hi Alan
On 2/15/2017 10:14 AM, Alan Tull wrote:
Document that getting a reference to a FPGA Manager has been
separated from locking the FPGA Mangager for use.
fpga_mgr_lock/unlock functions get/release mutex.
of_fpga_mgr_get, fpga_mgr_get, and fpga_mgr_put no longer lock
the FPGA manager mutex.
This makes it more straigtforward to save a reference to
a FPGA manager and only attempting to lock it when programming
the FPGA.
New to the FPGA world, but I like the idea of shorter lock. Separating
the lock from fpga_mgr_get will give underline FPGA device drivers more
flexibility to acquire the mgr pointer.
One newbie question, since the underline FPGA device driver does the
fpga_mgr_register during probe, each manager instance belongs to that
FPGA device only. What's the use to keep tracking the usage reference
with fpga_mgr_put/get function, or is it enough to increase/decrease dev
reference count in fpga_mgr_register/unregister function?
Thanks,
Yi
Signed-off-by: Alan Tull <at...@kernel.org>
---
Documentation/fpga/fpga-mgr.txt | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/Documentation/fpga/fpga-mgr.txt b/Documentation/fpga/fpga-mgr.txt
index 78f197f..06d5d5b 100644
--- a/Documentation/fpga/fpga-mgr.txt
+++ b/Documentation/fpga/fpga-mgr.txt
@@ -53,13 +53,26 @@ To get/put a reference to a FPGA manager:
struct fpga_manager *of_fpga_mgr_get(struct device_node *node);
struct fpga_manager *fpga_mgr_get(struct device *dev);
-Given a DT node or device, get an exclusive reference to a FPGA manager.
+Given a DT node or device, get an reference to a FPGA manager. Pointer
+can be saved until you are ready to program the FPGA.
void fpga_mgr_put(struct fpga_manager *mgr);
Release the reference.
+To get exclusive control of a FPGA manager:
+-------------------------------------------
+
+ int fpga_mgr_lock(struct fpga_magager *mgr);
+
+Call fpga_mgr_lock and verify that it returns 0 before attempting to
+program the FPGA.
+
+ void fpga_mgr_unlock(struct fpga_magager *mgr);
+
+Call fpga_mgr_unlock when done programming the FPGA.
+
To register or unregister the low level FPGA-specific driver:
-------------------------------------------------------------
@@ -95,11 +108,13 @@ int ret;
/* Get exclusive control of FPGA manager */
struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+ret = fpga_mgr_lock(mgr);
/* Load the buffer to the FPGA */
ret = fpga_mgr_buf_load(mgr, &info, buf, count);
/* Release the FPGA manager */
+fpga_mgr_unlock(mgr);
fpga_mgr_put(mgr);
@@ -124,11 +139,13 @@ int ret;
/* Get exclusive control of FPGA manager */
struct fpga_manager *mgr = of_fpga_mgr_get(mgr_node);
+ret = fpga_mgr_lock(mgr);
/* Get the firmware image (path) and load it to the FPGA */
ret = fpga_mgr_firmware_load(mgr, &info, path);
/* Release the FPGA manager */
+fpga_mgr_unlock(mgr);
fpga_mgr_put(mgr);
