path: root/drivers/net/wireless/ath/wil6210/txrx.c

/*
 * Copyright (c) 2012 Qualcomm Atheros, Inc.
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <linux/etherdevice.h>
#include <net/ieee80211_radiotap.h>
#include <linux/if_arp.h>
#include <linux/moduleparam.h>

#include "wil6210.h"
#include "wmi.h"
#include "txrx.h"
#include "trace.h"

static bool rtap_include_phy_info;
module_param(rtap_include_phy_info, bool, S_IRUGO);
MODULE_PARM_DESC(rtap_include_phy_info,
		 " Include PHY info in the radiotap header, default - no");

static inline int wil_vring_is_empty(struct vring *vring)
{
	return vring->swhead == vring->swtail;
}

static inline u32 wil_vring_next_tail(struct vring *vring)
{
	return (vring->swtail + 1) % vring->size;
}

static inline void wil_vring_advance_head(struct vring *vring, int n)
{
	vring->swhead = (vring->swhead + n) % vring->size;
}

static inline int wil_vring_is_full(struct vring *vring)
{
	return wil_vring_next_tail(vring) == vring->swhead;
}
/*
 * Available space in Tx Vring
 */
static inline int wil_vring_avail_tx(struct vring *vring)
{
	u32 swhead = vring->swhead;
	u32 swtail = vring->swtail;
	int used = (vring->size + swhead - swtail) % vring->size;

	return vring->size - used - 1;
}

static int wil_vring_alloc(struct wil6210_priv *wil, struct vring *vring)
{
	struct device *dev = wil_to_dev(wil);
	size_t sz = vring->size * sizeof(vring->va[0]);
	uint i;

	BUILD_BUG_ON(sizeof(vring->va[0]) != 32);

	vring->swhead = 0;
	vring->swtail = 0;
	vring->ctx = kcalloc(vring->size, sizeof(vring->ctx[0]), GFP_KERNEL);
	if (!vring->ctx) {
		vring->va = NULL;
		return -ENOMEM;
	}
	/*
	 * vring->va should be aligned on its size rounded up to power of 2
	 * This is granted by the dma_alloc_coherent
	 */
	vring->va = dma_alloc_coherent(dev, sz, &vring->pa, GFP_KERNEL);
	if (!vring->va) {
		kfree(vring->ctx);
		vring->ctx = NULL;
		return -ENOMEM;
	}
	/* initially, all descriptors are SW owned
	 * For Tx and Rx, ownership bit is at the same location, thus
	 * we can use any
	 */
	for (i = 0; i < vring->size; i++) {
		volatile struct vring_tx_desc *_d = &(vring->va[i].tx);
		_d->dma.status = TX_DMA_STATUS_DU;
	}

	wil_dbg_misc(wil, "vring[%d] 0x%p:0x%016llx 0x%p\n", vring->size,
		     vring->va, (unsigned long long)vring->pa, vring->ctx);

	return 0;
}

static void wil_vring_free(struct wil6210_priv *wil, struct vring *vring,
			   int tx)
{
	struct device *dev = wil_to_dev(wil);
	size_t sz = vring->size * sizeof(vring->va[0]);

	while (!wil_vring_is_empty(vring)) {
		dma_addr_t pa;
		u16 dmalen;
		struct wil_ctx *ctx;

		if (tx) {
			struct vring_tx_desc dd, *d = &dd;
			volatile struct vring_tx_desc *_d =
					&vring->va[vring->swtail].tx;

			ctx = &vring->ctx[vring->swtail];
			*d = *_d;
			pa = wil_desc_addr(&d->dma.addr);
			dmalen = le16_to_cpu(d->dma.length);
			if (vring->ctx[vring->swtail].mapped_as_page) {
				dma_unmap_page(dev, pa, dmalen,
					       DMA_TO_DEVICE);
			} else {
				dma_unmap_single(dev, pa, dmalen,
						 DMA_TO_DEVICE);
			}
			if (ctx->skb)
				dev_kfree_skb_any(ctx->skb);
			vring->swtail = wil_vring_next_tail(vring);
		} else { /* rx */
			struct vring_rx_desc dd, *d = &dd;
			volatile struct vring_rx_desc *_d =
					&vring->va[vring->swhead].rx;

			ctx = &vring->ctx[vring->swhead];
			*d = *_d;
			pa = wil_desc_addr(&d->dma.addr);
			dmalen = le16_to_cpu(d->dma.length);