mhi_prepare_for_transfer(9)

💅 mhi_prepare_for_transfer(9) — from the Kernel API Manual, bestie 🎀

okay so real talk, this one lives in the Kernel API Manual (section 9, the kernel-internals zone) and it's genuinely one of the cutest little setup functions in the MHI corner of the tree. like, it's the "get the girls ready" function. let's go ✨

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✨ NAME ✨

mhi_prepare_for_transfer — Setup UL and DL channels for data transfer. 💖

yes bestie, UL and DL, both of them, together, no picking favorites.

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🌸 SYNOPSIS 🌸

int mhi_prepare_for_transfer (struct mhi_device *mhi_dev );

it gives you back an int, and it takes exactly one thing. minimal. iconic. 🫶

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🦋 ARGUMENTS 🦋

• mhi_dev — Device associated with the channels. that's the whole vibe, she's just the device, that's it, that's her.

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👑 DESCRIPTION 👑

so here's what she actually does, and it's two whole things:

• Allocate and initialize the channel context — she sets up the channel context from scratch and gets it all cozy and initialized 💅
• Also issue the START channel command to both channels — not one, both. she sends START to both channels, she does not do half a job, periodt 🔥

and now the caveat, and listen, this one matters, do not skip it:

Channels can be started only if both the host and device execution environments match and the channels are in a DISABLED state.

like, both conditions. and, not or. if the host and device execution environments don't match, or a channel isn't sitting in DISABLED, she is not starting, bestie, it's giving "vibe check failed" 😭💀

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⭐ SEE ALSO ⭐

the whole friend group, no cap, everyone's invited, and yes I mean everyone 🧚‍♀️

first up, the Kernel file: ./include/linux/mhi.h

then the documented crew, one per bullet because I refuse to cram them and lose one:

• enum mhi_callback(9)
• enum mhi_flags(9)
• enum mhi_device_type(9)
• enum mhi_ch_type(9)
• struct mhi_buf(9)
• struct image_info(9)
• struct mhi_link_info(9)
• enum mhi_ee_type(9)
• enum mhi_state(9)
• enum mhi_ch_ee_mask(9)
• enum mhi_er_data_type(9)
• enum mhi_db_brst_mode(9)
• struct mhi_channel_config(9)
• struct mhi_event_config(9)
• struct mhi_controller_config(9)
• struct mhi_controller(9)
• struct mhi_device(9)
• struct mhi_result(9)
• struct mhi_driver(9)
• mhi_alloc_controller(9)
• mhi_free_controller(9)
• mhi_register_controller(9)
• mhi_unregister_controller(9)
• __mhi_driver_register(9)
• mhi_driver_unregister(9)
• mhi_set_mhi_state(9)
• mhi_notify(9)
• mhi_get_free_desc_count(9)
• mhi_prepare_for_power_up(9)
• mhi_async_power_up(9)
• mhi_sync_power_up(9)
• mhi_power_down(9)
• mhi_power_down_keep_dev(9)
• mhi_unprepare_after_power_down(9)
• mhi_pm_suspend(9)
• mhi_pm_resume(9)
• mhi_pm_resume_force(9)
• mhi_download_rddm_image(9)
• mhi_force_rddm_mode(9)
• mhi_get_exec_env(9)
• mhi_get_mhi_state(9)
• mhi_soc_reset(9)
• mhi_device_get_sync(9)
• mhi_device_put(9)
• mhi_unprepare_from_transfer(9)
• mhi_queue_buf(9)
• mhi_queue_skb(9)
• mhi_queue_is_full(9)
• mhi_get_channel_doorbell_offset(9)

iykyk 💜

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and that's the whole page, bestie, you ate that 🌈

sign-off time: this one comes from ./include/linux and it's dated October 2026 — mwah, see you in the next manpage 🍓💖✨