ntb_tool: Postpone memory window initialization for the user

In order to make the interface closer to the raw NTB API, this commit
changes memory windows so they are not initialized on link up.
Instead, the 'peer_trans*' debugfs files are introduced. When read,
they return information provided by ntb_mw_get_range. When written,
they create a buffer and initialize the memory window. The
value written is taken as the requested size of the buffer (which
is then rounded for alignment). Writing a value of zero frees the buffer
and tears down the memory window translation. The 'peer_mw*' file is
only created once the memory window translation is setup by the user.

Additionally, it was noticed that the read and write functions for the
'peer_mw*' files should have checked for a NULL pointer.
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Acked-by: Allen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>

drivers/ntb/test/ntb_tool.c

@@ -79,6 +79,13 @@
  * root@self# cat $DBG_DIR/spad
  *
  * Observe that spad 0 and 1 have the values set by the peer.
+ *
+ * # Check the memory window translation info
+ * cat $DBG_DIR/peer_trans0
+ *
+ * # Setup a 16k memory window buffer
+ * echo 16384 > $DBG_DIR/peer_trans0
+ *
  */
 
 #include <linux/init.h>
@@ -108,25 +115,22 @@ MODULE_DESCRIPTION(DRIVER_DESCRIPTION);
 
 #define MAX_MWS 16
 
-static unsigned long mw_size = 16;
-module_param(mw_size, ulong, 0644);
-MODULE_PARM_DESC(mw_size, "size order [n^2] of the memory window for testing");
-
 static struct dentry *tool_dbgfs;
 
 struct tool_mw {
+	int idx;
+	struct tool_ctx *tc;
+	resource_size_t win_size;
 	resource_size_t size;
 	u8 __iomem *local;
 	u8 *peer;
 	dma_addr_t peer_dma;
+	struct dentry *peer_dbg_file;
 };
 
 struct tool_ctx {
 	struct ntb_dev *ntb;
 	struct dentry *dbgfs;
-	struct work_struct link_cleanup;
-	bool link_is_up;
-	struct delayed_work link_work;
 	int mw_count;
 	struct tool_mw mws[MAX_MWS];
 };
@@ -143,111 +147,6 @@ struct tool_ctx {
 		.write = __write,		\
 	}
 
-static int tool_setup_mw(struct tool_ctx *tc, int idx)
-{
-	int rc;
-	struct tool_mw *mw = &tc->mws[idx];
-	phys_addr_t base;
-	resource_size_t size, align, align_size;
-
-	if (mw->local)
-		return 0;
-
-	rc = ntb_mw_get_range(tc->ntb, idx, &base, &size, &align,
-			      &align_size);
-	if (rc)
-		return rc;
-
-	mw->size = min_t(resource_size_t, 1 << mw_size, size);
-	mw->size = round_up(mw->size, align);
-	mw->size = round_up(mw->size, align_size);
-
-	mw->local = ioremap_wc(base, size);
-	if (mw->local == NULL)
-		return -EFAULT;
-
-	mw->peer = dma_alloc_coherent(&tc->ntb->pdev->dev, mw->size,
-				      &mw->peer_dma, GFP_KERNEL);
-
-	if (mw->peer == NULL)
-		return -ENOMEM;
-
-	rc = ntb_mw_set_trans(tc->ntb, idx, mw->peer_dma, mw->size);
-	if (rc)
-		return rc;
-
-	return 0;
-}
-
-static void tool_free_mws(struct tool_ctx *tc)
-{
-	int i;
-
-	for (i = 0; i < tc->mw_count; i++) {
-		if (tc->mws[i].peer) {
-			ntb_mw_clear_trans(tc->ntb, i);
-			dma_free_coherent(&tc->ntb->pdev->dev, tc->mws[i].size,
-					  tc->mws[i].peer,
-					  tc->mws[i].peer_dma);
-
-		}
-
-		tc->mws[i].peer = NULL;
-		tc->mws[i].peer_dma = 0;
-
-		if (tc->mws[i].local)
-			iounmap(tc->mws[i].local);
-
-		tc->mws[i].local = NULL;
-	}
-
-	tc->mw_count = 0;
-}
-
-static int tool_setup_mws(struct tool_ctx *tc)
-{
-	int i;
-	int rc;
-
-	tc->mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
-
-	for (i = 0; i < tc->mw_count; i++) {
-		rc = tool_setup_mw(tc, i);
-		if (rc)
-			goto err_out;
-	}
-
-	return 0;
-
-err_out:
-	tool_free_mws(tc);
-	return rc;
-}
-
-static void tool_link_work(struct work_struct *work)
-{
-	int rc;
-	struct tool_ctx *tc = container_of(work, struct tool_ctx,
-					   link_work.work);
-
-	tool_free_mws(tc);
-	rc = tool_setup_mws(tc);
-	if (rc)
-		dev_err(&tc->ntb->dev,
-			"Error setting up memory windows: %d\n", rc);
-
-	tc->link_is_up = true;
-}
-
-static void tool_link_cleanup(struct work_struct *work)
-{
-	struct tool_ctx *tc = container_of(work, struct tool_ctx,
-					   link_cleanup);
-
-	if (!tc->link_is_up)
-		cancel_delayed_work_sync(&tc->link_work);
-}
-
 static void tool_link_event(void *ctx)
 {
 	struct tool_ctx *tc = ctx;
@@ -260,10 +159,6 @@ static void tool_link_event(void *ctx)
 	dev_dbg(&tc->ntb->dev, "link is %s speed %d width %d\n",
 		up ? "up" : "down", speed, width);
 
-	if (up)
-		schedule_delayed_work(&tc->link_work, 2*HZ);
-	else
-		schedule_work(&tc->link_cleanup);
 }
 
 static void tool_db_event(void *ctx, int vec)
@@ -591,10 +486,10 @@ static ssize_t tool_mw_read(struct file *filep, char __user *ubuf,
 		return -EIO;
 	if (pos < 0)
 		return -EINVAL;
-	if (pos >= mw->size || !size)
+	if (pos >= mw->win_size || !size)
 		return 0;
-	if (size > mw->size - pos)
-		size = mw->size - pos;
+	if (size > mw->win_size - pos)
+		size = mw->win_size - pos;
 
 	buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
@@ -627,10 +522,10 @@ static ssize_t tool_mw_write(struct file *filep, const char __user *ubuf,
 
 	if (pos < 0)
 		return -EINVAL;
-	if (pos >= mw->size || !size)
+	if (pos >= mw->win_size || !size)
 		return 0;
-	if (size > mw->size - pos)
-		size = mw->size - pos;
+	if (size > mw->win_size - pos)
+		size = mw->win_size - pos;
 
 	buf = kmalloc(size, GFP_KERNEL);
 	if (!buf)
@@ -658,20 +553,25 @@ static TOOL_FOPS_RDWR(tool_mw_fops,
 		      tool_mw_read,
 		      tool_mw_write);
 
-
 static ssize_t tool_peer_mw_read(struct file *filep, char __user *ubuf,
-				   size_t size, loff_t *offp)
+				 size_t size, loff_t *offp)
 {
 	struct tool_mw *mw = filep->private_data;
 
+	if (!mw->peer)
+		return -ENXIO;
+
 	return simple_read_from_buffer(ubuf, size, offp, mw->peer, mw->size);
 }
 
 static ssize_t tool_peer_mw_write(struct file *filep, const char __user *ubuf,
-				    size_t size, loff_t *offp)
+				  size_t size, loff_t *offp)
 {
 	struct tool_mw *mw = filep->private_data;
 
+	if (!mw->peer)
+		return -ENXIO;
+
 	return simple_write_to_buffer(mw->peer, mw->size, offp, ubuf, size);
 }
 
@@ -679,9 +579,199 @@ static TOOL_FOPS_RDWR(tool_peer_mw_fops,
 		      tool_peer_mw_read,
 		      tool_peer_mw_write);
 
+static int tool_setup_mw(struct tool_ctx *tc, int idx, size_t req_size)
+{
+	int rc;
+	struct tool_mw *mw = &tc->mws[idx];
+	phys_addr_t base;
+	resource_size_t size, align, align_size;
+	char buf[16];
+
+	if (mw->peer)
+		return 0;
+
+	rc = ntb_mw_get_range(tc->ntb, idx, &base, &size, &align,
+			      &align_size);
+	if (rc)
+		return rc;
+
+	mw->size = min_t(resource_size_t, req_size, size);
+	mw->size = round_up(mw->size, align);
+	mw->size = round_up(mw->size, align_size);
+	mw->peer = dma_alloc_coherent(&tc->ntb->pdev->dev, mw->size,
+				      &mw->peer_dma, GFP_KERNEL);
+
+	if (!mw->peer)
+		return -ENOMEM;
+
+	rc = ntb_mw_set_trans(tc->ntb, idx, mw->peer_dma, mw->size);
+	if (rc)
+		goto err_free_dma;
+
+	snprintf(buf, sizeof(buf), "peer_mw%d", idx);
+	mw->peer_dbg_file = debugfs_create_file(buf, S_IRUSR | S_IWUSR,
+						mw->tc->dbgfs, mw,
+						&tool_peer_mw_fops);
+
+	return 0;
+
+err_free_dma:
+	dma_free_coherent(&tc->ntb->pdev->dev, mw->size,
+			  mw->peer,
+			  mw->peer_dma);
+	mw->peer = NULL;
+	mw->peer_dma = 0;
+	mw->size = 0;
+
+	return rc;
+}
+
+static void tool_free_mw(struct tool_ctx *tc, int idx)
+{
+	struct tool_mw *mw = &tc->mws[idx];
+
+	if (mw->peer) {
+		ntb_mw_clear_trans(tc->ntb, idx);
+		dma_free_coherent(&tc->ntb->pdev->dev, mw->size,
+				  mw->peer,
+				  mw->peer_dma);
+	}
+
+	mw->peer = NULL;
+	mw->peer_dma = 0;
+
+	debugfs_remove(mw->peer_dbg_file);
+
+	mw->peer_dbg_file = NULL;
+}
+
+static ssize_t tool_peer_mw_trans_read(struct file *filep,
+				       char __user *ubuf,
+				       size_t size, loff_t *offp)
+{
+	struct tool_mw *mw = filep->private_data;
+
+	char *buf;
+	size_t buf_size;
+	ssize_t ret, off = 0;
+
+	phys_addr_t base;
+	resource_size_t mw_size;
+	resource_size_t align;
+	resource_size_t align_size;
+
+	buf_size = min_t(size_t, size, 512);
+
+	buf = kmalloc(buf_size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ntb_mw_get_range(mw->tc->ntb, mw->idx,
+			 &base, &mw_size, &align, &align_size);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Peer MW %d Information:\n", mw->idx);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Physical Address      \t%pa[p]\n",
+			 &base);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Window Size           \t%lld\n",
+			 (unsigned long long)mw_size);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Alignment             \t%lld\n",
+			 (unsigned long long)align);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Size Alignment        \t%lld\n",
+			 (unsigned long long)align_size);
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Ready                 \t%c\n",
+			 (mw->peer) ? 'Y' : 'N');
+
+	off += scnprintf(buf + off, buf_size - off,
+			 "Allocated Size       \t%zd\n",
+			 (mw->peer) ? (size_t)mw->size : 0);
+
+	ret = simple_read_from_buffer(ubuf, size, offp, buf, off);
+	kfree(buf);
+	return ret;
+}
+
+static ssize_t tool_peer_mw_trans_write(struct file *filep,
+					const char __user *ubuf,
+					size_t size, loff_t *offp)
+{
+	struct tool_mw *mw = filep->private_data;
+
+	char buf[32];
+	size_t buf_size;
+	unsigned long long val;
+	int rc;
+
+	buf_size = min(size, (sizeof(buf) - 1));
+	if (copy_from_user(buf, ubuf, buf_size))
+		return -EFAULT;
+
+	buf[buf_size] = '\0';
+
+	rc = kstrtoull(buf, 0, &val);
+	if (rc)
+		return rc;
+
+	tool_free_mw(mw->tc, mw->idx);
+	if (val)
+		rc = tool_setup_mw(mw->tc, mw->idx, val);
+
+	if (rc)
+		return rc;
+
+	return size;
+}
+
+static TOOL_FOPS_RDWR(tool_peer_mw_trans_fops,
+		      tool_peer_mw_trans_read,
+		      tool_peer_mw_trans_write);
+
+static int tool_init_mw(struct tool_ctx *tc, int idx)
+{
+	struct tool_mw *mw = &tc->mws[idx];
+	phys_addr_t base;
+	int rc;
+
+	rc = ntb_mw_get_range(tc->ntb, idx, &base, &mw->win_size,
+			      NULL, NULL);
+	if (rc)
+		return rc;
+
+	mw->tc = tc;
+	mw->idx = idx;
+	mw->local = ioremap_wc(base, mw->win_size);
+	if (!mw->local)
+		return -EFAULT;
+
+	return 0;
+}
+
+static void tool_free_mws(struct tool_ctx *tc)
+{
+	int i;
+
+	for (i = 0; i < tc->mw_count; i++) {
+		tool_free_mw(tc, i);
+
+		if (tc->mws[i].local)
+			iounmap(tc->mws[i].local);
+
+		tc->mws[i].local = NULL;
+	}
+}
+
 static void tool_setup_dbgfs(struct tool_ctx *tc)
 {
-	int mw_count;
 	int i;
 
 	/* This modules is useless without dbgfs... */
@@ -713,18 +803,16 @@ static void tool_setup_dbgfs(struct tool_ctx *tc)
 	debugfs_create_file("peer_spad", S_IRUSR | S_IWUSR, tc->dbgfs,
 			    tc, &tool_peer_spad_fops);
 
-	mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
-	for (i = 0; i < mw_count; i++) {
+	for (i = 0; i < tc->mw_count; i++) {
 		char buf[30];
 
 		snprintf(buf, sizeof(buf), "mw%d", i);
 		debugfs_create_file(buf, S_IRUSR | S_IWUSR, tc->dbgfs,
 				    &tc->mws[i], &tool_mw_fops);
 
-		snprintf(buf, sizeof(buf), "peer_mw%d", i);
+		snprintf(buf, sizeof(buf), "peer_trans%d", i);
 		debugfs_create_file(buf, S_IRUSR | S_IWUSR, tc->dbgfs,
-				    &tc->mws[i], &tool_peer_mw_fops);
-
+				    &tc->mws[i], &tool_peer_mw_trans_fops);
 	}
 }
 
@@ -732,6 +820,7 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 {
 	struct tool_ctx *tc;
 	int rc;
+	int i;
 
 	if (ntb_db_is_unsafe(ntb))
 		dev_dbg(&ntb->dev, "doorbell is unsafe\n");
@@ -746,8 +835,13 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 	}
 
 	tc->ntb = ntb;
-	INIT_DELAYED_WORK(&tc->link_work, tool_link_work);
-	INIT_WORK(&tc->link_cleanup, tool_link_cleanup);
+
+	tc->mw_count = min(ntb_mw_count(tc->ntb), MAX_MWS);
+	for (i = 0; i < tc->mw_count; i++) {
+		rc = tool_init_mw(tc, i);
+		if (rc)
+			goto err_ctx;
+	}
 
 	tool_setup_dbgfs(tc);
 
@@ -761,9 +855,8 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 	return 0;
 
 err_ctx:
+	tool_free_mws(tc);
 	debugfs_remove_recursive(tc->dbgfs);
-	cancel_delayed_work_sync(&tc->link_work);
-	cancel_work_sync(&tc->link_cleanup);
 	kfree(tc);
 err_tc:
 	return rc;
@@ -773,9 +866,6 @@ static void tool_remove(struct ntb_client *self, struct ntb_dev *ntb)
 {
 	struct tool_ctx *tc = ntb->ctx;
 
-	cancel_delayed_work_sync(&tc->link_work);
-	cancel_work_sync(&tc->link_cleanup);
-
 	tool_free_mws(tc);
 
 	ntb_clear_ctx(ntb);