> From: Simon Glass <s...@chromium.org> > Date: Mon, 11 Oct 2021 11:00:34 -0600 > > Hi Mark, > > On Sun, 3 Oct 2021 at 12:31, Mark Kettenis <kette...@openbsd.org> wrote: > > > > This uclass is intended to manage IOMMUs on systems where the > > IOMMUs are not in bypass mode by default. In that case U-Boot > > cannot ignore the IOMMUs if it wants to use devices that need > > to do DMA and sit behind such an IOMMU. > > > > This initial IOMMU uclass implementation does not implement and > > device ops and is intended for IOMMUs that have a bypass mode > > that does not require address translation. Support for IOMMUs > > that do require address translation is planned and device ops > > will be defined when support for such IOMMUs will be added. > > > > Signed-off-by: Mark Kettenis <kette...@openbsd.org> > > --- > > drivers/Kconfig | 2 ++ > > drivers/Makefile | 1 + > > drivers/core/device.c | 8 +++++++ > > drivers/iommu/Kconfig | 13 +++++++++++ > > drivers/iommu/Makefile | 3 +++ > > drivers/iommu/iommu-uclass.c | 45 ++++++++++++++++++++++++++++++++++++ > > include/dm/uclass-id.h | 1 + > > include/iommu.h | 16 +++++++++++++ > > 8 files changed, 89 insertions(+) > > create mode 100644 drivers/iommu/Kconfig > > create mode 100644 drivers/iommu/Makefile > > create mode 100644 drivers/iommu/iommu-uclass.c > > create mode 100644 include/iommu.h > > > > diff --git a/drivers/Kconfig b/drivers/Kconfig > > index 417d6f88c2..b26ca8cf70 100644 > > --- a/drivers/Kconfig > > +++ b/drivers/Kconfig > > @@ -50,6 +50,8 @@ source "drivers/i2c/Kconfig" > > > > source "drivers/input/Kconfig" > > > > +source "drivers/iommu/Kconfig" > > + > > source "drivers/led/Kconfig" > > > > source "drivers/mailbox/Kconfig" > > diff --git a/drivers/Makefile b/drivers/Makefile > > index fd218c9056..166aeb9817 100644 > > --- a/drivers/Makefile > > +++ b/drivers/Makefile > > @@ -109,6 +109,7 @@ obj-y += mtd/ > > obj-y += pwm/ > > obj-y += reset/ > > obj-y += input/ > > +obj-y += iommu/ > > # SOC specific infrastructure drivers. > > obj-y += smem/ > > obj-y += thermal/ > > diff --git a/drivers/core/device.c b/drivers/core/device.c > > index 29668f6fb3..5f480ad443 100644 > > --- a/drivers/core/device.c > > +++ b/drivers/core/device.c > > @@ -28,6 +28,7 @@ > > #include <dm/uclass.h> > > #include <dm/uclass-internal.h> > > #include <dm/util.h> > > +#include <iommu.h> > > #include <linux/err.h> > > #include <linux/list.h> > > #include <power-domain.h> > > @@ -543,6 +544,13 @@ int device_probe(struct udevice *dev) > > goto fail; > > } > > > > + if (CONFIG_IS_ENABLED(IOMMU) && dev->parent && > > + (device_get_uclass_id(dev) != UCLASS_IOMMU)) { > > + ret = dev_iommu_probe(dev); > > + if (ret) > > + goto fail; > > + } > > + > > ret = device_get_dma_constraints(dev); > > if (ret) > > goto fail; > > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig > > new file mode 100644 > > index 0000000000..8cb377560e > > --- /dev/null > > +++ b/drivers/iommu/Kconfig > > @@ -0,0 +1,13 @@ > > +# > > +# IOMMU devices > > +# > > + > > +menu "IOMMU device drivers" > > + > > +config IOMMU > > + bool "Enable Driver Model for IOMMU drivers" > > + depends on DM > > + help > > + Enable driver model for IOMMU devices. > > Need at least three lines. What is an IOMMU? How does it relate to > other devices?
Not sure if I can describe what an IOMMU is in just a few lines, but I'll try. > > + > > +endmenu > > diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile > > new file mode 100644 > > index 0000000000..f1ceb10150 > > --- /dev/null > > +++ b/drivers/iommu/Makefile > > @@ -0,0 +1,3 @@ > > +# SPDX-License-Identifier: GPL-2.0+ > > + > > +obj-$(CONFIG_IOMMU) += iommu-uclass.o > > diff --git a/drivers/iommu/iommu-uclass.c b/drivers/iommu/iommu-uclass.c > > new file mode 100644 > > index 0000000000..5c55df3066 > > --- /dev/null > > +++ b/drivers/iommu/iommu-uclass.c > > @@ -0,0 +1,45 @@ > > +// SPDX-License-Identifier: GPL-2.0+ > > +/* > > + * Copyright (C) 2021 Mark Kettenis <kette...@openbsd.org> > > + */ > > + > > +#define LOG_CATEGORY UCLASS_IOMMU > > + > > +#include <common.h> > > +#include <dm.h> > > + > > +#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) > > +int dev_iommu_probe(struct udevice *dev) > > Can we rename to dev_iommus_enable()? I like to keep probe for use by > DM itself so it is confusing to talk about probing in a context other > than probing a single device. Sure. That was one of the names I considered myself when writing the code. > > +{ > > + struct ofnode_phandle_args args; > > + struct udevice *dev_iommu; > > + int i, count, ret = 0; > > + > > + count = dev_count_phandle_with_args(dev, "iommus", > > + "#iommu-cells", 0); > > Do you have a binding file you can add to docs/device-tree-bindings ? The binding is available in Documentation/bindings/iommu/iommu.txt in the Linux tree. But I don't think copying it into the u-boot tree makes sense. It will just get out of date. Especially because this will hopefully be converted into a proper DT schema in the near future. > > + for (i = 0; i < count; i++) { > > + ret = dev_read_phandle_with_args(dev, "iommus", > > + "#iommu-cells", 0, i, > > &args); > > + if (ret) { > > + debug("%s: dev_read_phandle_with_args failed: %d\n", > > + __func__, ret); > > + return ret; > > + } > > + > > + ret = uclass_get_device_by_ofnode(UCLASS_IOMMU, args.node, > > + &dev_iommu); > > + if (ret) { > > + debug("%s: uclass_get_device_by_ofnode failed: > > %d\n", > > + __func__, ret); > > + return ret; > > + } > > + } > > + > > + return 0; > > +} > > +#endif > > + > > +UCLASS_DRIVER(iommu) = { > > + .id = UCLASS_IOMMU, > > + .name = "iommu", > > +}; > > diff --git a/include/dm/uclass-id.h b/include/dm/uclass-id.h > > index e7edd409f3..56aa981613 100644 > > --- a/include/dm/uclass-id.h > > +++ b/include/dm/uclass-id.h > > @@ -61,6 +61,7 @@ enum uclass_id { > > UCLASS_I2C_MUX, /* I2C multiplexer */ > > UCLASS_I2S, /* I2S bus */ > > UCLASS_IDE, /* IDE device */ > > + UCLASS_IOMMU, /* IOMMU */ > > UCLASS_IRQ, /* Interrupt controller */ > > UCLASS_KEYBOARD, /* Keyboard input device */ > > UCLASS_LED, /* Light-emitting diode (LED) */ > > diff --git a/include/iommu.h b/include/iommu.h > > new file mode 100644 > > index 0000000000..d17a06a6f3 > > --- /dev/null > > +++ b/include/iommu.h > > @@ -0,0 +1,16 @@ > > +#ifndef _IOMMU_H > > +#define _IOMMU_H > > + > > +struct udevice; > > + > > +#if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) && \ > > + CONFIG_IS_ENABLED(IOMMU) > > +int dev_iommu_probe(struct udevice *dev); > > +#else > > +static inline int dev_iommu_probe(struct udevice *dev) > > +{ > > + return 0; > > +} > > +#endif > > + > > +#endif > > -- > > 2.33.0 > > > > Regards, > Simon >