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    SubjectRe: [PATCH v2 1/2] dma-mapping: move dma configuration to bus infrastructure
    On Wed, Mar 21, 2018 at 12:25:22PM +0530, Nipun Gupta wrote:
    > It's bus specific aspect to map a given device on the bus and
    > relevant firmware description of its DMA configuration.
    > So, this change introduces '/dma_configure/' as bus callback
    > giving flexibility to busses for implementing its own dma
    > configuration function.
    >
    > The change eases the addition of new busses w.r.t. adding the dma
    > configuration functionality.
    >
    > This patch also updates the PCI, Platform, ACPI and host1x bus to
    > use new introduced callbacks.
    >
    > Suggested-by: Christoph Hellwig <hch@lst.de>
    > Signed-off-by: Nipun Gupta <nipun.gupta@nxp.com>
    > ---
    > - The patches are based on the comments on:
    > https://patchwork.kernel.org/patch/10259087/
    >
    > Changes in v2:
    > - Do not have dma_deconfigure callback
    > - Have '/dma_common_configure/' API to provide a common DMA
    > configuration which can be used by busses if it suits them.
    > - Platform and ACPI bus to use '/dma_common_configure/' in
    > '/dma_configure/' callback.
    > - Updated commit message
    > - Updated pci_dma_configure API with changes suggested by Robin
    >
    > drivers/amba/bus.c | 7 +++++++
    > drivers/base/dma-mapping.c | 35 +++++++++++++++--------------------
    > drivers/base/platform.c | 6 ++++++
    > drivers/gpu/host1x/bus.c | 9 +++++++++
    > drivers/pci/pci-driver.c | 32 ++++++++++++++++++++++++++++++++
    > include/linux/device.h | 4 ++++
    > include/linux/dma-mapping.h | 1 +
    > 7 files changed, 74 insertions(+), 20 deletions(-)
    >
    > diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
    > index 594c228..2fa1e8b 100644
    > --- a/drivers/amba/bus.c
    > +++ b/drivers/amba/bus.c
    > @@ -20,6 +20,7 @@
    > #include <linux/sizes.h>
    > #include <linux/limits.h>
    > #include <linux/clk/clk-conf.h>
    > +#include <linux/dma-mapping.h>
    >
    > #include <asm/irq.h>
    >
    > @@ -171,6 +172,11 @@ static int amba_pm_runtime_resume(struct device *dev)
    > }
    > #endif /* CONFIG_PM */
    >
    > +static int amba_dma_configure(struct device *dev)
    > +{
    > + return dma_common_configure(dev);
    > +}
    > +
    > static const struct dev_pm_ops amba_pm = {
    > .suspend = pm_generic_suspend,
    > .resume = pm_generic_resume,
    > @@ -194,6 +200,7 @@ struct bus_type amba_bustype = {
    > .dev_groups = amba_dev_groups,
    > .match = amba_match,
    > .uevent = amba_uevent,
    > + .dma_configure = amba_dma_configure,
    > .pm = &amba_pm,
    > .force_dma = true,
    > };
    > diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
    > index 3b11835..48f9af0 100644
    > --- a/drivers/base/dma-mapping.c
    > +++ b/drivers/base/dma-mapping.c
    > @@ -331,38 +331,33 @@ void dma_common_free_remap(void *cpu_addr, size_t size, unsigned long vm_flags)
    > #endif
    >
    > /*
    > - * Common configuration to enable DMA API use for a device
    > + * Common configuration to enable DMA API use for a device.
    > + * A bus can use this function in its 'dma_configure' callback, if
    > + * suitable for the bus.
    > */
    > -#include <linux/pci.h>
    > -
    > -int dma_configure(struct device *dev)
    > +int dma_common_configure(struct device *dev)
    > {
    > - struct device *bridge = NULL, *dma_dev = dev;
    > enum dev_dma_attr attr;
    > int ret = 0;
    >
    > - 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) {
    > - ret = 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 (dev->of_node) {
    > + ret = of_dma_configure(dev, dev->of_node);
    > + } else if (has_acpi_companion(dev)) {
    > + attr = acpi_get_dma_attr(to_acpi_device_node(dev->fwnode));
    > if (attr != DEV_DMA_NOT_SUPPORTED)
    > ret = acpi_dma_configure(dev, attr);
    > }
    >
    > - if (bridge)
    > - pci_put_host_bridge_device(bridge);
    > -
    > return ret;
    > }
    >
    > +int dma_configure(struct device *dev)
    > +{
    > + if (dev->bus->dma_configure)
    > + return dev->bus->dma_configure(dev);
    > +
    > + return 0;
    > +}
    > void dma_deconfigure(struct device *dev)

    Empty line after this new function? Sorry, couldn't help it :)

    > {
    > of_dma_deconfigure(dev);
    > diff --git a/drivers/base/platform.c b/drivers/base/platform.c
    > index f1bf7b3..d2d5891 100644
    > --- a/drivers/base/platform.c
    > +++ b/drivers/base/platform.c
    > @@ -1130,6 +1130,11 @@ int platform_pm_restore(struct device *dev)
    >
    > #endif /* CONFIG_HIBERNATE_CALLBACKS */
    >
    > +static int platform_dma_configure(struct device *dev)
    > +{
    > + return dma_common_configure(dev);
    > +}
    > +
    > static const struct dev_pm_ops platform_dev_pm_ops = {
    > .runtime_suspend = pm_generic_runtime_suspend,
    > .runtime_resume = pm_generic_runtime_resume,
    > @@ -1141,6 +1146,7 @@ struct bus_type platform_bus_type = {
    > .dev_groups = platform_dev_groups,
    > .match = platform_match,
    > .uevent = platform_uevent,
    > + .dma_configure = platform_dma_configure,
    > .pm = &platform_dev_pm_ops,
    > .force_dma = true,
    > };
    > diff --git a/drivers/gpu/host1x/bus.c b/drivers/gpu/host1x/bus.c
    > index 88a3558..fa9896d 100644
    > --- a/drivers/gpu/host1x/bus.c
    > +++ b/drivers/gpu/host1x/bus.c
    > @@ -314,6 +314,14 @@ static int host1x_device_match(struct device *dev, struct device_driver *drv)
    > return strcmp(dev_name(dev), drv->name) == 0;
    > }
    >
    > +static int host1x_dma_configure(struct device *dev)
    > +{
    > + if (dev->of_node)
    > + return of_dma_configure(dev, dev->of_node);
    > +
    > + return 0;
    > +}
    > +
    > static const struct dev_pm_ops host1x_device_pm_ops = {
    > .suspend = pm_generic_suspend,
    > .resume = pm_generic_resume,
    > @@ -326,6 +334,7 @@ static int host1x_device_match(struct device *dev, struct device_driver *drv)
    > struct bus_type host1x_bus_type = {
    > .name = "host1x",
    > .match = host1x_device_match,
    > + .dma_configure = host1x_dma_configure,
    > .pm = &host1x_device_pm_ops,
    > .force_dma = true,
    > };
    > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c
    > index 3bed6be..b473a4c 100644
    > --- a/drivers/pci/pci-driver.c
    > +++ b/drivers/pci/pci-driver.c
    > @@ -18,6 +18,8 @@
    > #include <linux/pm_runtime.h>
    > #include <linux/suspend.h>
    > #include <linux/kexec.h>
    > +#include <linux/of_device.h>
    > +#include <linux/acpi.h>
    > #include "pci.h"
    >
    > struct pci_dynid {
    > @@ -1522,6 +1524,35 @@ static int pci_bus_num_vf(struct device *dev)
    > return pci_num_vf(to_pci_dev(dev));
    > }
    >
    > +/**
    > + * pci_dma_configure - Setup DMA configuration
    > + * @dev: ptr to dev structure
    > + *
    > + * 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 int pci_dma_configure(struct device *dev)
    > +{
    > + struct device *bridge;
    > + enum dev_dma_attr attr;
    > + int ret = 0;
    > +
    > + bridge = pci_get_host_bridge_device(to_pci_dev(dev));
    > +
    > + if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
    > + bridge->parent->of_node) {
    > + ret = of_dma_configure(dev, bridge->parent->of_node);
    > + } else if (has_acpi_companion(bridge)) {
    > + attr = acpi_get_dma_attr(to_acpi_device_node(bridge->fwnode));
    > + if (attr != DEV_DMA_NOT_SUPPORTED)
    > + ret = acpi_dma_configure(dev, attr);
    > + }
    > +
    > + pci_put_host_bridge_device(bridge);
    > +
    > + return ret;
    > +}
    > +
    > struct bus_type pci_bus_type = {
    > .name = "pci",
    > .match = pci_bus_match,
    > @@ -1534,6 +1565,7 @@ struct bus_type pci_bus_type = {
    > .drv_groups = pci_drv_groups,
    > .pm = PCI_PM_OPS_PTR,
    > .num_vf = pci_bus_num_vf,
    > + .dma_configure = pci_dma_configure,
    > .force_dma = true,
    > };
    > EXPORT_SYMBOL(pci_bus_type);
    > diff --git a/include/linux/device.h b/include/linux/device.h
    > index b093405..1832d90 100644
    > --- a/include/linux/device.h
    > +++ b/include/linux/device.h
    > @@ -88,6 +88,8 @@ extern int __must_check bus_create_file(struct bus_type *,
    > * @resume: Called to bring a device on this bus out of sleep mode.
    > * @num_vf: Called to find out how many virtual functions a device on this
    > * bus supports.
    > + * @dma_configure: Called to setup DMA configuration on a device on
    > + this bus.
    > * @pm: Power management operations of this bus, callback the specific
    > * device driver's pm-ops.
    > * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU
    > @@ -130,6 +132,8 @@ struct bus_type {
    >
    > int (*num_vf)(struct device *dev);
    >
    > + int (*dma_configure)(struct device *dev);
    > +
    > const struct dev_pm_ops *pm;
    >
    > const struct iommu_ops *iommu_ops;
    > diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
    > index eb9eab4..c15986b 100644
    > --- a/include/linux/dma-mapping.h
    > +++ b/include/linux/dma-mapping.h
    > @@ -761,6 +761,7 @@ void *dma_mark_declared_memory_occupied(struct device *dev,
    > }
    > #endif /* CONFIG_HAVE_GENERIC_DMA_COHERENT */
    >
    > +int dma_common_configure(struct device *dev);
    > #ifdef CONFIG_HAS_DMA

    Blank line after the new function declaration?

    Other than those very minor things, nice job, this looks good:

    Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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