NTB: Use DMA Engine to Transmit and Receive (282a2fee) · Commits · 戴 / test

drivers/ntb/ntb_hw.c

+17 −0

Original line number	Diff line number	Diff line
		@@ -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

drivers/ntb/ntb_hw.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -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);

drivers/ntb/ntb_transport.c

+277 −47

Original line number	Diff line number	Diff line
		@@ -47,6 +47,7 @@
		*/
		#include <linux/debugfs.h>
		#include <linux/delay.h>
		#include <linux/dmaengine.h>
		#include <linux/dma-mapping.h>
		#include <linux/errno.h>
		#include <linux/export.h>
		@@ -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;

		memcpy(entry->buf, offset, entry->len);
		/* Ensure that the data is fully copied out before clearing the flag */
		wmb();
		hdr->flags = 0;

		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,
		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;

		iowrite32(entry->len, &hdr->len);
		iowrite32((u32) qp->tx_pkts, &hdr->ver);

		if (!chan)
		goto err;

		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,
		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;

		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);

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