vme_master_read(9)

💖 vme_master_read — the Kernel API Manual, but make it make sense 💖

okay so bestie, we're literally in the Kernel API Manual today and the star of the show is vme_master_read. no cap, this one's a little function with a big job: it grabs data off the VME bus and drops it into your buffer. let's get into it 🫶

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✨ NAME ✨

vme_master_read — Read data from VME space into a buffer.

like, literally that's the whole vibe: read stuff, put it somewhere. iconic. 👑

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🌸 SYNOPSIS 🌸

ssize_t vme_master_read (struct vme_resource *resource , void *buf ,
       size_t count , loff_t offset );

write it exactly like that, bestie, every comma counts 🎀

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🦋 ARGUMENTS 🦋

• resource — Pointer to VME master resource. it's giving "main character" pointer energy 💅
• buf — Pointer to buffer where data should be transferred. this is the lil home the data's moving into 🏠
• count — Number of bytes to transfer. how many bytes we're moving, fr fr
• offset — Offset into VME master window at which to start transfer. like, where do we even begin ✨

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💜 DESCRIPTION 💜

so what it does is: perform read of count bytes of data from location on VME bus which maps into the VME master window at offset to buf. that's it, that's the whole task. read the bytes, yeet them into the buffer, slay. 🌈

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🔥 RETURN 🔥

• Returns the number of bytes read — the happy path, the "ate and left no crumbs" path 💅
• -EINVAL if resource is not a VME master resource or read operation is not supported. not me getting an error because the vibe was wrong 😭
• -EFAULT returned if invalid offset is provided. bad offset = bad time, bestie 🙈
• Hardware specific errors may also be returned. so like, sometimes the hardware just has its own opinions, iykyk 💀

⚠️ heads up: those last two are your red flags. if you see -EINVAL or -EFAULT, check your resource and offset first before you spiral.

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👑 SEE ALSO 👑

Kernel file ./drivers/staging/vme_user/vme.c — and honestly, the whole VME friend group is here. every single one, no gatekeeping:

vme_alloc_consistent(9), vme_free_consistent(9), vme_get_size(9), vme_slave_request(9), vme_slave_set(9), vme_slave_get(9), vme_slave_free(9), vme_master_request(9), vme_master_set(9), vme_master_get(9), vme_master_write(9), vme_master_rmw(9), vme_master_mmap_prepare(9), vme_master_free(9), vme_dma_request(9), vme_new_dma_list(9), vme_dma_pattern_attribute(9), vme_dma_pci_attribute(9), vme_dma_vme_attribute(9), vme_dma_free_attribute(9), vme_dma_list_add(9), vme_dma_list_exec(9), vme_dma_list_free(9), vme_dma_free(9), vme_irq_request(9), vme_irq_free(9), vme_irq_generate(9), vme_lm_request(9), vme_lm_count(9), vme_lm_set(9), vme_lm_get(9), vme_lm_attach(9), vme_lm_detach(9), vme_lm_free(9), vme_slot_num(9), vme_bus_num(9), vme_register_driver(9), vme_unregister_driver(9)

like, the whole roster. go read them. it's giving study group 📚💖

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and that's the page, bestie!! xoxo, this was the ./drivers/staging/vme_user page from October 2026, signed, sealed, delivered with love 🎀💌✨ no cap, you're gonna do great. 🦋💜🌸