linux-drivers/
drivers/mailbox

SoC mailbox and inter-processor communication controllers

Mailbox controllers are small hardware blocks inside modern systems-on-chip that let the main CPU exchange short messages with co-processors such as power-management cores, security enclaves, and remote DSPs. This subsystem provides the shared framework plus individual drivers for mailbox IP found in ARM, Qualcomm, Aspeed, SiFive/Microchip, T-Head, and other current SoCs.

keep conf=0.94 last_sold=2025 deploy=high replacement=none subsystem=mailbox category=infrastructure
94%

recommendation

It should stay because this is an actively developed subsystem, not a legacy driver. The core framework received substantive fixes and new features in 2024-2026, a brand new ARM MHUv3 driver landed in 2024, and Kconfig keeps gaining support for current-generation SoC blocks from Aspeed, SiFive, Qualcomm, T-Head, CIX, and others that ship in hardware sold new today.

repository signals

46 files
23,476 source lines
344 commits, 5y
+10,743 / −2,941 lines added / removed, 5y
127 authors, 5y
monthly commits · 2021-04-21 → 2026-04-21 · 344 total · active in 57/61 months
2021 2022 2023 2024 2025 2026 2021-04: 0 commits · +0 −0 2021-05: 7 commits · +142 −99 2021-06: 10 commits · +283 −5 2021-07: 2 commits · +10 −9 2021-08: 5 commits · +93 −23 2021-09: 28 commits · +485 −392 2021-10: 4 commits · +489 −43 2021-11: 5 commits · +87 −36 2021-12: 10 commits · +22 −20 2022-01: 1 commit · +1 −0 2022-02: 8 commits · +569 −48 2022-03: 6 commits · +68 −28 2022-04: 7 commits · +134 −40 2022-05: 4 commits · +30 −5 2022-06: 3 commits · +25 −29 2022-07: 0 commits · +0 −0 2022-08: 5 commits · +33 −19 2022-09: 4 commits · +66 −9 2022-10: 1 commit · +2 −1 2022-11: 11 commits · +86 −69 2022-12: 4 commits · +45 −2 2023-01: 1 commit · +1 −1 2023-02: 1 commit · +1 −0 2023-03: 14 commits · +53 −500 2023-04: 5 commits · +125 −85 2023-05: 2 commits · +20 −6 2023-06: 1 commit · +9 −3 2023-07: 8 commits · +27 −42 2023-08: 5 commits · +91 −28 2023-09: 2 commits · +30 −4 2023-10: 2 commits · +76 −34 2023-11: 1 commit · +5 −5 2023-12: 17 commits · +57 −71 2024-01: 1 commit · +4 −4 2024-02: 4 commits · +66 −22 2024-03: 1 commit · +19 −18 2024-04: 19 commits · +1,454 −481 2024-05: 4 commits · +161 −13 2024-06: 6 commits · +258 −32 2024-07: 5 commits · +24 −27 2024-08: 4 commits · +8 −23 2024-09: 1 commit · +2 −2 2024-10: 7 commits · +78 −23 2024-11: 8 commits · +687 −31 2024-12: 5 commits · +541 −4 2025-01: 3 commits · +231 −12 2025-02: 11 commits · +20 −35 2025-03: 10 commits · +66 −67 2025-04: 9 commits · +100 −158 2025-05: 4 commits · +260 −11 2025-06: 3 commits · +674 −7 2025-07: 5 commits · +1,004 −7 2025-08: 6 commits · +1,075 −39 2025-09: 4 commits · +13 −11 2025-10: 16 commits · +653 −128 2025-11: 6 commits · +39 −36 2025-12: 6 commits · +23 −27 2026-01: 8 commits · +100 −55 2026-02: 1 commit · +2 −2 2026-03: 0 commits · +0 −0 2026-04: 0 commits · +0 −0

sources

  1. lore.kernel.org

    Core mailbox framework still receives substantive 2026 fixes; this patch changes mbox_send_message() error handling in drivers/mailbox/mailbox.c.

  2. lore.kernel.org

    Core mailbox framework still receives feature work in 2026; this patch adds a debugfs list of used channels in drivers/mailbox/mailbox.c.

  3. lore.kernel.org

    The subsystem is still growing with new hardware support; ARM MHUv3 driver was added in 2024 under drivers/mailbox/arm_mhuv3.c.

  4. git.kernel.org

    Current Kconfig still advertises support for recent SoC mailbox blocks including ARM MHUv3, AST2700, CV1800, MPFS, TH1520, CIX, and QCOM IPCC, indicating ongoing relevance in modern SoCs.

codex reasoning notes (technical)

Keep. This is an active mailbox-controller subsystem, not a single legacy chip driver. `lore_file_timeline` on drivers/mailbox/mailbox.c showed heavy 2024-2026 traffic with recent fixes/features; `lore_file_timeline` on drivers/mailbox/arm_mhuv3.c showed a new driver added in 2024. Local inspection of drivers/mailbox/Kconfig shows multiple current-generation SoC IP blocks (AST2700/CV1800/TH1520/CIX/MPFS/QCOM IPCC), so hardware-still-sold is an inference from recent upstream enablement plus current Kconfig coverage. Local recent-subject grep found no remove/deprecate discussion.