diff mbox series

[03/10] bus/fsl-mc: add support for 'driver_override' in the mc-bus

Message ID 20200319154051.30609-4-diana.craciun@oss.nxp.com (mailing list archive)
State New, archived
Headers show
Series bus/fsl-mc: Extend mc-bus driver functionalities in preparation for mc-bus VFIO support | expand

Commit Message

Diana Madalina Craciun March 19, 2020, 3:40 p.m. UTC 
From: Bharat Bhushan <Bharat.Bhushan@nxp.com>

This patch is required for vfio-fsl-mc meta driver to successfully bind
layerscape container devices for device passthrough. This patch adds
a mechanism to allow a layerscape device to specify a driver rather than
a layerscape driver provide a device match.

Example to allow a device (dprc.1) to specifically bind
with driver (vfio-fsl-mc):-
 - echo vfio-fsl-mc > /sys/bus/fsl-mc/devices/dprc.1/driver_override
 - echo dprc.1 > /sys/bus/fsl-mc/drivers/fsl_mc_dprc/unbind
 - echo dprc.1 > /sys/bus/fsl-mc/drivers/vfio-fsl-mc/bind

Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
---
 drivers/bus/fsl-mc/fsl-mc-bus.c | 54 +++++++++++++++++++++++++++++++++
 include/linux/fsl/mc.h          |  1 +
 2 files changed, 55 insertions(+)

Comments

Laurentiu Tudor March 23, 2020, 12:30 p.m. UTC | #1 
On 3/19/2020 5:40 PM, Diana Craciun wrote:
> From: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> 
> This patch is required for vfio-fsl-mc meta driver to successfully bind
> layerscape container devices for device passthrough. This patch adds
> a mechanism to allow a layerscape device to specify a driver rather than
> a layerscape driver provide a device match.
> 
> Example to allow a device (dprc.1) to specifically bind
> with driver (vfio-fsl-mc):-
>  - echo vfio-fsl-mc > /sys/bus/fsl-mc/devices/dprc.1/driver_override
>  - echo dprc.1 > /sys/bus/fsl-mc/drivers/fsl_mc_dprc/unbind
>  - echo dprc.1 > /sys/bus/fsl-mc/drivers/vfio-fsl-mc/bind
> 
> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
> ---
>  drivers/bus/fsl-mc/fsl-mc-bus.c | 54 +++++++++++++++++++++++++++++++++
>  include/linux/fsl/mc.h          |  1 +
>  2 files changed, 55 insertions(+)
> 
> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
> index c78d10ea641f..baf8259262a9 100644
> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
> @@ -3,6 +3,7 @@
>   * Freescale Management Complex (MC) bus driver
>   *
>   * Copyright (C) 2014-2016 Freescale Semiconductor, Inc.
> + * Copyright 2019-2020 NXP
>   * Author: German Rivera <German.Rivera@freescale.com>
>   *
>   */
> @@ -83,6 +84,12 @@ static int fsl_mc_bus_match(struct device *dev, struct device_driver *drv)
>  	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
>  	bool found = false;
>  
> +	/* When driver_override is set, only bind to the matching driver */
> +	if (mc_dev->driver_override) {
> +		found = !strcmp(mc_dev->driver_override, mc_drv->driver.name);

I think we can use sysfs_streq() here and ...


> +		goto out;
> +	}
> +
>  	if (!mc_drv->match_id_table)
>  		goto out;
>  
> @@ -147,8 +154,52 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
>  }
>  static DEVICE_ATTR_RO(modalias);
>  
> +static ssize_t driver_override_store(struct device *dev,
> +				     struct device_attribute *attr,
> +				     const char *buf, size_t count)
> +{
> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
> +	const char *driver_override, *old = mc_dev->driver_override;
> +	char *cp;
> +
> +	if (WARN_ON(dev->bus != &fsl_mc_bus_type))
> +		return -EINVAL;
> +
> +	if (count >= (PAGE_SIZE - 1))
> +		return -EINVAL;
> +
> +	driver_override = kstrndup(buf, count, GFP_KERNEL);
> +	if (!driver_override)
> +		return -ENOMEM;
> +
> +	cp = strchr(driver_override, '\n');
> +	if (cp)
> +		*cp = '\0';

drop this strchr() ...

> +	if (strlen(driver_override)) {
> +		mc_dev->driver_override = driver_override;
> +	} else {
> +		kfree(driver_override);
> +		mc_dev->driver_override = NULL;
> +	}
> +
> +	kfree(old);
> +
> +	return count;
> +}
> +
> +static ssize_t driver_override_show(struct device *dev,
> +				    struct device_attribute *attr, char *buf)
> +{
> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
> +
> +	return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override);

and also the terminating '\n' here.

> +}
> +static DEVICE_ATTR_RW(driver_override);
> +
>  static struct attribute *fsl_mc_dev_attrs[] = {
>  	&dev_attr_modalias.attr,
> +	&dev_attr_driver_override.attr,
>  	NULL,
>  };
>  
> @@ -704,6 +755,9 @@ EXPORT_SYMBOL_GPL(fsl_mc_device_add);
>   */
>  void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
>  {
> +	kfree(mc_dev->driver_override);
> +	mc_dev->driver_override = NULL;
> +
>  	/*
>  	 * The device-specific remove callback will get invoked by device_del()
>  	 */
> diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h
> index 54d9436600c7..88095fd30c80 100644
> --- a/include/linux/fsl/mc.h
> +++ b/include/linux/fsl/mc.h
> @@ -194,6 +194,7 @@ struct fsl_mc_device {
>  	struct fsl_mc_device_irq **irqs;
>  	struct fsl_mc_resource *resource;
>  	struct device_link *consumer_link;
> +	const char *driver_override;

We probably don't want const here.

---
Best Regards, Laurentiu

>  };
>  
>  #define to_fsl_mc_device(_dev) \
>
Diana Madalina Craciun April 9, 2020, 11:14 a.m. UTC | #2 
On 3/23/2020 2:30 PM, Laurentiu Tudor wrote:
>
> On 3/19/2020 5:40 PM, Diana Craciun wrote:
>> From: Bharat Bhushan <Bharat.Bhushan@nxp.com>
>>
>> This patch is required for vfio-fsl-mc meta driver to successfully bind
>> layerscape container devices for device passthrough. This patch adds
>> a mechanism to allow a layerscape device to specify a driver rather than
>> a layerscape driver provide a device match.
>>
>> Example to allow a device (dprc.1) to specifically bind
>> with driver (vfio-fsl-mc):-
>>   - echo vfio-fsl-mc > /sys/bus/fsl-mc/devices/dprc.1/driver_override
>>   - echo dprc.1 > /sys/bus/fsl-mc/drivers/fsl_mc_dprc/unbind
>>   - echo dprc.1 > /sys/bus/fsl-mc/drivers/vfio-fsl-mc/bind
>>
>> Signed-off-by: Bharat Bhushan <Bharat.Bhushan@nxp.com>
>> Signed-off-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
>> Signed-off-by: Diana Craciun <diana.craciun@oss.nxp.com>
>> ---
>>   drivers/bus/fsl-mc/fsl-mc-bus.c | 54 +++++++++++++++++++++++++++++++++
>>   include/linux/fsl/mc.h          |  1 +
>>   2 files changed, 55 insertions(+)
>>
>> diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
>> index c78d10ea641f..baf8259262a9 100644
>> --- a/drivers/bus/fsl-mc/fsl-mc-bus.c
>> +++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
>> @@ -3,6 +3,7 @@
>>    * Freescale Management Complex (MC) bus driver
>>    *
>>    * Copyright (C) 2014-2016 Freescale Semiconductor, Inc.
>> + * Copyright 2019-2020 NXP
>>    * Author: German Rivera <German.Rivera@freescale.com>
>>    *
>>    */
>> @@ -83,6 +84,12 @@ static int fsl_mc_bus_match(struct device *dev, struct device_driver *drv)
>>   	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
>>   	bool found = false;
>>   
>> +	/* When driver_override is set, only bind to the matching driver */
>> +	if (mc_dev->driver_override) {
>> +		found = !strcmp(mc_dev->driver_override, mc_drv->driver.name);
> I think we can use sysfs_streq() here and ...

I would prefer to maintain consistency with other buses and store the 
driver_override string without the terminating newline.

>
>
>> +		goto out;
>> +	}
>> +
>>   	if (!mc_drv->match_id_table)
>>   		goto out;
>>   
>> @@ -147,8 +154,52 @@ static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
>>   }
>>   static DEVICE_ATTR_RO(modalias);
>>   
>> +static ssize_t driver_override_store(struct device *dev,
>> +				     struct device_attribute *attr,
>> +				     const char *buf, size_t count)
>> +{
>> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
>> +	const char *driver_override, *old = mc_dev->driver_override;
>> +	char *cp;
>> +
>> +	if (WARN_ON(dev->bus != &fsl_mc_bus_type))
>> +		return -EINVAL;
>> +
>> +	if (count >= (PAGE_SIZE - 1))
>> +		return -EINVAL;
>> +
>> +	driver_override = kstrndup(buf, count, GFP_KERNEL);
>> +	if (!driver_override)
>> +		return -ENOMEM;
>> +
>> +	cp = strchr(driver_override, '\n');
>> +	if (cp)
>> +		*cp = '\0';
> drop this strchr() ...
>
>> +	if (strlen(driver_override)) {
>> +		mc_dev->driver_override = driver_override;
>> +	} else {
>> +		kfree(driver_override);
>> +		mc_dev->driver_override = NULL;
>> +	}
>> +
>> +	kfree(old);
>> +
>> +	return count;
>> +}
>> +
>> +static ssize_t driver_override_show(struct device *dev,
>> +				    struct device_attribute *attr, char *buf)
>> +{
>> +	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
>> +
>> +	return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override);
> and also the terminating '\n' here.
>
>> +}
>> +static DEVICE_ATTR_RW(driver_override);
>> +
>>   static struct attribute *fsl_mc_dev_attrs[] = {
>>   	&dev_attr_modalias.attr,
>> +	&dev_attr_driver_override.attr,
>>   	NULL,
>>   };
>>   
>> @@ -704,6 +755,9 @@ EXPORT_SYMBOL_GPL(fsl_mc_device_add);
>>    */
>>   void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
>>   {
>> +	kfree(mc_dev->driver_override);
>> +	mc_dev->driver_override = NULL;
>> +
>>   	/*
>>   	 * The device-specific remove callback will get invoked by device_del()
>>   	 */
>> diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h
>> index 54d9436600c7..88095fd30c80 100644
>> --- a/include/linux/fsl/mc.h
>> +++ b/include/linux/fsl/mc.h
>> @@ -194,6 +194,7 @@ struct fsl_mc_device {
>>   	struct fsl_mc_device_irq **irqs;
>>   	struct fsl_mc_resource *resource;
>>   	struct device_link *consumer_link;
>> +	const char *driver_override;
> We probably don't want const here.

OK

>
> ---
> Best Regards, Laurentiu
>
>>   };
>>   
>>   #define to_fsl_mc_device(_dev) \
>>

Diana
diff mbox series

Patch

diff --git a/drivers/bus/fsl-mc/fsl-mc-bus.c b/drivers/bus/fsl-mc/fsl-mc-bus.c
index c78d10ea641f..baf8259262a9 100644
--- a/drivers/bus/fsl-mc/fsl-mc-bus.c
+++ b/drivers/bus/fsl-mc/fsl-mc-bus.c
@@ -3,6 +3,7 @@ 
  * Freescale Management Complex (MC) bus driver
  *
  * Copyright (C) 2014-2016 Freescale Semiconductor, Inc.
+ * Copyright 2019-2020 NXP
  * Author: German Rivera <German.Rivera@freescale.com>
  *
  */
@@ -83,6 +84,12 @@  static int fsl_mc_bus_match(struct device *dev, struct device_driver *drv)
 	struct fsl_mc_driver *mc_drv = to_fsl_mc_driver(drv);
 	bool found = false;
 
+	/* When driver_override is set, only bind to the matching driver */
+	if (mc_dev->driver_override) {
+		found = !strcmp(mc_dev->driver_override, mc_drv->driver.name);
+		goto out;
+	}
+
 	if (!mc_drv->match_id_table)
 		goto out;
 
@@ -147,8 +154,52 @@  static ssize_t modalias_show(struct device *dev, struct device_attribute *attr,
 }
 static DEVICE_ATTR_RO(modalias);
 
+static ssize_t driver_override_store(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
+	const char *driver_override, *old = mc_dev->driver_override;
+	char *cp;
+
+	if (WARN_ON(dev->bus != &fsl_mc_bus_type))
+		return -EINVAL;
+
+	if (count >= (PAGE_SIZE - 1))
+		return -EINVAL;
+
+	driver_override = kstrndup(buf, count, GFP_KERNEL);
+	if (!driver_override)
+		return -ENOMEM;
+
+	cp = strchr(driver_override, '\n');
+	if (cp)
+		*cp = '\0';
+
+	if (strlen(driver_override)) {
+		mc_dev->driver_override = driver_override;
+	} else {
+		kfree(driver_override);
+		mc_dev->driver_override = NULL;
+	}
+
+	kfree(old);
+
+	return count;
+}
+
+static ssize_t driver_override_show(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct fsl_mc_device *mc_dev = to_fsl_mc_device(dev);
+
+	return snprintf(buf, PAGE_SIZE, "%s\n", mc_dev->driver_override);
+}
+static DEVICE_ATTR_RW(driver_override);
+
 static struct attribute *fsl_mc_dev_attrs[] = {
 	&dev_attr_modalias.attr,
+	&dev_attr_driver_override.attr,
 	NULL,
 };
 
@@ -704,6 +755,9 @@  EXPORT_SYMBOL_GPL(fsl_mc_device_add);
  */
 void fsl_mc_device_remove(struct fsl_mc_device *mc_dev)
 {
+	kfree(mc_dev->driver_override);
+	mc_dev->driver_override = NULL;
+
 	/*
 	 * The device-specific remove callback will get invoked by device_del()
 	 */
diff --git a/include/linux/fsl/mc.h b/include/linux/fsl/mc.h
index 54d9436600c7..88095fd30c80 100644
--- a/include/linux/fsl/mc.h
+++ b/include/linux/fsl/mc.h
@@ -194,6 +194,7 @@  struct fsl_mc_device {
 	struct fsl_mc_device_irq **irqs;
 	struct fsl_mc_resource *resource;
 	struct device_link *consumer_link;
+	const char *driver_override;
 };
 
 #define to_fsl_mc_device(_dev) \