doc_read_page_getbytes(9)

💅 doc_read_page_getbytes — Kernel API Manual, bestie edition ✨

okay so you found a kernel doc page and you're like "what is this" — don't worry, I got you. this one is doc_read_page_getbytes, straight out of the Kernel API Manual, and it's giving "niche MTD driver lore" but honestly? kinda iconic.

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🌸 NAME 🌸

doc_read_page_getbytes — reads bytes from a prepared page. that's it. that's the whole vibe. 🎀

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✨ SYNOPSIS ✨

int doc_read_page_getbytes (struct docg3 *docg3 , int len , u_char *buf
, int first , int last_odd );

five arguments, one int coming back at you. she's compact. 💅

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🫶 ARGUMENTS 🫶

• docg3 — the device. your main character. the whole reason we're here. 👑
• len — how many bytes you wanna read. ⚠️ must be a multiple of 4 — do not test her on this, fr fr.
• buf — the buffer getting filled in. and yes, NULL is allowed — that literally means "forget the bytes," like you're just reading for the plot and not keeping receipts. 🙈
• first — 1 if this is the first time reading, in which case DOC_READADDRESS should be set. ⭐
• last_odd — 1 if the last read ended up on an odd byte. she's a little quirky like that. 🦋

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💖 DESCRIPTION 💖

so this function reads bytes from a prepared page. sounds simple, right? no. there's trickery here and I need you to pay attention bestie 😭

here's the situation: if the last read ended up on an odd offset in the 1024 bytes double page — that is, between the 2 planes — then the first byte has to be read apart. like, separately. on its own. no friends. 🧚

and why? because if a word (16bit) read was used, the read would return the byte of plane 2 as low and high endian, which will mess the read. 💀 so yeah. don't do that. that's the whole trickery. noted and respected.

this is one of those "the hardware said no" situations and the code had to get creative. lowkey obsessed with the workaround ngl.

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🔥 SEE ALSO 🔥

a truly unserious amount of friends. she knows everybody. kernel file ./drivers/mtd/devices/docg3.c — go say hi 💜

• doc_delay(9)
• doc_read_data_area(9)
• doc_write_data_area(9)
• doc_set_reliable_mode(9)
• doc_set_asic_mode(9)
• doc_set_device_id(9)
• doc_set_extra_page_mode(9)
• doc_setup_addr_sector(9)
• doc_setup_writeaddr_sector(9)
• doc_read_seek(9)
• doc_write_seek(9)
• doc_read_page_ecc_init(9)
• doc_write_page_ecc_init(9)
• doc_ecc_disable(9)
• doc_hamming_ecc_init(9)
• doc_ecc_bch_fix_data(9)
• doc_read_page_prepare(9)
• doc_write_page_putbytes(9)
• doc_get_bch_hw_ecc(9)
• doc_page_finish(9)
• doc_read_page_finish(9)
• calc_block_sector(9)
• doc_read_oob(9)
• doc_block_isbad(9)
• doc_get_erase_count(9)
• doc_get_op_status(9)
• doc_write_erase_wait_status(9)
• doc_erase_block(9)
• doc_erase(9)
• doc_write_page(9)
• doc_guess_autoecc(9)
• doc_fill_autooob(9)
• doc_backup_oob(9)
• doc_write_oob(9)
• doc_set_driver_info(9)
• doc_probe_device(9)
• doc_release_device(9)
• docg3_resume(9)
• docg3_suspend(9)
• docg3_probe(9)
• docg3_release(9)

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and that's the page!! 💅 this lil icon lives in ./drivers/mtd/devices and the doc is dated October 2026 — go off, calendar. mwah, bye bestie 🫶✨