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fpga: mgr: separate getting/locking FPGA manager

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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>
This commit is contained in:
Alan Tull
2017-11-15 14:20:13 -06:00
committed by Greg Kroah-Hartman
parent 5cf0c7f650
commit ebf877a51a
4 changed files with 77 additions and 27 deletions
Download Patch File Download Diff File Expand all files Collapse all files

35
Documentation/fpga/fpga-mgr.txt
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@@ -48,8 +48,20 @@ To get/put a reference to a FPGA manager:
struct fpga_manager *fpga_mgr_get(struct device *dev);
void fpga_mgr_put(struct fpga_manager *mgr);
Given a DT node or device, get an exclusive reference to a FPGA manager.
fpga_mgr_put releases the reference.
Given a DT node or device, get a reference to a FPGA manager. This pointer
can be saved until you are ready to program the FPGA. fpga_mgr_put releases
the reference.
To get exclusive control of a FPGA manager:
-------------------------------------------
int fpga_mgr_lock(struct fpga_manager *mgr);
void fpga_mgr_unlock(struct fpga_manager *mgr);
The user should call fpga_mgr_lock and verify that it returns 0 before
attempting to program the FPGA. Likewise, the user should call
fpga_mgr_unlock when done programming the FPGA.
To register or unregister the low level FPGA-specific driver:
@@ -67,13 +79,21 @@ device."
How to write an image buffer to a supported FPGA
================================================
/* Include to get the API */
#include <linux/fpga/fpga-mgr.h>
struct fpga_manager *mgr;
struct fpga_image_info *info;
int ret;
/*
* Get a reference to FPGA manager. The manager is not locked, so you can
* hold onto this reference without it preventing programming.
*
* This example uses the device node of the manager. Alternatively, use
* fpga_mgr_get(dev) instead if you have the device.
*/
mgr = of_fpga_mgr_get(mgr_node);
/* struct with information about the FPGA image to program. */
info = fpga_image_info_alloc(dev);
@@ -99,17 +119,14 @@ if (image is in a scatter gather table) {
}
/*
* Get a reference to FPGA manager. This example uses the device node of the
* manager. You could use fpga_mgr_get() instead if you have the device instead
* of the device node.
*/
mgr = of_fpga_mgr_get(mgr_node);
/* Get exclusive control of FPGA manager */
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);
/* Deallocate the image info if you're done with it */