Re: [PATCH v3] platform: generic: Tenstorrent Atlantis support

On Fri, Apr 24, 2026 at 11:55 AM Nicholas Piggin <[email protected]> wrote:
>
> Add the Tenstorrent Atlantis as a generic-platform. This initial support
> enables the single_fw_region option, and verifies and prints HART PMA
> CSR configuration.
>
> Signed-off-by: Nicholas Piggin <[email protected]>
> ---
> Since v2:
> - Fix silly 32-bit build issue.
>
> Since v1:
> - Drop the IOMMU since it depends on core PMP changes. I will work
>   on those in parallel.
>
> Note the Atlantis hardware is not yet released, and QEMU models are in
> the process of being upstreamed, but at the moment not complete. We
> will continue to expand support and improve documentation for QEMU/HW
> as we get more pieces in place.

LGTM.

Reviewed-by: Anup Patel <[email protected]>

Applied this patch to the riscv/opensbi repo.

Thanks,
Anup

>
> Thanks,
> Nick
> ---
>  docs/platform/generic.md                      |   2 +
>  docs/platform/tt-atlantis.md                  |  35 +++++
>  platform/generic/Kconfig                      |   6 +
>  platform/generic/configs/defconfig            |   1 +
>  .../generic/include/tenstorrent/ascalon.h     |  12 ++
>  platform/generic/include/tenstorrent/pma.h    |  18 +++
>  platform/generic/tenstorrent/Kconfig          |   5 +
>  platform/generic/tenstorrent/ascalon.c        |  53 +++++++
>  platform/generic/tenstorrent/atlantis.c       |  50 +++++++
>  platform/generic/tenstorrent/objects.mk       |  12 ++
>  platform/generic/tenstorrent/pma.c            | 138 ++++++++++++++++++
>  11 files changed, 332 insertions(+)
>  create mode 100644 docs/platform/tt-atlantis.md
>  create mode 100644 platform/generic/include/tenstorrent/ascalon.h
>  create mode 100644 platform/generic/include/tenstorrent/pma.h
>  create mode 100644 platform/generic/tenstorrent/Kconfig
>  create mode 100644 platform/generic/tenstorrent/ascalon.c
>  create mode 100644 platform/generic/tenstorrent/atlantis.c
>  create mode 100644 platform/generic/tenstorrent/objects.mk
>  create mode 100644 platform/generic/tenstorrent/pma.c
>
> diff --git a/docs/platform/generic.md b/docs/platform/generic.md
> index c48d6a9a..0b896ede 100644
> --- a/docs/platform/generic.md
> +++ b/docs/platform/generic.md
> @@ -47,6 +47,7 @@ RISC-V Platforms Using Generic Platform
>  * **SiFive HiFive Unleashed** (*[sifive_fu540.md]*)
>  * **Spike** (*[spike.md]*)
>  * **T-HEAD C9xx series Processors** (*[thead-c9xx.md]*)
> +* **Tenstorrent Atlantis Platform** (*[tt-atlantis.md]*)
>  * **OpenPiton FPGA SoC** (*[fpga-openpiton.md]*)
>  * **Ariane FPGA SoC** (*[fpga-ariane.md]*)
>
> @@ -57,5 +58,6 @@ RISC-V Platforms Using Generic Platform
>  [sifive_fu540.md]: sifive_fu540.md
>  [spike.md]: spike.md
>  [thead-c9xx.md]: thead-c9xx.md
> +[tt-atlantis.md]: tt-atlantis.md
>  [fpga-openpiton.md]: fpga-openpiton.md
>  [fpga-ariane.md]: fpga-ariane.md
> diff --git a/docs/platform/tt-atlantis.md b/docs/platform/tt-atlantis.md
> new file mode 100644
> index 00000000..b9bdd238
> --- /dev/null
> +++ b/docs/platform/tt-atlantis.md
> @@ -0,0 +1,35 @@
> +Tenstorrent Atlantis Platform
> +=============================
> +
> +The Tenstorrent Atlantis is an SoC and development board from
> +Tenstorrent in partnership with CoreLab Technology. It contains 8 RISC-V
> +RVA23 compliant Tenstorrent Ascalon cores with RISC-V AIA, RISC-V IOMMU,
> +and a range of devices and IO connectivity.
> +
> +To build the platform-specific library and firmware images, provide the
> +*PLATFORM=generic* parameter to the top level `make` command.
> +
> +Platform Options
> +----------------
> +
> +The *Tenstorrent Atlantis* platform does not have any platform-specific
> +options.
> +
> +Building Tenstorrent Atlantis Platform
> +--------------------------------------
> +
> +The Atlantis Platform is still under development. This section will be
> +expanded as firmware and support become available.
> +
> +QEMU support is currently being developed and initial support has been
> +proposed for upstream. To run QEMU that is patched with 'tt-atlantis'
> +machine support, run:
> +
> +```
> +qemu-system-riscv64 -M tt-atlantis -nographic \
> +       -bios build/platform/generic/firmware/fw_payload.bin \
> +    -kernel <linux_build_dir>/Image
> +```
> +
> +Recent (6.18) Linux/riscv 64-bit defconfig kernels should run the QEMU
> +tt-atlantis machine.
> diff --git a/platform/generic/Kconfig b/platform/generic/Kconfig
> index 600273d1..d594b140 100644
> --- a/platform/generic/Kconfig
> +++ b/platform/generic/Kconfig
> @@ -89,6 +89,11 @@ config PLATFORM_STARFIVE_JH7110
>         bool "StarFive JH7110 support"
>         default n
>
> +config PLATFORM_TENSTORRENT_ATLANTIS
> +       bool "Tenstorrent Atlantis support"
> +       select CPU_TENSTORRENT_ASCALON
> +       default n
> +
>  config PLATFORM_THEAD
>         bool "THEAD C9xx support"
>         select THEAD_C9XX_ERRATA
> @@ -114,6 +119,7 @@ config PLATFORM_MIPS_P8700_BOSTON
>
>  source "$(OPENSBI_SRC_DIR)/platform/generic/andes/Kconfig"
>  source "$(OPENSBI_SRC_DIR)/platform/generic/eswin/Kconfig"
> +source "$(OPENSBI_SRC_DIR)/platform/generic/tenstorrent/Kconfig"
>  source "$(OPENSBI_SRC_DIR)/platform/generic/thead/Kconfig"
>
>  endif
> diff --git a/platform/generic/configs/defconfig b/platform/generic/configs/defconfig
> index 1d3431e7..800f3f14 100644
> --- a/platform/generic/configs/defconfig
> +++ b/platform/generic/configs/defconfig
> @@ -10,6 +10,7 @@ CONFIG_PLATFORM_SIFIVE_FU540=y
>  CONFIG_PLATFORM_SIFIVE_FU740=y
>  CONFIG_PLATFORM_SOPHGO_SG2042=y
>  CONFIG_PLATFORM_STARFIVE_JH7110=y
> +CONFIG_PLATFORM_TENSTORRENT_ATLANTIS=y
>  CONFIG_PLATFORM_THEAD=y
>  CONFIG_PLATFORM_MIPS_P8700_EYEQ7H=y
>  CONFIG_PLATFORM_MIPS_P8700_BOSTON=y
> diff --git a/platform/generic/include/tenstorrent/ascalon.h b/platform/generic/include/tenstorrent/ascalon.h
> new file mode 100644
> index 00000000..5d7b7635
> --- /dev/null
> +++ b/platform/generic/include/tenstorrent/ascalon.h
> @@ -0,0 +1,12 @@
> +/*
> + * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> + * SPDX-License-Identifier: BSD-2-Clause
> + */
> +
> +#ifndef __TENSTORRENT_ASCALON_H__
> +#define __TENSTORRENT_ASCALON_H__
> +
> +void tt_ascalon_discover_pmas_from_boot_hart(void);
> +void tt_ascalon_verify_pmas_nonboot_hart(void);
> +
> +#endif
> diff --git a/platform/generic/include/tenstorrent/pma.h b/platform/generic/include/tenstorrent/pma.h
> new file mode 100644
> index 00000000..051764ee
> --- /dev/null
> +++ b/platform/generic/include/tenstorrent/pma.h
> @@ -0,0 +1,18 @@
> +/*
> + * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> + * SPDX-License-Identifier: BSD-2-Clause
> + */
> +
> +#ifndef __TENSTORRENT_PMA_H__
> +#define __TENSTORRENT_PMA_H__
> +
> +/* Max number of PMAs for devices (CPU, IOMMU) for Tenstorrent platforms. */
> +#define TT_MAX_PMAS    32
> +
> +u64 tt_pma_get(unsigned int n);
> +void tt_pma_set(unsigned int n, u64 pma);
> +bool tt_pma_validate(unsigned int i, u64 pma);
> +void tt_pma_print(unsigned int i, u64 pma);
> +
> +#endif
> +
> diff --git a/platform/generic/tenstorrent/Kconfig b/platform/generic/tenstorrent/Kconfig
> new file mode 100644
> index 00000000..76c7fb32
> --- /dev/null
> +++ b/platform/generic/tenstorrent/Kconfig
> @@ -0,0 +1,5 @@
> +# SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> +# SPDX-License-Identifier: BSD-2-Clause
> +
> +config CPU_TENSTORRENT_ASCALON
> +       bool
> diff --git a/platform/generic/tenstorrent/ascalon.c b/platform/generic/tenstorrent/ascalon.c
> new file mode 100644
> index 00000000..485144cd
> --- /dev/null
> +++ b/platform/generic/tenstorrent/ascalon.c
> @@ -0,0 +1,53 @@
> +/*
> + * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> + * SPDX-License-Identifier: BSD-2-Clause
> + */
> +
> +#include <sbi/riscv_asm.h>
> +#include <sbi/sbi_console.h>
> +#include <sbi/sbi_csr_detect.h>
> +
> +#include <tenstorrent/ascalon.h>
> +#include <tenstorrent/pma.h>
> +
> +#define CSR_PMACFG0    0x7e0
> +
> +void tt_ascalon_discover_pmas_from_boot_hart(void)
> +{
> +       struct sbi_trap_info trap = {0};
> +
> +       /* Whisper virtual platform does not implement PMA */
> +       csr_read_allowed(CSR_PMACFG0, &trap);
> +       if (trap.cause)
> +               return;
> +
> +       for (unsigned int i = 0; i < TT_MAX_PMAS; i++) {
> +               u64 pma = csr_read_num(CSR_PMACFG0 + i);
> +               if (!tt_pma_validate(i, pma)) {
> +                       sbi_printf("HART%d: Bad boot PMA%02d 0x%016lx\n",
> +                                  current_hartid(), i, pma);
> +               }
> +               tt_pma_set(i, pma);
> +
> +               if (pma)
> +                       tt_pma_print(i, pma);
> +       }
> +}
> +
> +void tt_ascalon_verify_pmas_nonboot_hart(void)
> +{
> +       struct sbi_trap_info trap = {0};
> +
> +       /* Whisper virtual platform does not implement PMA */
> +       csr_read_allowed(CSR_PMACFG0, &trap);
> +       if (trap.cause)
> +               return;
> +
> +       for (unsigned int i = 0; i < TT_MAX_PMAS; i++) {
> +               u64 pma = csr_read_num(CSR_PMACFG0 + i);
> +               if (pma != tt_pma_get(i)) {
> +                       sbi_printf("HART%d: Bad boot PMA%02d 0x%016lx does not match boot HART\n",
> +                                  current_hartid(), i, pma);
> +               }
> +       }
> +}
> diff --git a/platform/generic/tenstorrent/atlantis.c b/platform/generic/tenstorrent/atlantis.c
> new file mode 100644
> index 00000000..4c312f7e
> --- /dev/null
> +++ b/platform/generic/tenstorrent/atlantis.c
> @@ -0,0 +1,50 @@
> +/*
> + * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> + * SPDX-License-Identifier: BSD-2-Clause
> + */
> +
> +#include <platform_override.h>
> +#include <libfdt.h>
> +#include <sbi/sbi_error.h>
> +#include <sbi/sbi_hart.h>
> +#include <sbi/sbi_system.h>
> +#include <sbi/sbi_console.h>
> +
> +#include <tenstorrent/ascalon.h>
> +#include <tenstorrent/pma.h>
> +
> +static int tt_atlantis_final_init(bool cold_boot)
> +{
> +       if (cold_boot) {
> +               /* Boot firmware sets HART PMAs. Read and verify them. */
> +               tt_ascalon_discover_pmas_from_boot_hart();
> +       } else {
> +               /* Verify nonboot HARTs have PMAs matching boot HART */
> +               tt_ascalon_verify_pmas_nonboot_hart();
> +       }
> +
> +       return generic_final_init(cold_boot);
> +}
> +
> +static bool tt_atlantis_single_fw_region(void)
> +{
> +       return true;
> +}
> +
> +static int tt_atlantis_platform_init(const void *fdt, int nodeoff, const struct fdt_match *match)
> +{
> +       generic_platform_ops.final_init = tt_atlantis_final_init;
> +       generic_platform_ops.single_fw_region = tt_atlantis_single_fw_region;
> +
> +       return 0;
> +}
> +
> +static const struct fdt_match tt_atlantis_match[] = {
> +       { .compatible = "tenstorrent,atlantis" },
> +       { },
> +};
> +
> +const struct fdt_driver tenstorrent_atlantis = {
> +       .match_table = tt_atlantis_match,
> +       .init = tt_atlantis_platform_init,
> +};
> diff --git a/platform/generic/tenstorrent/objects.mk b/platform/generic/tenstorrent/objects.mk
> new file mode 100644
> index 00000000..17da2c5e
> --- /dev/null
> +++ b/platform/generic/tenstorrent/objects.mk
> @@ -0,0 +1,12 @@
> +#
> +# SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> +# SPDX-License-Identifier: BSD-2-Clause
> +#
> +
> +ifeq ($(PLATFORM_RISCV_XLEN), 64)
> +platform-objs-y += tenstorrent/pma.o
> +platform-objs-$(CONFIG_CPU_TENSTORRENT_ASCALON) += tenstorrent/ascalon.o
> +
> +carray-platform_override_modules-$(CONFIG_PLATFORM_TENSTORRENT_ATLANTIS) += tenstorrent_atlantis
> +platform-objs-$(CONFIG_PLATFORM_TENSTORRENT_ATLANTIS) += tenstorrent/atlantis.o
> +endif
> diff --git a/platform/generic/tenstorrent/pma.c b/platform/generic/tenstorrent/pma.c
> new file mode 100644
> index 00000000..daf60192
> --- /dev/null
> +++ b/platform/generic/tenstorrent/pma.c
> @@ -0,0 +1,138 @@
> +/*
> + * SPDX-FileCopyrightText: (c) 2025-2026 Tenstorrent USA, Inc.
> + * SPDX-License-Identifier: BSD-2-Clause
> + */
> +
> +#include <sbi/sbi_error.h>
> +#include <sbi/sbi_console.h>
> +#include <sbi/sbi_math.h>
> +#include <libfdt.h>
> +#include <sbi_utils/fdt/fdt_helper.h>
> +
> +#include <tenstorrent/pma.h>
> +
> +/*
> + * All PMAs in the system should be the same (after boot). The init code
> + * must have set PMAs for all HARTs.
> + */
> +
> +/*
> + * Ascalon CPU and IOMMU PMA layout:
> + * Field
> + * [2:0]       Permission      [0] Read, [1] Write, [2] Execute
> + * [4:3]       Memory type     00: Main memory, 01: IO memory relaxed,
> + *                             10: IO memory channel 0, 11: IO memory channel 1
> + * [6:5]       AMO type        00: AMONone, 01: AMOSwap,
> + *                             10: AMOLogical, 11: AMOArithmetic
> + * [7]         Cacheability (main memory type)
> + *                             1: Cacheable, 0: Non-cacheable
> + *             Combining Capability (IO memory type)
> + *                             1: Combining allowed, 0: Combining disallowed
> + * [8]         Routing (coherency)
> + *                             1: Coherent network, 0: Non-coherent network
> + * [11:9]      Reserved
> + * [51:12]     Physical address [51:12] base
> + * [63:58]     Size log 2 (number of address LSB to ignore when matching)
> + *             0 = invalid entry (no match)
> + */
> +
> +#define PMA_PERMISSION_R       0x1
> +#define PMA_PERMISSION_W       0x2
> +#define PMA_PERMISSION_X       0x4
> +#define PMA_PERMISSION_MASK    0x7
> +
> +#define PMA_TYPE_MAIN_MEMORY   0x0
> +#define PMA_TYPE_IO_RELAXED    0x8
> +#define PMA_TYPE_IO_ORDERED_0  0x10
> +#define PMA_TYPE_IO_ORDERED_1  0x18
> +#define PMA_TYPE_MASK          0x18
> +
> +#define PMA_AMO_NONE           0x0
> +#define PMA_AMO_SWAP           0x20
> +#define PMA_AMO_LOGICAL                0x40
> +#define PMA_AMO_ARITHMETIC     0x60
> +#define PMA_AMO_MASK           0x60
> +
> +#define PMA_MEMORY_CACHEABLE   0x80
> +#define PMA_IO_COMBINING       0x80
> +#define PMA_ROUTING_COHERENT   0x100
> +
> +#define PMA_FLAGS_MASK         0x00000000000001ffULL
> +#define PMA_ADDRESS_MASK       0x000ffffffffff000ULL
> +#define PMA_SIZE_MASK          0xfc00000000000000ULL
> +#define PMA_RESERVED_MASK      0x0300000000000e00ULL
> +
> +#define PMA_SIZE_SHIFT         58
> +
> +static u64 tt_pma_size(u64 pma)
> +{
> +       if ((pma & PMA_SIZE_MASK) == 0)
> +               return 0;
> +
> +       return 1ULL << ((pma & PMA_SIZE_MASK) >> PMA_SIZE_SHIFT);
> +}
> +
> +static u64 tt_pma_address(u64 pma)
> +{
> +       return (pma & PMA_ADDRESS_MASK) & ~((tt_pma_size(pma) - 1));
> +}
> +
> +bool tt_pma_validate(unsigned int i, u64 pma)
> +{
> +       if (!pma)
> +               return true;
> +
> +       if (pma & PMA_RESERVED_MASK) {
> +               sbi_printf("PMA%02u 0x%016lx contains reserved bits\n", i, pma);
> +               return false;
> +       }
> +
> +       if (tt_pma_size(pma) < 4096) {
> +               sbi_printf("PMA%02u 0x%016lx size < 4KB\n", i, pma);
> +               return false;
> +       }
> +
> +       if (tt_pma_address(pma) != (pma & PMA_ADDRESS_MASK)) {
> +               sbi_printf("PMA%02u 0x%016lx address is not aligned to size\n", i, pma);
> +               return false;
> +       }
> +
> +       return true;
> +}
> +
> +void tt_pma_print(unsigned int i, u64 pma)
> +{
> +       sbi_printf("PMA%02d                       : 0x%016lx-0x%016lx perm:%s%s%s type:%s %s %s amo:%s\n", i,
> +                       tt_pma_address(pma), tt_pma_address(pma) + tt_pma_size(pma) - 1,
> +                       pma & PMA_PERMISSION_R ? "R" : " ",
> +                       pma & PMA_PERMISSION_W ? "W" : " ",
> +                       pma & PMA_PERMISSION_X ? "X" : " ",
> +                       (pma & PMA_TYPE_MASK) == PMA_TYPE_MAIN_MEMORY ? "main-memory" :
> +                        ((pma & PMA_TYPE_MASK) == PMA_TYPE_IO_RELAXED ? "io-relaxed" :
> +                         ((pma & PMA_TYPE_MASK) == PMA_TYPE_IO_ORDERED_0 ? "io-ordered-0" : "io-ordered-1")),
> +                       (pma & PMA_TYPE_MASK) == PMA_TYPE_MAIN_MEMORY ?
> +                        (pma & PMA_MEMORY_CACHEABLE ? "cacheable" : "non-cacheable") :
> +                        (pma & PMA_IO_COMBINING ? "combining" : "non-combining"),
> +                       pma & PMA_ROUTING_COHERENT ? "coherent" : "non-coherent",
> +                       (pma & PMA_AMO_MASK) == PMA_AMO_NONE ? "none" :
> +                        ((pma & PMA_AMO_MASK) == PMA_AMO_SWAP ? "swap" :
> +                         ((pma & PMA_AMO_MASK) == PMA_AMO_LOGICAL ? "logical" : "arithmetic")));
> +}
> +
> +static u64 pmas[TT_MAX_PMAS];
> +
> +void tt_pma_set(unsigned int n, u64 pma)
> +{
> +       if (n >= TT_MAX_PMAS)
> +               sbi_panic("PMA exceeded TT_MAX_PMAS");
> +
> +       pmas[n] = pma;
> +}
> +
> +u64 tt_pma_get(unsigned int n)
> +{
> +       if (n >= TT_MAX_PMAS)
> +               sbi_panic("PMA exceeded TT_MAX_PMAS");
> +
> +       return pmas[n];
> +}
> --
> 2.53.0
>
>
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