powerpc/vas: Export HVWC to debugfs

Export the VAS Window context information to debugfs.

We need to hold a mutex when closing the window to prevent a race
with the debugfs read(). Rather than introduce a per-instance mutex,
we use the global vas_mutex for now, since it is not heavily contended.

The window->cop field is only relevant to a receive window so we were
not setting it for a send window (which is is paired to a receive window
anyway). But to simplify reporting in debugfs, set the 'cop' field for the
send window also.

Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 27 insertions, 7 deletions

diff --git a/arch/powerpc/platforms/powernv/vas-window.c b/arch/powerpc/platforms/powernv/vas-window.c
index 23c13a7dcf89..c030d4cf982e 100644
--- a/arch/powerpc/platforms/powernv/vas-window.c
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -145,23 +145,37 @@ static void unmap_paste_region(struct vas_window *window)
 }
 
 /*
- * Unmap the MMIO regions for a window.
+ * Unmap the MMIO regions for a window. Hold the vas_mutex so we don't
+ * unmap when the window's debugfs dir is in use. This serializes close
+ * of a window even on another VAS instance but since its not a critical
+ * path, just minimize the time we hold the mutex for now. We can add
+ * a per-instance mutex later if necessary.
  */
 static void unmap_winctx_mmio_bars(struct vas_window *window)
 {
 	int len;
+	void *uwc_map;
+	void *hvwc_map;
 	u64 busaddr_start;
 
-	if (window->hvwc_map) {
+	mutex_lock(&vas_mutex);
+
+	hvwc_map = window->hvwc_map;
+	window->hvwc_map = NULL;
+
+	uwc_map = window->uwc_map;
+	window->uwc_map = NULL;
+
+	mutex_unlock(&vas_mutex);
+
+	if (hvwc_map) {
 		get_hvwc_mmio_bar(window, &busaddr_start, &len);
-		unmap_region(window->hvwc_map, busaddr_start, len);
-		window->hvwc_map = NULL;
+		unmap_region(hvwc_map, busaddr_start, len);
 	}
 
-	if (window->uwc_map) {
+	if (uwc_map) {
 		get_uwc_mmio_bar(window, &busaddr_start, &len);
-		unmap_region(window->uwc_map, busaddr_start, len);
-		window->uwc_map = NULL;
+		unmap_region(uwc_map, busaddr_start, len);
 	}
 }
 
@@ -528,6 +542,9 @@ static void vas_window_free(struct vas_window *window)
 	struct vas_instance *vinst = window->vinst;
 
 	unmap_winctx_mmio_bars(window);
+
+	vas_window_free_dbgdir(window);
+
 	kfree(window);
 
 	vas_release_window_id(&vinst->ida, winid);
@@ -552,6 +569,8 @@ static struct vas_window *vas_window_alloc(struct vas_instance *vinst)
 	if (map_winctx_mmio_bars(window))
 		goto out_free;
 
+	vas_window_init_dbgdir(window);
+
 	return window;
 
 out_free:
@@ -974,6 +993,7 @@ struct vas_window *vas_tx_win_open(int vasid, enum vas_cop_type cop,
 		goto put_rxwin;
 	}
 
+	txwin->cop = cop;
 	txwin->tx_win = 1;
 	txwin->rxwin = rxwin;
 	txwin->nx_win = txwin->rxwin->nx_win;