From 282a2feeb9bfb1d1dfbad93df206b74eaf80d564 Mon Sep 17 00:00:00 2001 From: Jon Mason Date: Tue, 12 Feb 2013 09:52:50 -0700 Subject: [PATCH] NTB: Use DMA Engine to Transmit and Receive Allocate and use a DMA engine channel to transmit and receive data over NTB. If none is allocated, fall back to using the CPU to transfer data. Signed-off-by: Jon Mason Reviewed-by: Dan Williams Reviewed-by: Dave Jiang --- drivers/ntb/ntb_hw.c | 17 ++ drivers/ntb/ntb_hw.h | 1 + drivers/ntb/ntb_transport.c | 324 ++++++++++++++++++++++++++++++------ 3 files changed, 295 insertions(+), 47 deletions(-) diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c index ab34795cf125..0345817a8355 100644 --- a/drivers/ntb/ntb_hw.c +++ b/drivers/ntb/ntb_hw.c @@ -349,6 +349,23 @@ int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val) return 0; } +/** + * ntb_get_mw_base() - get addr for the NTB memory window + * @ndev: pointer to ntb_device instance + * @mw: memory window number + * + * This function provides the base address of the memory window specified. + * + * RETURNS: address, or NULL on error. + */ +resource_size_t ntb_get_mw_base(struct ntb_device *ndev, unsigned int mw) +{ + if (mw >= ntb_max_mw(ndev)) + return 0; + + return pci_resource_start(ndev->pdev, MW_TO_BAR(mw)); +} + /** * ntb_get_mw_vbase() - get virtual addr for the NTB memory window * @ndev: pointer to ntb_device instance diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h index d838bc13b956..4f42ed18103a 100644 --- a/drivers/ntb/ntb_hw.h +++ b/drivers/ntb/ntb_hw.h @@ -240,6 +240,7 @@ int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val); int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val); int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val); int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val); +resource_size_t ntb_get_mw_base(struct ntb_device *ndev, unsigned int mw); void __iomem *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw); u64 ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw); void ntb_ring_sdb(struct ntb_device *ndev, unsigned int idx); diff --git a/drivers/ntb/ntb_transport.c b/drivers/ntb/ntb_transport.c index f7380e959656..ae8657259ca0 100644 --- a/drivers/ntb/ntb_transport.c +++ b/drivers/ntb/ntb_transport.c @@ -47,6 +47,7 @@ */ #include #include +#include #include #include #include @@ -68,6 +69,10 @@ static unsigned char max_num_clients; module_param(max_num_clients, byte, 0644); MODULE_PARM_DESC(max_num_clients, "Maximum number of NTB transport clients"); +static unsigned int copy_bytes = 1024; +module_param(copy_bytes, uint, 0644); +MODULE_PARM_DESC(copy_bytes, "Threshold under which NTB will use the CPU to copy instead of DMA"); + struct ntb_queue_entry { /* ntb_queue list reference */ struct list_head entry; @@ -76,6 +81,13 @@ struct ntb_queue_entry { void *buf; unsigned int len; unsigned int flags; + + struct ntb_transport_qp *qp; + union { + struct ntb_payload_header __iomem *tx_hdr; + struct ntb_payload_header *rx_hdr; + }; + unsigned int index; }; struct ntb_rx_info { @@ -86,6 +98,7 @@ struct ntb_transport_qp { struct ntb_transport *transport; struct ntb_device *ndev; void *cb_data; + struct dma_chan *dma_chan; bool client_ready; bool qp_link; @@ -99,6 +112,7 @@ struct ntb_transport_qp { struct list_head tx_free_q; spinlock_t ntb_tx_free_q_lock; void __iomem *tx_mw; + dma_addr_t tx_mw_phys; unsigned int tx_index; unsigned int tx_max_entry; unsigned int tx_max_frame; @@ -114,6 +128,7 @@ struct ntb_transport_qp { unsigned int rx_index; unsigned int rx_max_entry; unsigned int rx_max_frame; + dma_cookie_t last_cookie; void (*event_handler) (void *data, int status); struct delayed_work link_work; @@ -129,9 +144,14 @@ struct ntb_transport_qp { u64 rx_err_no_buf; u64 rx_err_oflow; u64 rx_err_ver; + u64 rx_memcpy; + u64 rx_async; u64 tx_bytes; u64 tx_pkts; u64 tx_ring_full; + u64 tx_err_no_buf; + u64 tx_memcpy; + u64 tx_async; }; struct ntb_transport_mw { @@ -381,7 +401,7 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count, char *buf; ssize_t ret, out_offset, out_count; - out_count = 600; + out_count = 1000; buf = kmalloc(out_count, GFP_KERNEL); if (!buf) @@ -395,6 +415,10 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count, "rx_bytes - \t%llu\n", qp->rx_bytes); out_offset += snprintf(buf + out_offset, out_count - out_offset, "rx_pkts - \t%llu\n", qp->rx_pkts); + out_offset += snprintf(buf + out_offset, out_count - out_offset, + "rx_memcpy - \t%llu\n", qp->rx_memcpy); + out_offset += snprintf(buf + out_offset, out_count - out_offset, + "rx_async - \t%llu\n", qp->rx_async); out_offset += snprintf(buf + out_offset, out_count - out_offset, "rx_ring_empty - %llu\n", qp->rx_ring_empty); out_offset += snprintf(buf + out_offset, out_count - out_offset, @@ -414,8 +438,14 @@ static ssize_t debugfs_read(struct file *filp, char __user *ubuf, size_t count, "tx_bytes - \t%llu\n", qp->tx_bytes); out_offset += snprintf(buf + out_offset, out_count - out_offset, "tx_pkts - \t%llu\n", qp->tx_pkts); + out_offset += snprintf(buf + out_offset, out_count - out_offset, + "tx_memcpy - \t%llu\n", qp->tx_memcpy); + out_offset += snprintf(buf + out_offset, out_count - out_offset, + "tx_async - \t%llu\n", qp->tx_async); out_offset += snprintf(buf + out_offset, out_count - out_offset, "tx_ring_full - \t%llu\n", qp->tx_ring_full); + out_offset += snprintf(buf + out_offset, out_count - out_offset, + "tx_err_no_buf - %llu\n", qp->tx_err_no_buf); out_offset += snprintf(buf + out_offset, out_count - out_offset, "tx_mw - \t%p\n", qp->tx_mw); out_offset += snprintf(buf + out_offset, out_count - out_offset, @@ -488,11 +518,11 @@ static void ntb_transport_setup_qp_mw(struct ntb_transport *nt, num_qps_mw = nt->max_qps / mw_max; rx_size = (unsigned int) nt->mw[mw_num].size / num_qps_mw; - qp->remote_rx_info = nt->mw[mw_num].virt_addr + - (qp_num / mw_max * rx_size); + qp->rx_buff = nt->mw[mw_num].virt_addr + qp_num / mw_max * rx_size; rx_size -= sizeof(struct ntb_rx_info); - qp->rx_buff = qp->remote_rx_info + 1; + qp->remote_rx_info = qp->rx_buff + rx_size; + /* Due to housekeeping, there must be atleast 2 buffs */ qp->rx_max_frame = min(transport_mtu, rx_size / 2); qp->rx_max_entry = rx_size / qp->rx_max_frame; @@ -796,12 +826,13 @@ static void ntb_qp_link_work(struct work_struct *work) msecs_to_jiffies(NTB_LINK_DOWN_TIMEOUT)); } -static void ntb_transport_init_queue(struct ntb_transport *nt, +static int ntb_transport_init_queue(struct ntb_transport *nt, unsigned int qp_num) { struct ntb_transport_qp *qp; unsigned int num_qps_mw, tx_size; u8 mw_num, mw_max; + u64 qp_offset; mw_max = ntb_max_mw(nt->ndev); mw_num = QP_TO_MW(nt->ndev, qp_num); @@ -820,11 +851,18 @@ static void ntb_transport_init_queue(struct ntb_transport *nt, num_qps_mw = nt->max_qps / mw_max; tx_size = (unsigned int) ntb_get_mw_size(qp->ndev, mw_num) / num_qps_mw; - qp->rx_info = ntb_get_mw_vbase(nt->ndev, mw_num) + - (qp_num / mw_max * tx_size); + qp_offset = qp_num / mw_max * tx_size; + qp->tx_mw = ntb_get_mw_vbase(nt->ndev, mw_num) + qp_offset; + if (!qp->tx_mw) + return -EINVAL; + + qp->tx_mw_phys = ntb_get_mw_base(qp->ndev, mw_num) + qp_offset; + if (!qp->tx_mw_phys) + return -EINVAL; + tx_size -= sizeof(struct ntb_rx_info); + qp->rx_info = qp->tx_mw + tx_size; - qp->tx_mw = qp->rx_info + 1; /* Due to housekeeping, there must be atleast 2 buffs */ qp->tx_max_frame = min(transport_mtu, tx_size / 2); qp->tx_max_entry = tx_size / qp->tx_max_frame; @@ -851,6 +889,8 @@ static void ntb_transport_init_queue(struct ntb_transport *nt, INIT_LIST_HEAD(&qp->rx_pend_q); INIT_LIST_HEAD(&qp->rx_free_q); INIT_LIST_HEAD(&qp->tx_free_q); + + return 0; } int ntb_transport_init(struct pci_dev *pdev) @@ -889,8 +929,11 @@ int ntb_transport_init(struct pci_dev *pdev) nt->qp_bitmap = ((u64) 1 << nt->max_qps) - 1; - for (i = 0; i < nt->max_qps; i++) - ntb_transport_init_queue(nt, i); + for (i = 0; i < nt->max_qps; i++) { + rc = ntb_transport_init_queue(nt, i); + if (rc) + goto err3; + } INIT_DELAYED_WORK(&nt->link_work, ntb_transport_link_work); INIT_WORK(&nt->link_cleanup, ntb_transport_link_cleanup); @@ -956,13 +999,19 @@ void ntb_transport_free(void *transport) kfree(nt); } -static void ntb_rx_copy_task(struct ntb_transport_qp *qp, - struct ntb_queue_entry *entry, void *offset) +static void ntb_rx_copy_callback(void *data) { + struct ntb_queue_entry *entry = data; + struct ntb_transport_qp *qp = entry->qp; void *cb_data = entry->cb_data; unsigned int len = entry->len; + struct ntb_payload_header *hdr = entry->rx_hdr; + + /* Ensure that the data is fully copied out before clearing the flag */ + wmb(); + hdr->flags = 0; - memcpy(entry->buf, offset, entry->len); + iowrite32(entry->index, &qp->rx_info->entry); ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q); @@ -970,6 +1019,86 @@ static void ntb_rx_copy_task(struct ntb_transport_qp *qp, qp->rx_handler(qp, qp->cb_data, cb_data, len); } +static void ntb_memcpy_rx(struct ntb_queue_entry *entry, void *offset) +{ + void *buf = entry->buf; + size_t len = entry->len; + + memcpy(buf, offset, len); + + ntb_rx_copy_callback(entry); +} + +static void ntb_async_rx(struct ntb_queue_entry *entry, void *offset, + size_t len) +{ + struct dma_async_tx_descriptor *txd; + struct ntb_transport_qp *qp = entry->qp; + struct dma_chan *chan = qp->dma_chan; + struct dma_device *device; + size_t pay_off, buff_off; + dma_addr_t src, dest; + dma_cookie_t cookie; + void *buf = entry->buf; + unsigned long flags; + + entry->len = len; + + if (!chan) + goto err; + + if (len < copy_bytes) + goto err1; + + device = chan->device; + pay_off = (size_t) offset & ~PAGE_MASK; + buff_off = (size_t) buf & ~PAGE_MASK; + + if (!is_dma_copy_aligned(device, pay_off, buff_off, len)) + goto err1; + + dest = dma_map_single(device->dev, buf, len, DMA_FROM_DEVICE); + if (dma_mapping_error(device->dev, dest)) + goto err1; + + src = dma_map_single(device->dev, offset, len, DMA_TO_DEVICE); + if (dma_mapping_error(device->dev, src)) + goto err2; + + flags = DMA_COMPL_DEST_UNMAP_SINGLE | DMA_COMPL_SRC_UNMAP_SINGLE | + DMA_PREP_INTERRUPT; + txd = device->device_prep_dma_memcpy(chan, dest, src, len, flags); + if (!txd) + goto err3; + + txd->callback = ntb_rx_copy_callback; + txd->callback_param = entry; + + cookie = dmaengine_submit(txd); + if (dma_submit_error(cookie)) + goto err3; + + qp->last_cookie = cookie; + + qp->rx_async++; + + return; + +err3: + dma_unmap_single(device->dev, src, len, DMA_TO_DEVICE); +err2: + dma_unmap_single(device->dev, dest, len, DMA_FROM_DEVICE); +err1: + /* If the callbacks come out of order, the writing of the index to the + * last completed will be out of order. This may result in the + * receive stalling forever. + */ + dma_sync_wait(chan, qp->last_cookie); +err: + ntb_memcpy_rx(entry, offset); + qp->rx_memcpy++; +} + static int ntb_process_rxc(struct ntb_transport_qp *qp) { struct ntb_payload_header *hdr; @@ -1008,41 +1137,45 @@ static int ntb_process_rxc(struct ntb_transport_qp *qp) if (hdr->flags & LINK_DOWN_FLAG) { ntb_qp_link_down(qp); - ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, - &qp->rx_pend_q); - goto out; + goto err; } dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "rx offset %u, ver %u - %d payload received, buf size %d\n", qp->rx_index, hdr->ver, hdr->len, entry->len); - if (hdr->len <= entry->len) { - entry->len = hdr->len; - ntb_rx_copy_task(qp, entry, offset); - } else { - ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, - &qp->rx_pend_q); + qp->rx_bytes += hdr->len; + qp->rx_pkts++; + if (hdr->len > entry->len) { qp->rx_err_oflow++; dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "RX overflow! Wanted %d got %d\n", hdr->len, entry->len); + + goto err; } - qp->rx_bytes += hdr->len; - qp->rx_pkts++; + entry->index = qp->rx_index; + entry->rx_hdr = hdr; + + ntb_async_rx(entry, offset, hdr->len); out: + qp->rx_index++; + qp->rx_index %= qp->rx_max_entry; + + return 0; + +err: + ntb_list_add(&qp->ntb_rx_pend_q_lock, &entry->entry, + &qp->rx_pend_q); /* Ensure that the data is fully copied out before clearing the flag */ wmb(); hdr->flags = 0; iowrite32(qp->rx_index, &qp->rx_info->entry); - qp->rx_index++; - qp->rx_index %= qp->rx_max_entry; - - return 0; + goto out; } static void ntb_transport_rx(unsigned long data) @@ -1058,6 +1191,9 @@ static void ntb_transport_rx(unsigned long data) if (rc) break; } + + if (qp->dma_chan) + dma_async_issue_pending(qp->dma_chan); } static void ntb_transport_rxc_db(void *data, int db_num) @@ -1070,19 +1206,13 @@ static void ntb_transport_rxc_db(void *data, int db_num) tasklet_schedule(&qp->rx_work); } -static void ntb_tx_copy_task(struct ntb_transport_qp *qp, - struct ntb_queue_entry *entry, - void __iomem *offset) +static void ntb_tx_copy_callback(void *data) { - struct ntb_payload_header __iomem *hdr; - - memcpy_toio(offset, entry->buf, entry->len); + struct ntb_queue_entry *entry = data; + struct ntb_transport_qp *qp = entry->qp; + struct ntb_payload_header __iomem *hdr = entry->tx_hdr; - hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header); - iowrite32(entry->len, &hdr->len); - iowrite32((u32) qp->tx_pkts, &hdr->ver); - - /* Ensure that the data is fully copied out before setting the flag */ + /* Ensure that the data is fully copied out before setting the flags */ wmb(); iowrite32(entry->flags | DESC_DONE_FLAG, &hdr->flags); @@ -1103,15 +1233,81 @@ static void ntb_tx_copy_task(struct ntb_transport_qp *qp, ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q); } -static int ntb_process_tx(struct ntb_transport_qp *qp, - struct ntb_queue_entry *entry) +static void ntb_memcpy_tx(struct ntb_queue_entry *entry, void __iomem *offset) { + memcpy_toio(offset, entry->buf, entry->len); + + ntb_tx_copy_callback(entry); +} + +static void ntb_async_tx(struct ntb_transport_qp *qp, + struct ntb_queue_entry *entry) +{ + struct ntb_payload_header __iomem *hdr; + struct dma_async_tx_descriptor *txd; + struct dma_chan *chan = qp->dma_chan; + struct dma_device *device; + size_t dest_off, buff_off; + dma_addr_t src, dest; + dma_cookie_t cookie; void __iomem *offset; + size_t len = entry->len; + void *buf = entry->buf; + unsigned long flags; offset = qp->tx_mw + qp->tx_max_frame * qp->tx_index; + hdr = offset + qp->tx_max_frame - sizeof(struct ntb_payload_header); + entry->tx_hdr = hdr; - dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - offset %p, tx %u, entry len %d flags %x buff %p\n", - qp->tx_pkts, offset, qp->tx_index, entry->len, entry->flags, + iowrite32(entry->len, &hdr->len); + iowrite32((u32) qp->tx_pkts, &hdr->ver); + + if (!chan) + goto err; + + if (len < copy_bytes) + goto err; + + device = chan->device; + dest = qp->tx_mw_phys + qp->tx_max_frame * qp->tx_index; + buff_off = (size_t) buf & ~PAGE_MASK; + dest_off = (size_t) dest & ~PAGE_MASK; + + if (!is_dma_copy_aligned(device, buff_off, dest_off, len)) + goto err; + + src = dma_map_single(device->dev, buf, len, DMA_TO_DEVICE); + if (dma_mapping_error(device->dev, src)) + goto err; + + flags = DMA_COMPL_SRC_UNMAP_SINGLE | DMA_PREP_INTERRUPT; + txd = device->device_prep_dma_memcpy(chan, dest, src, len, flags); + if (!txd) + goto err1; + + txd->callback = ntb_tx_copy_callback; + txd->callback_param = entry; + + cookie = dmaengine_submit(txd); + if (dma_submit_error(cookie)) + goto err1; + + dma_async_issue_pending(chan); + qp->tx_async++; + + return; +err1: + dma_unmap_single(device->dev, src, len, DMA_TO_DEVICE); +err: + ntb_memcpy_tx(entry, offset); + qp->tx_memcpy++; +} + +static int ntb_process_tx(struct ntb_transport_qp *qp, + struct ntb_queue_entry *entry) +{ + dev_dbg(&ntb_query_pdev(qp->ndev)->dev, "%lld - tx %u, entry len %d flags %x buff %p\n", + qp->tx_pkts, qp->tx_index, entry->len, entry->flags, entry->buf); if (qp->tx_index == qp->remote_rx_info->entry) { qp->tx_ring_full++; @@ -1127,7 +1323,7 @@ static int ntb_process_tx(struct ntb_transport_qp *qp, return 0; } - ntb_tx_copy_task(qp, entry, offset); + ntb_async_tx(qp, entry); qp->tx_index++; qp->tx_index %= qp->tx_max_entry; @@ -1213,11 +1409,18 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev, qp->tx_handler = handlers->tx_handler; qp->event_handler = handlers->event_handler; + qp->dma_chan = dma_find_channel(DMA_MEMCPY); + if (!qp->dma_chan) + dev_info(&pdev->dev, "Unable to allocate DMA channel, using CPU instead\n"); + else + dmaengine_get(); + for (i = 0; i < NTB_QP_DEF_NUM_ENTRIES; i++) { entry = kzalloc(sizeof(struct ntb_queue_entry), GFP_ATOMIC); if (!entry) goto err1; + entry->qp = qp; ntb_list_add(&qp->ntb_rx_free_q_lock, &entry->entry, &qp->rx_free_q); } @@ -1227,6 +1430,7 @@ ntb_transport_create_queue(void *data, struct pci_dev *pdev, if (!entry) goto err2; + entry->qp = qp; ntb_list_add(&qp->ntb_tx_free_q_lock, &entry->entry, &qp->tx_free_q); } @@ -1272,11 +1476,26 @@ void ntb_transport_free_queue(struct ntb_transport_qp *qp) pdev = ntb_query_pdev(qp->ndev); - cancel_delayed_work_sync(&qp->link_work); + if (qp->dma_chan) { + struct dma_chan *chan = qp->dma_chan; + /* Putting the dma_chan to NULL will force any new traffic to be + * processed by the CPU instead of the DAM engine + */ + qp->dma_chan = NULL; + + /* Try to be nice and wait for any queued DMA engine + * transactions to process before smashing it with a rock + */ + dma_sync_wait(chan, qp->last_cookie); + dmaengine_terminate_all(chan); + dmaengine_put(); + } ntb_unregister_db_callback(qp->ndev, qp->qp_num); tasklet_disable(&qp->rx_work); + cancel_delayed_work_sync(&qp->link_work); + while ((entry = ntb_list_rm(&qp->ntb_rx_free_q_lock, &qp->rx_free_q))) kfree(entry); @@ -1382,8 +1601,10 @@ int ntb_transport_tx_enqueue(struct ntb_transport_qp *qp, void *cb, void *data, return -EINVAL; entry = ntb_list_rm(&qp->ntb_tx_free_q_lock, &qp->tx_free_q); - if (!entry) + if (!entry) { + qp->tx_err_no_buf++; return -ENOMEM; + } entry->cb_data = cb; entry->buf = data; @@ -1499,9 +1720,18 @@ EXPORT_SYMBOL_GPL(ntb_transport_qp_num); */ unsigned int ntb_transport_max_size(struct ntb_transport_qp *qp) { + unsigned int max; + if (!qp) return 0; - return qp->tx_max_frame - sizeof(struct ntb_payload_header); + if (!qp->dma_chan) + return qp->tx_max_frame - sizeof(struct ntb_payload_header); + + /* If DMA engine usage is possible, try to find the max size for that */ + max = qp->tx_max_frame - sizeof(struct ntb_payload_header); + max -= max % (1 << qp->dma_chan->device->copy_align); + + return max; } EXPORT_SYMBOL_GPL(ntb_transport_max_size); -- 2.34.1