drivers/usb/host/ohci-mem.c

Source file repositories/reference/linux-study-clean/drivers/usb/host/ohci-mem.c

File Facts

System
Linux kernel
Corpus path
drivers/usb/host/ohci-mem.c
Extension
.c
Size
4126 bytes
Lines
164
Domain
Driver Families
Bucket
drivers/usb
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

// SPDX-License-Identifier: GPL-1.0+
/*
 * OHCI HCD (Host Controller Driver) for USB.
 *
 * (C) Copyright 1999 Roman Weissgaerber <weissg@vienna.at>
 * (C) Copyright 2000-2002 David Brownell <dbrownell@users.sourceforge.net>
 *
 * This file is licenced under the GPL.
 */

/*-------------------------------------------------------------------------*/

/*
 * OHCI deals with three types of memory:
 *	- data used only by the HCD ... kmalloc is fine
 *	- async and periodic schedules, shared by HC and HCD ... these
 *	  need to use dma_pool or dma_alloc_coherent
 *	- driver buffers, read/written by HC ... the hcd glue or the
 *	  device driver provides us with dma addresses
 *
 * There's also "register" data, which is memory mapped.
 * No memory seen by this driver (or any HCD) may be paged out.
 */

/*-------------------------------------------------------------------------*/

static void ohci_hcd_init (struct ohci_hcd *ohci)
{
	ohci->next_statechange = jiffies;
	spin_lock_init (&ohci->lock);
	INIT_LIST_HEAD (&ohci->pending);
	INIT_LIST_HEAD(&ohci->eds_in_use);
}

/*-------------------------------------------------------------------------*/

static int ohci_mem_init (struct ohci_hcd *ohci)
{
	/*
	 * HCs with local memory allocate from localmem_pool so there's
	 * no need to create the below dma pools.
	 */
	if (ohci_to_hcd(ohci)->localmem_pool)
		return 0;

	ohci->td_cache = dma_pool_create ("ohci_td",
		ohci_to_hcd(ohci)->self.controller,
		sizeof (struct td),
		32 /* byte alignment */,
		0 /* no page-crossing issues */);
	if (!ohci->td_cache)
		return -ENOMEM;
	ohci->ed_cache = dma_pool_create ("ohci_ed",
		ohci_to_hcd(ohci)->self.controller,
		sizeof (struct ed),
		16 /* byte alignment */,
		0 /* no page-crossing issues */);
	if (!ohci->ed_cache) {
		dma_pool_destroy (ohci->td_cache);
		return -ENOMEM;
	}
	return 0;
}

static void ohci_mem_cleanup (struct ohci_hcd *ohci)
{
	dma_pool_destroy(ohci->td_cache);
	ohci->td_cache = NULL;
	dma_pool_destroy(ohci->ed_cache);
	ohci->ed_cache = NULL;
}

/*-------------------------------------------------------------------------*/

/* ohci "done list" processing needs this mapping */
static inline struct td *
dma_to_td (struct ohci_hcd *hc, dma_addr_t td_dma)
{
	struct td *td;

	td_dma &= TD_MASK;
	td = hc->td_hash [TD_HASH_FUNC(td_dma)];
	while (td && td->td_dma != td_dma)
		td = td->td_hash;
	return td;
}

/* TDs ... */
static struct td *
td_alloc (struct ohci_hcd *hc, gfp_t mem_flags)

Annotation

Implementation Notes