drivers/firewire/init_ohci1394_dma.c

1 // SPDX-License-Identifier: GPL-2.0-or-later
3  * init_ohci1394_dma.c - Initializes physical DMA on all OHCI 1394 controllers
5  * Copyright (C) 2006-2007      Bernhard Kaindl <bk@suse.de>
7  * Derived from drivers/ieee1394/ohci1394.c and arch/x86/kernel/early-quirks.c
9  * - scan the PCI very early on boot for all OHCI 1394-compliant controllers
10  * - reset and initialize them and make them join the IEEE1394 bus and
11  * - enable physical DMA on them to allow remote debugging
18  * be sure that the stack enables it and (re-)attach after the bus reset
28 #include <asm/pci-direct.h>	/* for direct PCI config space access */
42 	writel(data, ohci->registers + offset);  in reg_write()
47 	return readl(ohci->registers + offset);  in reg_read()
52 /* Reads a PHY register of an OHCI-1394 controller */
70 /* Writes to a PHY register of an OHCI-1394 controller */
84 /* Resets an OHCI-1394 controller (for sane state before initialization) */
103 /* Basic OHCI-1394 register and port inititalization */
169  * init_ohci1394_wait_for_busresets - wait until bus resets are completed
171  * OHCI1394 initialization itself and any device going on- or offline
172  * and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
173  * specifies that physical DMA is disabled on each bus reset and it
174  * has to be enabled after each bus reset when needed. We resort
175  * to polling here because on early boot, we have no interrupts.
191  * init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
203  * init_ohci1394_reset_and_init_dma - init controller and enable DMA
208 	/* Start off with a soft reset, clears everything to a sane state. */  in init_ohci1394_reset_and_init_dma()
222 	 * The initialization causes at least one IEEE1394 bus reset. Enabling  in init_ohci1394_reset_and_init_dma()
232  * init_ohci1394_controller - Map the registers of the controller and init DMA
240 	printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"  in init_ohci1394_controller()
254  * init_ohci1394_dma_on_all_controllers - scan for OHCI1394 controllers and init DMA on them
255  * Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
272 					continue; /* No device at this func */  in init_ohci1394_dma_on_all_controllers()
275 					continue; /* Not an OHCI-1394 device */  in init_ohci1394_dma_on_all_controllers()
286  * setup_ohci1394_dma - enables early OHCI1394 DMA initialization
295 /* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */