/*
 * 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 "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 0x%x\n",
			(unsigned int) seg);

	seg->trbs = dma_pool_alloc(xhci->segment_pool, flags, &dma);
	if (!seg->trbs) {
		kfree(seg);
		return 0;
	}
	xhci_dbg(xhci, "// Allocating segment at 0x%x (virtual) 0x%x (DMA)\n",
			(unsigned int) seg->trbs, (u32) 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 0x%x"
				" (virtual) 0x%x (DMA)\n",
				(unsigned int) seg->trbs, (u32) seg->dma);
		dma_pool_free(xhci->segment_pool, seg->trbs, seg->dma);
		seg->trbs = NULL;
	}
	xhci_dbg(xhci, "Freeing priv segment structure at 0x%x\n",
			(unsigned int) 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[0] = 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);
		prev->trbs[TRBS_PER_SEGMENT-1].link.control = val;
	}
	xhci_dbg(xhci, "Linking segment 0x%x to segment 0x%x (DMA)\n",
			prev->dma, next->dma);
}

/* XXX: Do we need the hcd structure in all these functions? */
static 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 0x%x\n", (unsigned int) 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 0x%x\n", (unsigned int) ring);
	if (!ring)
		return 0;

	if (num_segs == 0)
		return ring;

	ring->first_seg = xhci_segment_alloc(xhci, flags);
	if (!ring->first_seg)
		goto fail;
	num_segs--;

	prev = ring->first_seg;
	while (num_segs > 0) {
		struct xhci_segment	*next;

		next = xhci_segment_alloc(xhci, flags);
		if (!next)
			goto fail;
		xhci_link_segments(xhci, prev, next, link_trbs);

		prev = next;
		num_segs--;
	}
	xhci_link_segments(xhci, prev, ring->first_seg, link_trbs);

	if (link_trbs) {
		/* See section 4.9.2.1 and 6.4.4.1 */
		prev->trbs[TRBS_PER_SEGMENT-1].link.control |= (LINK_TOGGLE);
		xhci_dbg(xhci, "Wrote link toggle flag to"
				" segment 0x%x (virtual), 0x%x (DMA)\n",
				(unsigned int) prev, (u32) prev->dma);
	}
	/* The ring is empty, so the enqueue pointer == dequeue pointer */
	ring->enqueue = ring->first_seg->trbs;
	ring->dequeue = ring->enqueue;
	/* The ring is initialized to 0. The producer must write 1 to the cycle
	 * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
	 * compare CCS to the cycle bit to check ownership, so CCS = 1.
	 */
	ring->cycle_state = 1;

	return ring;

fail:
	xhci_ring_free(xhci, ring);
	return 0;
}

void xhci_mem_cleanup(struct xhci_hcd *xhci)
{
	struct pci_dev	*pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
	int size;

	/* XXX: Free all the segments in the various rings */

	/* Free the Event Ring Segment Table and the actual Event Ring */
	xhci_writel(xhci, 0, &xhci->ir_set->erst_size);
	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[1]);
	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[0]);
	xhci_writel(xhci, 0, &xhci->ir_set->erst_dequeue[1]);
	xhci_writel(xhci, 0, &xhci->ir_set->erst_dequeue[0]);
	size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);
	if (xhci->erst.entries)
		pci_free_consistent(pdev, size,
				xhci->erst.entries, xhci->erst.erst_dma_addr);
	xhci->erst.entries = NULL;
	xhci_dbg(xhci, "Freed ERST\n");
	if (xhci->event_ring)
		xhci_ring_free(xhci, xhci->event_ring);
	xhci->event_ring = NULL;
	xhci_dbg(xhci, "Freed event ring\n");

	xhci_writel(xhci, 0, &xhci->op_regs->cmd_ring[1]);
	xhci_writel(xhci, 0, &xhci->op_regs->cmd_ring[0]);
	if (xhci->cmd_ring)
		xhci_ring_free(xhci, xhci->cmd_ring);
	xhci->cmd_ring = NULL;
	xhci_dbg(xhci, "Freed command ring\n");
	if (xhci->segment_pool)
		dma_pool_destroy(xhci->segment_pool);
	xhci->segment_pool = NULL;
	xhci_dbg(xhci, "Freed segment pool\n");
	xhci_writel(xhci, 0, &xhci->op_regs->dcbaa_ptr[1]);
	xhci_writel(xhci, 0, &xhci->op_regs->dcbaa_ptr[0]);
	if (xhci->dcbaa)
		pci_free_consistent(pdev, sizeof(*xhci->dcbaa),
				xhci->dcbaa, xhci->dcbaa->dma);
	xhci->dcbaa = NULL;
	xhci->page_size = 0;
	xhci->page_shift = 0;
}

int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
{
	dma_addr_t	dma;
	struct device	*dev = xhci_to_hcd(xhci)->self.controller;
	unsigned int	val, val2;
	struct xhci_segment	*seg;
	u32 page_size;
	int i;

	page_size = xhci_readl(xhci, &xhci->op_regs->page_size);
	xhci_dbg(xhci, "Supported page size register = 0x%x\n", page_size);
	for (i = 0; i < 16; i++) {
		if ((0x1 & page_size) != 0)
			break;
		page_size = page_size >> 1;
	}
	if (i < 16)
		xhci_dbg(xhci, "Supported page size of %iK\n", (1 << (i+12)) / 1024);
	else
		xhci_warn(xhci, "WARN: no supported page size\n");
	/* Use 4K pages, since that's common and the minimum the HC supports */
	xhci->page_shift = 12;
	xhci->page_size = 1 << xhci->page_shift;
	xhci_dbg(xhci, "HCD page size set to %iK\n", xhci->page_size / 1024);

	/*
	 * Program the Number of Device Slots Enabled field in the CONFIG
	 * register with the max value of slots the HC can handle.
	 */
	val = HCS_MAX_SLOTS(xhci_readl(xhci, &xhci->cap_regs->hcs_params1));
	xhci_dbg(xhci, "// xHC can handle at most %d device slots.\n",
			(unsigned int) val);
	val2 = xhci_readl(xhci, &xhci->op_regs->config_reg);
	val |= (val2 & ~HCS_SLOTS_MASK);
	xhci_dbg(xhci, "// Setting Max device slots reg = 0x%x.\n",
			(unsigned int) val);
	xhci_writel(xhci, val, &xhci->op_regs->config_reg);

	/*
	 * Section 5.4.8 - doorbell array must be
	 * "physically contiguous and 64-byte (cache line) aligned".
	 */
	xhci->dcbaa = pci_alloc_consistent(to_pci_dev(dev),
			sizeof(*xhci->dcbaa), &dma);
	if (!xhci->dcbaa)
		goto fail;
	memset(xhci->dcbaa, 0, sizeof *(xhci->dcbaa));
	xhci->dcbaa->dma = dma;
	xhci_dbg(xhci, "// Setting device context base array address to 0x%x\n",
			xhci->dcbaa->dma);
	xhci_writel(xhci, (u32) 0, &xhci->op_regs->dcbaa_ptr[1]);
	xhci_writel(xhci, dma, &xhci->op_regs->dcbaa_ptr[0]);

	/*
	 * Initialize the ring segment pool.  The ring must be a contiguous
	 * structure comprised of TRBs.  The TRBs must be 16 byte aligned,
	 * however, the command ring segment needs 64-byte aligned segments,
	 * so we pick the greater alignment need.
	 */
	xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
			SEGMENT_SIZE, 64, xhci->page_size);
	if (!xhci->segment_pool)
		goto fail;

	/* Set up the command ring to have one segments for now. */
	xhci->cmd_ring = xhci_ring_alloc(xhci, 1, true, flags);
	if (!xhci->cmd_ring)
		goto fail;
	xhci_dbg(xhci, "Allocated command ring at 0x%x\n", (unsigned int) xhci->cmd_ring);
	xhci_dbg(xhci, "First segment DMA is 0x%x\n", (unsigned int) xhci->cmd_ring->first_seg->dma);

	/* Set the address in the Command Ring Control register */
	val = xhci_readl(xhci, &xhci->op_regs->cmd_ring[0]);
	val = (val & ~CMD_RING_ADDR_MASK) |
		(xhci->cmd_ring->first_seg->dma & CMD_RING_ADDR_MASK) |
		xhci->cmd_ring->cycle_state;
	xhci_dbg(xhci, "// Setting command ring address high bits to 0x0\n");
	xhci_writel(xhci, (u32) 0, &xhci->op_regs->cmd_ring[1]);
	xhci_dbg(xhci, "// Setting command ring address low bits to 0x%x\n", val);
	xhci_writel(xhci, val, &xhci->op_regs->cmd_ring[0]);
	xhci_dbg_cmd_ptrs(xhci);

	val = xhci_readl(xhci, &xhci->cap_regs->db_off);
	val &= DBOFF_MASK;
	xhci_dbg(xhci, "// Doorbell array is located at offset 0x%x"
			" from cap regs base addr\n", val);
	xhci->dba = (void *) xhci->cap_regs + val;
	xhci_dbg_regs(xhci);
	xhci_print_run_regs(xhci);
	/* Set ir_set to interrupt register set 0 */
	xhci->ir_set = (void *) xhci->run_regs->ir_set;

	/*
	 * Event ring setup: Allocate a normal ring, but also setup
	 * the event ring segment table (ERST).  Section 4.9.3.
	 */
	xhci_dbg(xhci, "// Allocating event ring\n");
	xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, false, flags);
	if (!xhci->event_ring)
		goto fail;

	xhci->erst.entries = pci_alloc_consistent(to_pci_dev(dev),
			sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS, &dma);
	if (!xhci->erst.entries)
		goto fail;
	xhci_dbg(xhci, "// Allocated event ring segment table at 0x%x\n", dma);

	memset(xhci->erst.entries, 0, sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS);
	xhci->erst.num_entries = ERST_NUM_SEGS;
	xhci->erst.erst_dma_addr = dma;
	xhci_dbg(xhci, "Set ERST to 0; private num segs = %i, virt addr = 0x%x, dma addr = 0x%x\n",
			xhci->erst.num_entries,
			(unsigned int) xhci->erst.entries,
			xhci->erst.erst_dma_addr);

	/* set ring base address and size for each segment table entry */
	for (val = 0, seg = xhci->event_ring->first_seg; val < ERST_NUM_SEGS; val++) {
		struct xhci_erst_entry *entry = &xhci->erst.entries[val];
		entry->seg_addr[1] = 0;
		entry->seg_addr[0] = seg->dma;
		entry->seg_size = TRBS_PER_SEGMENT;
		entry->rsvd = 0;
		seg = seg->next;
	}

	/* set ERST count with the number of entries in the segment table */
	val = xhci_readl(xhci, &xhci->ir_set->erst_size);
	val &= ERST_SIZE_MASK;
	val |= ERST_NUM_SEGS;
	xhci_dbg(xhci, "// Write ERST size = %i to ir_set 0 (some bits preserved)\n",
			val);
	xhci_writel(xhci, val, &xhci->ir_set->erst_size);

	xhci_dbg(xhci, "// Set ERST entries to point to event ring.\n");
	/* set the segment table base address */
	xhci_dbg(xhci, "// Set ERST base address for ir_set 0 = 0x%x\n",
			xhci->erst.erst_dma_addr);
	xhci_writel(xhci, 0, &xhci->ir_set->erst_base[1]);
	val = xhci_readl(xhci, &xhci->ir_set->erst_base[0]);
	val &= ERST_PTR_MASK;
	val |= (xhci->erst.erst_dma_addr & ~ERST_PTR_MASK);
	xhci_writel(xhci, val, &xhci->ir_set->erst_base[0]);

	/* Set the event ring dequeue address */
	xhci_dbg(xhci, "// Set ERST dequeue address for ir_set 0 = 0x%x%x\n",
			xhci->erst.entries[0].seg_addr[1], xhci->erst.entries[0].seg_addr[0]);
	val = xhci_readl(xhci, &xhci->run_regs->ir_set[0].erst_dequeue[0]);
	val &= ERST_PTR_MASK;
	val |= (xhci->erst.entries[0].seg_addr[0] & ~ERST_PTR_MASK);
	xhci_writel(xhci, val, &xhci->run_regs->ir_set[0].erst_dequeue[0]);
	xhci_writel(xhci, xhci->erst.entries[0].seg_addr[1],
			&xhci->run_regs->ir_set[0].erst_dequeue[1]);
	xhci_dbg(xhci, "Wrote ERST address to ir_set 0.\n");
	xhci_print_ir_set(xhci, xhci->ir_set, 0);

	/*
	 * XXX: Might need to set the Interrupter Moderation Register to
	 * something other than the default (~1ms minimum between interrupts).
	 * See section 5.5.1.2.
	 */

	return 0;
fail:
	xhci_warn(xhci, "Couldn't initialize memory\n");
	xhci_mem_cleanup(xhci);
	return -ENOMEM;
}