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Commit ebf877a5 authored by Alan Tull's avatar Alan Tull Committed by Greg Kroah-Hartman
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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: default avatarAlan Tull <atull@kernel.org>
Acked-by: default avatarMoritz Fischer <mdf@kernel.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5cf0c7f6

Documentation/fpga/fpga-mgr.txt

+26 −9
Original line number Diff line number Diff line
@@ -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 */

drivers/fpga/fpga-mgr.c

+36 −16
Original line number Diff line number Diff line
@@ -410,28 +410,19 @@ ATTRIBUTE_GROUPS(fpga_mgr); 
static struct fpga_manager *__fpga_mgr_get(struct device *dev)

{

	struct fpga_manager *mgr;

	int ret = -ENODEV;



	mgr = to_fpga_manager(dev);

	if (!mgr)

		goto err_dev;



	/* Get exclusive use of fpga manager */

	if (!mutex_trylock(&mgr->ref_mutex)) {

		ret = -EBUSY;

		goto err_dev;

	}



	if (!try_module_get(dev->parent->driver->owner))

		goto err_ll_mod;

		goto err_dev;



	return mgr;



err_ll_mod:

	mutex_unlock(&mgr->ref_mutex);

err_dev:

	put_device(dev);

	return ERR_PTR(ret);

	return ERR_PTR(-ENODEV);

}



static int fpga_mgr_dev_match(struct device *dev, const void *data)
@@ -440,10 +431,10 @@ static int fpga_mgr_dev_match(struct device *dev, const void *data) 
}



/**

 * fpga_mgr_get - get an exclusive reference to a fpga mgr

 * fpga_mgr_get - get a reference to a fpga mgr

 * @dev:	parent device that fpga mgr was registered with

 *

 * Given a device, get an exclusive reference to a fpga mgr.

 * Given a device, get a reference to a fpga mgr.

 *

 * Return: fpga manager struct or IS_ERR() condition containing error code.

 */
@@ -464,10 +455,10 @@ static int fpga_mgr_of_node_match(struct device *dev, const void *data) 
}



/**

 * of_fpga_mgr_get - get an exclusive reference to a fpga mgr

 * of_fpga_mgr_get - get a reference to a fpga mgr

 * @node:	device node

 *

 * Given a device node, get an exclusive reference to a fpga mgr.

 * Given a device node, get a reference to a fpga mgr.

 *

 * Return: fpga manager struct or IS_ERR() condition containing error code.

 */
@@ -491,11 +482,40 @@ EXPORT_SYMBOL_GPL(of_fpga_mgr_get); 
void fpga_mgr_put(struct fpga_manager *mgr)

{

	module_put(mgr->dev.parent->driver->owner);

	mutex_unlock(&mgr->ref_mutex);

	put_device(&mgr->dev);

}

EXPORT_SYMBOL_GPL(fpga_mgr_put);



/**

 * fpga_mgr_lock - Lock FPGA manager for exclusive use

 * @mgr:	fpga manager

 *

 * Given a pointer to FPGA Manager (from fpga_mgr_get() or

 * of_fpga_mgr_put()) attempt to get the mutex.

 *

 * Return: 0 for success or -EBUSY

 */

int fpga_mgr_lock(struct fpga_manager *mgr)

{

	if (!mutex_trylock(&mgr->ref_mutex)) {

		dev_err(&mgr->dev, "FPGA manager is in use.\n");

		return -EBUSY;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(fpga_mgr_lock);



/**

 * fpga_mgr_unlock - Unlock FPGA manager

 * @mgr:	fpga manager

 */

void fpga_mgr_unlock(struct fpga_manager *mgr)

{

	mutex_unlock(&mgr->ref_mutex);

}

EXPORT_SYMBOL_GPL(fpga_mgr_unlock);



/**

 * fpga_mgr_register - register a low level fpga manager driver

 * @dev:	fpga manager device from pdev

drivers/fpga/fpga-region.c

+12 −2
Original line number Diff line number Diff line
@@ -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:

include/linux/fpga/fpga-mgr.h

+3 −0
Original line number Diff line number Diff line
@@ -155,6 +155,9 @@ void fpga_image_info_free(struct fpga_image_info *info); 


int fpga_mgr_load(struct fpga_manager *mgr, struct fpga_image_info *info);



int fpga_mgr_lock(struct fpga_manager *mgr);

void fpga_mgr_unlock(struct fpga_manager *mgr);



struct fpga_manager *of_fpga_mgr_get(struct device_node *node);



struct fpga_manager *fpga_mgr_get(struct device *dev);