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Date:   Tue, 4 Apr 2017 13:17:40 +0100
From:   Robin Murphy <robin.murphy@....com>
To:     Sricharan R <sricharan@...eaurora.org>, will.deacon@....com,
        joro@...tes.org, lorenzo.pieralisi@....com,
        iommu@...ts.linux-foundation.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, m.szyprowski@...sung.com,
        bhelgaas@...gle.com, linux-pci@...r.kernel.org,
        linux-acpi@...r.kernel.org, tn@...ihalf.com, hanjun.guo@...aro.org,
        okaya@...eaurora.org, robh+dt@...nel.org, frowand.list@...il.com,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        sudeep.holla@....com, rjw@...ysocki.net, lenb@...nel.org,
        catalin.marinas@....com, arnd@...db.de, linux-arch@...r.kernel.org,
        gregkh@...uxfoundation.org
Subject: Re: [PATCH V10 07/12] of/acpi: Configure dma operations at probe time
 for platform/amba/pci bus devices

On 04/04/17 11:18, 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.
> 
> This patch changes the dma ops configuration to probe time for
> both OF and ACPI based platform/amba/pci bus devices.

Reviewed-by: Robin Murphy <robin.murphy@....com>

It's possible we could subsume {of,acpi}_dma_deconfigure() into
dma_deconfigure() entirely in future if it becomes clear that neither of
them will ever need to do anything firmware-specific, but I think for
now it's probably safer to keep the current symmetry - calling
arch_teardown_dma_ops() twice is benign (and even if it weren't, I'd say
it really should be!)

Robin.

> Tested-by: Marek Szyprowski <m.szyprowski@...sung.com>
> Tested-by: Hanjun Guo <hanjun.guo@...aro.org>
> Acked-by: Bjorn Helgaas <bhelgaas@...gle.com> (drivers/pci part)
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> Signed-off-by: Sricharan R <sricharan@...eaurora.org>
> ---
> 
>  [V10] Added dummy dma_(de)configure functions in case
>        of !CONFIG_HAS_DMA to avoid build breaks.
> 
>  drivers/acpi/glue.c         |  5 -----
>  drivers/base/dd.c           |  9 +++++++++
>  drivers/base/dma-mapping.c  | 40 ++++++++++++++++++++++++++++++++++++++++
>  drivers/of/platform.c       |  5 +----
>  drivers/pci/probe.c         | 28 ----------------------------
>  include/linux/dma-mapping.h | 12 ++++++++++++
>  6 files changed, 62 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/acpi/glue.c b/drivers/acpi/glue.c
> index fb19e1c..c05f241 100644
> --- a/drivers/acpi/glue.c
> +++ b/drivers/acpi/glue.c
> @@ -176,7 +176,6 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
>  	struct list_head *physnode_list;
>  	unsigned int node_id;
>  	int retval = -EINVAL;
> -	enum dev_dma_attr attr;
>  
>  	if (has_acpi_companion(dev)) {
>  		if (acpi_dev) {
> @@ -233,10 +232,6 @@ int acpi_bind_one(struct device *dev, struct acpi_device *acpi_dev)
>  	if (!has_acpi_companion(dev))
>  		ACPI_COMPANION_SET(dev, acpi_dev);
>  
> -	attr = acpi_get_dma_attr(acpi_dev);
> -	if (attr != DEV_DMA_NOT_SUPPORTED)
> -		acpi_dma_configure(dev, attr);
> -
>  	acpi_physnode_link_name(physical_node_name, node_id);
>  	retval = sysfs_create_link(&acpi_dev->dev.kobj, &dev->kobj,
>  				   physical_node_name);
> 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..449b948 100644
> --- a/drivers/base/dma-mapping.c
> +++ b/drivers/base/dma-mapping.c
> @@ -7,9 +7,11 @@
>   * This file is released under the GPLv2.
>   */
>  
> +#include <linux/acpi.h>
>  #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 +343,41 @@ 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 *bridge = NULL, *dma_dev = dev;
> +	enum dev_dma_attr attr;
> +
> +	if (dev_is_pci(dev)) {
> +		bridge = pci_get_host_bridge_device(to_pci_dev(dev));
> +		dma_dev = bridge;
> +		if (IS_ENABLED(CONFIG_OF) && dma_dev->parent &&
> +		    dma_dev->parent->of_node)
> +			dma_dev = dma_dev->parent;
> +	}
> +
> +	if (dma_dev->of_node) {
> +		of_dma_configure(dev, dma_dev->of_node);
> +	} else if (has_acpi_companion(dma_dev)) {
> +		attr = acpi_get_dma_attr(to_acpi_device_node(dma_dev->fwnode));
> +		if (attr != DEV_DMA_NOT_SUPPORTED)
> +			acpi_dma_configure(dev, attr);
> +	}
> +
> +	if (bridge)
> +		pci_put_host_bridge_device(bridge);
> +
> +	return 0;
> +}
> +
> +void dma_deconfigure(struct device *dev)
> +{
> +	of_dma_deconfigure(dev);
> +	acpi_dma_deconfigure(dev);
> +}
> diff --git a/drivers/of/platform.c b/drivers/of/platform.c
> index 5344db5..2aa4ebb 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 dfc9a27..5a8dd43 100644
> --- a/drivers/pci/probe.c
> +++ b/drivers/pci/probe.c
> @@ -1893,33 +1893,6 @@ static void pci_set_msi_domain(struct pci_dev *dev)
>  	dev_set_msi_domain(&dev->dev, d);
>  }
>  
> -/**
> - * pci_dma_configure - Setup DMA configuration
> - * @dev: ptr to pci_dev struct of the PCI device
> - *
> - * Function to update PCI devices's DMA configuration using the same
> - * info from the OF node or ACPI node of host bridge's parent (if any).
> - */
> -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)) {
> -		struct acpi_device *adev = to_acpi_device_node(bridge->fwnode);
> -		enum dev_dma_attr attr = acpi_get_dma_attr(adev);
> -
> -		if (attr == DEV_DMA_NOT_SUPPORTED)
> -			dev_warn(&dev->dev, "DMA not supported.\n");
> -		else
> -			acpi_dma_configure(&dev->dev, attr);
> -	}
> -
> -	pci_put_host_bridge_device(bridge);
> -}
> -
>  void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  {
>  	int ret;
> @@ -1933,7 +1906,6 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
>  	dev->dev.dma_mask = &dev->dma_mask;
>  	dev->dev.dma_parms = &dev->dma_parms;
>  	dev->dev.coherent_dma_mask = 0xffffffffull;
> -	pci_dma_configure(dev);
>  
>  	pci_set_dma_max_seg_size(dev, 65536);
>  	pci_set_dma_seg_boundary(dev, 0xffffffff);
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index 0977317..4f3eece 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -728,6 +728,18 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
>  }
>  #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
>  
> +#ifdef CONFIG_HAS_DMA
> +int dma_configure(struct device *dev);
> +void dma_deconfigure(struct device *dev);
> +#else
> +static inline int dma_configure(struct device *dev)
> +{
> +	return 0;
> +}
> +
> +static inline void dma_deconfigure(struct device *dev) {}
> +#endif
> +
>  /*
>   * Managed DMA API
>   */
> 

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