Re: [PATCH V5 05/12] drivers: platform: Configure dma operations at probe time

[Lorenzo Pieralisi <lorenzo.pieralisi-5wv7dgnIgG8@public.gmane.org>]

On Thu, Jan 19, 2017 at 08:35:49PM +0530, Sricharan R wrote:
> Configuring DMA ops at probe time will allow deferring device probe when
> the IOMMU isn't available yet. The dma_configure for the device is
> now called from the generic device_attach callback just before the
> bus/driver probe is called. This way, configuring the DMA ops for the
> device would be called at the same place for all bus_types, hence the
> deferred probing mechanism should work for all buses as well.
> 
> pci_bus_add_devices    (platform/amba)(_device_create/driver_register)
>        |                         |
> pci_bus_add_device     (device_add/driver_register)
>        |                         |
> device_attach           device_initial_probe
>        |                         |
> __device_attach_driver    __device_attach_driver
>        |
> driver_probe_device
>        |
> really_probe
>        |
> dma_configure
> 
> Similarly on the device/driver_unregister path __device_release_driver is
> called which inturn calls dma_deconfigure.
> 
> Signed-off-by: Sricharan R <sricharan-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>
> ---
>  * Removed the dma configuration for the pci devices in case of DT
>    from pci_dma_configure which was hanging outside separately and
>    doing it in dma_configure function itself.

Rename the patch subject then, it is misleading.

Thanks,
Lorenzo

>  drivers/base/dd.c           |  9 +++++++++
>  drivers/base/dma-mapping.c  | 32 ++++++++++++++++++++++++++++++++
>  drivers/of/platform.c       |  5 +----
>  drivers/pci/probe.c         |  5 +----
>  include/linux/dma-mapping.h |  3 +++
>  5 files changed, 46 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/base/dd.c b/drivers/base/dd.c
> index a1fbf55..4882f06 100644
> --- a/drivers/base/dd.c
> +++ b/drivers/base/dd.c
> @@ -19,6 +19,7 @@
>  
>  #include <linux/device.h>
>  #include <linux/delay.h>
> +#include <linux/dma-mapping.h>
>  #include <linux/module.h>
>  #include <linux/kthread.h>
>  #include <linux/wait.h>
> @@ -356,6 +357,10 @@ static int really_probe(struct device *dev, struct device_driver *drv)
>  	if (ret)
>  		goto pinctrl_bind_failed;
>  
> +	ret = dma_configure(dev);
> +	if (ret)
> +		goto dma_failed;
> +
>  	if (driver_sysfs_add(dev)) {
>  		printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n",
>  			__func__, dev_name(dev));
> @@ -417,6 +422,8 @@ static int really_probe(struct device *dev, struct device_driver *drv)
>  	goto done;
>  
>  probe_failed:
> +	dma_deconfigure(dev);
> +dma_failed:
>  	if (dev->bus)
>  		blocking_notifier_call_chain(&dev->bus->p->bus_notifier,
>  					     BUS_NOTIFY_DRIVER_NOT_BOUND, dev);
> @@ -826,6 +833,8 @@ static void __device_release_driver(struct device *dev, struct device *parent)
>  			drv->remove(dev);
>  
>  		device_links_driver_cleanup(dev);
> +		dma_deconfigure(dev);
> +
>  		devres_release_all(dev);
>  		dev->driver = NULL;
>  		dev_set_drvdata(dev, NULL);
> diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
> index efd71cf..dfe6fd7 100644
> --- a/drivers/base/dma-mapping.c
> +++ b/drivers/base/dma-mapping.c
> @@ -10,6 +10,7 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/export.h>
>  #include <linux/gfp.h>
> +#include <linux/of_device.h>
>  #include <linux/slab.h>
>  #include <linux/vmalloc.h>
>  
> @@ -341,3 +342,34 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
>  	vunmap(cpu_addr);
>  }
>  #endif
> +
> +/*
> + * Common configuration to enable DMA API use for a device
> + */
> +#include <linux/pci.h>
> +
> +int dma_configure(struct device *dev)
> +{
> +	struct device *_dev = dev;
> +	int is_pci = dev_is_pci(dev);
> +
> +	if (is_pci) {
> +		_dev = pci_get_host_bridge_device(to_pci_dev(dev));
> +		if (IS_ENABLED(CONFIG_OF) && _dev->parent &&
> +		    _dev->parent->of_node)
> +			_dev = _dev->parent;
> +	}
> +
> +	if (_dev->of_node)
> +		of_dma_configure(dev, _dev->of_node);
> +
> +	if (is_pci)
> +		pci_put_host_bridge_device(_dev);
> +
> +	return 0;
> +}
> +
> +void dma_deconfigure(struct device *dev)
> +{
> +	of_dma_deconfigure(dev);
> +}
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 57418f7..cf35030 100644
> --- a/drivers/of/platform.c
> +++ b/drivers/of/platform.c
> @@ -22,6 +22,7 @@
>  #include <linux/slab.h>
>  #include <linux/of_address.h>
>  #include <linux/of_device.h>
> +#include <linux/of_iommu.h>
>  #include <linux/of_irq.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> @@ -186,11 +187,9 @@ static struct platform_device *of_platform_device_create_pdata(
>  
>  	dev->dev.bus = &platform_bus_type;
>  	dev->dev.platform_data = platform_data;
> -	of_dma_configure(&dev->dev, dev->dev.of_node);
>  	of_msi_configure(&dev->dev, dev->dev.of_node);
>  
>  	if (of_device_add(dev) != 0) {
> -		of_dma_deconfigure(&dev->dev);
>  		platform_device_put(dev);
>  		goto err_clear_flag;
>  	}
> @@ -248,7 +247,6 @@ static struct amba_device *of_amba_device_create(struct device_node *node,
>  		dev_set_name(&dev->dev, "%s", bus_id);
>  	else
>  		of_device_make_bus_id(&dev->dev);
> -	of_dma_configure(&dev->dev, dev->dev.of_node);
>  
>  	/* Allow the HW Peripheral ID to be overridden */
>  	prop = of_get_property(node, "arm,primecell-periphid", NULL);
> @@ -542,7 +540,6 @@ static int of_platform_device_destroy(struct device *dev, void *data)
>  		amba_device_unregister(to_amba_device(dev));
>  #endif
>  
> -	of_dma_deconfigure(dev);
>  	of_node_clear_flag(dev->of_node, OF_POPULATED);
>  	of_node_clear_flag(dev->of_node, OF_POPULATED_BUS);
>  	return 0;
> diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> index e164b5c..634d34e 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1873,10 +1873,7 @@ static void pci_dma_configure(struct pci_dev *dev)
>  {
>  	struct device *bridge = pci_get_host_bridge_device(dev);
>  
> -	if (IS_ENABLED(CONFIG_OF) &&
> -		bridge->parent && bridge->parent->of_node) {
> -			of_dma_configure(&dev->dev, bridge->parent->of_node);
> -	} else if (has_acpi_companion(bridge)) {
> +	if (has_acpi_companion(bridge)) {
>  		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
>  		enum dev_dma_attr attr = acpi_get_dma_attr(adev);
>  
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index abf685ed..b56320a 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -718,6 +718,9 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
>  }
>  #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
>  
> +int dma_configure(struct device *dev);
> +void dma_deconfigure(struct device *dev);
> +
>  /*
>   * Managed DMA API
>   */
> -- 
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