Re: [PATCH v2 2/7] iommu/riscv: Add RISC-V IOMMU platform device driver

Tomasz Jeznach
2024-04-24T21:59:20Z

On Thu, Apr 18, 2024 at 2:22 PM Robin Murphy <robin.murphy@arm.com> wrote:
>
> On 2024-04-18 5:32 pm, Tomasz Jeznach wrote:
> > Introduce platform device driver for implementation of RISC-V IOMMU
> > architected hardware.
> >
> > Hardware interface definition located in file iommu-bits.h is based on
> > ratified RISC-V IOMMU Architecture Specification version 1.0.0.
> >
> > This patch implements platform device initialization, early check and
> > configuration of the IOMMU interfaces and enables global pass-through
> > address translation mode (iommu_mode == BARE), without registering
> > hardware instance in the IOMMU subsystem.
> >
> > Link: https://github.com/riscv-non-isa/riscv-iommu
> > Co-developed-by: Nick Kossifidis <mick@ics.forth.gr>
> > Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
> > Co-developed-by: Sebastien Boeuf <seb@rivosinc.com>
> > Signed-off-by: Sebastien Boeuf <seb@rivosinc.com>
> > Signed-off-by: Tomasz Jeznach <tjeznach@rivosinc.com>
> > ---
> > MAINTAINERS | 6 +
> > drivers/iommu/Kconfig | 1 +
> > drivers/iommu/Makefile | 2 +-
> > drivers/iommu/riscv/Kconfig | 16 +
> > drivers/iommu/riscv/Makefile | 2 +
> > drivers/iommu/riscv/iommu-bits.h | 707 +++++++++++++++++++++++++++
> > drivers/iommu/riscv/iommu-platform.c | 94 ++++
> > drivers/iommu/riscv/iommu.c | 89 ++++
> > drivers/iommu/riscv/iommu.h | 62 +++
> > 9 files changed, 978 insertions(+), 1 deletion(-)
> > create mode 100644 drivers/iommu/riscv/Kconfig
> > create mode 100644 drivers/iommu/riscv/Makefile
> > create mode 100644 drivers/iommu/riscv/iommu-bits.h
> > create mode 100644 drivers/iommu/riscv/iommu-platform.c
> > create mode 100644 drivers/iommu/riscv/iommu.c
> > create mode 100644 drivers/iommu/riscv/iommu.h
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 2657f9eae84c..051599c76585 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -18972,6 +18972,12 @@ L: iommu@lists.linux.dev
> > L: linux-riscv@lists.infradead.org
> > S: Maintained
> > F: Documentation/devicetree/bindings/iommu/riscv,iommu.yaml
> > +F: drivers/iommu/riscv/Kconfig
> > +F: drivers/iommu/riscv/Makefile
> > +F: drivers/iommu/riscv/iommu-bits.h
> > +F: drivers/iommu/riscv/iommu-platform.c
> > +F: drivers/iommu/riscv/iommu.c
> > +F: drivers/iommu/riscv/iommu.h
>
> I'm pretty sure a single "F: drivers/iommu/riscv/" pattern will suffice.
>

Correct. But will required a workaround for pretty naive MAINTAINERS update
check in scripts/checkpatch.pl:3014 in next patch.

> > RISC-V MICROCHIP FPGA SUPPORT
> > M: Conor Dooley <conor.dooley@microchip.com>
> > diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> > index 0af39bbbe3a3..ae762db0365e 100644
> > --- a/drivers/iommu/Kconfig
> > +++ b/drivers/iommu/Kconfig
> > @@ -195,6 +195,7 @@ config MSM_IOMMU
> > source "drivers/iommu/amd/Kconfig"
> > source "drivers/iommu/intel/Kconfig"
> > source "drivers/iommu/iommufd/Kconfig"
> > +source "drivers/iommu/riscv/Kconfig"
> >
> > config IRQ_REMAP
> > bool "Support for Interrupt Remapping"
> > diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
> > index 542760d963ec..5e5a83c6c2aa 100644
> > --- a/drivers/iommu/Makefile
> > +++ b/drivers/iommu/Makefile
> > @@ -1,5 +1,5 @@
> > # SPDX-License-Identifier: GPL-2.0
> > -obj-y += amd/ intel/ arm/ iommufd/
> > +obj-y += amd/ intel/ arm/ iommufd/ riscv/
> > obj-$(CONFIG_IOMMU_API) += iommu.o
> > obj-$(CONFIG_IOMMU_API) += iommu-traces.o
> > obj-$(CONFIG_IOMMU_API) += iommu-sysfs.o
> > diff --git a/drivers/iommu/riscv/Kconfig b/drivers/iommu/riscv/Kconfig
> > new file mode 100644
> > index 000000000000..d02326bddb4c
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/Kconfig
> > @@ -0,0 +1,16 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +# RISC-V IOMMU support
> > +
> > +config RISCV_IOMMU
> > + def_bool y if RISCV && 64BIT && MMU
>
> Drop the dependencies here, they're already dependencies. However, also
> consider allowing users to configure this out without disabling
> IOMMU_SUPPORT entirely - I imagine other IOMMU implementations are going
> to end up paired wiothg RISC-V CPUs sooner or later. Furthermore, if
> it's a regular driver model driver, consider allowing it to build as a
> module. Not to mention that the help text below is rather pointless if
> there's no prompt offered in the first place.
>

Ack. Changed to optional builtin driver for now, also cleaned up all
module info.
I'll revisit proper module build later.

> > + depends on RISCV && 64BIT && MMU
> > + select DMA_OPS
>
> Drop this, you're not (and shouldn't be) architecture code implementing
> DMA ops.
>
> > + select IOMMU_API
> > + select IOMMU_IOVA
>
> Drop this, you're not using the IOVA library either.
>
> > + help
> > + Support for implementations of the RISC-V IOMMU architecture that
> > + complements the RISC-V MMU capabilities, providing similar address
> > + translation and protection functions for accesses from I/O devices.
> > +
> > + Say Y here if your SoC includes an IOMMU device implementing
> > + the RISC-V IOMMU architecture.
> > diff --git a/drivers/iommu/riscv/Makefile b/drivers/iommu/riscv/Makefile
> > new file mode 100644
> > index 000000000000..e4c189de58d3
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/Makefile
> > @@ -0,0 +1,2 @@
> > +# SPDX-License-Identifier: GPL-2.0-only
> > +obj-$(CONFIG_RISCV_IOMMU) += iommu.o iommu-platform.o
> > diff --git a/drivers/iommu/riscv/iommu-bits.h b/drivers/iommu/riscv/iommu-bits.h
> > new file mode 100644
> > index 000000000000..ba093c29de9f
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/iommu-bits.h
> > @@ -0,0 +1,707 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright © 2022-2024 Rivos Inc.
> > + * Copyright © 2023 FORTH-ICS/CARV
> > + * Copyright © 2023 RISC-V IOMMU Task Group
> > + *
> > + * RISC-V IOMMU - Register Layout and Data Structures.
> > + *
> > + * Based on the 'RISC-V IOMMU Architecture Specification', Version 1.0
> > + * Published at https://github.com/riscv-non-isa/riscv-iommu
> > + *
> > + */
> > +
> > +#ifndef _RISCV_IOMMU_BITS_H_
> > +#define _RISCV_IOMMU_BITS_H_
> > +
> > +#include <linux/types.h>
> > +#include <linux/bitfield.h>
> > +#include <linux/bits.h>
> > +
> > +/*
> > + * Chapter 5: Memory Mapped register interface
> > + */
> > +
> > +/* Common field positions */
> > +#define RISCV_IOMMU_PPN_FIELD GENMASK_ULL(53, 10)
> > +#define RISCV_IOMMU_QUEUE_LOGSZ_FIELD GENMASK_ULL(4, 0)
> > +#define RISCV_IOMMU_QUEUE_INDEX_FIELD GENMASK_ULL(31, 0)
> > +#define RISCV_IOMMU_QUEUE_ENABLE BIT(0)
> > +#define RISCV_IOMMU_QUEUE_INTR_ENABLE BIT(1)
> > +#define RISCV_IOMMU_QUEUE_MEM_FAULT BIT(8)
> > +#define RISCV_IOMMU_QUEUE_OVERFLOW BIT(9)
> > +#define RISCV_IOMMU_QUEUE_ACTIVE BIT(16)
> > +#define RISCV_IOMMU_QUEUE_BUSY BIT(17)
> > +
> > +#define RISCV_IOMMU_ATP_PPN_FIELD GENMASK_ULL(43, 0)
> > +#define RISCV_IOMMU_ATP_MODE_FIELD GENMASK_ULL(63, 60)
> > +
> > +/* 5.3 IOMMU Capabilities (64bits) */
> > +#define RISCV_IOMMU_REG_CAP 0x0000
> > +#define RISCV_IOMMU_CAP_VERSION GENMASK_ULL(7, 0)
> > +#define RISCV_IOMMU_CAP_S_SV32 BIT_ULL(8)
> > +#define RISCV_IOMMU_CAP_S_SV39 BIT_ULL(9)
> > +#define RISCV_IOMMU_CAP_S_SV48 BIT_ULL(10)
> > +#define RISCV_IOMMU_CAP_S_SV57 BIT_ULL(11)
> > +#define RISCV_IOMMU_CAP_SVPBMT BIT_ULL(15)
> > +#define RISCV_IOMMU_CAP_G_SV32 BIT_ULL(16)
> > +#define RISCV_IOMMU_CAP_G_SV39 BIT_ULL(17)
> > +#define RISCV_IOMMU_CAP_G_SV48 BIT_ULL(18)
> > +#define RISCV_IOMMU_CAP_G_SV57 BIT_ULL(19)
> > +#define RISCV_IOMMU_CAP_AMO_MRIF BIT_ULL(21)
> > +#define RISCV_IOMMU_CAP_MSI_FLAT BIT_ULL(22)
> > +#define RISCV_IOMMU_CAP_MSI_MRIF BIT_ULL(23)
> > +#define RISCV_IOMMU_CAP_AMO_HWAD BIT_ULL(24)
> > +#define RISCV_IOMMU_CAP_ATS BIT_ULL(25)
> > +#define RISCV_IOMMU_CAP_T2GPA BIT_ULL(26)
> > +#define RISCV_IOMMU_CAP_END BIT_ULL(27)
> > +#define RISCV_IOMMU_CAP_IGS GENMASK_ULL(29, 28)
> > +#define RISCV_IOMMU_CAP_HPM BIT_ULL(30)
> > +#define RISCV_IOMMU_CAP_DBG BIT_ULL(31)
> > +#define RISCV_IOMMU_CAP_PAS GENMASK_ULL(37, 32)
> > +#define RISCV_IOMMU_CAP_PD8 BIT_ULL(38)
> > +#define RISCV_IOMMU_CAP_PD17 BIT_ULL(39)
> > +#define RISCV_IOMMU_CAP_PD20 BIT_ULL(40)
> > +
> > +#define RISCV_IOMMU_CAP_VERSION_VER_MASK 0xF0
> > +#define RISCV_IOMMU_CAP_VERSION_REV_MASK 0x0F
> > +
> > +/**
> > + * enum riscv_iommu_igs_settings - Interrupt Generation Support Settings
> > + * @RISCV_IOMMU_CAP_IGS_MSI: I/O MMU supports only MSI generation
> > + * @RISCV_IOMMU_CAP_IGS_WSI: I/O MMU supports only Wired-Signaled interrupt
> > + * @RISCV_IOMMU_CAP_IGS_BOTH: I/O MMU supports both MSI and WSI generation
> > + * @RISCV_IOMMU_CAP_IGS_RSRV: Reserved for standard use
> > + */
> > +enum riscv_iommu_igs_settings {
> > + RISCV_IOMMU_CAP_IGS_MSI = 0,
> > + RISCV_IOMMU_CAP_IGS_WSI = 1,
> > + RISCV_IOMMU_CAP_IGS_BOTH = 2,
> > + RISCV_IOMMU_CAP_IGS_RSRV = 3
> > +};
> > +
> > +/* 5.4 Features control register (32bits) */
> > +#define RISCV_IOMMU_REG_FCTL 0x0008
> > +#define RISCV_IOMMU_FCTL_BE BIT(0)
> > +#define RISCV_IOMMU_FCTL_WSI BIT(1)
> > +#define RISCV_IOMMU_FCTL_GXL BIT(2)
> > +
> > +/* 5.5 Device-directory-table pointer (64bits) */
> > +#define RISCV_IOMMU_REG_DDTP 0x0010
> > +#define RISCV_IOMMU_DDTP_MODE GENMASK_ULL(3, 0)
> > +#define RISCV_IOMMU_DDTP_BUSY BIT_ULL(4)
> > +#define RISCV_IOMMU_DDTP_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/**
> > + * enum riscv_iommu_ddtp_modes - I/O MMU translation modes
> > + * @RISCV_IOMMU_DDTP_MODE_OFF: No inbound transactions allowed
> > + * @RISCV_IOMMU_DDTP_MODE_BARE: Pass-through mode
> > + * @RISCV_IOMMU_DDTP_MODE_1LVL: One-level DDT
> > + * @RISCV_IOMMU_DDTP_MODE_2LVL: Two-level DDT
> > + * @RISCV_IOMMU_DDTP_MODE_3LVL: Three-level DDT
> > + * @RISCV_IOMMU_DDTP_MODE_MAX: Max value allowed by specification
> > + */
> > +enum riscv_iommu_ddtp_modes {
> > + RISCV_IOMMU_DDTP_MODE_OFF = 0,
> > + RISCV_IOMMU_DDTP_MODE_BARE = 1,
> > + RISCV_IOMMU_DDTP_MODE_1LVL = 2,
> > + RISCV_IOMMU_DDTP_MODE_2LVL = 3,
> > + RISCV_IOMMU_DDTP_MODE_3LVL = 4,
> > + RISCV_IOMMU_DDTP_MODE_MAX = 4
> > +};
> > +
> > +/* 5.6 Command Queue Base (64bits) */
> > +#define RISCV_IOMMU_REG_CQB 0x0018
> > +#define RISCV_IOMMU_CQB_ENTRIES RISCV_IOMMU_QUEUE_LOGSZ_FIELD
> > +#define RISCV_IOMMU_CQB_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/* 5.7 Command Queue head (32bits) */
> > +#define RISCV_IOMMU_REG_CQH 0x0020
> > +#define RISCV_IOMMU_CQH_INDEX RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.8 Command Queue tail (32bits) */
> > +#define RISCV_IOMMU_REG_CQT 0x0024
> > +#define RISCV_IOMMU_CQT_INDEX RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.9 Fault Queue Base (64bits) */
> > +#define RISCV_IOMMU_REG_FQB 0x0028
> > +#define RISCV_IOMMU_FQB_ENTRIES RISCV_IOMMU_QUEUE_LOGSZ_FIELD
> > +#define RISCV_IOMMU_FQB_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/* 5.10 Fault Queue Head (32bits) */
> > +#define RISCV_IOMMU_REG_FQH 0x0030
> > +#define RISCV_IOMMU_FQH_INDEX RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.11 Fault Queue tail (32bits) */
> > +#define RISCV_IOMMU_REG_FQT 0x0034
> > +#define RISCV_IOMMU_FQT_INDEX RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.12 Page Request Queue base (64bits) */
> > +#define RISCV_IOMMU_REG_PQB 0x0038
> > +#define RISCV_IOMMU_PQB_ENTRIES RISCV_IOMMU_QUEUE_LOGSZ_FIELD
> > +#define RISCV_IOMMU_PQB_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/* 5.13 Page Request Queue head (32bits) */
> > +#define RISCV_IOMMU_REG_PQH 0x0040
> > +#define RISCV_IOMMU_PQH_INDEX RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.14 Page Request Queue tail (32bits) */
> > +#define RISCV_IOMMU_REG_PQT 0x0044
> > +#define RISCV_IOMMU_PQT_INDEX_MASK RISCV_IOMMU_QUEUE_INDEX_FIELD
> > +
> > +/* 5.15 Command Queue CSR (32bits) */
> > +#define RISCV_IOMMU_REG_CQCSR 0x0048
> > +#define RISCV_IOMMU_CQCSR_CQEN RISCV_IOMMU_QUEUE_ENABLE
> > +#define RISCV_IOMMU_CQCSR_CIE RISCV_IOMMU_QUEUE_INTR_ENABLE
> > +#define RISCV_IOMMU_CQCSR_CQMF RISCV_IOMMU_QUEUE_MEM_FAULT
> > +#define RISCV_IOMMU_CQCSR_CMD_TO BIT(9)
> > +#define RISCV_IOMMU_CQCSR_CMD_ILL BIT(10)
> > +#define RISCV_IOMMU_CQCSR_FENCE_W_IP BIT(11)
> > +#define RISCV_IOMMU_CQCSR_CQON RISCV_IOMMU_QUEUE_ACTIVE
> > +#define RISCV_IOMMU_CQCSR_BUSY RISCV_IOMMU_QUEUE_BUSY
> > +
> > +/* 5.16 Fault Queue CSR (32bits) */
> > +#define RISCV_IOMMU_REG_FQCSR 0x004C
> > +#define RISCV_IOMMU_FQCSR_FQEN RISCV_IOMMU_QUEUE_ENABLE
> > +#define RISCV_IOMMU_FQCSR_FIE RISCV_IOMMU_QUEUE_INTR_ENABLE
> > +#define RISCV_IOMMU_FQCSR_FQMF RISCV_IOMMU_QUEUE_MEM_FAULT
> > +#define RISCV_IOMMU_FQCSR_FQOF RISCV_IOMMU_QUEUE_OVERFLOW
> > +#define RISCV_IOMMU_FQCSR_FQON RISCV_IOMMU_QUEUE_ACTIVE
> > +#define RISCV_IOMMU_FQCSR_BUSY RISCV_IOMMU_QUEUE_BUSY
> > +
> > +/* 5.17 Page Request Queue CSR (32bits) */
> > +#define RISCV_IOMMU_REG_PQCSR 0x0050
> > +#define RISCV_IOMMU_PQCSR_PQEN RISCV_IOMMU_QUEUE_ENABLE
> > +#define RISCV_IOMMU_PQCSR_PIE RISCV_IOMMU_QUEUE_INTR_ENABLE
> > +#define RISCV_IOMMU_PQCSR_PQMF RISCV_IOMMU_QUEUE_MEM_FAULT
> > +#define RISCV_IOMMU_PQCSR_PQOF RISCV_IOMMU_QUEUE_OVERFLOW
> > +#define RISCV_IOMMU_PQCSR_PQON RISCV_IOMMU_QUEUE_ACTIVE
> > +#define RISCV_IOMMU_PQCSR_BUSY RISCV_IOMMU_QUEUE_BUSY
> > +
> > +/* 5.18 Interrupt Pending Status (32bits) */
> > +#define RISCV_IOMMU_REG_IPSR 0x0054
> > +
> > +#define RISCV_IOMMU_INTR_CQ 0
> > +#define RISCV_IOMMU_INTR_FQ 1
> > +#define RISCV_IOMMU_INTR_PM 2
> > +#define RISCV_IOMMU_INTR_PQ 3
> > +#define RISCV_IOMMU_INTR_COUNT 4
> > +
> > +#define RISCV_IOMMU_IPSR_CIP BIT(RISCV_IOMMU_INTR_CQ)
> > +#define RISCV_IOMMU_IPSR_FIP BIT(RISCV_IOMMU_INTR_FQ)
> > +#define RISCV_IOMMU_IPSR_PMIP BIT(RISCV_IOMMU_INTR_PM)
> > +#define RISCV_IOMMU_IPSR_PIP BIT(RISCV_IOMMU_INTR_PQ)
> > +
> > +/* 5.19 Performance monitoring counter overflow status (32bits) */
> > +#define RISCV_IOMMU_REG_IOCOUNTOVF 0x0058
> > +#define RISCV_IOMMU_IOCOUNTOVF_CY BIT(0)
> > +#define RISCV_IOMMU_IOCOUNTOVF_HPM GENMASK_ULL(31, 1)
> > +
> > +/* 5.20 Performance monitoring counter inhibits (32bits) */
> > +#define RISCV_IOMMU_REG_IOCOUNTINH 0x005C
> > +#define RISCV_IOMMU_IOCOUNTINH_CY BIT(0)
> > +#define RISCV_IOMMU_IOCOUNTINH_HPM GENMASK(31, 1)
> > +
> > +/* 5.21 Performance monitoring cycles counter (64bits) */
> > +#define RISCV_IOMMU_REG_IOHPMCYCLES 0x0060
> > +#define RISCV_IOMMU_IOHPMCYCLES_COUNTER GENMASK_ULL(62, 0)
> > +#define RISCV_IOMMU_IOHPMCYCLES_OVF BIT_ULL(63)
> > +
> > +/* 5.22 Performance monitoring event counters (31 * 64bits) */
> > +#define RISCV_IOMMU_REG_IOHPMCTR_BASE 0x0068
> > +#define RISCV_IOMMU_REG_IOHPMCTR(_n) (RISCV_IOMMU_REG_IOHPMCTR_BASE + ((_n) * 0x8))
> > +
> > +/* 5.23 Performance monitoring event selectors (31 * 64bits) */
> > +#define RISCV_IOMMU_REG_IOHPMEVT_BASE 0x0160
> > +#define RISCV_IOMMU_REG_IOHPMEVT(_n) (RISCV_IOMMU_REG_IOHPMEVT_BASE + ((_n) * 0x8))
> > +#define RISCV_IOMMU_IOHPMEVT_CNT 31
> > +#define RISCV_IOMMU_IOHPMEVT_EVENT_ID GENMASK_ULL(14, 0)
> > +#define RISCV_IOMMU_IOHPMEVT_DMASK BIT_ULL(15)
> > +#define RISCV_IOMMU_IOHPMEVT_PID_PSCID GENMASK_ULL(35, 16)
> > +#define RISCV_IOMMU_IOHPMEVT_DID_GSCID GENMASK_ULL(59, 36)
> > +#define RISCV_IOMMU_IOHPMEVT_PV_PSCV BIT_ULL(60)
> > +#define RISCV_IOMMU_IOHPMEVT_DV_GSCV BIT_ULL(61)
> > +#define RISCV_IOMMU_IOHPMEVT_IDT BIT_ULL(62)
> > +#define RISCV_IOMMU_IOHPMEVT_OF BIT_ULL(63)
> > +
> > +/**
> > + * enum riscv_iommu_hpmevent_id - Performance-monitoring event identifier
> > + *
> > + * @RISCV_IOMMU_HPMEVENT_INVALID: Invalid event, do not count
> > + * @RISCV_IOMMU_HPMEVENT_URQ: Untranslated requests
> > + * @RISCV_IOMMU_HPMEVENT_TRQ: Translated requests
> > + * @RISCV_IOMMU_HPMEVENT_ATS_RQ: ATS translation requests
> > + * @RISCV_IOMMU_HPMEVENT_TLB_MISS: TLB misses
> > + * @RISCV_IOMMU_HPMEVENT_DD_WALK: Device directory walks
> > + * @RISCV_IOMMU_HPMEVENT_PD_WALK: Process directory walks
> > + * @RISCV_IOMMU_HPMEVENT_S_VS_WALKS: S/VS-Stage page table walks
> > + * @RISCV_IOMMU_HPMEVENT_G_WALKS: G-Stage page table walks
> > + * @RISCV_IOMMU_HPMEVENT_MAX: Value to denote maximum Event IDs
> > + */
> > +enum riscv_iommu_hpmevent_id {
> > + RISCV_IOMMU_HPMEVENT_INVALID = 0,
> > + RISCV_IOMMU_HPMEVENT_URQ = 1,
> > + RISCV_IOMMU_HPMEVENT_TRQ = 2,
> > + RISCV_IOMMU_HPMEVENT_ATS_RQ = 3,
> > + RISCV_IOMMU_HPMEVENT_TLB_MISS = 4,
> > + RISCV_IOMMU_HPMEVENT_DD_WALK = 5,
> > + RISCV_IOMMU_HPMEVENT_PD_WALK = 6,
> > + RISCV_IOMMU_HPMEVENT_S_VS_WALKS = 7,
> > + RISCV_IOMMU_HPMEVENT_G_WALKS = 8,
> > + RISCV_IOMMU_HPMEVENT_MAX = 9
> > +};
> > +
> > +/* 5.24 Translation request IOVA (64bits) */
> > +#define RISCV_IOMMU_REG_TR_REQ_IOVA 0x0258
> > +#define RISCV_IOMMU_TR_REQ_IOVA_VPN GENMASK_ULL(63, 12)
> > +
> > +/* 5.25 Translation request control (64bits) */
> > +#define RISCV_IOMMU_REG_TR_REQ_CTL 0x0260
> > +#define RISCV_IOMMU_TR_REQ_CTL_GO_BUSY BIT_ULL(0)
> > +#define RISCV_IOMMU_TR_REQ_CTL_PRIV BIT_ULL(1)
> > +#define RISCV_IOMMU_TR_REQ_CTL_EXE BIT_ULL(2)
> > +#define RISCV_IOMMU_TR_REQ_CTL_NW BIT_ULL(3)
> > +#define RISCV_IOMMU_TR_REQ_CTL_PID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_TR_REQ_CTL_PV BIT_ULL(32)
> > +#define RISCV_IOMMU_TR_REQ_CTL_DID GENMASK_ULL(63, 40)
> > +
> > +/* 5.26 Translation request response (64bits) */
> > +#define RISCV_IOMMU_REG_TR_RESPONSE 0x0268
> > +#define RISCV_IOMMU_TR_RESPONSE_FAULT BIT_ULL(0)
> > +#define RISCV_IOMMU_TR_RESPONSE_PBMT GENMASK_ULL(8, 7)
> > +#define RISCV_IOMMU_TR_RESPONSE_SZ BIT_ULL(9)
> > +#define RISCV_IOMMU_TR_RESPONSE_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/* 5.27 Interrupt cause to vector (64bits) */
> > +#define RISCV_IOMMU_REG_IVEC 0x02F8
> > +#define RISCV_IOMMU_IVEC_CIV GENMASK_ULL(3, 0)
> > +#define RISCV_IOMMU_IVEC_FIV GENMASK_ULL(7, 4)
> > +#define RISCV_IOMMU_IVEC_PMIV GENMASK_ULL(11, 8)
> > +#define RISCV_IOMMU_IVEC_PIV GENMASK_ULL(15, 12)
> > +
> > +/* 5.28 MSI Configuration table (32 * 64bits) */
> > +#define RISCV_IOMMU_REG_MSI_CONFIG 0x0300
> > +#define RISCV_IOMMU_REG_MSI_ADDR(_n) (RISCV_IOMMU_REG_MSI_CONFIG + ((_n) * 0x10))
> > +#define RISCV_IOMMU_MSI_ADDR GENMASK_ULL(55, 2)
> > +#define RISCV_IOMMU_REG_MSI_DATA(_n) (RISCV_IOMMU_REG_MSI_CONFIG + ((_n) * 0x10) + 0x08)
> > +#define RISCV_IOMMU_MSI_DATA GENMASK_ULL(31, 0)
> > +#define RISCV_IOMMU_REG_MSI_VEC_CTL(_n) (RISCV_IOMMU_REG_MSI_CONFIG + ((_n) * 0x10) + 0x0C)
> > +#define RISCV_IOMMU_MSI_VEC_CTL_M BIT_ULL(0)
> > +
> > +#define RISCV_IOMMU_REG_SIZE 0x1000
> > +
> > +/*
> > + * Chapter 2: Data structures
> > + */
> > +
> > +/*
> > + * Device Directory Table macros for non-leaf nodes
> > + */
> > +#define RISCV_IOMMU_DDTE_VALID BIT_ULL(0)
> > +#define RISCV_IOMMU_DDTE_PPN RISCV_IOMMU_PPN_FIELD
> > +
> > +/**
> > + * struct riscv_iommu_dc - Device Context
> > + * @tc: Translation Control
> > + * @iohgatp: I/O Hypervisor guest address translation and protection
> > + * (Second stage context)
> > + * @ta: Translation Attributes
> > + * @fsc: First stage context
> > + * @msiptp: MSI page table pointer
> > + * @msi_addr_mask: MSI address mask
> > + * @msi_addr_pattern: MSI address pattern
> > + * @_reserved: Reserved for future use, padding
> > + *
> > + * This structure is used for leaf nodes on the Device Directory Table,
> > + * in case RISCV_IOMMU_CAP_MSI_FLAT is not set, the bottom 4 fields are
> > + * not present and are skipped with pointer arithmetic to avoid
> > + * casting, check out riscv_iommu_get_dc().
> > + * See section 2.1 for more details
> > + */
> > +struct riscv_iommu_dc {
> > + u64 tc;
> > + u64 iohgatp;
> > + u64 ta;
> > + u64 fsc;
> > + u64 msiptp;
> > + u64 msi_addr_mask;
> > + u64 msi_addr_pattern;
> > + u64 _reserved;
> > +};
> > +
> > +/* Translation control fields */
> > +#define RISCV_IOMMU_DC_TC_V BIT_ULL(0)
> > +#define RISCV_IOMMU_DC_TC_EN_ATS BIT_ULL(1)
> > +#define RISCV_IOMMU_DC_TC_EN_PRI BIT_ULL(2)
> > +#define RISCV_IOMMU_DC_TC_T2GPA BIT_ULL(3)
> > +#define RISCV_IOMMU_DC_TC_DTF BIT_ULL(4)
> > +#define RISCV_IOMMU_DC_TC_PDTV BIT_ULL(5)
> > +#define RISCV_IOMMU_DC_TC_PRPR BIT_ULL(6)
> > +#define RISCV_IOMMU_DC_TC_GADE BIT_ULL(7)
> > +#define RISCV_IOMMU_DC_TC_SADE BIT_ULL(8)
> > +#define RISCV_IOMMU_DC_TC_DPE BIT_ULL(9)
> > +#define RISCV_IOMMU_DC_TC_SBE BIT_ULL(10)
> > +#define RISCV_IOMMU_DC_TC_SXL BIT_ULL(11)
> > +
> > +/* Second-stage (aka G-stage) context fields */
> > +#define RISCV_IOMMU_DC_IOHGATP_PPN RISCV_IOMMU_ATP_PPN_FIELD
> > +#define RISCV_IOMMU_DC_IOHGATP_GSCID GENMASK_ULL(59, 44)
> > +#define RISCV_IOMMU_DC_IOHGATP_MODE RISCV_IOMMU_ATP_MODE_FIELD
> > +
> > +/**
> > + * enum riscv_iommu_dc_iohgatp_modes - Guest address translation/protection modes
> > + * @RISCV_IOMMU_DC_IOHGATP_MODE_BARE: No translation/protection
> > + * @RISCV_IOMMU_DC_IOHGATP_MODE_SV32X4: Sv32x4 (2-bit extension of Sv32), when fctl.GXL == 1
> > + * @RISCV_IOMMU_DC_IOHGATP_MODE_SV39X4: Sv39x4 (2-bit extension of Sv39), when fctl.GXL == 0
> > + * @RISCV_IOMMU_DC_IOHGATP_MODE_SV48X4: Sv48x4 (2-bit extension of Sv48), when fctl.GXL == 0
> > + * @RISCV_IOMMU_DC_IOHGATP_MODE_SV57X4: Sv57x4 (2-bit extension of Sv57), when fctl.GXL == 0
> > + */
> > +enum riscv_iommu_dc_iohgatp_modes {
> > + RISCV_IOMMU_DC_IOHGATP_MODE_BARE = 0,
> > + RISCV_IOMMU_DC_IOHGATP_MODE_SV32X4 = 8,
> > + RISCV_IOMMU_DC_IOHGATP_MODE_SV39X4 = 8,
> > + RISCV_IOMMU_DC_IOHGATP_MODE_SV48X4 = 9,
> > + RISCV_IOMMU_DC_IOHGATP_MODE_SV57X4 = 10
> > +};
> > +
> > +/* Translation attributes fields */
> > +#define RISCV_IOMMU_DC_TA_PSCID GENMASK_ULL(31, 12)
> > +
> > +/* First-stage context fields */
> > +#define RISCV_IOMMU_DC_FSC_PPN RISCV_IOMMU_ATP_PPN_FIELD
> > +#define RISCV_IOMMU_DC_FSC_MODE RISCV_IOMMU_ATP_MODE_FIELD
> > +
> > +/**
> > + * enum riscv_iommu_dc_fsc_atp_modes - First stage address translation/protection modes
> > + * @RISCV_IOMMU_DC_FSC_MODE_BARE: No translation/protection
> > + * @RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV32: Sv32, when dc.tc.SXL == 1
> > + * @RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39: Sv39, when dc.tc.SXL == 0
> > + * @RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48: Sv48, when dc.tc.SXL == 0
> > + * @RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57: Sv57, when dc.tc.SXL == 0
> > + * @RISCV_IOMMU_DC_FSC_PDTP_MODE_PD8: 1lvl PDT, 8bit process ids
> > + * @RISCV_IOMMU_DC_FSC_PDTP_MODE_PD17: 2lvl PDT, 17bit process ids
> > + * @RISCV_IOMMU_DC_FSC_PDTP_MODE_PD20: 3lvl PDT, 20bit process ids
> > + *
> > + * FSC holds IOSATP when RISCV_IOMMU_DC_TC_PDTV is 0 and PDTP otherwise.
> > + * IOSATP controls the first stage address translation (same as the satp register on
> > + * the RISC-V MMU), and PDTP holds the process directory table, used to select a
> > + * first stage page table based on a process id (for devices that support multiple
> > + * process ids).
> > + */
> > +enum riscv_iommu_dc_fsc_atp_modes {
> > + RISCV_IOMMU_DC_FSC_MODE_BARE = 0,
> > + RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV32 = 8,
> > + RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV39 = 8,
> > + RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV48 = 9,
> > + RISCV_IOMMU_DC_FSC_IOSATP_MODE_SV57 = 10,
> > + RISCV_IOMMU_DC_FSC_PDTP_MODE_PD8 = 1,
> > + RISCV_IOMMU_DC_FSC_PDTP_MODE_PD17 = 2,
> > + RISCV_IOMMU_DC_FSC_PDTP_MODE_PD20 = 3
> > +};
> > +
> > +/* MSI page table pointer */
> > +#define RISCV_IOMMU_DC_MSIPTP_PPN RISCV_IOMMU_ATP_PPN_FIELD
> > +#define RISCV_IOMMU_DC_MSIPTP_MODE RISCV_IOMMU_ATP_MODE_FIELD
> > +#define RISCV_IOMMU_DC_MSIPTP_MODE_OFF 0
> > +#define RISCV_IOMMU_DC_MSIPTP_MODE_FLAT 1
> > +
> > +/* MSI address mask */
> > +#define RISCV_IOMMU_DC_MSI_ADDR_MASK GENMASK_ULL(51, 0)
> > +
> > +/* MSI address pattern */
> > +#define RISCV_IOMMU_DC_MSI_PATTERN GENMASK_ULL(51, 0)
> > +
> > +/**
> > + * struct riscv_iommu_pc - Process Context
> > + * @ta: Translation Attributes
> > + * @fsc: First stage context
> > + *
> > + * This structure is used for leaf nodes on the Process Directory Table
> > + * See section 2.3 for more details
> > + */
> > +struct riscv_iommu_pc {
> > + u64 ta;
> > + u64 fsc;
> > +};
> > +
> > +/* Translation attributes fields */
> > +#define RISCV_IOMMU_PC_TA_V BIT_ULL(0)
> > +#define RISCV_IOMMU_PC_TA_ENS BIT_ULL(1)
> > +#define RISCV_IOMMU_PC_TA_SUM BIT_ULL(2)
> > +#define RISCV_IOMMU_PC_TA_PSCID GENMASK_ULL(31, 12)
> > +
> > +/* First stage context fields */
> > +#define RISCV_IOMMU_PC_FSC_PPN RISCV_IOMMU_ATP_PPN_FIELD
> > +#define RISCV_IOMMU_PC_FSC_MODE RISCV_IOMMU_ATP_MODE_FIELD
> > +
> > +/*
> > + * Chapter 3: In-memory queue interface
> > + */
> > +
> > +/**
> > + * struct riscv_iommu_command - Generic I/O MMU command structure
> > + * @dword0: Includes the opcode and the function identifier
> > + * @dword1: Opcode specific data
> > + *
> > + * The commands are interpreted as two 64bit fields, where the first
> > + * 7bits of the first field are the opcode which also defines the
> > + * command's format, followed by a 3bit field that specifies the
> > + * function invoked by that command, and the rest is opcode-specific.
> > + * This is a generic struct which will be populated differently
> > + * according to each command. For more infos on the commands and
> > + * the command queue check section 3.1.
> > + */
> > +struct riscv_iommu_command {
> > + u64 dword0;
> > + u64 dword1;
> > +};
> > +
> > +/* Fields on dword0, common for all commands */
> > +#define RISCV_IOMMU_CMD_OPCODE GENMASK_ULL(6, 0)
> > +#define RISCV_IOMMU_CMD_FUNC GENMASK_ULL(9, 7)
> > +
> > +/* 3.1.1 I/O MMU Page-table cache invalidation */
> > +/* Fields on dword0 */
> > +#define RISCV_IOMMU_CMD_IOTINVAL_OPCODE 1
> > +#define RISCV_IOMMU_CMD_IOTINVAL_FUNC_VMA 0
> > +#define RISCV_IOMMU_CMD_IOTINVAL_FUNC_GVMA 1
> > +#define RISCV_IOMMU_CMD_IOTINVAL_AV BIT_ULL(10)
> > +#define RISCV_IOMMU_CMD_IOTINVAL_PSCID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_CMD_IOTINVAL_PSCV BIT_ULL(32)
> > +#define RISCV_IOMMU_CMD_IOTINVAL_GV BIT_ULL(33)
> > +#define RISCV_IOMMU_CMD_IOTINVAL_GSCID GENMASK_ULL(59, 44)
> > +/* dword1[61:10] is the 4K-aligned page address */
> > +#define RISCV_IOMMU_CMD_IOTINVAL_ADDR GENMASK_ULL(61, 10)
> > +
> > +/* 3.1.2 I/O MMU Command Queue Fences */
> > +/* Fields on dword0 */
> > +#define RISCV_IOMMU_CMD_IOFENCE_OPCODE 2
> > +#define RISCV_IOMMU_CMD_IOFENCE_FUNC_C 0
> > +#define RISCV_IOMMU_CMD_IOFENCE_AV BIT_ULL(10)
> > +#define RISCV_IOMMU_CMD_IOFENCE_WSI BIT_ULL(11)
> > +#define RISCV_IOMMU_CMD_IOFENCE_PR BIT_ULL(12)
> > +#define RISCV_IOMMU_CMD_IOFENCE_PW BIT_ULL(13)
> > +#define RISCV_IOMMU_CMD_IOFENCE_DATA GENMASK_ULL(63, 32)
> > +/* dword1 is the address, word-size aligned and shifted to the right by two bits. */
> > +
> > +/* 3.1.3 I/O MMU Directory cache invalidation */
> > +/* Fields on dword0 */
> > +#define RISCV_IOMMU_CMD_IODIR_OPCODE 3
> > +#define RISCV_IOMMU_CMD_IODIR_FUNC_INVAL_DDT 0
> > +#define RISCV_IOMMU_CMD_IODIR_FUNC_INVAL_PDT 1
> > +#define RISCV_IOMMU_CMD_IODIR_PID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_CMD_IODIR_DV BIT_ULL(33)
> > +#define RISCV_IOMMU_CMD_IODIR_DID GENMASK_ULL(63, 40)
> > +/* dword1 is reserved for standard use */
> > +
> > +/* 3.1.4 I/O MMU PCIe ATS */
> > +/* Fields on dword0 */
> > +#define RISCV_IOMMU_CMD_ATS_OPCODE 4
> > +#define RISCV_IOMMU_CMD_ATS_FUNC_INVAL 0
> > +#define RISCV_IOMMU_CMD_ATS_FUNC_PRGR 1
> > +#define RISCV_IOMMU_CMD_ATS_PID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_CMD_ATS_PV BIT_ULL(32)
> > +#define RISCV_IOMMU_CMD_ATS_DSV BIT_ULL(33)
> > +#define RISCV_IOMMU_CMD_ATS_RID GENMASK_ULL(55, 40)
> > +#define RISCV_IOMMU_CMD_ATS_DSEG GENMASK_ULL(63, 56)
> > +/* dword1 is the ATS payload, two different payload types for INVAL and PRGR */
> > +
> > +/* ATS.INVAL payload*/
> > +#define RISCV_IOMMU_CMD_ATS_INVAL_G BIT_ULL(0)
> > +/* Bits 1 - 10 are zeroed */
> > +#define RISCV_IOMMU_CMD_ATS_INVAL_S BIT_ULL(11)
> > +#define RISCV_IOMMU_CMD_ATS_INVAL_UADDR GENMASK_ULL(63, 12)
> > +
> > +/* ATS.PRGR payload */
> > +/* Bits 0 - 31 are zeroed */
> > +#define RISCV_IOMMU_CMD_ATS_PRGR_PRG_INDEX GENMASK_ULL(40, 32)
> > +/* Bits 41 - 43 are zeroed */
> > +#define RISCV_IOMMU_CMD_ATS_PRGR_RESP_CODE GENMASK_ULL(47, 44)
> > +#define RISCV_IOMMU_CMD_ATS_PRGR_DST_ID GENMASK_ULL(63, 48)
> > +
> > +/**
> > + * struct riscv_iommu_fq_record - Fault/Event Queue Record
> > + * @hdr: Header, includes fault/event cause, PID/DID, transaction type etc
> > + * @_reserved: Low 32bits for custom use, high 32bits for standard use
> > + * @iotval: Transaction-type/cause specific format
> > + * @iotval2: Cause specific format
> > + *
> > + * The fault/event queue reports events and failures raised when
> > + * processing transactions. Each record is a 32byte structure where
> > + * the first dword has a fixed format for providing generic infos
> > + * regarding the fault/event, and two more dwords are there for
> > + * fault/event-specific information. For more details see section
> > + * 3.2.
> > + */
> > +struct riscv_iommu_fq_record {
> > + u64 hdr;
> > + u64 _reserved;
> > + u64 iotval;
> > + u64 iotval2;
> > +};
> > +
> > +/* Fields on header */
> > +#define RISCV_IOMMU_FQ_HDR_CAUSE GENMASK_ULL(11, 0)
> > +#define RISCV_IOMMU_FQ_HDR_PID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_FQ_HDR_PV BIT_ULL(32)
> > +#define RISCV_IOMMU_FQ_HDR_PRIV BIT_ULL(33)
> > +#define RISCV_IOMMU_FQ_HDR_TTYPE GENMASK_ULL(39, 34)
> > +#define RISCV_IOMMU_FQ_HDR_DID GENMASK_ULL(63, 40)
> > +
> > +/**
> > + * enum riscv_iommu_fq_causes - Fault/event cause values
> > + * @RISCV_IOMMU_FQ_CAUSE_INST_FAULT: Instruction access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_RD_ADDR_MISALIGNED: Read address misaligned
> > + * @RISCV_IOMMU_FQ_CAUSE_RD_FAULT: Read load fault
> > + * @RISCV_IOMMU_FQ_CAUSE_WR_ADDR_MISALIGNED: Write/AMO address misaligned
> > + * @RISCV_IOMMU_FQ_CAUSE_WR_FAULT: Write/AMO access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_INST_FAULT_S: Instruction page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_RD_FAULT_S: Read page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_WR_FAULT_S: Write/AMO page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_INST_FAULT_VS: Instruction guest page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_RD_FAULT_VS: Read guest page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_WR_FAULT_VS: Write/AMO guest page fault
> > + * @RISCV_IOMMU_FQ_CAUSE_DMA_DISABLED: All inbound transactions disallowed
> > + * @RISCV_IOMMU_FQ_CAUSE_DDT_LOAD_FAULT: DDT entry load access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_DDT_INVALID: DDT entry invalid
> > + * @RISCV_IOMMU_FQ_CAUSE_DDT_MISCONFIGURED: DDT entry misconfigured
> > + * @RISCV_IOMMU_FQ_CAUSE_TTYPE_BLOCKED: Transaction type disallowed
> > + * @RISCV_IOMMU_FQ_CAUSE_MSI_LOAD_FAULT: MSI PTE load access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_MSI_INVALID: MSI PTE invalid
> > + * @RISCV_IOMMU_FQ_CAUSE_MSI_MISCONFIGURED: MSI PTE misconfigured
> > + * @RISCV_IOMMU_FQ_CAUSE_MRIF_FAULT: MRIF access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_PDT_LOAD_FAULT: PDT entry load access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_PDT_INVALID: PDT entry invalid
> > + * @RISCV_IOMMU_FQ_CAUSE_PDT_MISCONFIGURED: PDT entry misconfigured
> > + * @RISCV_IOMMU_FQ_CAUSE_DDT_CORRUPTED: DDT data corruption
> > + * @RISCV_IOMMU_FQ_CAUSE_PDT_CORRUPTED: PDT data corruption
> > + * @RISCV_IOMMU_FQ_CAUSE_MSI_PT_CORRUPTED: MSI page table data corruption
> > + * @RISCV_IOMMU_FQ_CAUSE_MRIF_CORRUIPTED: MRIF data corruption
> > + * @RISCV_IOMMU_FQ_CAUSE_INTERNAL_DP_ERROR: Internal data path error
> > + * @RISCV_IOMMU_FQ_CAUSE_MSI_WR_FAULT: IOMMU MSI write access fault
> > + * @RISCV_IOMMU_FQ_CAUSE_PT_CORRUPTED: First/second stage page table data corruption
> > + *
> > + * Values are on table 11 of the spec, encodings 275 - 2047 are reserved for standard
> > + * use, and 2048 - 4095 for custom use.
> > + */
> > +enum riscv_iommu_fq_causes {
> > + RISCV_IOMMU_FQ_CAUSE_INST_FAULT = 1,
> > + RISCV_IOMMU_FQ_CAUSE_RD_ADDR_MISALIGNED = 4,
> > + RISCV_IOMMU_FQ_CAUSE_RD_FAULT = 5,
> > + RISCV_IOMMU_FQ_CAUSE_WR_ADDR_MISALIGNED = 6,
> > + RISCV_IOMMU_FQ_CAUSE_WR_FAULT = 7,
> > + RISCV_IOMMU_FQ_CAUSE_INST_FAULT_S = 12,
> > + RISCV_IOMMU_FQ_CAUSE_RD_FAULT_S = 13,
> > + RISCV_IOMMU_FQ_CAUSE_WR_FAULT_S = 15,
> > + RISCV_IOMMU_FQ_CAUSE_INST_FAULT_VS = 20,
> > + RISCV_IOMMU_FQ_CAUSE_RD_FAULT_VS = 21,
> > + RISCV_IOMMU_FQ_CAUSE_WR_FAULT_VS = 23,
> > + RISCV_IOMMU_FQ_CAUSE_DMA_DISABLED = 256,
> > + RISCV_IOMMU_FQ_CAUSE_DDT_LOAD_FAULT = 257,
> > + RISCV_IOMMU_FQ_CAUSE_DDT_INVALID = 258,
> > + RISCV_IOMMU_FQ_CAUSE_DDT_MISCONFIGURED = 259,
> > + RISCV_IOMMU_FQ_CAUSE_TTYPE_BLOCKED = 260,
> > + RISCV_IOMMU_FQ_CAUSE_MSI_LOAD_FAULT = 261,
> > + RISCV_IOMMU_FQ_CAUSE_MSI_INVALID = 262,
> > + RISCV_IOMMU_FQ_CAUSE_MSI_MISCONFIGURED = 263,
> > + RISCV_IOMMU_FQ_CAUSE_MRIF_FAULT = 264,
> > + RISCV_IOMMU_FQ_CAUSE_PDT_LOAD_FAULT = 265,
> > + RISCV_IOMMU_FQ_CAUSE_PDT_INVALID = 266,
> > + RISCV_IOMMU_FQ_CAUSE_PDT_MISCONFIGURED = 267,
> > + RISCV_IOMMU_FQ_CAUSE_DDT_CORRUPTED = 268,
> > + RISCV_IOMMU_FQ_CAUSE_PDT_CORRUPTED = 269,
> > + RISCV_IOMMU_FQ_CAUSE_MSI_PT_CORRUPTED = 270,
> > + RISCV_IOMMU_FQ_CAUSE_MRIF_CORRUIPTED = 271,
> > + RISCV_IOMMU_FQ_CAUSE_INTERNAL_DP_ERROR = 272,
> > + RISCV_IOMMU_FQ_CAUSE_MSI_WR_FAULT = 273,
> > + RISCV_IOMMU_FQ_CAUSE_PT_CORRUPTED = 274
> > +};
> > +
> > +/**
> > + * enum riscv_iommu_fq_ttypes: Fault/event transaction types
> > + * @RISCV_IOMMU_FQ_TTYPE_NONE: None. Fault not caused by an inbound transaction.
> > + * @RISCV_IOMMU_FQ_TTYPE_UADDR_INST_FETCH: Instruction fetch from untranslated address
> > + * @RISCV_IOMMU_FQ_TTYPE_UADDR_RD: Read from untranslated address
> > + * @RISCV_IOMMU_FQ_TTYPE_UADDR_WR: Write/AMO to untranslated address
> > + * @RISCV_IOMMU_FQ_TTYPE_TADDR_INST_FETCH: Instruction fetch from translated address
> > + * @RISCV_IOMMU_FQ_TTYPE_TADDR_RD: Read from translated address
> > + * @RISCV_IOMMU_FQ_TTYPE_TADDR_WR: Write/AMO to translated address
> > + * @RISCV_IOMMU_FQ_TTYPE_PCIE_ATS_REQ: PCIe ATS translation request
> > + * @RISCV_IOMMU_FW_TTYPE_PCIE_MSG_REQ: PCIe message request
> > + *
> > + * Values are on table 12 of the spec, type 4 and 10 - 31 are reserved for standard use
> > + * and 31 - 63 for custom use.
> > + */
> > +enum riscv_iommu_fq_ttypes {
> > + RISCV_IOMMU_FQ_TTYPE_NONE = 0,
> > + RISCV_IOMMU_FQ_TTYPE_UADDR_INST_FETCH = 1,
> > + RISCV_IOMMU_FQ_TTYPE_UADDR_RD = 2,
> > + RISCV_IOMMU_FQ_TTYPE_UADDR_WR = 3,
> > + RISCV_IOMMU_FQ_TTYPE_TADDR_INST_FETCH = 5,
> > + RISCV_IOMMU_FQ_TTYPE_TADDR_RD = 6,
> > + RISCV_IOMMU_FQ_TTYPE_TADDR_WR = 7,
> > + RISCV_IOMMU_FQ_TTYPE_PCIE_ATS_REQ = 8,
> > + RISCV_IOMMU_FW_TTYPE_PCIE_MSG_REQ = 9,
> > +};
> > +
> > +/**
> > + * struct riscv_iommu_pq_record - PCIe Page Request record
> > + * @hdr: Header, includes PID, DID etc
> > + * @payload: Holds the page address, request group and permission bits
> > + *
> > + * For more infos on the PCIe Page Request queue see chapter 3.3.
> > + */
> > +struct riscv_iommu_pq_record {
> > + u64 hdr;
> > + u64 payload;
> > +};
> > +
> > +/* Header fields */
> > +#define RISCV_IOMMU_PREQ_HDR_PID GENMASK_ULL(31, 12)
> > +#define RISCV_IOMMU_PREQ_HDR_PV BIT_ULL(32)
> > +#define RISCV_IOMMU_PREQ_HDR_PRIV BIT_ULL(33)
> > +#define RISCV_IOMMU_PREQ_HDR_EXEC BIT_ULL(34)
> > +#define RISCV_IOMMU_PREQ_HDR_DID GENMASK_ULL(63, 40)
> > +
> > +/* Payload fields */
> > +#define RISCV_IOMMU_PREQ_PAYLOAD_R BIT_ULL(0)
> > +#define RISCV_IOMMU_PREQ_PAYLOAD_W BIT_ULL(1)
> > +#define RISCV_IOMMU_PREQ_PAYLOAD_L BIT_ULL(2)
> > +#define RISCV_IOMMU_PREQ_PAYLOAD_M GENMASK_ULL(2, 0) /* Mask of RWL for convenience */
> > +#define RISCV_IOMMU_PREQ_PRG_INDEX GENMASK_ULL(11, 3)
> > +#define RISCV_IOMMU_PREQ_UADDR GENMASK_ULL(63, 12)
> > +
> > +/**
> > + * struct riscv_iommu_msi_pte - MSI Page Table Entry
> > + * @pte: MSI PTE
> > + * @mrif_info: Memory-resident interrupt file info
> > + *
> > + * The MSI Page Table is used for virtualizing MSIs, so that when
> > + * a device sends an MSI to a guest, the IOMMU can reroute it
> > + * by translating the MSI address, either to a guest interrupt file
> > + * or a memory resident interrupt file (MRIF). Note that this page table
> > + * is an array of MSI PTEs, not a multi-level pt, each entry
> > + * is a leaf entry. For more infos check out the AIA spec, chapter 9.5.
> > + *
> > + * Also in basic mode the mrif_info field is ignored by the IOMMU and can
> > + * be used by software, any other reserved fields on pte must be zeroed-out
> > + * by software.
> > + */
> > +struct riscv_iommu_msi_pte {
> > + u64 pte;
> > + u64 mrif_info;
> > +};
> > +
> > +/* Fields on pte */
> > +#define RISCV_IOMMU_MSI_PTE_V BIT_ULL(0)
> > +#define RISCV_IOMMU_MSI_PTE_M GENMASK_ULL(2, 1)
> > +#define RISCV_IOMMU_MSI_PTE_MRIF_ADDR GENMASK_ULL(53, 7) /* When M == 1 (MRIF mode) */
> > +#define RISCV_IOMMU_MSI_PTE_PPN RISCV_IOMMU_PPN_FIELD /* When M == 3 (basic mode) */
> > +#define RISCV_IOMMU_MSI_PTE_C BIT_ULL(63)
> > +
> > +/* Fields on mrif_info */
> > +#define RISCV_IOMMU_MSI_MRIF_NID GENMASK_ULL(9, 0)
> > +#define RISCV_IOMMU_MSI_MRIF_NPPN RISCV_IOMMU_PPN_FIELD
> > +#define RISCV_IOMMU_MSI_MRIF_NID_MSB BIT_ULL(60)
> > +
> > +#endif /* _RISCV_IOMMU_BITS_H_ */
> > diff --git a/drivers/iommu/riscv/iommu-platform.c b/drivers/iommu/riscv/iommu-platform.c
> > new file mode 100644
> > index 000000000000..770086ae2ab3
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/iommu-platform.c
> > @@ -0,0 +1,94 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * RISC-V IOMMU as a platform device
> > + *
> > + * Copyright © 2023 FORTH-ICS/CARV
> > + * Copyright © 2023-2024 Rivos Inc.
> > + *
> > + * Authors
> > + * Nick Kossifidis <mick@ics.forth.gr>
> > + * Tomasz Jeznach <tjeznach@rivosinc.com>
> > + */
> > +
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/platform_device.h>
> > +
> > +#include "iommu-bits.h"
> > +#include "iommu.h"
> > +
> > +static int riscv_iommu_platform_probe(struct platform_device *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct riscv_iommu_device *iommu = NULL;
> > + struct resource *res = NULL;
> > + int vec;
> > +
> > + iommu = devm_kzalloc(dev, sizeof(*iommu), GFP_KERNEL);
> > + if (!iommu)
> > + return -ENOMEM;
> > +
> > + iommu->dev = dev;
> > + iommu->reg = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> > + if (IS_ERR(iommu->reg))
> > + return dev_err_probe(dev, PTR_ERR(iommu->reg),
> > + "could not map register region\n");
> > +
> > + dev_set_drvdata(dev, iommu);
> > +
> > + /* Check device reported capabilities / features. */
> > + iommu->caps = riscv_iommu_readq(iommu, RISCV_IOMMU_REG_CAP);
> > + iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
> > +
> > + /* For now we only support WSI */
> > + switch (FIELD_GET(RISCV_IOMMU_CAP_IGS, iommu->caps)) {
> > + case RISCV_IOMMU_CAP_IGS_WSI:
> > + case RISCV_IOMMU_CAP_IGS_BOTH:
> > + break;
> > + default:
> > + return dev_err_probe(dev, -ENODEV,
> > + "unable to use wire-signaled interrupts\n");
> > + }
> > +
> > + iommu->irqs_count = platform_irq_count(pdev);
> > + if (iommu->irqs_count <= 0)
> > + return dev_err_probe(dev, -ENODEV,
> > + "no IRQ resources provided\n");
> > +
> > + for (vec = 0; vec < iommu->irqs_count; vec++)
> > + iommu->irqs[vec] = platform_get_irq(pdev, vec);
>
> And if I've specified 97 interrupts in my DT because I won't let schema
> be the boss of me?
>
> > + /* Enable wire-signaled interrupts, fctl.WSI */
> > + if (!(iommu->fctl & RISCV_IOMMU_FCTL_WSI)) {
> > + iommu->fctl ^= RISCV_IOMMU_FCTL_WSI;
>
> Using XOR to only ever set a 0 bit to 1 seems a bit obtuse.
>
> > + riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL, iommu->fctl);
> > + }
> > +
> > + return riscv_iommu_init(iommu);
> > +};
> > +
> > +static void riscv_iommu_platform_remove(struct platform_device *pdev)
> > +{
> > + riscv_iommu_remove(dev_get_drvdata(&pdev->dev));
> > +};
> > +
> > +static const struct of_device_id riscv_iommu_of_match[] = {
> > + {.compatible = "riscv,iommu",},
> > + {},
> > +};
> > +
> > +MODULE_DEVICE_TABLE(of, riscv_iommu_of_match);
>
> And yet it cannot be a module?
>
> > +static struct platform_driver riscv_iommu_platform_driver = {
> > + .probe = riscv_iommu_platform_probe,
> > + .remove_new = riscv_iommu_platform_remove,
> > + .driver = {
> > + .name = "riscv,iommu",
> > + .of_match_table = riscv_iommu_of_match,
> > + .suppress_bind_attrs = true,
> > + },
> > +};
> > +
> > +module_driver(riscv_iommu_platform_driver, platform_driver_register,
> > + platform_driver_unregister);
>
> module_platform_driver() is a thing. Or builtin_platform_driver(), as
> things currently stand.
>
> > diff --git a/drivers/iommu/riscv/iommu.c b/drivers/iommu/riscv/iommu.c
> > new file mode 100644
> > index 000000000000..af68c89200a9
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/iommu.c
> > @@ -0,0 +1,89 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * IOMMU API for RISC-V IOMMU implementations.
> > + *
> > + * Copyright © 2022-2024 Rivos Inc.
> > + * Copyright © 2023 FORTH-ICS/CARV
> > + *
> > + * Authors
> > + * Tomasz Jeznach <tjeznach@rivosinc.com>
> > + * Nick Kossifidis <mick@ics.forth.gr>
> > + */
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
>
> I guess that ends up as "iommu:"? Given that that prefix already belongs
> to the core code, please pick something more specific.
>
> > +#include <linux/compiler.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/init.h>
> > +#include <linux/iommu.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +
> > +#include "iommu-bits.h"
> > +#include "iommu.h"
> > +
> > +MODULE_DESCRIPTION("Driver for RISC-V IOMMU");
> > +MODULE_AUTHOR("Tomasz Jeznach <tjeznach@rivosinc.com>");
> > +MODULE_AUTHOR("Nick Kossifidis <mick@ics.forth.gr>");
> > +MODULE_LICENSE("GPL");
> > +
> > +/* Timeouts in [us] */
> > +#define RISCV_IOMMU_DDTP_TIMEOUT 50000
> > +
> > +static int riscv_iommu_init_check(struct riscv_iommu_device *iommu)
> > +{
> > + u64 ddtp;
> > +
> > + /* Hardware must be configured in OFF | BARE mode at system initialization. */
> > + riscv_iommu_readq_timeout(iommu, RISCV_IOMMU_REG_DDTP,
> > + ddtp, !(ddtp & RISCV_IOMMU_DDTP_BUSY),
> > + 10, RISCV_IOMMU_DDTP_TIMEOUT);
> > + if (FIELD_GET(RISCV_IOMMU_DDTP_MODE, ddtp) > RISCV_IOMMU_DDTP_MODE_BARE)
> > + return -EBUSY;
>
> It looks like RISC-V already supports kdump, so you probably want to be
> prepared to find the IOMMU with its pants down and deal with it from day
> one.
>

This is the simplest check/fail for the kexec and/or boot loaders
leaving IOMMU translations active.
I've been already looking into kexec path to quiesce all devices and
IOMMU in shutdown path.
I'm not convinced it's ready for the prime time on RISC-V, will
address this in follow up patches.

> > +
> > + /* Configure accesses to in-memory data structures for CPU-native byte order. */
> > + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) != !!(iommu->fctl & RISCV_IOMMU_FCTL_BE)) {
> > + if (!(iommu->caps & RISCV_IOMMU_CAP_END))
> > + return -EINVAL;
> > + riscv_iommu_writel(iommu, RISCV_IOMMU_REG_FCTL,
> > + iommu->fctl ^ RISCV_IOMMU_FCTL_BE);
> > + iommu->fctl = riscv_iommu_readl(iommu, RISCV_IOMMU_REG_FCTL);
> > + if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN) != !!(iommu->fctl & RISCV_IOMMU_FCTL_BE))
> > + return -EINVAL;
> > + }
>
> That's fun. It could be reorganised to avoid the duplicate check, but it
> is rather majestic as-is :)
>
> > +
> > + dma_set_mask_and_coherent(iommu->dev,
> > + DMA_BIT_MASK(FIELD_GET(RISCV_IOMMU_CAP_PAS, iommu->caps)));
>
> This isn't a check, so I would think it belongs to "_init" rather than
> "_init_check".
>
> Thanks,
> Robin.
>

ACK to all other comments.

Thanks
- Tomasz

> > +
> > + return 0;
> > +}
> > +
> > +void riscv_iommu_remove(struct riscv_iommu_device *iommu)
> > +{
> > + iommu_device_sysfs_remove(&iommu->iommu);
> > +}
> > +
> > +int riscv_iommu_init(struct riscv_iommu_device *iommu)
> > +{
> > + int rc;
> > +
> > + rc = riscv_iommu_init_check(iommu);
> > + if (rc)
> > + return dev_err_probe(iommu->dev, rc, "unexpected device state\n");
> > + /*
> > + * Placeholder for a complete IOMMU device initialization.
> > + * For now, only bare minimum: enable global identity mapping mode and register sysfs.
> > + */
> > + riscv_iommu_writeq(iommu, RISCV_IOMMU_REG_DDTP,
> > + FIELD_PREP(RISCV_IOMMU_DDTP_MODE, RISCV_IOMMU_DDTP_MODE_BARE));
> > +
> > + rc = iommu_device_sysfs_add(&iommu->iommu, NULL, NULL, "riscv-iommu@%s",
> > + dev_name(iommu->dev));
> > + if (WARN(rc, "cannot register sysfs interface\n"))
> > + goto err_sysfs;
> > +
> > + return 0;
> > +
> > +err_sysfs:
> > + return rc;
> > +}
> > diff --git a/drivers/iommu/riscv/iommu.h b/drivers/iommu/riscv/iommu.h
> > new file mode 100644
> > index 000000000000..700e33dc2446
> > --- /dev/null
> > +++ b/drivers/iommu/riscv/iommu.h
> > @@ -0,0 +1,62 @@
> > +/* SPDX-License-Identifier: GPL-2.0-only */
> > +/*
> > + * Copyright © 2022-2024 Rivos Inc.
> > + * Copyright © 2023 FORTH-ICS/CARV
> > + *
> > + * Authors
> > + * Tomasz Jeznach <tjeznach@rivosinc.com>
> > + * Nick Kossifidis <mick@ics.forth.gr>
> > + */
> > +
> > +#ifndef _RISCV_IOMMU_H_
> > +#define _RISCV_IOMMU_H_
> > +
> > +#include <linux/iommu.h>
> > +#include <linux/types.h>
> > +#include <linux/iopoll.h>
> > +
> > +#include "iommu-bits.h"
> > +
> > +struct riscv_iommu_device {
> > + /* iommu core interface */
> > + struct iommu_device iommu;
> > +
> > + /* iommu hardware */
> > + struct device *dev;
> > +
> > + /* hardware control register space */
> > + void __iomem *reg;
> > +
> > + /* supported and enabled hardware capabilities */
> > + u64 caps;
> > + u32 fctl;
> > +
> > + /* available interrupt numbers, MSI or WSI */
> > + unsigned int irqs[RISCV_IOMMU_INTR_COUNT];
> > + unsigned int irqs_count;
> > +};
> > +
> > +int riscv_iommu_init(struct riscv_iommu_device *iommu);
> > +void riscv_iommu_remove(struct riscv_iommu_device *iommu);
> > +
> > +#define riscv_iommu_readl(iommu, addr) \
> > + readl_relaxed((iommu)->reg + (addr))
> > +
> > +#define riscv_iommu_readq(iommu, addr) \
> > + readq_relaxed((iommu)->reg + (addr))
> > +
> > +#define riscv_iommu_writel(iommu, addr, val) \
> > + writel_relaxed((val), (iommu)->reg + (addr))
> > +
> > +#define riscv_iommu_writeq(iommu, addr, val) \
> > + writeq_relaxed((val), (iommu)->reg + (addr))
> > +
> > +#define riscv_iommu_readq_timeout(iommu, addr, val, cond, delay_us, timeout_us) \
> > + readx_poll_timeout(readq_relaxed, (iommu)->reg + (addr), val, cond, \
> > + delay_us, timeout_us)
> > +
> > +#define riscv_iommu_readl_timeout(iommu, addr, val, cond, delay_us, timeout_us) \
> > + readx_poll_timeout(readl_relaxed, (iommu)->reg + (addr), val, cond, \
> > + delay_us, timeout_us)
> > +
> > +#endif