Re: [PATCH v3 1/2] dma-mapping: move dma configuration to bus infrastructure

From: Bjorn Helgaas
Date: Tue Apr 10 2018 - 15:20:53 EST

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On Fri, Mar 30, 2018 at 01:24:44PM +0530, Nipun Gupta wrote:
> It is 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.

s/dma/DMA/ consistently above.

> Suggested-by: Christoph Hellwig <hch@xxxxxx>
> Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx>
> Reviewed-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

Acked-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> # PCI parts

I assume you'll merge this via some non-PCI tree. Let me know if you
need anything else from me.

> ---
> - 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
>
> Changes in v3
> - Move dma_common_configure() within platform_dma_configure() and
> reuse platofrm_dma_configure() for AMBA bus too
> - Declare 'attr' in pci_dma_configure() inside the else statement
> where it is used.
>
> drivers/amba/bus.c | 4 ++++
> drivers/base/dma-mapping.c | 31 ++++---------------------------
> drivers/base/platform.c | 17 +++++++++++++++++
> drivers/gpu/host1x/bus.c | 8 ++++++++
> drivers/pci/pci-driver.c | 32 ++++++++++++++++++++++++++++++++
> include/linux/device.h | 4 ++++
> include/linux/platform_device.h | 2 ++
> 7 files changed, 71 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
> index 594c228..867dc2b 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/platform_device.h>
>
> #include <asm/irq.h>
>
> @@ -188,12 +189,15 @@ static int amba_pm_runtime_resume(struct device *dev)
> /*
> * Primecells are part of the Advanced Microcontroller Bus Architecture,
> * so we call the bus "amba".
> + * DMA configuration for platform and AMBA bus is same. So here we reuse
> + * platform's DMA config routine.
> */
> struct bus_type amba_bustype = {
> .name = "amba",
> .dev_groups = amba_dev_groups,
> .match = amba_match,
> .uevent = amba_uevent,
> + .dma_configure = platform_dma_configure,
> .pm = &amba_pm,
> .force_dma = true,
> };
> diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c
> index 3b11835..fdc1502 100644
> --- a/drivers/base/dma-mapping.c
> +++ b/drivers/base/dma-mapping.c
> @@ -331,36 +331,13 @@ 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
> + * enables 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;
> - 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 (attr != DEV_DMA_NOT_SUPPORTED)
> - ret = acpi_dma_configure(dev, attr);
> - }
> -
> - if (bridge)
> - pci_put_host_bridge_device(bridge);
> -
> - return ret;
> + if (dev->bus->dma_configure)
> + return dev->bus->dma_configure(dev);
> + return 0;
> }
>
> void dma_deconfigure(struct device *dev)
> diff --git a/drivers/base/platform.c b/drivers/base/platform.c
> index f1bf7b3..72fdbf6 100644
> --- a/drivers/base/platform.c
> +++ b/drivers/base/platform.c
> @@ -1130,6 +1130,22 @@ int platform_pm_restore(struct device *dev)
>
> #endif /* CONFIG_HIBERNATE_CALLBACKS */
>
> +int platform_dma_configure(struct device *dev)
> +{
> + enum dev_dma_attr attr;
> + int ret = 0;
> +
> + 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);
> + }
> +
> + return ret;
> +}
> +
> static const struct dev_pm_ops platform_dev_pm_ops = {
> .runtime_suspend = pm_generic_runtime_suspend,
> .runtime_resume = pm_generic_runtime_resume,
> @@ -1141,6 +1157,7 @@ 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..a9ec99d 100644
> --- a/drivers/gpu/host1x/bus.c
> +++ b/drivers/gpu/host1x/bus.c
> @@ -314,6 +314,13 @@ 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 +333,7 @@ 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..78e507f 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;
> + 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)) {
> + 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)
> + 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/platform_device.h b/include/linux/platform_device.h
> index 49f634d..3097c94 100644
> --- a/include/linux/platform_device.h
> +++ b/include/linux/platform_device.h
> @@ -356,6 +356,8 @@ static inline char *early_platform_driver_setup_func(void) \
> #define platform_pm_restore NULL
> #endif
>
> +extern int platform_dma_configure(struct device *dev);
> +
> #ifdef CONFIG_PM_SLEEP
> #define USE_PLATFORM_PM_SLEEP_OPS \
> .suspend = platform_pm_suspend, \
> --
> 1.9.1
>

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