ntb_tool: Add memory window debug support

We allocate some memory window buffers when the link comes up, then we
provide debugfs files to read/write each side of the link.

This is useful for debugging the mapping when writing new drivers.
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

@@ -89,6 +89,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/pci.h>
 #include <linux/slab.h>
+#include <linux/uaccess.h>
 
 #include <linux/ntb.h>
 
@@ -105,11 +106,29 @@ MODULE_VERSION(DRIVER_VERSION);
 MODULE_AUTHOR(DRIVER_AUTHOR);
 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 {
+	resource_size_t size;
+	u8 __iomem *local;
+	u8 *peer;
+	dma_addr_t peer_dma;
+};
+
 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];
 };
 
 #define SPAD_FNAME_SIZE 0x10
@@ -124,6 +143,111 @@ 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;
@@ -135,6 +259,11 @@ 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)
@@ -449,8 +578,112 @@ static TOOL_FOPS_RDWR(tool_peer_spad_fops,
 		      tool_peer_spad_read,
 		      tool_peer_spad_write);
 
+
+static ssize_t tool_mw_read(struct file *filep, char __user *ubuf,
+			    size_t size, loff_t *offp)
+{
+	struct tool_mw *mw = filep->private_data;
+	ssize_t rc;
+	loff_t pos = *offp;
+	void *buf;
+
+	if (mw->local == NULL)
+		return -EIO;
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= mw->size || !size)
+		return 0;
+	if (size > mw->size - pos)
+		size = mw->size - pos;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	memcpy_fromio(buf, mw->local + pos, size);
+	rc = copy_to_user(ubuf, buf, size);
+	if (rc == size) {
+		rc = -EFAULT;
+		goto err_free;
+	}
+
+	size -= rc;
+	*offp = pos + size;
+	rc = size;
+
+err_free:
+	kfree(buf);
+
+	return rc;
+}
+
+static ssize_t tool_mw_write(struct file *filep, const char __user *ubuf,
+			     size_t size, loff_t *offp)
+{
+	struct tool_mw *mw = filep->private_data;
+	ssize_t rc;
+	loff_t pos = *offp;
+	void *buf;
+
+	if (pos < 0)
+		return -EINVAL;
+	if (pos >= mw->size || !size)
+		return 0;
+	if (size > mw->size - pos)
+		size = mw->size - pos;
+
+	buf = kmalloc(size, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	rc = copy_from_user(buf, ubuf, size);
+	if (rc == size) {
+		rc = -EFAULT;
+		goto err_free;
+	}
+
+	size -= rc;
+	*offp = pos + size;
+	rc = size;
+
+	memcpy_toio(mw->local + pos, buf, size);
+
+err_free:
+	kfree(buf);
+
+	return rc;
+}
+
+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)
+{
+	struct tool_mw *mw = filep->private_data;
+
+	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)
+{
+	struct tool_mw *mw = filep->private_data;
+
+	return simple_write_to_buffer(mw->peer, mw->size, offp, ubuf, size);
+}
+
+static TOOL_FOPS_RDWR(tool_peer_mw_fops,
+		      tool_peer_mw_read,
+		      tool_peer_mw_write);
+
 static void tool_setup_dbgfs(struct tool_ctx *tc)
 {
+	int mw_count;
+	int i;
+
 	/* This modules is useless without dbgfs... */
 	if (!tool_dbgfs) {
 		tc->dbgfs = NULL;
@@ -479,6 +712,20 @@ 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++) {
+		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);
+		debugfs_create_file(buf, S_IRUSR | S_IWUSR, tc->dbgfs,
+				    &tc->mws[i], &tool_peer_mw_fops);
+
+	}
 }
 
 static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
@@ -492,13 +739,15 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 	if (ntb_spad_is_unsafe(ntb))
 		dev_dbg(&ntb->dev, "scratchpad is unsafe\n");
 
-	tc = kmalloc(sizeof(*tc), GFP_KERNEL);
+	tc = kzalloc(sizeof(*tc), GFP_KERNEL);
 	if (!tc) {
 		rc = -ENOMEM;
 		goto err_tc;
 	}
 
 	tc->ntb = ntb;
+	INIT_DELAYED_WORK(&tc->link_work, tool_link_work);
+	INIT_WORK(&tc->link_cleanup, tool_link_cleanup);
 
 	tool_setup_dbgfs(tc);
 
@@ -513,6 +762,8 @@ static int tool_probe(struct ntb_client *self, struct ntb_dev *ntb)
 
 err_ctx:
 	debugfs_remove_recursive(tc->dbgfs);
+	cancel_delayed_work_sync(&tc->link_work);
+	cancel_work_sync(&tc->link_cleanup);
 	kfree(tc);
 err_tc:
 	return rc;
@@ -522,6 +773,11 @@ 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);
 	ntb_link_disable(ntb);