coresight: removing bind/unbind options from sysfs

The coresight drivers have absolutely no control over bind and unbind
operations triggered from sysfs. The operations simply can't be
cancelled or denied event when one or several tracing sessions are
under way.  Since the memory associated to individual device is
invariably freed, the end result is a kernel crash when the path from
source to sink is travelled again as demonstrated here[1].

One solution could be to keep track of all the path (i.e tracing
session) that get created and iterate through the elements of those path
looking for the coresight device that is being removed.  This proposition
doesn't scale well since there is no upper bound on the amount of
concurrent trace session that can be created.

With the above in mind, this patch prevent devices from being unbounded
from their driver by using the driver->suppress_bind_attr option.  That way
trace sessions can be managed without fearing to loose devices.

Since device can't be removed anymore the xyz_remove() functions found in
each driver is also removed.

[1]. http://www.spinics.net/lists/arm-kernel/msg474952.html

Reported-by: Rabin Vincent <rabin@rab.in>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/hwtracing/coresight/coresight-etb10.c

@@ -489,15 +489,6 @@ err_misc_register:
 	return ret;
 }
 
-static int etb_remove(struct amba_device *adev)
-{
-	struct etb_drvdata *drvdata = amba_get_drvdata(adev);
-
-	misc_deregister(&drvdata->miscdev);
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int etb_runtime_suspend(struct device *dev)
 {
@@ -537,10 +528,10 @@ static struct amba_driver etb_driver = {
 		.name	= "coresight-etb10",
 		.owner	= THIS_MODULE,
 		.pm	= &etb_dev_pm_ops,
+		.suppress_bind_attrs = true,
 
 	},
 	.probe		= etb_probe,
-	.remove		= etb_remove,
 	.id_table	= etb_ids,
 };
 

drivers/hwtracing/coresight/coresight-etm3x.c

@@ -1877,17 +1877,6 @@ err_arch_supported:
 	return ret;
 }
 
-static int etm_remove(struct amba_device *adev)
-{
-	struct etm_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	if (--etm_count == 0)
-		unregister_hotcpu_notifier(&etm_cpu_notifier);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int etm_runtime_suspend(struct device *dev)
 {
@@ -1948,9 +1937,9 @@ static struct amba_driver etm_driver = {
 		.name	= "coresight-etm3x",
 		.owner	= THIS_MODULE,
 		.pm	= &etm_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= etm_probe,
-	.remove		= etm_remove,
 	.id_table	= etm_ids,
 };
 

drivers/hwtracing/coresight/coresight-etm4x.c

@@ -2684,17 +2684,6 @@ err_coresight_register:
 	return ret;
 }
 
-static int etm4_remove(struct amba_device *adev)
-{
-	struct etmv4_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	if (--etm4_count == 0)
-		unregister_hotcpu_notifier(&etm4_cpu_notifier);
-
-	return 0;
-}
-
 static struct amba_id etm4_ids[] = {
 	{       /* ETM 4.0 - Qualcomm */
 		.id	= 0x0003b95d,
@@ -2712,9 +2701,9 @@ static struct amba_id etm4_ids[] = {
 static struct amba_driver etm4x_driver = {
 	.drv = {
 		.name   = "coresight-etm4x",
+		.suppress_bind_attrs = true,
 	},
 	.probe		= etm4_probe,
-	.remove		= etm4_remove,
 	.id_table	= etm4_ids,
 };
 

drivers/hwtracing/coresight/coresight-funnel.c

@@ -226,14 +226,6 @@ static int funnel_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int funnel_remove(struct amba_device *adev)
-{
-	struct funnel_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int funnel_runtime_suspend(struct device *dev)
 {
@@ -273,9 +265,9 @@ static struct amba_driver funnel_driver = {
 		.name	= "coresight-funnel",
 		.owner	= THIS_MODULE,
 		.pm	= &funnel_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= funnel_probe,
-	.remove		= funnel_remove,
 	.id_table	= funnel_ids,
 };
 

drivers/hwtracing/coresight/coresight-replicator-qcom.c

@@ -156,15 +156,6 @@ static int replicator_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int replicator_remove(struct amba_device *adev)
-{
-	struct replicator_state *drvdata = amba_get_drvdata(adev);
-
-	pm_runtime_disable(&adev->dev);
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int replicator_runtime_suspend(struct device *dev)
 {
@@ -206,9 +197,9 @@ static struct amba_driver replicator_driver = {
 	.drv = {
 		.name	= "coresight-replicator-qcom",
 		.pm	= &replicator_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= replicator_probe,
-	.remove		= replicator_remove,
 	.id_table	= replicator_ids,
 };
 

drivers/hwtracing/coresight/coresight-replicator.c

@@ -127,20 +127,6 @@ out_disable_pm:
 	return ret;
 }
 
-static int replicator_remove(struct platform_device *pdev)
-{
-	struct replicator_drvdata *drvdata = platform_get_drvdata(pdev);
-
-	coresight_unregister(drvdata->csdev);
-	pm_runtime_get_sync(&pdev->dev);
-	if (!IS_ERR(drvdata->atclk))
-		clk_disable_unprepare(drvdata->atclk);
-	pm_runtime_put_noidle(&pdev->dev);
-	pm_runtime_disable(&pdev->dev);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int replicator_runtime_suspend(struct device *dev)
 {
@@ -175,11 +161,11 @@ static const struct of_device_id replicator_match[] = {
 
 static struct platform_driver replicator_driver = {
 	.probe          = replicator_probe,
-	.remove         = replicator_remove,
 	.driver         = {
 		.name   = "coresight-replicator",
 		.of_match_table = replicator_match,
 		.pm	= &replicator_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 };
 

drivers/hwtracing/coresight/coresight-tmc.c

@@ -770,19 +770,6 @@ err_devm_kzalloc:
 	return ret;
 }
 
-static int tmc_remove(struct amba_device *adev)
-{
-	struct tmc_drvdata *drvdata = amba_get_drvdata(adev);
-
-	misc_deregister(&drvdata->miscdev);
-	coresight_unregister(drvdata->csdev);
-	if (drvdata->config_type == TMC_CONFIG_TYPE_ETR)
-		dma_free_coherent(drvdata->dev, drvdata->size,
-				  &drvdata->paddr, GFP_KERNEL);
-
-	return 0;
-}
-
 static struct amba_id tmc_ids[] = {
 	{
 		.id     = 0x0003b961,
@@ -795,9 +782,9 @@ static struct amba_driver tmc_driver = {
 	.drv = {
 		.name   = "coresight-tmc",
 		.owner  = THIS_MODULE,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= tmc_probe,
-	.remove		= tmc_remove,
 	.id_table	= tmc_ids,
 };
 

drivers/hwtracing/coresight/coresight-tpiu.c

@@ -172,14 +172,6 @@ static int tpiu_probe(struct amba_device *adev, const struct amba_id *id)
 	return 0;
 }
 
-static int tpiu_remove(struct amba_device *adev)
-{
-	struct tpiu_drvdata *drvdata = amba_get_drvdata(adev);
-
-	coresight_unregister(drvdata->csdev);
-	return 0;
-}
-
 #ifdef CONFIG_PM
 static int tpiu_runtime_suspend(struct device *dev)
 {
@@ -223,9 +215,9 @@ static struct amba_driver tpiu_driver = {
 		.name	= "coresight-tpiu",
 		.owner	= THIS_MODULE,
 		.pm	= &tpiu_dev_pm_ops,
+		.suppress_bind_attrs = true,
 	},
 	.probe		= tpiu_probe,
-	.remove		= tpiu_remove,
 	.id_table	= tpiu_ids,
 };