[PATCH] IB uverbs: add mthca user doorbell record support

Add support for userspace doorbell records to mthca.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 136 insertions, 5 deletions

diff --git a/drivers/infiniband/hw/mthca/mthca_memfree.c b/drivers/infiniband/hw/mthca/mthca_memfree.c
index 6d3b05dd9e3f..2a8646150355 100644
--- a/drivers/infiniband/hw/mthca/mthca_memfree.c
+++ b/drivers/infiniband/hw/mthca/mthca_memfree.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2004, 2005 Topspin Communications.  All rights reserved.
+ * Copyright (c) 2005 Cisco Systems.  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
@@ -47,6 +48,15 @@ enum {
         MTHCA_TABLE_CHUNK_SIZE = 1 << 18
 };
 
+struct mthca_user_db_table {
+        struct semaphore mutex;
+        struct {
+                u64                uvirt;
+                struct scatterlist mem;
+                int                refcount;
+        }                page[0];
+};
+
 void mthca_free_icm(struct mthca_dev *dev, struct mthca_icm *icm)
 {
         struct mthca_icm_chunk *chunk, *tmp;
@@ -344,13 +354,133 @@ void mthca_free_icm_table(struct mthca_dev *dev, struct mthca_icm_table *table)
         kfree(table);
 }
 
-static u64 mthca_uarc_virt(struct mthca_dev *dev, int page)
+static u64 mthca_uarc_virt(struct mthca_dev *dev, struct mthca_uar *uar, int page)
 {
         return dev->uar_table.uarc_base +
-                dev->driver_uar.index * dev->uar_table.uarc_size +
+                uar->index * dev->uar_table.uarc_size +
                 page * 4096;
 }
 
+int mthca_map_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
+                      struct mthca_user_db_table *db_tab, int index, u64 uaddr)
+{
+        int ret = 0;
+        u8 status;
+        int i;
+
+        if (!mthca_is_memfree(dev))
+                return 0;
+
+        if (index < 0 || index > dev->uar_table.uarc_size / 8)
+                return -EINVAL;
+
+        down(&db_tab->mutex);
+
+        i = index / MTHCA_DB_REC_PER_PAGE;
+
+        if ((db_tab->page[i].refcount >= MTHCA_DB_REC_PER_PAGE)       ||
+            (db_tab->page[i].uvirt && db_tab->page[i].uvirt != uaddr) ||
+            (uaddr & 4095)) {
+                ret = -EINVAL;
+                goto out;
+        }
+
+        if (db_tab->page[i].refcount) {
+                ++db_tab->page[i].refcount;
+                goto out;
+        }
+
+        ret = get_user_pages(current, current->mm, uaddr & PAGE_MASK, 1, 1, 0,
+                             &db_tab->page[i].mem.page, NULL);
+        if (ret < 0)
+                goto out;
+
+        db_tab->page[i].mem.length = 4096;
+        db_tab->page[i].mem.offset = uaddr & ~PAGE_MASK;
+
+        ret = pci_map_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
+        if (ret < 0) {
+                put_page(db_tab->page[i].mem.page);
+                goto out;
+        }
+
+        ret = mthca_MAP_ICM_page(dev, sg_dma_address(&db_tab->page[i].mem),
+                                 mthca_uarc_virt(dev, uar, i), &status);
+        if (!ret && status)
+                ret = -EINVAL;
+        if (ret) {
+                pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
+                put_page(db_tab->page[i].mem.page);
+                goto out;
+        }
+
+        db_tab->page[i].uvirt    = uaddr;
+        db_tab->page[i].refcount = 1;
+
+out:
+        up(&db_tab->mutex);
+        return ret;
+}
+
+void mthca_unmap_user_db(struct mthca_dev *dev, struct mthca_uar *uar,
+                         struct mthca_user_db_table *db_tab, int index)
+{
+        if (!mthca_is_memfree(dev))
+                return;
+
+        /*
+         * To make our bookkeeping simpler, we don't unmap DB
+         * pages until we clean up the whole db table.
+         */
+
+        down(&db_tab->mutex);
+
+        --db_tab->page[index / MTHCA_DB_REC_PER_PAGE].refcount;
+
+        up(&db_tab->mutex);
+}
+
+struct mthca_user_db_table *mthca_init_user_db_tab(struct mthca_dev *dev)
+{
+        struct mthca_user_db_table *db_tab;
+        int npages;
+        int i;
+
+        if (!mthca_is_memfree(dev))
+                return NULL;
+
+        npages = dev->uar_table.uarc_size / 4096;
+        db_tab = kmalloc(sizeof *db_tab + npages * sizeof *db_tab->page, GFP_KERNEL);
+        if (!db_tab)
+                return ERR_PTR(-ENOMEM);
+
+        init_MUTEX(&db_tab->mutex);
+        for (i = 0; i < npages; ++i) {
+                db_tab->page[i].refcount = 0;
+                db_tab->page[i].uvirt    = 0;
+        }
+
+        return db_tab;
+}
+
+void mthca_cleanup_user_db_tab(struct mthca_dev *dev, struct mthca_uar *uar,
+                               struct mthca_user_db_table *db_tab)
+{
+        int i;
+        u8 status;
+
+        if (!mthca_is_memfree(dev))
+                return;
+
+        for (i = 0; i < dev->uar_table.uarc_size / 4096; ++i) {
+                if (db_tab->page[i].uvirt) {
+                        mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, uar, i), 1, &status);
+                        pci_unmap_sg(dev->pdev, &db_tab->page[i].mem, 1, PCI_DMA_TODEVICE);
+                        put_page(db_tab->page[i].mem.page);
+                }
+        }
+}
+
 int mthca_alloc_db(struct mthca_dev *dev, int type, u32 qn, u32 **db)
 {
         int group;
@@ -407,7 +537,8 @@ int mthca_alloc_db(struct mthca_dev *dev, int type, u32 qn, u32 **db)
         }
         memset(page->db_rec, 0, 4096);
 
-        ret = mthca_MAP_ICM_page(dev, page->mapping, mthca_uarc_virt(dev, i), &status);
+        ret = mthca_MAP_ICM_page(dev, page->mapping,
+                                 mthca_uarc_virt(dev, &dev->driver_uar, i), &status);
         if (!ret && status)
                 ret = -EINVAL;
         if (ret) {
@@ -461,7 +592,7 @@ void mthca_free_db(struct mthca_dev *dev, int type, int db_index)
 
         if (bitmap_empty(page->used, MTHCA_DB_REC_PER_PAGE) &&
             i >= dev->db_tab->max_group1 - 1) {
-                mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, i), 1, &status);
+                mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1, &status);
 
                 dma_free_coherent(&dev->pdev->dev, 4096,
                                   page->db_rec, page->mapping);
@@ -530,7 +661,7 @@ void mthca_cleanup_db_tab(struct mthca_dev *dev)
                 if (!bitmap_empty(dev->db_tab->page[i].used, MTHCA_DB_REC_PER_PAGE))
                         mthca_warn(dev, "Kernel UARC page %d not empty\n", i);
 
-                mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, i), 1, &status);
+                mthca_UNMAP_ICM(dev, mthca_uarc_virt(dev, &dev->driver_uar, i), 1, &status);
 
                 dma_free_coherent(&dev->pdev->dev, 4096,
                                   dev->db_tab->page[i].db_rec,