path: root/drivers/usb/host/xhci-mem.c

/*
 * xHCI host controller driver
 *
 * Copyright (C) 2008 Intel Corp.
 *
 * Author: Sarah Sharp
 * Some code borrowed from the Linux EHCI driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/usb.h>
#include <linux/pci.h>
#include <linux/dmapool.h>

#include "xhci.h"

/*
 * Allocates a generic ring segment from the ring pool, sets the dma address,
 * initializes the segment to zero, and sets the private next pointer to NULL.
 *
 * Section 4.11.1.1:
 * "All components of all Command and Transfer TRBs shall be initialized to '0'"
 */
static struct xhci_segment *xhci_segment_alloc(struct xhci_hcd *xhci, gfp_t flags)
{
	struct xhci_segment *seg;
	dma_addr_t	dma;

	seg = kzalloc(sizeof *seg, flags);
	if (!seg)
		return 0;
	xhci_dbg(xhci, "Allocating priv segment structure at %p\n", seg);

	seg->trbs = dma_pool_alloc(xhci->segment_pool, flags, &dma);
	if (!seg->trbs) {
		kfree(seg);
		return 0;
	}
	xhci_dbg(xhci, "// Allocating segment at %p (virtual) 0x%llx (DMA)\n",
			seg->trbs, (unsigned long long)dma);

	memset(seg->trbs, 0, SEGMENT_SIZE);
	seg->dma = dma;
	seg->next = NULL;

	return seg;
}

static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
{
	if (!seg)
		return;
	if (seg->trbs) {
		xhci_dbg(xhci, "Freeing DMA segment at %p (virtual) 0x%llx (DMA)\n",
				seg->trbs, (unsigned long long)seg->dma);
		dma_pool_free(xhci->segment_pool, seg->trbs, seg->dma);
		seg->trbs = NULL;
	}
	xhci_dbg(xhci, "Freeing priv segment structure at %p\n", seg);
	kfree(seg);
}

/*
 * Make the prev segment point to the next segment.
 *
 * Change the last TRB in the prev segment to be a Link TRB which points to the
 * DMA address of the next segment.  The caller needs to set any Link TRB
 * related flags, such as End TRB, Toggle Cycle, and no snoop.
 */
static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
		struct xhci_segment *next, bool link_trbs)
{
	u32 val;

	if (!prev || !next)
		return;
	prev->next = next;
	if (link_trbs) {
		prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr = next->dma;

		/* Set the last TRB in the segment to have a TRB type ID of Link TRB */
		val = prev->trbs[TRBS_PER_SEGMENT-1].link.control;
		val &= ~TRB_TYPE_BITMASK;
		val |= TRB_TYPE(TRB_LINK);
		/* Always set the chain bit with 0.95 hardware */
		if (xhci_link_trb_quirk(xhci))
			val |= TRB_CHAIN;
		prev->trbs[TRBS_PER_SEGMENT-1].link.control = val;
	}
	xhci_dbg(xhci, "Linking segment 0x%llx to segment 0x%llx (DMA)\n",
			(unsigned long long)prev->dma,
			(unsigned long long)next->dma);
}

/* XXX: Do we need the hcd structure in all these functions? */
void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
{
	struct xhci_segment *seg;
	struct xhci_segment *first_seg;

	if (!ring || !ring->first_seg)
		return;
	first_seg = ring->first_seg;
	seg = first_seg->next;
	xhci_dbg(xhci, "Freeing ring at %p\n", ring);
	while (seg != first_seg) {
		struct xhci_segment *next = seg->next;
		xhci_segment_free(xhci, seg);
		seg = next;
	}
	xhci_segment_free(xhci, first_seg);
	ring->first_seg = NULL;
	kfree(ring);
}

/**
 * Create a new ring with zero or more segments.
 *
 * Link each segment together into a ring.
 * Set the end flag and the cycle toggle bit on the last segment.
 * See section 4.9.1 and figures 15 and 16.
 */
static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
		unsigned int num_segs, bool link_trbs, gfp_t flags)
{
	struct xhci_ring	*ring;
	struct xhci_segment	*prev;

	ring = kzalloc(sizeof *(ring), flags);
	xhci_dbg(xhci, "Allocating ring at %p\n", ring);
	if