IB/ipath: User mode send DMA

/*

 * Copyright (c) 2007, 2008 QLogic Corporation. 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/mm.h>

#include <linux/types.h>

#include <linux/device.h>

#include <linux/dmapool.h>

#include <linux/slab.h>

#include <linux/list.h>

#include <linux/highmem.h>

#include <linux/io.h>

#include <linux/uio.h>

#include <linux/rbtree.h>

#include <linux/spinlock.h>

#include <linux/delay.h>

#include "ipath_kernel.h"

#include "ipath_user_sdma.h"

/* minimum size of header */

#define IPATH_USER_SDMA_MIN_HEADER_LENGTH	64

/* expected size of headers (for dma_pool) */

#define IPATH_USER_SDMA_EXP_HEADER_LENGTH	64

/* length mask in PBC (lower 11 bits) */

#define IPATH_PBC_LENGTH_MASK			((1 << 11) - 1)

struct ipath_user_sdma_pkt {

	u8 naddr;		/* dimension of addr (1..3) ... */

	u32 counter;		/* sdma pkts queued counter for this entry */

	u64 added;		/* global descq number of entries */

	struct {

		u32 offset;			/* offset for kvaddr, addr */

		u32 length;			/* length in page */

		u8  put_page;			/* should we put_page? */

		u8  dma_mapped;			/* is page dma_mapped? */

		struct page *page;		/* may be NULL (coherent mem) */

		void *kvaddr;			/* FIXME: only for pio hack */

		dma_addr_t addr;

	} addr[4];   /* max pages, any more and we coalesce */

	struct list_head list;	/* list element */

};

struct ipath_user_sdma_queue {

	/*

	 * pkts sent to dma engine are queued on this

	 * list head.  the type of the elements of this

	 * list are struct ipath_user_sdma_pkt...

	 */

	struct list_head sent;

	/* headers with expected length are allocated from here... */

	char header_cache_name[64];

	struct dma_pool *header_cache;

	/* packets are allocated from the slab cache... */

	char pkt_slab_name[64];

	struct kmem_cache *pkt_slab;

	/* as packets go on the queued queue, they are counted... */

	u32 counter;

	u32 sent_counter;

	/* dma page table */

	struct rb_root dma_pages_root;

	/* protect everything above... */

	struct mutex lock;

};

struct ipath_user_sdma_queue *

ipath_user_sdma_queue_create(struct device *dev, int unit, int port, int sport)

{

	struct ipath_user_sdma_queue *pq =

		kmalloc(sizeof(struct ipath_user_sdma_queue), GFP_KERNEL);

	if (!pq)

		goto done;

	pq->counter = 0;

	pq->sent_counter = 0;

	INIT_LIST_HEAD(&pq->sent);

	mutex_init(&pq->lock);

	snprintf(pq->pkt_slab_name, sizeof(pq->pkt_slab_name),

		 "ipath-user-sdma-pkts-%u-%02u.%02u", unit, port, sport);

	pq->pkt_slab = kmem_cache_create(pq->pkt_slab_name,

					 sizeof(struct ipath_user_sdma_pkt),

					 0, 0, NULL);

	if (!pq->pkt_slab)

		goto err_kfree;

	snprintf(pq->header_cache_name, sizeof(pq->header_cache_name),

		 "ipath-user-sdma-headers-%u-%02u.%02u", unit, port, sport);

	pq->header_cache = dma_pool_create(pq->header_cache_name,

					   dev,

					   IPATH_USER_SDMA_EXP_HEADER_LENGTH,

					   4, 0);

	if (!pq->header_cache)

		goto err_slab;

	pq->dma_pages_root = RB_ROOT;

	goto done;

err_slab:

	kmem_cache_destroy(pq->pkt_slab);

err_kfree:

	kfree(pq);

	pq = NULL;

done:

	return pq;

}

static void ipath_user_sdma_init_frag(struct ipath_user_sdma_pkt *pkt,

				      int i, size_t offset, size_t len,

				      int put_page, int dma_mapped,

				      struct page *page,

				      void *kvaddr, dma_addr_t dma_addr)

{

	pkt->addr[i].offset = offset;

	pkt->addr[i].length = len;

	pkt->addr[i].put_page = put_page;

	pkt->addr[i].dma_mapped = dma_mapped;

	pkt->addr[i].page = page;

	pkt->addr[i].kvaddr = kvaddr;

	pkt->addr[i].addr = dma_addr;

}

static void ipath_user_sdma_init_header(struct ipath_user_sdma_pkt *pkt,

					u32 counter, size_t offset,

					size_t len, int dma_mapped,

					struct page *page,

					void *kvaddr, dma_addr_t dma_addr)

{

	pkt->naddr = 1;

	pkt->counter = counter;

	ipath_user_sdma_init_frag(pkt, 0, offset, len, 0, dma_mapped, page,

				  kvaddr, dma_addr);

}

/* we've too many pages in the iovec, coalesce to a single page */

static int ipath_user_sdma_coalesce(const struct ipath_devdata *dd,

				    struct ipath_user_sdma_pkt *pkt,

				    const struct iovec *iov,

				    unsigned long niov) {

	int ret = 0;

	struct page *page = alloc_page(GFP_KERNEL);

	void *mpage_save;

	char *mpage;

	int i;

	int len = 0;

	dma_addr_t dma_addr;

	if (!page) {

		ret = -ENOMEM;

		goto done;

	}

	mpage = kmap(page);

	mpage_save = mpage;

	for (i = 0; i < niov; i++) {

		int cfur;

		cfur = copy_from_user(mpage,

				      iov[i].iov_base, iov[i].iov_len);

		if (cfur) {

			ret = -EFAULT;

			goto free_unmap;

		}

		mpage += iov[i].iov_len;

		len += iov[i].iov_len;

	}

	dma_addr = dma_map_page(&dd->pcidev->dev, page, 0, len,

				DMA_TO_DEVICE);

	if (dma_mapping_error(dma_addr)) {

		ret = -ENOMEM;

		goto free_unmap;

	}

	ipath_user_sdma_init_frag(pkt, 1, 0, len, 0, 1, page, mpage_save,

				  dma_addr);

	pkt->naddr = 2;

	goto done;

free_unmap:

	kunmap(page);

	__free_page(page);

done:

	return ret;

}

/* how many pages in this iovec element? */

static int ipath_user_sdma_num_pages(const struct iovec *iov)

{

	const unsigned long addr  = (unsigned long) iov->iov_base;

	const unsigned long  len  = iov->iov_len;

	const unsigned long spage = addr & PAGE_MASK;

	const unsigned long epage = (addr + len - 1) & PAGE_MASK;

	return 1 + ((epage - spage) >> PAGE_SHIFT);

}

/* truncate length to page boundry */

static int ipath_user_sdma_page_length(unsigned long addr, unsigned long len)

{

	const unsigned long offset = addr & ~PAGE_MASK;

	return ((offset + len) > PAGE_SIZE) ? (PAGE_SIZE - offset) : len;

}

static void ipath_user_sdma_free_pkt_frag(struct device *dev,

					  struct ipath_user_sdma_queue *pq,

					  struct ipath_user_sdma_pkt *pkt,

					  int frag)

{

	const int i = frag;

	if (pkt->addr[i].page) {

		if (pkt->addr[i].dma_mapped)

			dma_unmap_page(dev,

				       pkt->addr[i].addr,

				       pkt->addr[i].length,

				       DMA_TO_DEVICE);

		if (pkt->addr[i].kvaddr)

			kunmap(pkt->addr[i].page);

		if (pkt->addr[i].put_page)

			put_page(pkt->addr[i].page);

		else

			__free_page(pkt->addr[i].page);

	} else if (pkt->addr[i].kvaddr)

		/* free coherent mem from cache... */

		dma_pool_free(pq->header_cache,

			      pkt->addr[i].kvaddr, pkt->addr[i].addr);

}

/* return number of pages pinned... */

static int ipath_user_sdma_pin_pages(const struct ipath_devdata *dd,

				     struct ipath_user_sdma_pkt *pkt,

				     unsigned long addr, int tlen, int npages)

{

	struct page *pages[2];

	int j;

	int ret;

	ret = get_user_pages(current, current->mm, addr,

			     npages, 0, 1, pages, NULL);

	if (ret != npages) {

		int i;

		for (i = 0; i < ret; i++)

			put_page(pages[i]);

		ret = -ENOMEM;

		goto done;

	}

	for (j = 0; j < npages; j++) {

		/* map the pages... */

		const int flen =

			ipath_user_sdma_page_length(addr, tlen);

		dma_addr_t dma_addr =

			dma_map_page(&dd->pcidev->dev,

				     pages[j], 0, flen, DMA_TO_DEVICE);

		unsigned long fofs = addr & ~PAGE_MASK;

		if (dma_mapping_error(dma_addr)) {

			ret = -ENOMEM;

			goto done;

		}

		ipath_user_sdma_init_frag(pkt, pkt->naddr, fofs, flen, 1, 1,

					  pages[j], kmap(pages[j]),

					  dma_addr);

		pkt->naddr++;

		addr += flen;

		tlen -= flen;

	}

done:

	return ret;

}

static int ipath_user_sdma_pin_pkt(const struct ipath_devdata *dd,

				   struct ipath_user_sdma_queue *pq,

				   struct ipath_user_sdma_pkt *pkt,

				   const struct iovec *iov,

				   unsigned long niov)

{

	int ret = 0;

	unsigned long idx;

	for (idx = 0; idx < niov; idx++) {

		const int npages = ipath_user_sdma_num_pages(iov + idx);

		const unsigned long addr = (unsigned long) iov[idx].iov_base;

		ret = ipath_user_sdma_pin_pages(dd, pkt,

						addr, iov[idx].iov_len,

						npages);

		if (ret < 0)

			goto free_pkt;

	}

	goto done;

free_pkt:

	for (idx = 0; idx < pkt->naddr; idx++)

		ipath_user_sdma_free_pkt_frag(&dd->pcidev->dev, pq, pkt, idx);

done:

	return ret;

}

static int ipath_user_sdma_init_payload(const struct ipath_devdata *dd,

					struct ipath_user_sdma_queue *pq,

					struct ipath_user_sdma_pkt *pkt,

					const struct iovec *iov,

					unsigned long niov, int npages)

{

	int ret = 0;

	if (npages >= ARRAY_SIZE(pkt->addr))

		ret = ipath_user_sdma_coalesce(dd, pkt, iov, niov);

	else

		ret = ipath_user_sdma_pin_pkt(dd, pq, pkt, iov, niov);

	return ret;

}

/* free a packet list -- return counter value of last packet */

static void ipath_user_sdma_free_pkt_list(struct device *dev,

					  struct ipath_user_sdma_queue *pq,

					  struct list_head *list)

{

	struct ipath_user_sdma_pkt *pkt, *pkt_next;

	list_for_each_entry_safe(pkt, pkt_next, list, list) {

		int i;

		for (i = 0; i < pkt->naddr; i++)

			ipath_user_sdma_free_pkt_frag(dev, pq, pkt, i);

		kmem_cache_free(pq->pkt_slab, pkt);

	}

}

/*

 * copy headers, coalesce etc -- pq->lock must be held

 *

 * we queue all the packets to list, returning the

 * number of bytes total.  list must be empty initially,

 * as, if there is an error we clean it...

 */

static int ipath_user_sdma_queue_pkts(const struct ipath_devdata *dd,

				      struct ipath_user_sdma_queue *pq,

				      struct list_head *list,

				      const struct iovec *iov,

				      unsigned long niov,

				      int maxpkts)

{

	unsigned long idx = 0;

	int ret = 0;

	int npkts = 0;

	struct page *page = NULL;

	__le32 *pbc;

	dma_addr_t dma_addr;

	struct ipath_user_sdma_pkt *pkt = NULL;

	size_t len;

	size_t nw;

	u32 counter = pq->counter;

	int dma_mapped = 0;

	while (idx < niov && npkts < maxpkts) {

		const unsigned long addr = (unsigned long) iov[idx].iov_base;

		const unsigned long idx_save = idx;

		unsigned pktnw;

		unsigned pktnwc;

		int nfrags = 0;

		int npages = 0;

		int cfur;

		dma_mapped = 0;

		len = iov[idx].iov_len;

		nw = len >> 2;

		page = NULL;

		pkt = kmem_cache_alloc(pq->pkt_slab, GFP_KERNEL);

		if (!pkt) {

			ret = -ENOMEM;

			goto free_list;

		}

		if (len < IPATH_USER_SDMA_MIN_HEADER_LENGTH ||

		    len > PAGE_SIZE || len & 3 || addr & 3) {

			ret = -EINVAL;

			goto free_pkt;

		}

		if (len == IPATH_USER_SDMA_EXP_HEADER_LENGTH)

			pbc = dma_pool_alloc(pq->header_cache, GFP_KERNEL,

					     &dma_addr);

		else

			pbc = NULL;

		if (!pbc) {

			page = alloc_page(GFP_KERNEL);

			if (!page) {

				ret = -ENOMEM;

				goto free_pkt;

			}

			pbc = kmap(page);

		}

		cfur = copy_from_user(pbc, iov[idx].iov_base, len);

		if (cfur) {

			ret = -EFAULT;

			goto free_pbc;

		}

		/*

		 * this assignment is a bit strange.  it's because the

		 * the pbc counts the number of 32 bit words in the full

		 * packet _except_ the first word of the pbc itself...

		 */

		pktnwc = nw - 1;

		/*

		 * pktnw computation yields the number of 32 bit words

		 * that the caller has indicated in the PBC.  note that

		 * this is one less than the total number of words that

		 * goes to the send DMA engine as the first 32 bit word

		 * of the PBC itself is not counted.  Armed with this count,

		 * we can verify that the packet is consistent with the

		 * iovec lengths.

		 */

		pktnw = le32_to_cpu(*pbc) & IPATH_PBC_LENGTH_MASK;

		if (pktnw < pktnwc || pktnw > pktnwc + (PAGE_SIZE >> 2)) {

			ret = -EINVAL;

			goto free_pbc;

		}

		idx++;

		while (pktnwc < pktnw && idx < niov) {

			const size_t slen = iov[idx].iov_len;

			const unsigned long faddr =

				(unsigned long) iov[idx].iov_base;

			if (slen & 3 || faddr & 3 || !slen ||

			    slen > PAGE_SIZE) {

				ret = -EINVAL;

				goto free_pbc;

			}

			npages++;

			if ((faddr & PAGE_MASK) !=

			    ((faddr + slen - 1) & PAGE_MASK))

				npages++;

			pktnwc += slen >> 2;

			idx++;

			nfrags++;

		}

		if (pktnwc != pktnw) {

			ret = -EINVAL;

			goto free_pbc;

		}

		if (page) {

			dma_addr = dma_map_page(&dd->pcidev->dev,

						page, 0, len, DMA_TO_DEVICE);

			if (dma_mapping_error(dma_addr)) {

				ret = -ENOMEM;

				goto free_pbc;

			}

			dma_mapped = 1;

		}

		ipath_user_sdma_init_header(pkt, counter, 0, len, dma_mapped,

					    page, pbc, dma_addr);

		if (nfrags) {

			ret = ipath_user_sdma_init_payload(dd, pq, pkt,

							   iov + idx_save + 1,

							   nfrags, npages);

			if (ret < 0)

				goto free_pbc_dma;

		}

		counter++;

		npkts++;

		list_add_tail(&pkt->list, list);

	}

	ret = idx;

	goto done;

free_pbc_dma:

	if (dma_mapped)

		dma_unmap_page(&dd->pcidev->dev, dma_addr, len, DMA_TO_DEVICE);

free_pbc:

	if (page) {

		kunmap(page);

		__free_page(page);

	} else

		dma_pool_free(pq->header_cache, pbc, dma_addr);

free_pkt:

	kmem_cache_free(pq->pkt_slab, pkt);

free_list:

	ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, list);

done:

	return ret;

}

static void ipath_user_sdma_set_complete_counter(struct ipath_user_sdma_queue *pq,

						 u32 c)

{

	pq->sent_counter = c;

}

/* try to clean out queue -- needs pq->lock */

static int ipath_user_sdma_queue_clean(const struct ipath_devdata *dd,

				       struct ipath_user_sdma_queue *pq)

{

	struct list_head free_list;

	struct ipath_user_sdma_pkt *pkt;

	struct ipath_user_sdma_pkt *pkt_prev;

	int ret = 0;

	INIT_LIST_HEAD(&free_list);

	list_for_each_entry_safe(pkt, pkt_prev, &pq->sent, list) {

		s64 descd = dd->ipath_sdma_descq_removed - pkt->added;

		if (descd < 0)

			break;

		list_move_tail(&pkt->list, &free_list);

		/* one more packet cleaned */

		ret++;

	}

	if (!list_empty(&free_list)) {

		u32 counter;

		pkt = list_entry(free_list.prev,

				 struct ipath_user_sdma_pkt, list);

		counter = pkt->counter;

		ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);

		ipath_user_sdma_set_complete_counter(pq, counter);

	}

	return ret;

}

void ipath_user_sdma_queue_destroy(struct ipath_user_sdma_queue *pq)

{

	if (!pq)

		return;

	kmem_cache_destroy(pq->pkt_slab);

	dma_pool_destroy(pq->header_cache);

	kfree(pq);

}

/* clean descriptor queue, returns > 0 if some elements cleaned */

static int ipath_user_sdma_hwqueue_clean(struct ipath_devdata *dd)

{

	int ret;

	unsigned long flags;

	spin_lock_irqsave(&dd->ipath_sdma_lock, flags);

	ret = ipath_sdma_make_progress(dd);

	spin_unlock_irqrestore(&dd->ipath_sdma_lock, flags);

	return ret;

}

/* we're in close, drain packets so that we can cleanup successfully... */

void ipath_user_sdma_queue_drain(struct ipath_devdata *dd,

				 struct ipath_user_sdma_queue *pq)

{

	int i;

	if (!pq)

		return;

	for (i = 0; i < 100; i++) {

		mutex_lock(&pq->lock);

		if (list_empty(&pq->sent)) {

			mutex_unlock(&pq->lock);

			break;

		}

		ipath_user_sdma_hwqueue_clean(dd);

		ipath_user_sdma_queue_clean(dd, pq);

		mutex_unlock(&pq->lock);

		msleep(10);

	}

	if (!list_empty(&pq->sent)) {

		struct list_head free_list;

		printk(KERN_INFO "drain: lists not empty: forcing!\n");

		INIT_LIST_HEAD(&free_list);

		mutex_lock(&pq->lock);

		list_splice_init(&pq->sent, &free_list);

		ipath_user_sdma_free_pkt_list(&dd->pcidev->dev, pq, &free_list);

		mutex_unlock(&pq->lock);

	}

}

static inline __le64 ipath_sdma_make_desc0(struct ipath_devdata *dd,

					   u64 addr, u64 dwlen, u64 dwoffset)

{

	return cpu_to_le64(/* SDmaPhyAddr[31:0] */

			   ((addr & 0xfffffffcULL) << 32) |

			   /* SDmaGeneration[1:0] */

			   ((dd->ipath_sdma_generation & 3ULL) << 30) |

			   /* SDmaDwordCount[10:0] */

			   ((dwlen & 0x7ffULL) << 16) |

			   /* SDmaBufOffset[12:2] */

			   (dwoffset & 0x7ffULL));

}

static inline __le64 ipath_sdma_make_first_desc0(__le64 descq)

{

	return descq | __constant_cpu_to_le64(1ULL << 12);

}

static inline __le64 ipath_sdma_make_last_desc0(__le64 descq)

{

					      /* last */  /* dma head */

	return descq | __constant_cpu_to_le64(1ULL << 11 | 1ULL << 13);

}

static inline __le64 ipath_sdma_make_desc1(u64 addr)

{

	/* SDmaPhyAddr[47:32] */

	return cpu_to_le64(addr >> 32);

}

static void ipath_user_sdma_send_frag(struct ipath_devdata *dd,

				      struct ipath_user_sdma_pkt *pkt, int idx,

				      unsigned ofs, u16 tail)

{

	const u64 addr = (u64) pkt->addr[idx].addr +

		(u64) pkt->addr[idx].offset;

	const u64 dwlen = (u64) pkt->addr[idx].length / 4;

	__le64 *descqp;

	__le64 descq0;

	descqp = &dd->ipath_sdma_descq[tail].qw[0];

	descq0 = ipath_sdma_make_desc0(dd, addr, dwlen, ofs);

	if (idx == 0)

		descq0 = ipath_sdma_make_first_desc0(descq0);

	if (idx == pkt->naddr - 1)

		descq0 = ipath_sdma_make_last_desc0(descq0);

	descqp[0] = descq0;

	descqp[1] = ipath_sdma_make_desc1(addr);

}

/* pq->lock must be held, get packets on the wire... */