/*
 * Copyright (c) 2012-2013, NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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, see <http://www.gnu.org/licenses/>.
 */

#include "nvshm_types.h"
#include "nvshm_if.h"
#include "nvshm_priv.h"
#include "nvshm_ipc.h"
#include "nvshm_queue.h"
#include "nvshm_iobuf.h"

#include <mach/tegra_bb.h>

/* Flush cache lines associated with iobuf list */
static void flush_iob_list(struct nvshm_handle *handle, struct nvshm_iobuf *iob)
{
	struct nvshm_iobuf *phy_list, *leaf, *next, *sg_next;

	phy_list = iob;
	while (phy_list) {
		leaf = phy_list;
		next = phy_list->next;
		while (leaf) {
			sg_next = leaf->sg_next;
			BUG_ON(nvshm_iobuf_check(leaf) < 0);
			/* Flush associated data */
			if (leaf->length) {
				FLUSH_CPU_DCACHE(NVSHM_B2A(handle,
							   (int)leaf->npdu_data
							   + leaf->data_offset),
						 leaf->length);
			}
			/* Flush iobuf */
			FLUSH_CPU_DCACHE(leaf, sizeof(struct nvshm_iobuf));
			if (sg_next)
				leaf = NVSHM_B2A(handle, sg_next);
			else
				leaf = NULL;
		}
		if (next)
			phy_list = NVSHM_B2A(handle, next);
		else
			phy_list = NULL;
	}
}

/* Invalidate cache lines associated with iobuf list */
/* Return 0 if ok or non zero otherwise */
static int inv_iob_list(struct nvshm_handle *handle, struct nvshm_iobuf *iob)
{
	struct nvshm_iobuf *phy_list, *leaf;

	phy_list = iob;
	while (phy_list) {
		leaf = phy_list;
		while (leaf) {
			/* Check leaf address before any operation on it */
			/* Cannot use nvshm_iobuf_check because iobuf */
			/* is not invalidated so content will be wrong */
			if (ADDR_OUTSIDE(leaf, handle->ipc_base_virt,
					handle->ipc_size)) {
				return -EIO;
			}
			/* Invalidate iobuf */
			INV_CPU_DCACHE(leaf, sizeof(struct nvshm_iobuf));
			/* Check iobuf */
			if (nvshm_iobuf_check(leaf))
				return -EIO;
			/* Invalidate associated data */
			if (leaf->length) {
				INV_CPU_DCACHE(NVSHM_B2A(handle,
							   (int)leaf->npdu_data
							   + leaf->data_offset),
							   leaf->length);
			}
			if (leaf->sg_next)
				leaf = NVSHM_B2A(handle, leaf->sg_next);
			else
				leaf = NULL;
		}
		if (phy_list->next)
			phy_list = NVSHM_B2A(handle, phy_list->next);
		else
			phy_list = NULL;
	}
	return 0;
}

struct nvshm_iobuf *nvshm_queue_get(struct nvshm_handle *handle)
{
	struct nvshm_iobuf *dummy, *ret;

	if (!handle->shared_queue_head) {
		pr_err("%s: Queue not init!\n", __func__);
		return NULL;
	}

	dummy = handle->shared_queue_head;
	/* Invalidate lower part of iobuf - upper part can be written by AP */

	INV_CPU_DCACHE(&dummy->qnext,
		       sizeof(struct nvshm_iobuf) / 2);
	ret = NVSHM_B2A(handle, dummy->qnext);

	if (dummy->qnext == NULL)
		return NULL;

	/* Invalidate iobuf(s) and check validity */
	handle->errno = inv_iob_list(handle, ret);

	if (handle->errno) {
		pr_err("%s: queue corruption\n", __func__);
		return NULL;
	}

	handle->shared_queue_head = ret;

	/* Update queue_bb_offset for debug purpose */
	handle->conf->queue_bb_offset = (int)ret
		- (int)handle->ipc_base_virt;

	if ((handle->conf->queue_bb_offset < 0) ||
	    (handle->conf->queue_bb_offset > handle->conf->shmem_size))
		pr_err("%s: out of bound descriptor offset %d addr 0x%p/0x%p\n",
		       __func__,
		       handle->conf->queue_bb_offset,
		       ret,
		       NVSHM_A2B(handle, ret));

	pr_debug("%s (%p)->%p->(%p)\n", __func__,
		 dummy, ret, ret->qnext);

	dummy->qnext = NULL;
	nvshm_iobuf_free(dummy);

	return ret;
}

int nvshm_queue_put(struct nvshm_handle *handle, struct nvshm_iobuf *iob)
{
	unsigned long f;

	spin_lock_irqsave(&handle->qlock, f);
	if (!handle->shared_queue_tail) {
		spin_unlock_irqrestore(&handle->qlock, f);
		pr_err("%s: Queue not init!\n", __func__);
		return -EINVAL;
	}

	if (!iob) {
		pr_err("%s: Queueing null pointer!\n", __func__);
		spin_unlock_irqrestore(&handle->qlock, f);
		return -EINVAL;
	}

	/* Sanity check */
	if (handle->shared_queue_tail->qnext) {
		pr_err("%s: illegal queue pointer detected!\n", __func__);
		spin_unlock_irqrestore(&handle->qlock, f);
		return -EINVAL;
	}

	pr_debug("%s (%p)->%p/%d/%d->%p\n", __func__,
		handle->shared_queue_tail,
		iob, iob->chan, iob->length,
		iob->next);

	/* Take a reference on queued iobuf */
	nvshm_iobuf_ref(iob);
	/* Flush iobuf(s) in cache */
	flush_iob_list(handle, iob);
	handle->shared_queue_tail->qnext = NVSHM_A2B(handle, iob);
	/* Flush guard element from cache */
	FLUSH_CPU_DCACHE(handle->shared_queue_tail, sizeof(struct nvshm_iobuf));
	handle->shared_queue_tail = iob;

	spin_unlock_irqrestore(&handle->qlock, f);
	return 0;
}

int nvshm_init_queue(struct nvshm_handle *handle)
{

	pr_debug("%s instance %d\n", __func__, handle->instance);
	/* Catch config issues */
	if ((!handle->ipc_base_virt) || (!handle->desc_base_virt)) {
		pr_err("%s IPC or DESC base not defined!", __func__);
		return -ENOMEM;
	}

	if ((handle->desc_size % sizeof(struct nvshm_iobuf))) {
		pr_err("%s DESC zone illegal size!", __func__);
		return -EINVAL;
	}
	return 0;
}
/*
 * Called from IPC workqueue
 */
void nvshm_process_queue(struct nvshm_handle *handle)
{
	struct nvshm_iobuf *iob;
	struct nvshm_if_operations *ops;
	int chan;

	spin_lock_bh(&handle->lock);
	iob = nvshm_queue_get(handle);
	while (iob) {
		pr_debug("%s %p/%d/%d/%d->%p\n", __func__,
			iob, iob->chan, iob->length, iob->ref, iob->next);
		tegra_bb_clear_ipc(handle->tegra_bb);
		chan = iob->chan;
		if (iob->pool_id < NVSHM_AP_POOL_ID) {
			ops = handle->chan[chan].ops;
			if (ops) {
				spin_unlock_bh(&handle->lock);
				ops->rx_event(
					&handle->chan[chan],
					iob);
				spin_lock_bh(&handle->lock);
			} else {
				nvshm_iobuf_free_cluster(
					iob);
			}
		} else {
			/* freed iobuf can form a tree */
			/* Process attached iobufs but do not touch iob */
			/* as it will be freed by next queue_get */
			if (iob->next) {
				nvshm_iobuf_process_freed(
					NVSHM_B2A(handle, iob->next));
			}
		}
		iob = nvshm_queue_get(handle);
	}
	spin_unlock_bh(&handle->lock);
	/* Finalize BBC free */
	nvshm_iobuf_bbc_free(handle);
}

void nvshm_abort_queue(struct nvshm_handle *handle)
{
	pr_debug("%s:abort queue\n", __func__);
	/* Clear IPC to avoid warning in kernel log */
	tegra_bb_abort_ipc(handle->tegra_bb);
}