> -----Original Message----- > From: Robin Murphy [mailto:robin.murphy@xxxxxxx] > Sent: Tuesday, March 13, 2018 17:06 > > On 12/03/18 15:24, Nipun Gupta wrote: > > The change introduces 'dma_configure' & 'dma_deconfigure'as > > bus callback functions so each bus can choose to implement > > its own dma configuration function. > > This eases the addition of new busses w.r.t. adding the dma > > configuration functionality. > > It's probably worth clarifying - either in the commit message, the > kerneldoc, or both - that the bus-specific aspect is that of mapping > between a given device on the bus and the relevant firmware description > of its DMA configuration. Okay. > > > The change also updates the PCI, Platform and ACPI bus to use > > new introduced callbacks. > > > > Signed-off-by: Nipun Gupta <nipun.gupta@xxxxxxx> > > --- > > - This patch is based on the comments on: > > > https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwo > rk.kernel.org%2Fpatch%2F10259087%2F&data=02%7C01%7Cnipun.gupta%40nxp.com%7 > Cc541100ecb944e7650a408d588d69ab0%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0%7 > C0%7C636565377665676631&sdata=k2Xjn5B1GECx4UjCg9tChOpOrD3NPM7BkzIXLLSv3rI% > 3D&reserved=0 > > - I have validated for PCI and platform, but not for AMBA as I > > do not have infrastructure to validate it. > > Can anyone please validate them on AMBA? > > > > drivers/amba/bus.c | 38 ++++++++++++++++++++++++----- > > drivers/base/dd.c | 14 +++++++---- > > drivers/base/dma-mapping.c | 41 ------------------------------- > > drivers/base/platform.c | 36 ++++++++++++++++++++++----- > > drivers/pci/pci-driver.c | 59 ++++++++++++++++++++++++++++++++++++- > -------- > > include/linux/device.h | 6 +++++ > > include/linux/dma-mapping.h | 12 --------- > > 7 files changed, 124 insertions(+), 82 deletions(-) > > > > diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c > > index 594c228..58241d2 100644 > > --- a/drivers/amba/bus.c > > +++ b/drivers/amba/bus.c > > @@ -20,6 +20,8 @@ > > #include <linux/sizes.h> > > #include <linux/limits.h> > > #include <linux/clk/clk-conf.h> > > +#include <linux/acpi.h> > > +#include <linux/of_device.h> > > > > #include <asm/irq.h> > > > > @@ -171,6 +173,28 @@ static int amba_pm_runtime_resume(struct device > *dev) > > } > > #endif /* CONFIG_PM */ > > > > +int amba_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; > > +} > > I would be inclined to have amba_bustype just reference > platform_dma_configure() directly rather than duplicate it like this, > since there's no sensible reason for them to ever differ. I think dma_common_configure() having this as the common code seems pretty Decent. All the busses will probably call this API. > > > + > > +void amba_dma_deconfigure(struct device *dev) > > +{ > > + of_dma_deconfigure(dev); > > + acpi_dma_deconfigure(dev); > > +} > > + > > static const struct dev_pm_ops amba_pm = { > > .suspend = pm_generic_suspend, > > .resume = pm_generic_resume, > > @@ -190,12 +214,14 @@ static int amba_pm_runtime_resume(struct device > *dev) > > * so we call the bus "amba". > > */ > > struct bus_type amba_bustype = { > > - .name = "amba", > > - .dev_groups = amba_dev_groups, > > - .match = amba_match, > > - .uevent = amba_uevent, > > - .pm = &amba_pm, > > - .force_dma = true, > > + .name = "amba", > > + .dev_groups = amba_dev_groups, > > + .match = amba_match, > > + .uevent = amba_uevent, > > + .pm = &amba_pm, > > + .dma_configure = amba_dma_configure, > > + .dma_deconfigure = amba_dma_deconfigure, > > + .force_dma = true, > > This patch should also be removing force_dma because it no longer makes > sense. If DMA configuration is now done by a bus-level callback, then a > bus which wants its children to get DMA configuration needs to implement > that callback; there's nowhere to force a "default" global behaviour any > more. Agree. We will also need to pass a force_dma flag in of_dma_configure() as Christoph suggests. Ill update this. > > > }; > > > > static int __init amba_init(void) > > diff --git a/drivers/base/dd.c b/drivers/base/dd.c > > index de6fd09..f124f3f 100644 > > --- a/drivers/base/dd.c > > +++ b/drivers/base/dd.c > > @@ -421,9 +421,11 @@ 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 (dev->bus->dma_configure) { > > + ret = dev->bus->dma_configure(dev); > > + if (ret) > > + goto dma_failed; > > + } > > > > if (driver_sysfs_add(dev)) { > > printk(KERN_ERR "%s: driver_sysfs_add(%s) failed\n", > > @@ -486,7 +488,8 @@ static int really_probe(struct device *dev, struct > device_driver *drv) > > goto done; > > > > probe_failed: > > - dma_deconfigure(dev); > > + if (dev->bus->dma_deconfigure) > > + dev->bus->dma_deconfigure(dev); > > dma_failed: > > if (dev->bus) > > blocking_notifier_call_chain(&dev->bus->p->bus_notifier, > > @@ -895,7 +898,8 @@ static void __device_release_driver(struct device > *dev, struct device *parent) > > drv->remove(dev); > > > > device_links_driver_cleanup(dev); > > - dma_deconfigure(dev); > > + if (dev->bus->dma_deconfigure) > > + dev->bus->dma_deconfigure(dev); > > > > devres_release_all(dev); > > dev->driver = NULL; > > diff --git a/drivers/base/dma-mapping.c b/drivers/base/dma-mapping.c > > index 3b11835..f16bd49 100644 > > --- a/drivers/base/dma-mapping.c > > +++ b/drivers/base/dma-mapping.c > > @@ -6,11 +6,9 @@ > > * Copyright (c) 2006 Tejun Heo <teheo@xxxxxxx> > > */ > > > > -#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> > > > > @@ -329,42 +327,3 @@ 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; > > - 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; > > -} > > - > > -void dma_deconfigure(struct device *dev) > > -{ > > - of_dma_deconfigure(dev); > > - acpi_dma_deconfigure(dev); > > -} > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > > index f1bf7b3..adf94eb 100644 > > --- a/drivers/base/platform.c > > +++ b/drivers/base/platform.c > > @@ -1130,6 +1130,28 @@ 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; > > +} > > + > > +void platform_dma_deconfigure(struct device *dev) > > +{ > > + of_dma_deconfigure(dev); > > + acpi_dma_deconfigure(dev); > > +} > > + > > static const struct dev_pm_ops platform_dev_pm_ops = { > > .runtime_suspend = pm_generic_runtime_suspend, > > .runtime_resume = pm_generic_runtime_resume, > > @@ -1137,12 +1159,14 @@ int platform_pm_restore(struct device *dev) > > }; > > > > struct bus_type platform_bus_type = { > > - .name = "platform", > > - .dev_groups = platform_dev_groups, > > - .match = platform_match, > > - .uevent = platform_uevent, > > - .pm = &platform_dev_pm_ops, > > - .force_dma = true, > > + .name = "platform", > > + .dev_groups = platform_dev_groups, > > + .match = platform_match, > > + .uevent = platform_uevent, > > + .pm = &platform_dev_pm_ops, > > + .dma_configure = platform_dma_configure, > > + .dma_deconfigure = platform_dma_deconfigure, > > + .force_dma = true, > > }; > > EXPORT_SYMBOL_GPL(platform_bus_type); > > > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > > index 3bed6be..4a77814 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/acpi.h> > > +#include <linux/of_device.h> > > #include "pci.h" > > > > struct pci_dynid { > > @@ -1522,19 +1524,52 @@ static int pci_bus_num_vf(struct device *dev) > > return pci_num_vf(to_pci_dev(dev)); > > } > > > > +int pci_dma_configure(struct device *dev) > > +{ > > + struct device *bridge, *dma_dev; > > You don't need dma_dev here; see the code removed in 09515ef5ddad for > how the logic originally worked. Okay. I will have a look in this commit id. > > > + enum dev_dma_attr attr; > > + int ret = 0; > > + > > + 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); > > + } > > + > > + pci_put_host_bridge_device(bridge); > > + > > + return ret; > > +} > > + > > +void pci_dma_deconfigure(struct device *dev) > > +{ > > + of_dma_deconfigure(dev); > > + acpi_dma_deconfigure(dev); > > +} > > + > > struct bus_type pci_bus_type = { > > - .name = "pci", > > - .match = pci_bus_match, > > - .uevent = pci_uevent, > > - .probe = pci_device_probe, > > - .remove = pci_device_remove, > > - .shutdown = pci_device_shutdown, > > - .dev_groups = pci_dev_groups, > > - .bus_groups = pci_bus_groups, > > - .drv_groups = pci_drv_groups, > > - .pm = PCI_PM_OPS_PTR, > > - .num_vf = pci_bus_num_vf, > > - .force_dma = true, > > + .name = "pci", > > + .match = pci_bus_match, > > + .uevent = pci_uevent, > > + .probe = pci_device_probe, > > + .remove = pci_device_remove, > > + .shutdown = pci_device_shutdown, > > + .dev_groups = pci_dev_groups, > > + .bus_groups = pci_bus_groups, > > + .drv_groups = pci_drv_groups, > > + .pm = PCI_PM_OPS_PTR, > > + .num_vf = pci_bus_num_vf, > > + .dma_configure = pci_dma_configure, > > + .dma_deconfigure = pci_dma_deconfigure, > > + .force_dma = true, > > }; > > EXPORT_SYMBOL(pci_bus_type); > > > > diff --git a/include/linux/device.h b/include/linux/device.h > > index b093405..9b2dcf6 100644 > > --- a/include/linux/device.h > > +++ b/include/linux/device.h > > @@ -88,6 +88,9 @@ 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. > > + * @dma_deconfigure: Called to tear down the DMA configuration. > > * @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 +133,9 @@ struct bus_type { > > > > int (*num_vf)(struct device *dev); > > > > + int (*dma_configure)(struct device *dev); > > + void (*dma_deconfigure)(struct device *dev); > > Seeing it laid out in the patch, I really don't think we need a > deconfigure callback like this - the fact that we're just copy-pasting > the existing implementation everywhere is a big hint, but more > conceptually I can't see a good reason for it to ever need bus-specific > behaviour in the same way that configure does. > > Maybe that means we keep dma_configure() around for the sake of > symmetry, but just reduce it to: > > int dma_configure(struct device *dev) > { > if (dev->bus->dma_configure) > return dev->bus->dma_configure(dev); > return 0; > } > > Realistically though, dma_deconfigure() only exists for the sake of > calling arch_teardown_dma_ops(), and that only really exists for the > sake of the old ARM IOMMU code, so I'm not inclined to pretend it's > anywhere near as important as the dma_configure() path in design terms. Yes, I will remove dma_deconfigure callback. Thanks, Nipun > > Robin. > > > + > > 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..039224b 100644 > > --- a/include/linux/dma-mapping.h > > +++ b/include/linux/dma-mapping.h > > @@ -761,18 +761,6 @@ 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 > > */ > >
