMEM;
 
-	platform_set_drvdata(pdev, drv_data);
-
 	hpriv = ahci_platform_get_resources(pdev);
 	if (IS_ERR(hpriv))
 		return PTR_ERR(hpriv);
+	hpriv->plat_data = drv_data;
 
-	drv_data->hpriv = hpriv;
-
-	err = st_ahci_probe_resets(pdev);
+	err = st_ahci_probe_resets(hpriv, &pdev->dev);
 	if (err)
 		return err;
 
@@ -170,7 +168,7 @@ static int st_ahci_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
-	st_ahci_configure_oob(drv_data->hpriv->mmio);
+	st_ahci_configure_oob(hpriv->mmio);
 
 	err = ahci_platform_init_host(pdev, hpriv, &st_ahci_port_info,
 				      &ahci_platform_sht);
@@ -185,8 +183,9 @@ static int st_ahci_probe(struct platform_device *pdev)
 #ifdef CONFIG_PM_SLEEP
 static int st_ahci_suspend(struct device *dev)
 {
-	struct st_ahci_drv_data *drv_data = dev_get_drvdata(dev);
-	struct ahci_host_priv *hpriv = drv_data->hpriv;
+	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);
@@ -208,21 +207,21 @@ static int st_ahci_suspend(struct device *dev)
 
 static int st_ahci_resume(struct device *dev)
 {
-	struct st_ahci_drv_data *drv_data = dev_get_drvdata(dev);
-	struct ahci_host_priv *hpriv = drv_data->hpriv;
+	struct ata_host *host = dev_get_drvdata(dev);
+	struct ahci_host_priv *hpriv = host->private_data;
 	int err;
 
 	err = ahci_platform_enable_resources(hpriv);
 	if (err)
 		return err;
 
-	err = st_ahci_deassert_resets(dev);
+	err = st_ahci_deassert_resets(hpriv, dev);
 	if (err) {
 		ahci_platform_disable_resources(hpriv);
 		return err;
 	}
 
-	st_ahci_configure_oob(drv_data->hpriv->mmio);
+	st_ahci_configure_oob(hpriv->mmio);
 
 	return ahci_platform_resume_host(dev);
 }
-- 
1.9.1

[PATCH v2] ata: ahci_st: fixup layering violations / drvdata errors

[Maxime Coquelin]

Hi Peter,

On 04/20/2015 03:41 PM, Peter Griffin wrote:
> Brian noticed while working on another SATA driver that uses libahci_platform,
> an error in this driver; it tries to the the driver data for its
> device, while libata also thinks it can set the driver data. See:
>
>    ahci_platform_init_host()
>    -> ata_host_alloc_pinfo()
>       -> ata_host_alloc()
>          -> dev_set_drvdata()
>
> So instead of sticking the IP-specific platform data into drvdata, let's
> use the plat_data variable that is reserved for this use.
>
> Addtionally plat_data isn't set until ahci_platform_init_host() has been
> called further down in probe(). So re-work the st_ahci_probe_resets and
> st_ahci_deassert_resets functions to take ahci_host_priv *hpriv as a
> parameter.
>
> Signed-off-by: Peter Griffin <peter.griffin@linaro.org>
> Suggested-by: Brian Norris <computersforpeace@gmail.com>
> Cc: Srinivas Kandagatla <srinivas.kandagatla@gmail.com>
> Cc: Maxime Coquelin <maxime.coquelin@st.com>
> Cc: Patrice Chotard <patrice.chotard@st.com>
> ---
>

You can add my:
Acked-by: Maxime Coquelin <maxime.coquelin@st.com>

Thanks!
Maxime

[PATCH v2] ata: ahci_st: fixup layering violations / drvdata errors

[Brian Norris]

On Mon, Apr 20, 2015 at 02:41:04PM +0100, Peter Griffin wrote:
> Brian - I'm not sure of the correct patch etiquette here. Currently I have
> taken authorship of the patch and added a "Suggested-by" tag on the V2.
> Maybe I should have also kept your "Signed-off-by" or done something else?
> Please let me know if this is OK or if you would like something changed.

No problem. 'Suggested-by' seems appropriate to me.

For the patch:

Acked-by: Brian Norris <computersforpeace@gmail.com>