diff options
Diffstat (limited to 'drivers/net/cxgb4vf/sge.c')
| -rw-r--r-- | drivers/net/cxgb4vf/sge.c | 2454 |
1 files changed, 2454 insertions, 0 deletions
diff --git a/drivers/net/cxgb4vf/sge.c b/drivers/net/cxgb4vf/sge.c new file mode 100644 index 000000000000..eb5a1c9cb2d3 --- /dev/null +++ b/drivers/net/cxgb4vf/sge.c @@ -0,0 +1,2454 @@ +/* + * This file is part of the Chelsio T4 PCI-E SR-IOV Virtual Function Ethernet + * driver for Linux. + * + * Copyright (c) 2009-2010 Chelsio Communications, Inc. All rights reserved. + * + * This software is available to you under a choice of one of two + * licenses. You may choose to be licensed under the terms of the GNU + * General Public License (GPL) Version 2, available from the file + * COPYING in the main directory of this source tree, or the + * OpenIB.org BSD license below: + * + * Redistribution and use in source and binary forms, with or + * without modification, are permitted provided that the following + * conditions are met: + * + * - Redistributions of source code must retain the above + * copyright notice, this list of conditions and the following + * disclaimer. + * + * - Redistributions in binary form must reproduce the above + * copyright notice, this list of conditions and the following + * disclaimer in the documentation and/or other materials + * provided with the distribution. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS + * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN + * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN + * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE + * SOFTWARE. + */ + +#include <linux/skbuff.h> +#include <linux/netdevice.h> +#include <linux/etherdevice.h> +#include <linux/if_vlan.h> +#include <linux/ip.h> +#include <net/ipv6.h> +#include <net/tcp.h> +#include <linux/dma-mapping.h> + +#include "t4vf_common.h" +#include "t4vf_defs.h" + +#include "../cxgb4/t4_regs.h" +#include "../cxgb4/t4fw_api.h" +#include "../cxgb4/t4_msg.h" + +/* + * Decoded Adapter Parameters. + */ +static u32 FL_PG_ORDER; /* large page allocation size */ +static u32 STAT_LEN; /* length of status page at ring end */ +static u32 PKTSHIFT; /* padding between CPL and packet data */ +static u32 FL_ALIGN; /* response queue message alignment */ + +/* + * Constants ... + */ +enum { + /* + * Egress Queue sizes, producer and consumer indices are all in units + * of Egress Context Units bytes. Note that as far as the hardware is + * concerned, the free list is an Egress Queue (the host produces free + * buffers which the hardware consumes) and free list entries are + * 64-bit PCI DMA addresses. + */ + EQ_UNIT = SGE_EQ_IDXSIZE, + FL_PER_EQ_UNIT = EQ_UNIT / sizeof(__be64), + TXD_PER_EQ_UNIT = EQ_UNIT / sizeof(__be64), + + /* + * Max number of TX descriptors we clean up at a time. Should be + * modest as freeing skbs isn't cheap and it happens while holding + * locks. We just need to free packets faster than they arrive, we + * eventually catch up and keep the amortized cost reasonable. + */ + MAX_TX_RECLAIM = 16, + + /* + * Max number of Rx buffers we replenish at a time. Again keep this + * modest, allocating buffers isn't cheap either. + */ + MAX_RX_REFILL = 16, + + /* + * Period of the Rx queue check timer. This timer is infrequent as it + * has something to do only when the system experiences severe memory + * shortage. + */ + RX_QCHECK_PERIOD = (HZ / 2), + + /* + * Period of the TX queue check timer and the maximum number of TX + * descriptors to be reclaimed by the TX timer. + */ + TX_QCHECK_PERIOD = (HZ / 2), + MAX_TIMER_TX_RECLAIM = 100, + + /* + * An FL with <= FL_STARVE_THRES buffers is starving and a periodic + * timer will attempt to refill it. + */ + FL_STARVE_THRES = 4, + + /* + * Suspend an Ethernet TX queue with fewer available descriptors than + * this. We always want to have room for a maximum sized packet: + * inline immediate data + MAX_SKB_FRAGS. This is the same as + * calc_tx_flits() for a TSO packet with nr_frags == MAX_SKB_FRAGS + * (see that function and its helpers for a description of the + * calculation). + */ + ETHTXQ_MAX_FRAGS = MAX_SKB_FRAGS + 1, + ETHTXQ_MAX_SGL_LEN = ((3 * (ETHTXQ_MAX_FRAGS-1))/2 + + ((ETHTXQ_MAX_FRAGS-1) & 1) + + 2), + ETHTXQ_MAX_HDR = (sizeof(struct fw_eth_tx_pkt_vm_wr) + + sizeof(struct cpl_tx_pkt_lso_core) + + sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64), + ETHTXQ_MAX_FLITS = ETHTXQ_MAX_SGL_LEN + ETHTXQ_MAX_HDR, + + ETHTXQ_STOP_THRES = 1 + DIV_ROUND_UP(ETHTXQ_MAX_FLITS, TXD_PER_EQ_UNIT), + + /* + * Max TX descriptor space we allow for an Ethernet packet to be + * inlined into a WR. This is limited by the maximum value which + * we can specify for immediate data in the firmware Ethernet TX + * Work Request. + */ + MAX_IMM_TX_PKT_LEN = FW_WR_IMMDLEN_MASK, + + /* + * Max size of a WR sent through a control TX queue. + */ + MAX_CTRL_WR_LEN = 256, + + /* + * Maximum amount of data which we'll ever need to inline into a + * TX ring: max(MAX_IMM_TX_PKT_LEN, MAX_CTRL_WR_LEN). + */ + MAX_IMM_TX_LEN = (MAX_IMM_TX_PKT_LEN > MAX_CTRL_WR_LEN + ? MAX_IMM_TX_PKT_LEN + : MAX_CTRL_WR_LEN), + + /* + * For incoming packets less than RX_COPY_THRES, we copy the data into + * an skb rather than referencing the data. We allocate enough + * in-line room in skb's to accommodate pulling in RX_PULL_LEN bytes + * of the data (header). + */ + RX_COPY_THRES = 256, + RX_PULL_LEN = 128, +}; + +/* + * Can't define this in the above enum because PKTSHIFT isn't a constant in + * the VF Driver ... + */ +#define RX_PKT_PULL_LEN (RX_PULL_LEN + PKTSHIFT) + +/* + * Software state per TX descriptor. + */ +struct tx_sw_desc { + struct sk_buff *skb; /* socket buffer of TX data source */ + struct ulptx_sgl *sgl; /* scatter/gather list in TX Queue */ +}; + +/* + * Software state per RX Free List descriptor. We keep track of the allocated + * FL page, its size, and its PCI DMA address (if the page is mapped). The FL + * page size and its PCI DMA mapped state are stored in the low bits of the + * PCI DMA address as per below. + */ +struct rx_sw_desc { + struct page *page; /* Free List page buffer */ + dma_addr_t dma_addr; /* PCI DMA address (if mapped) */ + /* and flags (see below) */ +}; + +/* + * The low bits of rx_sw_desc.dma_addr have special meaning. Note that the + * SGE also uses the low 4 bits to determine the size of the buffer. It uses + * those bits to index into the SGE_FL_BUFFER_SIZE[index] register array. + * Since we only use SGE_FL_BUFFER_SIZE0 and SGE_FL_BUFFER_SIZE1, these low 4 + * bits can only contain a 0 or a 1 to indicate which size buffer we're giving + * to the SGE. Thus, our software state of "is the buffer mapped for DMA" is + * maintained in an inverse sense so the hardware never sees that bit high. + */ +enum { + RX_LARGE_BUF = 1 << 0, /* buffer is SGE_FL_BUFFER_SIZE[1] */ + RX_UNMAPPED_BUF = 1 << 1, /* buffer is not mapped */ +}; + +/** + * get_buf_addr - return DMA buffer address of software descriptor + * @sdesc: pointer to the software buffer descriptor + * + * Return the DMA buffer address of a software descriptor (stripping out + * our low-order flag bits). + */ +static inline dma_addr_t get_buf_addr(const struct rx_sw_desc *sdesc) +{ + return sdesc->dma_addr & ~(dma_addr_t)(RX_LARGE_BUF | RX_UNMAPPED_BUF); +} + +/** + * is_buf_mapped - is buffer mapped for DMA? + * @sdesc: pointer to the software buffer descriptor + * + * Determine whether the buffer associated with a software descriptor in + * mapped for DMA or not. + */ +static inline bool is_buf_mapped(const struct rx_sw_desc *sdesc) +{ + return !(sdesc->dma_addr & RX_UNMAPPED_BUF); +} + +/** + * need_skb_unmap - does the platform need unmapping of sk_buffs? + * + * Returns true if the platfrom needs sk_buff unmapping. The compiler + * optimizes away unecessary code if this returns true. + */ +static inline int need_skb_unmap(void) +{ +#ifdef CONFIG_NEED_DMA_MAP_STATE + return 1; +#else + return 0; +#endif +} + +/** + * txq_avail - return the number of available slots in a TX queue + * @tq: the TX queue + * + * Returns the number of available descriptors in a TX queue. + */ +static inline unsigned int txq_avail(const struct sge_txq *tq) +{ + return tq->size - 1 - tq->in_use; +} + +/** + * fl_cap - return the capacity of a Free List + * @fl: the Free List + * + * Returns the capacity of a Free List. The capacity is less than the + * size because an Egress Queue Index Unit worth of descriptors needs to + * be left unpopulated, otherwise the Producer and Consumer indices PIDX + * and CIDX will match and the hardware will think the FL is empty. + */ +static inline unsigned int fl_cap(const struct sge_fl *fl) +{ + return fl->size - FL_PER_EQ_UNIT; +} + +/** + * fl_starving - return whether a Free List is starving. + * @fl: the Free List + * + * Tests specified Free List to see whether the number of buffers + * available to the hardware has falled below our "starvation" + * threshhold. + */ +static inline bool fl_starving(const struct sge_fl *fl) +{ + return fl->avail - fl->pend_cred <= FL_STARVE_THRES; +} + +/** + * map_skb - map an skb for DMA to the device + * @dev: the egress net device + * @skb: the packet to map + * @addr: a pointer to the base of the DMA mapping array + * + * Map an skb for DMA to the device and return an array of DMA addresses. + */ +static int map_skb(struct device *dev, const struct sk_buff *skb, + dma_addr_t *addr) +{ + const skb_frag_t *fp, *end; + const struct skb_shared_info *si; + + *addr = dma_map_single(dev, skb->data, skb_headlen(skb), DMA_TO_DEVICE); + if (dma_mapping_error(dev, *addr)) + goto out_err; + + si = skb_shinfo(skb); + end = &si->frags[si->nr_frags]; + for (fp = si->frags; fp < end; fp++) { + *++addr = dma_map_page(dev, fp->page, fp->page_offset, fp->size, + DMA_TO_DEVICE); + if (dma_mapping_error(dev, *addr)) + goto unwind; + } + return 0; + +unwind: + while (fp-- > si->frags) + dma_unmap_page(dev, *--addr, fp->size, DMA_TO_DEVICE); + dma_unmap_single(dev, addr[-1], skb_headlen(skb), DMA_TO_DEVICE); + +out_err: + return -ENOMEM; +} + +static void unmap_sgl(struct device *dev, const struct sk_buff *skb, + const struct ulptx_sgl *sgl, const struct sge_txq *tq) +{ + const struct ulptx_sge_pair *p; + unsigned int nfrags = skb_shinfo(skb)->nr_frags; + + if (likely(skb_headlen(skb))) + dma_unmap_single(dev, be64_to_cpu(sgl->addr0), + be32_to_cpu(sgl->len0), DMA_TO_DEVICE); + else { + dma_unmap_page(dev, be64_to_cpu(sgl->addr0), + be32_to_cpu(sgl->len0), DMA_TO_DEVICE); + nfrags--; + } + + /* + * the complexity below is because of the possibility of a wrap-around + * in the middle of an SGL + */ + for (p = sgl->sge; nfrags >= 2; nfrags -= 2) { + if (likely((u8 *)(p + 1) <= (u8 *)tq->stat)) { +unmap: + dma_unmap_page(dev, be64_to_cpu(p->addr[0]), + be32_to_cpu(p->len[0]), DMA_TO_DEVICE); + dma_unmap_page(dev, be64_to_cpu(p->addr[1]), + be32_to_cpu(p->len[1]), DMA_TO_DEVICE); + p++; + } else if ((u8 *)p == (u8 *)tq->stat) { + p = (const struct ulptx_sge_pair *)tq->desc; + goto unmap; + } else if ((u8 *)p + 8 == (u8 *)tq->stat) { + const __be64 *addr = (const __be64 *)tq->desc; + + dma_unmap_page(dev, be64_to_cpu(addr[0]), + be32_to_cpu(p->len[0]), DMA_TO_DEVICE); + dma_unmap_page(dev, be64_to_cpu(addr[1]), + be32_to_cpu(p->len[1]), DMA_TO_DEVICE); + p = (const struct ulptx_sge_pair *)&addr[2]; + } else { + const __be64 *addr = (const __be64 *)tq->desc; + + dma_unmap_page(dev, be64_to_cpu(p->addr[0]), + be32_to_cpu(p->len[0]), DMA_TO_DEVICE); + dma_unmap_page(dev, be64_to_cpu(addr[0]), + be32_to_cpu(p->len[1]), DMA_TO_DEVICE); + p = (const struct ulptx_sge_pair *)&addr[1]; + } + } + if (nfrags) { + __be64 addr; + + if ((u8 *)p == (u8 *)tq->stat) + p = (const struct ulptx_sge_pair *)tq->desc; + addr = ((u8 *)p + 16 <= (u8 *)tq->stat + ? p->addr[0] + : *(const __be64 *)tq->desc); + dma_unmap_page(dev, be64_to_cpu(addr), be32_to_cpu(p->len[0]), + DMA_TO_DEVICE); + } +} + +/** + * free_tx_desc - reclaims TX descriptors and their buffers + * @adapter: the adapter + * @tq: the TX queue to reclaim descriptors from + * @n: the number of descriptors to reclaim + * @unmap: whether the buffers should be unmapped for DMA + * + * Reclaims TX descriptors from an SGE TX queue and frees the associated + * TX buffers. Called with the TX queue lock held. + */ +static void free_tx_desc(struct adapter *adapter, struct sge_txq *tq, + unsigned int n, bool unmap) +{ + struct tx_sw_desc *sdesc; + unsigned int cidx = tq->cidx; + struct device *dev = adapter->pdev_dev; + + const int need_unmap = need_skb_unmap() && unmap; + + sdesc = &tq->sdesc[cidx]; + while (n--) { + /* + * If we kept a reference to the original TX skb, we need to + * unmap it from PCI DMA space (if required) and free it. + */ + if (sdesc->skb) { + if (need_unmap) + unmap_sgl(dev, sdesc->skb, sdesc->sgl, tq); + kfree_skb(sdesc->skb); + sdesc->skb = NULL; + } + + sdesc++; + if (++cidx == tq->size) { + cidx = 0; + sdesc = tq->sdesc; + } + } + tq->cidx = cidx; +} + +/* + * Return the number of reclaimable descriptors in a TX queue. + */ +static inline int reclaimable(const struct sge_txq *tq) +{ + int hw_cidx = be16_to_cpu(tq->stat->cidx); + int reclaimable = hw_cidx - tq->cidx; + if (reclaimable < 0) + reclaimable += tq->size; + return reclaimable; +} + +/** + * reclaim_completed_tx - reclaims completed TX descriptors + * @adapter: the adapter + * @tq: the TX queue to reclaim completed descriptors from + * @unmap: whether the buffers should be unmapped for DMA + * + * Reclaims TX descriptors that the SGE has indicated it has processed, + * and frees the associated buffers if possible. Called with the TX + * queue locked. + */ +static inline void reclaim_completed_tx(struct adapter *adapter, + struct sge_txq *tq, + bool unmap) +{ + int avail = reclaimable(tq); + + if (avail) { + /* + * Limit the amount of clean up work we do at a time to keep + * the TX lock hold time O(1). + */ + if (avail > MAX_TX_RECLAIM) + avail = MAX_TX_RECLAIM; + + free_tx_desc(adapter, tq, avail, unmap); + tq->in_use -= avail; + } +} + +/** + * get_buf_size - return the size of an RX Free List buffer. + * @sdesc: pointer to the software buffer descriptor + */ +static inline int get_buf_size(const struct rx_sw_desc *sdesc) +{ + return FL_PG_ORDER > 0 && (sdesc->dma_addr & RX_LARGE_BUF) + ? (PAGE_SIZE << FL_PG_ORDER) + : PAGE_SIZE; +} + +/** + * free_rx_bufs - free RX buffers on an SGE Free List + * @adapter: the adapter + * @fl: the SGE Free List to free buffers from + * @n: how many buffers to free + * + * Release the next @n buffers on an SGE Free List RX queue. The + * buffers must be made inaccessible to hardware before calling this + * function. + */ +static void free_rx_bufs(struct adapter *adapter, struct sge_fl *fl, int n) +{ + while (n--) { + struct rx_sw_desc *sdesc = &fl->sdesc[fl->cidx]; + + if (is_buf_mapped(sdesc)) + dma_unmap_page(adapter->pdev_dev, get_buf_addr(sdesc), + get_buf_size(sdesc), PCI_DMA_FROMDEVICE); + put_page(sdesc->page); + sdesc->page = NULL; + if (++fl->cidx == fl->size) + fl->cidx = 0; + fl->avail--; + } +} + +/** + * unmap_rx_buf - unmap the current RX buffer on an SGE Free List + * @adapter: the adapter + * @fl: the SGE Free List + * + * Unmap the current buffer on an SGE Free List RX queue. The + * buffer must be made inaccessible to HW before calling this function. + * + * This is similar to @free_rx_bufs above but does not free the buffer. + * Do note that the FL still loses any further access to the buffer. + * This is used predominantly to "transfer ownership" of an FL buffer + * to another entity (typically an skb's fragment list). + */ +static void unmap_rx_buf(struct adapter *adapter, struct sge_fl *fl) +{ + struct rx_sw_desc *sdesc = &fl->sdesc[fl->cidx]; + + if (is_buf_mapped(sdesc)) + dma_unmap_page(adapter->pdev_dev, get_buf_addr(sdesc), + get_buf_size(sdesc), PCI_DMA_FROMDEVICE); + sdesc->page = NULL; + if (++fl->cidx == fl->size) + fl->cidx = 0; + fl->avail--; +} + +/** + * ring_fl_db - righ doorbell on free list + * @adapter: the adapter + * @fl: the Free List whose doorbell should be rung ... + * + * Tell the Scatter Gather Engine that there are new free list entries + * available. + */ +static inline void ring_fl_db(struct adapter *adapter, struct sge_fl *fl) +{ + /* + * The SGE keeps track of its Producer and Consumer Indices in terms + * of Egress Queue Units so we can only tell it about integral numbers + * of multiples of Free List Entries per Egress Queue Units ... + */ + if (fl->pend_cred >= FL_PER_EQ_UNIT) { + wmb(); + t4_write_reg(adapter, T4VF_SGE_BASE_ADDR + SGE_VF_KDOORBELL, + DBPRIO | + QID(fl->cntxt_id) | + PIDX(fl->pend_cred / FL_PER_EQ_UNIT)); + fl->pend_cred %= FL_PER_EQ_UNIT; + } +} + +/** + * set_rx_sw_desc - initialize software RX buffer descriptor + * @sdesc: pointer to the softwore RX buffer descriptor + * @page: pointer to the page data structure backing the RX buffer + * @dma_addr: PCI DMA address (possibly with low-bit flags) + */ +static inline void set_rx_sw_desc(struct rx_sw_desc *sdesc, struct page *page, + dma_addr_t dma_addr) +{ + sdesc->page = page; + sdesc->dma_addr = dma_addr; +} + +/* + * Support for poisoning RX buffers ... + */ +#define POISON_BUF_VAL -1 + +static inline void poison_buf(struct page *page, size_t sz) +{ +#if POISON_BUF_VAL >= 0 + memset(page_address(page), POISON_BUF_VAL, sz); +#endif +} + +/** + * refill_fl - refill an SGE RX buffer ring + * @adapter: the adapter + * @fl: the Free List ring to refill + * @n: the number of new buffers to allocate + * @gfp: the gfp flags for the allocations + * + * (Re)populate an SGE free-buffer queue with up to @n new packet buffers, + * allocated with the supplied gfp flags. The caller must assure that + * @n does not exceed the queue's capacity -- i.e. (cidx == pidx) _IN + * EGRESS QUEUE UNITS_ indicates an empty Free List! Returns the number + * of buffers allocated. If afterwards the queue is found critically low, + * mark it as starving in the bitmap of starving FLs. + */ +static unsigned int refill_fl(struct adapter *adapter, struct sge_fl *fl, + int n, gfp_t gfp) +{ + struct page *page; + dma_addr_t dma_addr; + unsigned int cred = fl->avail; + __be64 *d = &fl->desc[fl->pidx]; + struct rx_sw_desc *sdesc = &fl->sdesc[fl->pidx]; + + /* + * Sanity: ensure that the result of adding n Free List buffers + * won't result in wrapping the SGE's Producer Index around to + * it's Consumer Index thereby indicating an empty Free List ... + */ + BUG_ON(fl->avail + n > fl->size - FL_PER_EQ_UNIT); + + /* + * If we support large pages, prefer large buffers and fail over to + * small pages if we can't allocate large pages to satisfy the refill. + * If we don't support large pages, drop directly into the small page + * allocation code. + */ + if (FL_PG_ORDER == 0) + goto alloc_small_pages; + + while (n) { + page = alloc_pages(gfp | __GFP_COMP | __GFP_NOWARN, + FL_PG_ORDER); + if (unlikely(!page)) { + /* + * We've failed inour attempt to allocate a "large + * page". Fail over to the "small page" allocation + * below. + */ + fl->large_alloc_failed++; + break; + } + poison_buf(page, PAGE_SIZE << FL_PG_ORDER); + + dma_addr = dma_map_page(adapter->pdev_dev, page, 0, + PAGE_SIZE << FL_PG_ORDER, + PCI_DMA_FROMDEVICE); + if (unlikely(dma_mapping_error(adapter->pdev_dev, dma_addr))) { + /* + * We've run out of DMA mapping space. Free up the + * buffer and return with what we've managed to put + * into the free list. We don't want to fail over to + * the small page allocation below in this case + * because DMA mapping resources are typically + * critical resources once they become scarse. + */ + __free_pages(page, FL_PG_ORDER); + goto out; + } + dma_addr |= RX_LARGE_BUF; + *d++ = cpu_to_be64(dma_addr); + + set_rx_sw_desc(sdesc, page, dma_addr); + sdesc++; + + fl->avail++; + if (++fl->pidx == fl->size) { + fl->pidx = 0; + sdesc = fl->sdesc; + d = fl->desc; + } + n--; + } + +alloc_small_pages: + while (n--) { + page = __netdev_alloc_page(adapter->port[0], + gfp | __GFP_NOWARN); + if (unlikely(!page)) { + fl->alloc_failed++; + break; + } + poison_buf(page, PAGE_SIZE); + + dma_addr = dma_map_page(adapter->pdev_dev, page, 0, PAGE_SIZE, + PCI_DMA_FROMDEVICE); + if (unlikely(dma_mapping_error(adapter->pdev_dev, dma_addr))) { + netdev_free_page(adapter->port[0], page); + break; + } + *d++ = cpu_to_be64(dma_addr); + + set_rx_sw_desc(sdesc, page, dma_addr); + sdesc++; + + fl->avail++; + if (++fl->pidx == fl->size) { + fl->pidx = 0; + sdesc = fl->sdesc; + d = fl->desc; + } + } + +out: + /* + * Update our accounting state to incorporate the new Free List + * buffers, tell the hardware about them and return the number of + * bufers which we were able to allocate. + */ + cred = fl->avail - cred; + fl->pend_cred += cred; + ring_fl_db(adapter, fl); + + if (unlikely(fl_starving(fl))) { + smp_wmb(); + set_bit(fl->cntxt_id, adapter->sge.starving_fl); + } + + return cred; +} + +/* + * Refill a Free List to its capacity or the Maximum Refill Increment, + * whichever is smaller ... + */ +static inline void __refill_fl(struct adapter *adapter, struct sge_fl *fl) +{ + refill_fl(adapter, fl, + min((unsigned int)MAX_RX_REFILL, fl_cap(fl) - fl->avail), + GFP_ATOMIC); +} + +/** + * alloc_ring - allocate resources for an SGE descriptor ring + * @dev: the PCI device's core device + * @nelem: the number of descriptors + * @hwsize: the size of each hardware descriptor + * @swsize: the size of each software descriptor + * @busaddrp: the physical PCI bus address of the allocated ring + * @swringp: return address pointer for software ring + * @stat_size: extra space in hardware ring for status information + * + * Allocates resources for an SGE descriptor ring, such as TX queues, + * free buffer lists, response queues, etc. Each SGE ring requires + * space for its hardware descriptors plus, optionally, space for software + * state associated with each hardware entry (the metadata). The function + * returns three values: the virtual address for the hardware ring (the + * return value of the function), the PCI bus address of the hardware + * ring (in *busaddrp), and the address of the software ring (in swringp). + * Both the hardware and software rings are returned zeroed out. + */ +static void *alloc_ring(struct device *dev, size_t nelem, size_t hwsize, + size_t swsize, dma_addr_t *busaddrp, void *swringp, + size_t stat_size) +{ + /* + * Allocate the hardware ring and PCI DMA bus address space for said. + */ + size_t hwlen = nelem * hwsize + stat_size; + void *hwring = dma_alloc_coherent(dev, hwlen, busaddrp, GFP_KERNEL); + + if (!hwring) + return NULL; + + /* + * If the caller wants a software ring, allocate it and return a + * pointer to it in *swringp. + */ + BUG_ON((swsize != 0) != (swringp != NULL)); + if (swsize) { + void *swring = kcalloc(nelem, swsize, GFP_KERNEL); + + if (!swring) { + dma_free_coherent(dev, hwlen, hwring, *busaddrp); + return NULL; + } + *(void **)swringp = swring; + } + + /* + * Zero out the hardware ring and return its address as our function + * value. + */ + memset(hwring, 0, hwlen); + return hwring; +} + +/** + * sgl_len - calculates the size of an SGL of the given capacity + * @n: the number of SGL entries + * + * Calculates the number of flits (8-byte units) needed for a Direct + * Scatter/Gather List that can hold the given number of entries. + */ +static inline unsigned int sgl_len(unsigned int n) +{ + /* + * A Direct Scatter Gather List uses 32-bit lengths and 64-bit PCI DMA + * addresses. The DSGL Work Request starts off with a 32-bit DSGL + * ULPTX header, then Length0, then Address0, then, for 1 <= i <= N, + * repeated sequences of { Length[i], Length[i+1], Address[i], + * Address[i+1] } (this ensures that all addresses are on 64-bit + * boundaries). If N is even, then Length[N+1] should be set to 0 and + * Address[N+1] is omitted. + * + * The following calculation incorporates all of the above. It's + * somewhat hard to follow but, briefly: the "+2" accounts for the + * first two flits which include the DSGL header, Length0 and + * Address0; the "(3*(n-1))/2" covers the main body of list entries (3 + * flits for every pair of the remaining N) +1 if (n-1) is odd; and + * finally the "+((n-1)&1)" adds the one remaining flit needed if + * (n-1) is odd ... + */ + n--; + return (3 * n) / 2 + (n & 1) + 2; +} + +/** + * flits_to_desc - returns the num of TX descriptors for the given flits + * @flits: the number of flits + * + * Returns the number of TX descriptors needed for the supplied number + * of flits. + */ +static inline unsigned int flits_to_desc(unsigned int flits) +{ + BUG_ON(flits > SGE_MAX_WR_LEN / sizeof(__be64)); + return DIV_ROUND_UP(flits, TXD_PER_EQ_UNIT); +} + +/** + * is_eth_imm - can an Ethernet packet be sent as immediate data? + * @skb: the packet + * + * Returns whether an Ethernet packet is small enough to fit completely as + * immediate data. + */ +static inline int is_eth_imm(const struct sk_buff *skb) +{ + /* + * The VF Driver uses the FW_ETH_TX_PKT_VM_WR firmware Work Request + * which does not accommodate immediate data. We could dike out all + * of the support code for immediate data but that would tie our hands + * too much if we ever want to enhace the firmware. It would also + * create more differences between the PF and VF Drivers. + */ + return false; +} + +/** + * calc_tx_flits - calculate the number of flits for a packet TX WR + * @skb: the packet + * + * Returns the number of flits needed for a TX Work Request for the + * given Ethernet packet, including the needed WR and CPL headers. + */ +static inline unsigned int calc_tx_flits(const struct sk_buff *skb) +{ + unsigned int flits; + + /* + * If the skb is small enough, we can pump it out as a work request + * with only immediate data. In that case we just have to have the + * TX Packet header plus the skb data in the Work Request. + */ + if (is_eth_imm(skb)) + return DIV_ROUND_UP(skb->len + sizeof(struct cpl_tx_pkt), + sizeof(__be64)); + + /* + * Otherwise, we're going to have to construct a Scatter gather list + * of the skb body and fragments. We also include the flits necessary + * for the TX Packet Work Request and CPL. We always have a firmware + * Write Header (incorporated as part of the cpl_tx_pkt_lso and + * cpl_tx_pkt structures), followed by either a TX Packet Write CPL + * message or, if we're doing a Large Send Offload, an LSO CPL message + * with an embeded TX Packet Write CPL message. + */ + flits = sgl_len(skb_shinfo(skb)->nr_frags + 1); + if (skb_shinfo(skb)->gso_size) + flits += (sizeof(struct fw_eth_tx_pkt_vm_wr) + + sizeof(struct cpl_tx_pkt_lso_core) + + sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64); + else + flits += (sizeof(struct fw_eth_tx_pkt_vm_wr) + + sizeof(struct cpl_tx_pkt_core)) / sizeof(__be64); + return flits; +} + +/** + * write_sgl - populate a Scatter/Gather List for a packet + * @skb: the packet + * @tq: the TX queue we are writing into + * @sgl: starting location for writing the SGL + * @end: points right after the end of the SGL + * @start: start offset into skb main-body data to include in the SGL + * @addr: the list of DMA bus addresses for the SGL elements + * + * Generates a Scatter/Gather List for the buffers that make up a packet. + * The caller must provide adequate space for the SGL that will be written. + * The SGL includes all of the packet's page fragments and the data in its + * main body except for the first @start bytes. @pos must be 16-byte + * aligned and within a TX descriptor with available space. @end points + * write after the end of the SGL but does not account for any potential + * wrap around, i.e., @end > @tq->stat. + */ +static void write_sgl(const struct sk_buff *skb, struct sge_txq *tq, + struct ulptx_sgl *sgl, u64 *end, unsigned int start, + const dma_addr_t *addr) +{ + unsigned int i, len; + struct ulptx_sge_pair *to; + const struct skb_shared_info *si = skb_shinfo(skb); + unsigned int nfrags = si->nr_frags; + struct ulptx_sge_pair buf[MAX_SKB_FRAGS / 2 + 1]; + + len = skb_headlen(skb) - start; + if (likely(len)) { + sgl->len0 = htonl(len); + sgl->addr0 = cpu_to_be64(addr[0] + start); + nfrags++; + } else { + sgl->len0 = htonl(si->frags[0].size); + sgl->addr0 = cpu_to_be64(addr[1]); + } + + sgl->cmd_nsge = htonl(ULPTX_CMD(ULP_TX_SC_DSGL) | + ULPTX_NSGE(nfrags)); + if (likely(--nfrags == 0)) + return; + /* + * Most of the complexity below deals with the possibility we hit the + * end of the queue in the middle of writing the SGL. For this case + * only we create the SGL in a temporary buffer and then copy it. + */ + to = (u8 *)end > (u8 *)tq->stat ? buf : sgl->sge; + + for (i = (nfrags != si->nr_frags); nfrags >= 2; nfrags -= 2, to++) { + to->len[0] = cpu_to_be32(si->frags[i].size); + to->len[1] = cpu_to_be32(si->frags[++i].size); + to->addr[0] = cpu_to_be64(addr[i]); + to->addr[1] = cpu_to_be64(addr[++i]); + } + if (nfrags) { + to->len[0] = cpu_to_be32(si->frags[i].size); + to->len[1] = cpu_to_be32(0); + to->addr[0] = cpu_to_be64(addr[i + 1]); + } + if (unlikely((u8 *)end > (u8 *)tq->stat)) { + unsigned int part0 = (u8 *)tq->stat - (u8 *)sgl->sge, part1; + + if (likely(part0)) + memcpy(sgl->sge, buf, part0); + part1 = (u8 *)end - (u8 *)tq->stat; + memcpy(tq->desc, (u8 *)buf + part0, part1); + end = (void *)tq->desc + part1; + } + if ((uintptr_t)end & 8) /* 0-pad to multiple of 16 */ + *(u64 *)end = 0; +} + +/** + * check_ring_tx_db - check and potentially ring a TX queue's doorbell + * @adapter: the adapter + * @tq: the TX queue + * @n: number of new descriptors to give to HW + * + * Ring the doorbel for a TX queue. + */ +static inline void ring_tx_db(struct adapter *adapter, struct sge_txq *tq, + int n) +{ + /* + * Warn if we write doorbells with the wrong priority and write + * descriptors before telling HW. + */ + WARN_ON((QID(tq->cntxt_id) | PIDX(n)) & DBPRIO); + wmb(); + t4_write_reg(adapter, T4VF_SGE_BASE_ADDR + SGE_VF_KDOORBELL, + QID(tq->cntxt_id) | PIDX(n)); +} + +/** + * inline_tx_skb - inline a packet's data into TX descriptors + * @skb: the packet + * @tq: the TX queue where the packet will be inlined + * @pos: starting position in the TX queue to inline the packet + * + * Inline a packet's contents directly into TX descriptors, starting at + * the given position within the TX DMA ring. + * Most of the complexity of this operation is dealing with wrap arounds + * in the middle of the packet we want to inline. + */ +static void inline_tx_skb(const struct sk_buff *skb, const struct sge_txq *tq, + void *pos) +{ + u64 *p; + int left = (void *)tq->stat - pos; + + if (likely(skb->len <= left)) { + if (likely(!skb->data_len)) + skb_copy_from_linear_data(skb, pos, skb->len); + else + skb_copy_bits(skb, 0, pos, skb->len); + pos += skb->len; + } else { + skb_copy_bits(skb, 0, pos, left); + skb_copy_bits(skb, left, tq->desc, skb->len - left); + pos = (void *)tq->desc + (skb->len - left); + } + + /* 0-pad to multiple of 16 */ + p = PTR_ALIGN(pos, 8); + if ((uintptr_t)p & 8) + *p = 0; +} + +/* + * Figure out what HW csum a packet wants and return the appropriate control + * bits. + */ +static u64 hwcsum(const struct sk_buff *skb) +{ + int csum_type; + const struct iphdr *iph = ip_hdr(skb); + + if (iph->version == 4) { + if (iph->protocol == IPPROTO_TCP) + csum_type = TX_CSUM_TCPIP; + else if (iph->protocol == IPPROTO_UDP) + csum_type = TX_CSUM_UDPIP; + else { +nocsum: + /* + * unknown protocol, disable HW csum + * and hope a bad packet is detected + */ + return TXPKT_L4CSUM_DIS; + } + } else { + /* + * this doesn't work with extension headers + */ + const struct ipv6hdr *ip6h = (const struct ipv6hdr *)iph; + + if (ip6h->nexthdr == IPPROTO_TCP) + csum_type = TX_CSUM_TCPIP6; + else if (ip6h->nexthdr == IPPROTO_UDP) + csum_type = TX_CSUM_UDPIP6; + else + goto nocsum; + } + + if (likely(csum_type >= TX_CSUM_TCPIP)) + return TXPKT_CSUM_TYPE(csum_type) | + TXPKT_IPHDR_LEN(skb_network_header_len(skb)) | + TXPKT_ETHHDR_LEN(skb_network_offset(skb) - ETH_HLEN); + else { + int start = skb_transport_offset(skb); + + return TXPKT_CSUM_TYPE(csum_type) | + TXPKT_CSUM_START(start) | + TXPKT_CSUM_LOC(start + skb->csum_offset); + } +} + +/* + * Stop an Ethernet TX queue and record that state change. + */ +static void txq_stop(struct sge_eth_txq *txq) +{ + netif_tx_stop_queue(txq->txq); + txq->q.stops++; +} + +/* + * Advance our software state for a TX queue by adding n in use descriptors. + */ +static inline void txq_advance(struct sge_txq *tq, unsigned int n) +{ + tq->in_use += n; + tq->pidx += n; + if (tq->pidx >= tq->size) + tq->pidx -= tq->size; +} + +/** + * t4vf_eth_xmit - add a packet to an Ethernet TX queue + * @skb: the packet + * @dev: the egress net device + * + * Add a packet to an SGE Ethernet TX queue. Runs with softirqs disabled. + */ +int t4vf_eth_xmit(struct sk_buff *skb, struct net_device *dev) +{ + u32 wr_mid; + u64 cntrl, *end; + int qidx, credits; + unsigned int flits, ndesc; + struct adapter *adapter; + struct sge_eth_txq *txq; + const struct port_info *pi; + struct fw_eth_tx_pkt_vm_wr *wr; + struct cpl_tx_pkt_core *cpl; + const struct skb_shared_info *ssi; + dma_addr_t addr[MAX_SKB_FRAGS + 1]; + const size_t fw_hdr_copy_len = (sizeof(wr->ethmacdst) + + sizeof(wr->ethmacsrc) + + sizeof(wr->ethtype) + + sizeof(wr->vlantci)); + + /* + * The chip minimum packet length is 10 octets but the firmware + * command that we are using requires that we copy the Ethernet header + * (including the VLAN tag) into the header so we reject anything + * smaller than that ... + */ + if (unlikely(skb->len < fw_hdr_copy_len)) + goto out_free; + + /* + * Figure out which TX Queue we're going to use. + */ + pi = netdev_priv(dev); + adapter = pi->adapter; + qidx = skb_get_queue_mapping(skb); + BUG_ON(qidx >= pi->nqsets); + txq = &adapter->sge.ethtxq[pi->first_qset + qidx]; + + /* + * Take this opportunity to reclaim any TX Descriptors whose DMA + * transfers have completed. + */ |