prepare_dma(9)

💖 NAME 💖

okay bestie, welcome to prepare_dma(9) from the Kernel API Manual ✨ this is the page for prepare_dma — this function creates and initializes the DMA chain for the request. no cap, that’s the whole vibe 🫶

🌸 SYNOPSIS 🌸

int prepare_dma (struct pch_udc_ep *ep , struct pch_udc_request *req ,
gfp_t gfp );

🎀 ARGUMENTS 🎀

• ep — reference to the endpoint structure 💅
• req — reference to the request 🫶
• gfp — flag to be used while mapping the data buffer 🌈

✨ DESCRIPTION ✨

Return codes, straight up:

• 0 — Success 🎉
• Other 0 — linux error number on failure 😭

That’s literally the whole description, bestie. Short and iconic 👑

🦋 SEE ALSO 🦋

Kernel file ./drivers/usb/gadget/udc/pch_udc.c struct pch_udc_data_dma_desc(9), struct pch_udc_stp_dma_desc(9), struct pch_udc_cfg_data(9), struct pch_udc_ep(9), struct pch_vbus_gpio_data(9), struct pch_udc_dev(9), struct pch_udc_request(9), pch_udc_csr_busy(9), pch_udc_write_csr(9), pch_udc_read_csr(9), pch_udc_rmt_wakeup(9), pch_udc_get_frame(9), pch_udc_clear_selfpowered(9), pch_udc_set_selfpowered(9), pch_udc_set_disconnect(9), pch_udc_clear_disconnect(9), pch_udc_reconnect(9), pch_udc_vbus_session(9), pch_udc_ep_set_stall(9), pch_udc_ep_clear_stall(9), pch_udc_ep_set_trfr_type(9), pch_udc_ep_set_bufsz(9), pch_udc_ep_set_maxpkt(9), pch_udc_ep_set_subptr(9), pch_udc_ep_set_ddptr(9), pch_udc_ep_set_pd(9), pch_udc_ep_set_rrdy(9), pch_udc_ep_clear_rrdy(9), pch_udc_set_dma(9), pch_udc_clear_dma(9), pch_udc_set_csr_done(9), pch_udc_disable_interrupts(9), pch_udc_enable_interrupts(9), pch_udc_disable_ep_interrupts(9), pch_udc_enable_ep_interrupts(9), pch_udc_read_device_interrupts(9), pch_udc_write_device_interrupts(9), pch_udc_read_ep_interrupts(9), pch_udc_write_ep_interrupts(9), pch_udc_read_device_status(9), pch_udc_read_ep_control(9), pch_udc_clear_ep_control(9), pch_udc_read_ep_status(9), pch_udc_clear_ep_status(9), pch_udc_ep_set_nak(9), pch_udc_ep_clear_nak(9), pch_udc_ep_fifo_flush(9), pch_udc_ep_enable(9), pch_udc_ep_disable(9), pch_udc_wait_ep_stall(9), pch_udc_init(9), pch_udc_exit(9), pch_udc_pcd_get_frame(9), pch_udc_pcd_wakeup(9), pch_udc_pcd_selfpowered(9), pch_udc_pcd_pullup(9), pch_udc_pcd_vbus_session(9), pch_udc_pcd_vbus_draw(9), pch_vbus_gpio_get_value(9), pch_vbus_gpio_work_fall(9), pch_vbus_gpio_work_rise(9), pch_vbus_gpio_irq(9), pch_vbus_gpio_init(9), pch_vbus_gpio_free(9), complete_req(9), empty_req_queue(9), pch_udc_free_dma_chain(9), pch_udc_create_dma_chain(9), process_zlp(9), pch_udc_start_rxrequest(9), pch_udc_pcd_ep_enable(9), pch_udc_pcd_ep_disable(9), pch_udc_alloc_request(9), pch_udc_free_request(9), pch_udc_pcd_queue(9), pch_udc_pcd_dequeue(9), pch_udc_pcd_set_halt(9), pch_udc_pcd_set_wedge(9), pch_udc_pcd_fifo_flush(9), pch_udc_init_setup_buff(9), pch_udc_start_next_txrequest(9), pch_udc_complete_transfer(9), pch_udc_complete_receiver(9), pch_udc_svc_data_in(9), pch_udc_svc_data_out(9), pch_udc_svc_control_in(9), pch_udc_svc_control_out(9), pch_udc_postsvc_epinters(9), pch_udc_read_all_epstatus(9), pch_udc_activate_control_ep(9), pch_udc_svc_ur_interrupt(9), pch_udc_svc_enum_interrupt(9), pch_udc_svc_intf_interrupt(9), pch_udc_svc_cfg_interrupt(9), pch_udc_dev_isr(9), pch_udc_isr(9), pch_udc_setup_ep0(9), pch_udc_pcd_reinit(9), pch_udc_pcd_init(9), init_dma_pools(9)

later, bestie! 💅 this page came from the ./drivers/usb/gadget/udc source/version and is dated October 2026 — mwah! 💖