drivers/staging/octeon/ethernet-rx.c - linux - Git at Google

 /*
  * This file is based on code from OCTEON SDK by Cavium Networks.
  *
  * Copyright (c) 2003-2010 Cavium Networks
  *
  * This file 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.
  */

 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/cache.h>
 #include <linux/cpumask.h>
 #include <linux/netdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/ip.h>
 #include <linux/string.h>
 #include <linux/prefetch.h>
 #include <linux/ratelimit.h>
 #include <linux/smp.h>
 #include <linux/interrupt.h>
 #include <net/dst.h>
 #ifdef CONFIG_XFRM
 #include <linux/xfrm.h>
 #include <net/xfrm.h>
 #endif /* CONFIG_XFRM */

 #include <asm/octeon/octeon.h>

 #include "ethernet-defines.h"
 #include "ethernet-mem.h"
 #include "ethernet-rx.h"
 #include "octeon-ethernet.h"
 #include "ethernet-util.h"

 #include <asm/octeon/cvmx-helper.h>
 #include <asm/octeon/cvmx-wqe.h>
 #include <asm/octeon/cvmx-fau.h>
 #include <asm/octeon/cvmx-pow.h>
 #include <asm/octeon/cvmx-pip.h>
 #include <asm/octeon/cvmx-scratch.h>

 #include <asm/octeon/cvmx-gmxx-defs.h>

 static struct napi_struct cvm_oct_napi;

 /**
  * cvm_oct_do_interrupt - interrupt handler.
  * @cpl: Interrupt number. Unused
  * @dev_id: Cookie to identify the device. Unused
  *
  * The interrupt occurs whenever the POW has packets in our group.
  *
  */
 static irqreturn_t cvm_oct_do_interrupt(int cpl, void *dev_id)
 {
 	/* Disable the IRQ and start napi_poll. */
 	disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);
 	napi_schedule(&cvm_oct_napi);

 	return IRQ_HANDLED;
 }

 /**
  * cvm_oct_check_rcv_error - process receive errors
  * @work: Work queue entry pointing to the packet.
  *
  * Returns Non-zero if the packet can be dropped, zero otherwise.
  */
 static inline int cvm_oct_check_rcv_error(cvmx_wqe_t *work)
 {
 	int port;

 	if (octeon_has_feature(OCTEON_FEATURE_PKND))
 		port = work->word0.pip.cn68xx.pknd;
 	else
 		port = work->word1.cn38xx.ipprt;

 	if ((work->word2.snoip.err_code == 10) && (work->word1.len <= 64)) {
 		/*
 		 * Ignore length errors on min size packets. Some
 		 * equipment incorrectly pads packets to 64+4FCS
 		 * instead of 60+4FCS.  Note these packets still get
 		 * counted as frame errors.
 		 */
 	} else if (work->word2.snoip.err_code == 5 ||
 		   work->word2.snoip.err_code == 7) {
 		/*
 		 * We received a packet with either an alignment error
 		 * or a FCS error. This may be signalling that we are
 		 * running 10Mbps with GMXX_RXX_FRM_CTL[PRE_CHK]
 		 * off. If this is the case we need to parse the
 		 * packet to determine if we can remove a non spec
 		 * preamble and generate a correct packet.
 		 */
 		int interface = cvmx_helper_get_interface_num(port);
 		int index = cvmx_helper_get_interface_index_num(port);
 		union cvmx_gmxx_rxx_frm_ctl gmxx_rxx_frm_ctl;

 		gmxx_rxx_frm_ctl.u64 =
 		    cvmx_read_csr(CVMX_GMXX_RXX_FRM_CTL(index, interface));
 		if (gmxx_rxx_frm_ctl.s.pre_chk == 0) {
 			u8 *ptr =
 			    cvmx_phys_to_ptr(work->packet_ptr.s.addr);
 			int i = 0;

 			while (i < work->word1.len - 1) {
 				if (*ptr != 0x55)
 					break;
 				ptr++;
 				i++;
 			}

 			if (*ptr == 0xd5) {
 				/* Port received 0xd5 preamble */
 				work->packet_ptr.s.addr += i + 1;
 				work->word1.len -= i + 5;
 			} else if ((*ptr & 0xf) == 0xd) {
 				/* Port received 0xd preamble */
 				work->packet_ptr.s.addr += i;
 				work->word1.len -= i + 4;
 				for (i = 0; i < work->word1.len; i++) {
 					*ptr =
 					    ((*ptr & 0xf0) >> 4) |
 					    ((*(ptr + 1) & 0xf) << 4);
 					ptr++;
 				}
 			} else {
 				printk_ratelimited("Port %d unknown preamble, packet dropped\n",
 						   port);
 				cvm_oct_free_work(work);
 				return 1;
 			}
 		}
 	} else {
 		printk_ratelimited("Port %d receive error code %d, packet dropped\n",
 				   port, work->word2.snoip.err_code);
 		cvm_oct_free_work(work);
 		return 1;
 	}

 	return 0;
 }

 /**
  * cvm_oct_napi_poll - the NAPI poll function.
  * @napi: The NAPI instance, or null if called from cvm_oct_poll_controller
  * @budget: Maximum number of packets to receive.
  *
  * Returns the number of packets processed.
  */
 static int cvm_oct_napi_poll(struct napi_struct *napi, int budget)
 {
 	const int	coreid = cvmx_get_core_num();
 	u64	old_group_mask;
 	u64	old_scratch;
 	int		rx_count = 0;
 	int		did_work_request = 0;
 	int		packet_not_copied;

 	/* Prefetch cvm_oct_device since we know we need it soon */
 	prefetch(cvm_oct_device);

 	if (USE_ASYNC_IOBDMA) {
 		/* Save scratch in case userspace is using it */
 		CVMX_SYNCIOBDMA;
 		old_scratch = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
 	}

 	/* Only allow work for our group (and preserve priorities) */
 	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
 		old_group_mask = cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid));
 		cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid),
 			       1ull << pow_receive_group);
 		cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */
 	} else {
 		old_group_mask = cvmx_read_csr(CVMX_POW_PP_GRP_MSKX(coreid));
 		cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid),
 			       (old_group_mask & ~0xFFFFull) |
 			       1 << pow_receive_group);
 	}

 	if (USE_ASYNC_IOBDMA) {
 		cvmx_pow_work_request_async(CVMX_SCR_SCRATCH, CVMX_POW_NO_WAIT);
 		did_work_request = 1;
 	}

 	while (rx_count < budget) {
 		struct sk_buff *skb = NULL;
 		struct sk_buff **pskb = NULL;
 		int skb_in_hw;
 		cvmx_wqe_t *work;
 		int port;

 		if (USE_ASYNC_IOBDMA && did_work_request)
 			work = cvmx_pow_work_response_async(CVMX_SCR_SCRATCH);
 		else
 			work = cvmx_pow_work_request_sync(CVMX_POW_NO_WAIT);

 		prefetch(work);
 		did_work_request = 0;
 		if (!work) {
 			if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
 				cvmx_write_csr(CVMX_SSO_WQ_IQ_DIS,
 					       1ull << pow_receive_group);
 				cvmx_write_csr(CVMX_SSO_WQ_INT,
 					       1ull << pow_receive_group);
 			} else {
 				union cvmx_pow_wq_int wq_int;

 				wq_int.u64 = 0;
 				wq_int.s.iq_dis = 1 << pow_receive_group;
 				wq_int.s.wq_int = 1 << pow_receive_group;
 				cvmx_write_csr(CVMX_POW_WQ_INT, wq_int.u64);
 			}
 			break;
 		}
 		pskb = (struct sk_buff **)
 			(cvm_oct_get_buffer_ptr(work->packet_ptr) -
 			sizeof(void *));
 		prefetch(pskb);

 		if (USE_ASYNC_IOBDMA && rx_count < (budget - 1)) {
 			cvmx_pow_work_request_async_nocheck(CVMX_SCR_SCRATCH,
 							    CVMX_POW_NO_WAIT);
 			did_work_request = 1;
 		}
 		rx_count++;

 		skb_in_hw = work->word2.s.bufs == 1;
 		if (likely(skb_in_hw)) {
 			skb = *pskb;
 			prefetch(&skb->head);
 			prefetch(&skb->len);
 		}

 		if (octeon_has_feature(OCTEON_FEATURE_PKND))
 			port = work->word0.pip.cn68xx.pknd;
 		else
 			port = work->word1.cn38xx.ipprt;

 		prefetch(cvm_oct_device[port]);

 		/* Immediately throw away all packets with receive errors */
 		if (unlikely(work->word2.snoip.rcv_error)) {
 			if (cvm_oct_check_rcv_error(work))
 				continue;
 		}

 		/*
 		 * We can only use the zero copy path if skbuffs are
 		 * in the FPA pool and the packet fits in a single
 		 * buffer.
 		 */
 		if (likely(skb_in_hw)) {
 			skb->data = skb->head + work->packet_ptr.s.addr -
 				cvmx_ptr_to_phys(skb->head);
 			prefetch(skb->data);
 			skb->len = work->word1.len;
 			skb_set_tail_pointer(skb, skb->len);
 			packet_not_copied = 1;
 		} else {
 			/*
 			 * We have to copy the packet. First allocate
 			 * an skbuff for it.
 			 */
 			skb = dev_alloc_skb(work->word1.len);
 			if (!skb) {
 				cvm_oct_free_work(work);
 				continue;
 			}

 			/*
 			 * Check if we've received a packet that was
 			 * entirely stored in the work entry.
 			 */
 			if (unlikely(work->word2.s.bufs == 0)) {
 				u8 *ptr = work->packet_data;

 				if (likely(!work->word2.s.not_IP)) {
 					/*
 					 * The beginning of the packet
 					 * moves for IP packets.
 					 */
 					if (work->word2.s.is_v6)
 						ptr += 2;
 					else
 						ptr += 6;
 				}
 				memcpy(skb_put(skb, work->word1.len), ptr,
 				       work->word1.len);
 				/* No packet buffers to free */
 			} else {
 				int segments = work->word2.s.bufs;
 				union cvmx_buf_ptr segment_ptr =
 				    work->packet_ptr;
 				int len = work->word1.len;

 				while (segments--) {
 					union cvmx_buf_ptr next_ptr =
 					    *(union cvmx_buf_ptr *)
 					      cvmx_phys_to_ptr(
 					      segment_ptr.s.addr - 8);

 			/*
 			 * Octeon Errata PKI-100: The segment size is
 			 * wrong. Until it is fixed, calculate the
 			 * segment size based on the packet pool
 			 * buffer size. When it is fixed, the
 			 * following line should be replaced with this
 			 * one: int segment_size =
 			 * segment_ptr.s.size;
 			 */
 					int segment_size =
 					    CVMX_FPA_PACKET_POOL_SIZE -
 					    (segment_ptr.s.addr -
 					     (((segment_ptr.s.addr >> 7) -
 					       segment_ptr.s.back) << 7));
 					/*
 					 * Don't copy more than what
 					 * is left in the packet.
 					 */
 					if (segment_size > len)
 						segment_size = len;
 					/* Copy the data into the packet */
 					memcpy(skb_put(skb, segment_size),
 					       cvmx_phys_to_ptr(
 					       segment_ptr.s.addr),
 					       segment_size);
 					len -= segment_size;
 					segment_ptr = next_ptr;
 				}
 			}
 			packet_not_copied = 0;
 		}
 		if (likely((port < TOTAL_NUMBER_OF_PORTS) &&
 			   cvm_oct_device[port])) {
 			struct net_device *dev = cvm_oct_device[port];
 			struct octeon_ethernet *priv = netdev_priv(dev);

 			/*
 			 * Only accept packets for devices that are
 			 * currently up.
 			 */
 			if (likely(dev->flags & IFF_UP)) {
 				skb->protocol = eth_type_trans(skb, dev);
 				skb->dev = dev;

 				if (unlikely(work->word2.s.not_IP ||
 					     work->word2.s.IP_exc ||
 					     work->word2.s.L4_error ||
 					     !work->word2.s.tcp_or_udp))
 					skb->ip_summed = CHECKSUM_NONE;
 				else
 					skb->ip_summed = CHECKSUM_UNNECESSARY;

 				/* Increment RX stats for virtual ports */
 				if (port >= CVMX_PIP_NUM_INPUT_PORTS) {
 					priv->stats.rx_packets++;
 					priv->stats.rx_bytes += skb->len;
 				}
 				netif_receive_skb(skb);
 			} else {
 				/*
 				 * Drop any packet received for a device that
 				 * isn't up.
 				 */
 				priv->stats.rx_dropped++;
 				dev_kfree_skb_irq(skb);
 			}
 		} else {
 			/*
 			 * Drop any packet received for a device that
 			 * doesn't exist.
 			 */
 			printk_ratelimited("Port %d not controlled by Linux, packet dropped\n",
 					   port);
 			dev_kfree_skb_irq(skb);
 		}
 		/*
 		 * Check to see if the skbuff and work share the same
 		 * packet buffer.
 		 */
 		if (likely(packet_not_copied)) {
 			/*
 			 * This buffer needs to be replaced, increment
 			 * the number of buffers we need to free by
 			 * one.
 			 */
 			cvmx_fau_atomic_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE,
 					      1);

 			cvmx_fpa_free(work, CVMX_FPA_WQE_POOL, 1);
 		} else {
 			cvm_oct_free_work(work);
 		}
 	}
 	/* Restore the original POW group mask */
 	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
 		cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid), old_group_mask);
 		cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */
 	} else {
 		cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid), old_group_mask);
 	}

 	if (USE_ASYNC_IOBDMA) {
 		/* Restore the scratch area */
 		cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch);
 	}
 	cvm_oct_rx_refill_pool(0);

 	if (rx_count < budget && napi) {
 		/* No more work */
 		napi_complete(napi);
 		enable_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group);
 	}
 	return rx_count;
 }

 #ifdef CONFIG_NET_POLL_CONTROLLER
 /**
  * cvm_oct_poll_controller - poll for receive packets
  * device.
  *
  * @dev:    Device to poll. Unused
  */
 void cvm_oct_poll_controller(struct net_device *dev)
 {
 	cvm_oct_napi_poll(NULL, 16);
 }
 #endif

 void cvm_oct_rx_initialize(void)
 {
 	int i;
 	struct net_device *dev_for_napi = NULL;

 	for (i = 0; i < TOTAL_NUMBER_OF_PORTS; i++) {
 		if (cvm_oct_device[i]) {
 			dev_for_napi = cvm_oct_device[i];
 			break;
 		}
 	}

 	if (!dev_for_napi)
 		panic("No net_devices were allocated.");

 	netif_napi_add(dev_for_napi, &cvm_oct_napi, cvm_oct_napi_poll,
 		       rx_napi_weight);
 	napi_enable(&cvm_oct_napi);

 	/* Register an IRQ handler to receive POW interrupts */
 	i = request_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group,
 			cvm_oct_do_interrupt, 0, "Ethernet", cvm_oct_device);

 	if (i)
 		panic("Could not acquire Ethernet IRQ %d\n",
 		      OCTEON_IRQ_WORKQ0 + pow_receive_group);

 	disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);

 	/* Enable POW interrupt when our port has at least one packet */
 	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
 		union cvmx_sso_wq_int_thrx int_thr;
 		union cvmx_pow_wq_int_pc int_pc;

 		int_thr.u64 = 0;
 		int_thr.s.tc_en = 1;
 		int_thr.s.tc_thr = 1;
 		cvmx_write_csr(CVMX_SSO_WQ_INT_THRX(pow_receive_group),
 			       int_thr.u64);

 		int_pc.u64 = 0;
 		int_pc.s.pc_thr = 5;
 		cvmx_write_csr(CVMX_SSO_WQ_INT_PC, int_pc.u64);
 	} else {
 		union cvmx_pow_wq_int_thrx int_thr;
 		union cvmx_pow_wq_int_pc int_pc;

 		int_thr.u64 = 0;
 		int_thr.s.tc_en = 1;
 		int_thr.s.tc_thr = 1;
 		cvmx_write_csr(CVMX_POW_WQ_INT_THRX(pow_receive_group),
 			       int_thr.u64);

 		int_pc.u64 = 0;
 		int_pc.s.pc_thr = 5;
 		cvmx_write_csr(CVMX_POW_WQ_INT_PC, int_pc.u64);
 	}

 	/* Schedule NAPI now. This will indirectly enable the interrupt. */
 	napi_schedule(&cvm_oct_napi);
 }

 void cvm_oct_rx_shutdown(void)
 {
 	netif_napi_del(&cvm_oct_napi);
 }
	/*
	* This file is based on code from OCTEON SDK by Cavium Networks.
	*
	* Copyright (c) 2003-2010 Cavium Networks
	*
	* This file 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.
	*/

	#include <linux/module.h>
	#include <linux/kernel.h>
	#include <linux/cache.h>
	#include <linux/cpumask.h>
	#include <linux/netdevice.h>
	#include <linux/etherdevice.h>
	#include <linux/ip.h>
	#include <linux/string.h>
	#include <linux/prefetch.h>
	#include <linux/ratelimit.h>
	#include <linux/smp.h>
	#include <linux/interrupt.h>
	#include <net/dst.h>
	#ifdef CONFIG_XFRM
	#include <linux/xfrm.h>
	#include <net/xfrm.h>
	#endif /* CONFIG_XFRM */

	#include <asm/octeon/octeon.h>

	#include "ethernet-defines.h"
	#include "ethernet-mem.h"
	#include "ethernet-rx.h"
	#include "octeon-ethernet.h"
	#include "ethernet-util.h"

	#include <asm/octeon/cvmx-helper.h>
	#include <asm/octeon/cvmx-wqe.h>
	#include <asm/octeon/cvmx-fau.h>
	#include <asm/octeon/cvmx-pow.h>
	#include <asm/octeon/cvmx-pip.h>
	#include <asm/octeon/cvmx-scratch.h>

	#include <asm/octeon/cvmx-gmxx-defs.h>

	static struct napi_struct cvm_oct_napi;

	/**
	* cvm_oct_do_interrupt - interrupt handler.
	* @cpl: Interrupt number. Unused
	* @dev_id: Cookie to identify the device. Unused
	*
	* The interrupt occurs whenever the POW has packets in our group.
	*
	*/
	static irqreturn_t cvm_oct_do_interrupt(int cpl, void *dev_id)
	{
	/* Disable the IRQ and start napi_poll. */
	disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);
	napi_schedule(&cvm_oct_napi);

	return IRQ_HANDLED;
	}

	/**
	* cvm_oct_check_rcv_error - process receive errors
	* @work: Work queue entry pointing to the packet.
	*
	* Returns Non-zero if the packet can be dropped, zero otherwise.
	*/
	static inline int cvm_oct_check_rcv_error(cvmx_wqe_t *work)
	{
	int port;

	if (octeon_has_feature(OCTEON_FEATURE_PKND))
	port = work->word0.pip.cn68xx.pknd;
	else
	port = work->word1.cn38xx.ipprt;

	if ((work->word2.snoip.err_code == 10) && (work->word1.len <= 64)) {
	/*
	* Ignore length errors on min size packets. Some
	* equipment incorrectly pads packets to 64+4FCS
	* instead of 60+4FCS. Note these packets still get
	* counted as frame errors.
	*/
	} else if (work->word2.snoip.err_code == 5 \|\|
	work->word2.snoip.err_code == 7) {
	/*
	* We received a packet with either an alignment error
	* or a FCS error. This may be signalling that we are
	* running 10Mbps with GMXX_RXX_FRM_CTL[PRE_CHK]
	* off. If this is the case we need to parse the
	* packet to determine if we can remove a non spec
	* preamble and generate a correct packet.
	*/
	int interface = cvmx_helper_get_interface_num(port);
	int index = cvmx_helper_get_interface_index_num(port);
	union cvmx_gmxx_rxx_frm_ctl gmxx_rxx_frm_ctl;

	gmxx_rxx_frm_ctl.u64 =
	cvmx_read_csr(CVMX_GMXX_RXX_FRM_CTL(index, interface));
	if (gmxx_rxx_frm_ctl.s.pre_chk == 0) {
	u8 *ptr =
	cvmx_phys_to_ptr(work->packet_ptr.s.addr);
	int i = 0;

	while (i < work->word1.len - 1) {
	if (*ptr != 0x55)
	break;
	ptr++;
	i++;
	}

	if (*ptr == 0xd5) {
	/* Port received 0xd5 preamble */
	work->packet_ptr.s.addr += i + 1;
	work->word1.len -= i + 5;
	} else if ((*ptr & 0xf) == 0xd) {
	/* Port received 0xd preamble */
	work->packet_ptr.s.addr += i;
	work->word1.len -= i + 4;
	for (i = 0; i < work->word1.len; i++) {
	*ptr =
	((*ptr & 0xf0) >> 4) \|
	((*(ptr + 1) & 0xf) << 4);
	ptr++;
	}
	} else {
	printk_ratelimited("Port %d unknown preamble, packet dropped\n",
	port);
	cvm_oct_free_work(work);
	return 1;
	}
	}
	} else {
	printk_ratelimited("Port %d receive error code %d, packet dropped\n",
	port, work->word2.snoip.err_code);
	cvm_oct_free_work(work);
	return 1;
	}

	return 0;
	}

	/**
	* cvm_oct_napi_poll - the NAPI poll function.
	* @napi: The NAPI instance, or null if called from cvm_oct_poll_controller
	* @budget: Maximum number of packets to receive.
	*
	* Returns the number of packets processed.
	*/
	static int cvm_oct_napi_poll(struct napi_struct *napi, int budget)
	{
	const int coreid = cvmx_get_core_num();
	u64 old_group_mask;
	u64 old_scratch;
	int rx_count = 0;
	int did_work_request = 0;
	int packet_not_copied;

	/* Prefetch cvm_oct_device since we know we need it soon */
	prefetch(cvm_oct_device);

	if (USE_ASYNC_IOBDMA) {
	/* Save scratch in case userspace is using it */
	CVMX_SYNCIOBDMA;
	old_scratch = cvmx_scratch_read64(CVMX_SCR_SCRATCH);
	}

	/* Only allow work for our group (and preserve priorities) */
	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
	old_group_mask = cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid));
	cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid),
	1ull << pow_receive_group);
	cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */
	} else {
	old_group_mask = cvmx_read_csr(CVMX_POW_PP_GRP_MSKX(coreid));
	cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid),
	(old_group_mask & ~0xFFFFull) \|
	1 << pow_receive_group);
	}

	if (USE_ASYNC_IOBDMA) {
	cvmx_pow_work_request_async(CVMX_SCR_SCRATCH, CVMX_POW_NO_WAIT);
	did_work_request = 1;
	}

	while (rx_count < budget) {
	struct sk_buff *skb = NULL;
	struct sk_buff **pskb = NULL;
	int skb_in_hw;
	cvmx_wqe_t *work;
	int port;

	if (USE_ASYNC_IOBDMA && did_work_request)
	work = cvmx_pow_work_response_async(CVMX_SCR_SCRATCH);
	else
	work = cvmx_pow_work_request_sync(CVMX_POW_NO_WAIT);

	prefetch(work);
	did_work_request = 0;
	if (!work) {
	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
	cvmx_write_csr(CVMX_SSO_WQ_IQ_DIS,
	1ull << pow_receive_group);
	cvmx_write_csr(CVMX_SSO_WQ_INT,
	1ull << pow_receive_group);
	} else {
	union cvmx_pow_wq_int wq_int;

	wq_int.u64 = 0;
	wq_int.s.iq_dis = 1 << pow_receive_group;
	wq_int.s.wq_int = 1 << pow_receive_group;
	cvmx_write_csr(CVMX_POW_WQ_INT, wq_int.u64);
	}
	break;
	}
	pskb = (struct sk_buff **)
	(cvm_oct_get_buffer_ptr(work->packet_ptr) -
	sizeof(void *));
	prefetch(pskb);

	if (USE_ASYNC_IOBDMA && rx_count < (budget - 1)) {
	cvmx_pow_work_request_async_nocheck(CVMX_SCR_SCRATCH,
	CVMX_POW_NO_WAIT);
	did_work_request = 1;
	}
	rx_count++;

	skb_in_hw = work->word2.s.bufs == 1;
	if (likely(skb_in_hw)) {
	skb = *pskb;
	prefetch(&skb->head);
	prefetch(&skb->len);
	}

	if (octeon_has_feature(OCTEON_FEATURE_PKND))
	port = work->word0.pip.cn68xx.pknd;
	else
	port = work->word1.cn38xx.ipprt;

	prefetch(cvm_oct_device[port]);

	/* Immediately throw away all packets with receive errors */
	if (unlikely(work->word2.snoip.rcv_error)) {
	if (cvm_oct_check_rcv_error(work))
	continue;
	}

	/*
	* We can only use the zero copy path if skbuffs are
	* in the FPA pool and the packet fits in a single
	* buffer.
	*/
	if (likely(skb_in_hw)) {
	skb->data = skb->head + work->packet_ptr.s.addr -
	cvmx_ptr_to_phys(skb->head);
	prefetch(skb->data);
	skb->len = work->word1.len;
	skb_set_tail_pointer(skb, skb->len);
	packet_not_copied = 1;
	} else {
	/*
	* We have to copy the packet. First allocate
	* an skbuff for it.
	*/
	skb = dev_alloc_skb(work->word1.len);
	if (!skb) {
	cvm_oct_free_work(work);
	continue;
	}

	/*
	* Check if we've received a packet that was
	* entirely stored in the work entry.
	*/
	if (unlikely(work->word2.s.bufs == 0)) {
	u8 *ptr = work->packet_data;

	if (likely(!work->word2.s.not_IP)) {
	/*
	* The beginning of the packet
	* moves for IP packets.
	*/
	if (work->word2.s.is_v6)
	ptr += 2;
	else
	ptr += 6;
	}
	memcpy(skb_put(skb, work->word1.len), ptr,
	work->word1.len);
	/* No packet buffers to free */
	} else {
	int segments = work->word2.s.bufs;
	union cvmx_buf_ptr segment_ptr =
	work->packet_ptr;
	int len = work->word1.len;

	while (segments--) {
	union cvmx_buf_ptr next_ptr =
	(union cvmx_buf_ptr )
	cvmx_phys_to_ptr(
	segment_ptr.s.addr - 8);

	/*
	* Octeon Errata PKI-100: The segment size is
	* wrong. Until it is fixed, calculate the
	* segment size based on the packet pool
	* buffer size. When it is fixed, the
	* following line should be replaced with this
	* one: int segment_size =
	* segment_ptr.s.size;
	*/
	int segment_size =
	CVMX_FPA_PACKET_POOL_SIZE -
	(segment_ptr.s.addr -
	(((segment_ptr.s.addr >> 7) -
	segment_ptr.s.back) << 7));
	/*
	* Don't copy more than what
	* is left in the packet.
	*/
	if (segment_size > len)
	segment_size = len;
	/* Copy the data into the packet */
	memcpy(skb_put(skb, segment_size),
	cvmx_phys_to_ptr(
	segment_ptr.s.addr),
	segment_size);
	len -= segment_size;
	segment_ptr = next_ptr;
	}
	}
	packet_not_copied = 0;
	}
	if (likely((port < TOTAL_NUMBER_OF_PORTS) &&
	cvm_oct_device[port])) {
	struct net_device *dev = cvm_oct_device[port];
	struct octeon_ethernet *priv = netdev_priv(dev);

	/*
	* Only accept packets for devices that are
	* currently up.
	*/
	if (likely(dev->flags & IFF_UP)) {
	skb->protocol = eth_type_trans(skb, dev);
	skb->dev = dev;

	if (unlikely(work->word2.s.not_IP \|\|
	work->word2.s.IP_exc \|\|
	work->word2.s.L4_error \|\|
	!work->word2.s.tcp_or_udp))
	skb->ip_summed = CHECKSUM_NONE;
	else
	skb->ip_summed = CHECKSUM_UNNECESSARY;

	/* Increment RX stats for virtual ports */
	if (port >= CVMX_PIP_NUM_INPUT_PORTS) {
	priv->stats.rx_packets++;
	priv->stats.rx_bytes += skb->len;
	}
	netif_receive_skb(skb);
	} else {
	/*
	* Drop any packet received for a device that
	* isn't up.
	*/
	priv->stats.rx_dropped++;
	dev_kfree_skb_irq(skb);
	}
	} else {
	/*
	* Drop any packet received for a device that
	* doesn't exist.
	*/
	printk_ratelimited("Port %d not controlled by Linux, packet dropped\n",
	port);
	dev_kfree_skb_irq(skb);
	}
	/*
	* Check to see if the skbuff and work share the same
	* packet buffer.
	*/
	if (likely(packet_not_copied)) {
	/*
	* This buffer needs to be replaced, increment
	* the number of buffers we need to free by
	* one.
	*/
	cvmx_fau_atomic_add32(FAU_NUM_PACKET_BUFFERS_TO_FREE,
	1);

	cvmx_fpa_free(work, CVMX_FPA_WQE_POOL, 1);
	} else {
	cvm_oct_free_work(work);
	}
	}
	/* Restore the original POW group mask */
	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
	cvmx_write_csr(CVMX_SSO_PPX_GRP_MSK(coreid), old_group_mask);
	cvmx_read_csr(CVMX_SSO_PPX_GRP_MSK(coreid)); /* Flush */
	} else {
	cvmx_write_csr(CVMX_POW_PP_GRP_MSKX(coreid), old_group_mask);
	}

	if (USE_ASYNC_IOBDMA) {
	/* Restore the scratch area */
	cvmx_scratch_write64(CVMX_SCR_SCRATCH, old_scratch);
	}
	cvm_oct_rx_refill_pool(0);

	if (rx_count < budget && napi) {
	/* No more work */
	napi_complete(napi);
	enable_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group);
	}
	return rx_count;
	}

	#ifdef CONFIG_NET_POLL_CONTROLLER
	/**
	* cvm_oct_poll_controller - poll for receive packets
	* device.
	*
	* @dev: Device to poll. Unused
	*/
	void cvm_oct_poll_controller(struct net_device *dev)
	{
	cvm_oct_napi_poll(NULL, 16);
	}
	#endif

	void cvm_oct_rx_initialize(void)
	{
	int i;
	struct net_device *dev_for_napi = NULL;

	for (i = 0; i < TOTAL_NUMBER_OF_PORTS; i++) {
	if (cvm_oct_device[i]) {
	dev_for_napi = cvm_oct_device[i];
	break;
	}
	}

	if (!dev_for_napi)
	panic("No net_devices were allocated.");

	netif_napi_add(dev_for_napi, &cvm_oct_napi, cvm_oct_napi_poll,
	rx_napi_weight);
	napi_enable(&cvm_oct_napi);

	/* Register an IRQ handler to receive POW interrupts */
	i = request_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group,
	cvm_oct_do_interrupt, 0, "Ethernet", cvm_oct_device);

	if (i)
	panic("Could not acquire Ethernet IRQ %d\n",
	OCTEON_IRQ_WORKQ0 + pow_receive_group);

	disable_irq_nosync(OCTEON_IRQ_WORKQ0 + pow_receive_group);

	/* Enable POW interrupt when our port has at least one packet */
	if (OCTEON_IS_MODEL(OCTEON_CN68XX)) {
	union cvmx_sso_wq_int_thrx int_thr;
	union cvmx_pow_wq_int_pc int_pc;

	int_thr.u64 = 0;
	int_thr.s.tc_en = 1;
	int_thr.s.tc_thr = 1;
	cvmx_write_csr(CVMX_SSO_WQ_INT_THRX(pow_receive_group),
	int_thr.u64);

	int_pc.u64 = 0;
	int_pc.s.pc_thr = 5;
	cvmx_write_csr(CVMX_SSO_WQ_INT_PC, int_pc.u64);
	} else {
	union cvmx_pow_wq_int_thrx int_thr;
	union cvmx_pow_wq_int_pc int_pc;

	int_thr.u64 = 0;
	int_thr.s.tc_en = 1;
	int_thr.s.tc_thr = 1;
	cvmx_write_csr(CVMX_POW_WQ_INT_THRX(pow_receive_group),
	int_thr.u64);

	int_pc.u64 = 0;
	int_pc.s.pc_thr = 5;
	cvmx_write_csr(CVMX_POW_WQ_INT_PC, int_pc.u64);
	}

	/* Schedule NAPI now. This will indirectly enable the interrupt. */
	napi_schedule(&cvm_oct_napi);
	}

	void cvm_oct_rx_shutdown(void)
	{
	netif_napi_del(&cvm_oct_napi);
	}