fpga: mgr: separate getting/locking FPGA manager

Previously when the user gets a FPGA manager, it was locked
and nobody else could use it for programming.

This commit makes it straightforward to save a reference to an
FPGA manager and only lock it when programming the FPGA.

Add functions that get an FPGA manager's mutex for exclusive use:
* fpga_mgr_lock
* fpga_mgr_unlock

The following functions no longer lock an FPGA manager's mutex:
* of_fpga_mgr_get
* fpga_mgr_get
* fpga_mgr_put

Signed-off-by: Alan Tull <atull@kernel.org>
Acked-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
index 120c496eb7bd..1e1640a29306 100644
--- a/drivers/fpga/fpga-region.c
+++ b/drivers/fpga/fpga-region.c
@@ -125,7 +125,7 @@ static void fpga_region_put(struct fpga_region *region)
 }
 
 /**
- * fpga_region_get_manager - get exclusive reference for FPGA manager
+ * fpga_region_get_manager - get reference for FPGA manager
  * @region: FPGA region
  *
  * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
@@ -233,6 +233,7 @@ static int fpga_region_get_bridges(struct fpga_region *region,
 static int fpga_region_program_fpga(struct fpga_region *region,
                                     struct device_node *overlay)
 {
+        struct device *dev = &region->dev;
         struct fpga_manager *mgr;
         int ret;
 
@@ -249,10 +250,16 @@ static int fpga_region_program_fpga(struct fpga_region *region,
                 goto err_put_region;
         }
 
+        ret = fpga_mgr_lock(mgr);
+        if (ret) {
+                dev_err(dev, "FPGA manager is busy\n");
+                goto err_put_mgr;
+        }
+
         ret = fpga_region_get_bridges(region, overlay);
         if (ret) {
                 pr_err("failed to get fpga region bridges\n");
-                goto err_put_mgr;
+                goto err_unlock_mgr;
         }
 
         ret = fpga_bridges_disable(&region->bridge_list);
@@ -273,6 +280,7 @@ static int fpga_region_program_fpga(struct fpga_region *region,
                 goto err_put_br;
         }
 
+        fpga_mgr_unlock(mgr);
         fpga_mgr_put(mgr);
         fpga_region_put(region);
 
@@ -280,6 +288,8 @@ static int fpga_region_program_fpga(struct fpga_region *region,
 
 err_put_br:
         fpga_bridges_put(&region->bridge_list);
+err_unlock_mgr:
+        fpga_mgr_unlock(mgr);
 err_put_mgr:
         fpga_mgr_put(mgr);
 err_put_region: