Date:   Thu, 14 Sep 2017 08:50:06 -0700 (PDT)
From:   matthew.gerlach@...ux.intel.com
To:     Alan Tull <atull@...nel.org>
cc:     Moritz Fischer <mdf@...nel.org>, linux-kernel@...r.kernel.org,
        linux-fpga@...r.kernel.org
Subject: Re: [PATCH v4 15/18] fpga: region: move device tree support to
 of-fpga-region.c


Hi Alan,

Just a couple of minor nits.

Matthew Gerlach

On Wed, 13 Sep 2017, Alan Tull wrote:

> Create of-fpga-region.c and ove the following functions without

s/ove/move/
> modification from fpga-region.c.
>
> * of_fpga_region_find
> * of_fpga_region_get_mgr
> * of_fpga_region_get_bridges
> * child_regions_with_firmware
> * of_fpga_region_parse_ov
> * of_fpga_region_notify_pre_apply
> * of_fpga_region_notify_post_remove
> * of_fpga_region_notify
> * of_fpga_region_probe
> * of_fpga_region_remove
>
> Create two new function with some code from fpga_region_init/exit.
s/function/functions/

>
> * of_fpga_region_init
> * of_fpga_region_exit
>
> Signed-off-by: Alan Tull <atull@...nel.org>
> ---
> v2: split out code changes into other patches, only move code here
> v3: updated to move changed code to of-fpga-region.c
> v4: rebase on current for-next
>    remove fpga-bridge dependency on CONFIG_OF
> ---
> drivers/fpga/Kconfig          |  14 +-
> drivers/fpga/Makefile         |   1 +
> drivers/fpga/fpga-region.c    | 451 +-------------------------------------
> drivers/fpga/of-fpga-region.c | 495 ++++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 507 insertions(+), 454 deletions(-)
> create mode 100644 drivers/fpga/of-fpga-region.c
>
> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index ad5448f..529b729 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -13,10 +13,17 @@ if FPGA
>
> config FPGA_REGION
> 	tristate "FPGA Region"
> -	depends on OF && FPGA_BRIDGE
> +	depends on FPGA_BRIDGE
> +	help
> +	  FPGA Region common code.  A FPGA Region controls a FPGA Manager
> +	  and the FPGA Bridges associated with either a reconfigurable
> +	  region of an FPGA or a whole FPGA.
> +
> +config OF_FPGA_REGION
> +	tristate "FPGA Region Device Tree Overlay Support"
> +	depends on OF && FPGA_REGION
> 	help
> -	  FPGA Regions allow loading FPGA images under control of
> -	  the Device Tree.
> +	  Support for loading FPGA images under control of Device Tree.

Support for loading FPGA images by applying a Device Tree Overlay.

>
> config FPGA_MGR_ICE40_SPI
> 	tristate "Lattice iCE40 SPI"
> @@ -74,7 +81,6 @@ config FPGA_MGR_ZYNQ_FPGA
>
> config FPGA_BRIDGE
> 	tristate "FPGA Bridge Framework"
> -	depends on OF
> 	help
> 	  Say Y here if you want to support bridges connected between host
> 	  processors and FPGAs or between FPGAs.
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index e09895f..8f56766 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -25,3 +25,4 @@ obj-$(CONFIG_XILINX_PR_DECOUPLER)	+= xilinx-pr-decoupler.o
>
> # High Level Interfaces
> obj-$(CONFIG_FPGA_REGION)		+= fpga-region.o
> +obj-$(CONFIG_OF_FPGA_REGION)		+= of-fpga-region.o
> diff --git a/drivers/fpga/fpga-region.c b/drivers/fpga/fpga-region.c
> index 5f2fa5f6..afc6188 100644
> --- a/drivers/fpga/fpga-region.c
> +++ b/drivers/fpga/fpga-region.c
> @@ -2,6 +2,7 @@
>  * FPGA Region - Device Tree support for FPGA programming under Linux
>  *
>  *  Copyright (C) 2013-2016 Altera Corporation
> + *  Copyright (C) 2017 Intel Corporation
>  *
>  * This program is free software; you can redistribute it and/or modify it
>  * under the terms and conditions of the GNU General Public License,
> @@ -23,7 +24,6 @@
> #include <linux/kernel.h>
> #include <linux/list.h>
> #include <linux/module.h>
> -#include <linux/of_platform.h>
> #include <linux/slab.h>
> #include <linux/spinlock.h>
>
> @@ -44,30 +44,6 @@ struct fpga_region *fpga_region_class_find(
> }
> EXPORT_SYMBOL_GPL(fpga_region_class_find);
>
> -static const struct of_device_id fpga_region_of_match[] = {
> -	{ .compatible = "fpga-region", },
> -	{},
> -};
> -MODULE_DEVICE_TABLE(of, fpga_region_of_match);
> -
> -static int fpga_region_of_node_match(struct device *dev, const void *data)
> -{
> -	return dev->of_node == data;
> -}
> -
> -/**
> - * of_fpga_region_find - find FPGA region
> - * @np: device node of FPGA Region
> - *
> - * Caller will need to put_device(&region->dev) when done.
> - *
> - * Returns FPGA Region struct or NULL
> - */
> -static struct fpga_region *of_fpga_region_find(struct device_node *np)
> -{
> -	return fpga_region_class_find(NULL, np, fpga_region_of_node_match);
> -}
> -
> /**
>  * fpga_region_get - get an exclusive reference to a fpga region
>  * @region: FPGA Region struct
> @@ -116,102 +92,6 @@ static void fpga_region_put(struct fpga_region *region)
> }
>
> /**
> - * of_fpga_region_get_mgr - get reference for FPGA manager
> - * @np: device node of FPGA region
> - *
> - * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
> - *
> - * Caller should call fpga_mgr_put() when done with manager.
> - *
> - * Return: fpga manager struct or IS_ERR() condition containing error code.
> - */
> -static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
> -{
> -	struct device_node  *mgr_node;
> -	struct fpga_manager *mgr;
> -
> -	of_node_get(np);
> -	while (np) {
> -		if (of_device_is_compatible(np, "fpga-region")) {
> -			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
> -			if (mgr_node) {
> -				mgr = of_fpga_mgr_get(mgr_node);
> -				of_node_put(np);
> -				return mgr;
> -			}
> -		}
> -		np = of_get_next_parent(np);
> -	}
> -	of_node_put(np);
> -
> -	return ERR_PTR(-EINVAL);
> -}
> -
> -/**
> - * of_fpga_region_get_bridges - create a list of bridges
> - * @region: FPGA region
> - *
> - * Create a list of bridges including the parent bridge and the bridges
> - * specified by "fpga-bridges" property.  Note that the
> - * fpga_bridges_enable/disable/put functions are all fine with an empty list
> - * if that happens.
> - *
> - * Caller should call fpga_bridges_put(&region->bridge_list) when
> - * done with the bridges.
> - *
> - * Return 0 for success (even if there are no bridges specified)
> - * or -EBUSY if any of the bridges are in use.
> - */
> -static int of_fpga_region_get_bridges(struct fpga_region *region)
> -{
> -	struct device *dev = &region->dev;
> -	struct device_node *region_np = dev->of_node;
> -	struct fpga_image_info *info = region->info;
> -	struct device_node *br, *np, *parent_br = NULL;
> -	int i, ret;
> -
> -	/* If parent is a bridge, add to list */
> -	ret = of_fpga_bridge_get_to_list(region_np->parent, info,
> -					 &region->bridge_list);
> -
> -	/* -EBUSY means parent is a bridge that is under use. Give up. */
> -	if (ret == -EBUSY)
> -		return ret;
> -
> -	/* Zero return code means parent was a bridge and was added to list. */
> -	if (!ret)
> -		parent_br = region_np->parent;
> -
> -	/* If overlay has a list of bridges, use it. */
> -	if (of_parse_phandle(info->overlay, "fpga-bridges", 0))
> -		np = info->overlay;
> -	else
> -		np = region_np;
> -
> -	for (i = 0; ; i++) {
> -		br = of_parse_phandle(np, "fpga-bridges", i);
> -		if (!br)
> -			break;
> -
> -		/* If parent bridge is in list, skip it. */
> -		if (br == parent_br)
> -			continue;
> -
> -		/* If node is a bridge, get it and add to list */
> -		ret = of_fpga_bridge_get_to_list(br, info,
> -						 &region->bridge_list);
> -
> -		/* If any of the bridges are in use, give up */
> -		if (ret == -EBUSY) {
> -			fpga_bridges_put(&region->bridge_list);
> -			return -EBUSY;
> -		}
> -	}
> -
> -	return 0;
> -}
> -
> -/**
>  * fpga_region_program_fpga - program FPGA
>  * @region: FPGA region
>  * Program an FPGA using fpga image info (region->info).
> @@ -282,259 +162,6 @@ int fpga_region_program_fpga(struct fpga_region *region)
> }
> EXPORT_SYMBOL_GPL(fpga_region_program_fpga);
>
> -/**
> - * child_regions_with_firmware
> - * @overlay: device node of the overlay
> - *
> - * If the overlay adds child FPGA regions, they are not allowed to have
> - * firmware-name property.
> - *
> - * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
> - */
> -static int child_regions_with_firmware(struct device_node *overlay)
> -{
> -	struct device_node *child_region;
> -	const char *child_firmware_name;
> -	int ret = 0;
> -
> -	of_node_get(overlay);
> -
> -	child_region = of_find_matching_node(overlay, fpga_region_of_match);
> -	while (child_region) {
> -		if (!of_property_read_string(child_region, "firmware-name",
> -					     &child_firmware_name)) {
> -			ret = -EINVAL;
> -			break;
> -		}
> -		child_region = of_find_matching_node(child_region,
> -						     fpga_region_of_match);
> -	}
> -
> -	of_node_put(child_region);
> -
> -	if (ret)
> -		pr_err("firmware-name not allowed in child FPGA region: %pOF",
> -		       child_region);
> -
> -	return ret;
> -}
> -
> -/**
> - * of_fpga_region_parse_ov - parse and check overlay applied to region
> - *
> - * @region: FPGA region
> - * @overlay: overlay applied to the FPGA region
> - *
> - * Given an overlay applied to a FPGA region, parse the FPGA image specific
> - * info in the overlay and do some checking.
> - *
> - * Returns:
> - *   NULL if overlay doesn't direct us to program the FPGA.
> - *   fpga_image_info struct if there is an image to program.
> - *   error code for invalid overlay.
> - */
> -static struct fpga_image_info *of_fpga_region_parse_ov(
> -						struct fpga_region *region,
> -						struct device_node *overlay)
> -{
> -	struct device *dev = &region->dev;
> -	struct fpga_image_info *info;
> -	const char *firmware_name;
> -	int ret;
> -
> -	if (region->info) {
> -		dev_err(dev, "Region already has overlay applied.\n");
> -		return ERR_PTR(-EINVAL);
> -	}
> -
> -	/*
> -	 * Reject overlay if child FPGA Regions added in the overlay have
> -	 * firmware-name property (would mean that an FPGA region that has
> -	 * not been added to the live tree yet is doing FPGA programming).
> -	 */
> -	ret = child_regions_with_firmware(overlay);
> -	if (ret)
> -		return ERR_PTR(ret);
> -
> -	info = fpga_image_info_alloc(dev);
> -	if (!info)
> -		return ERR_PTR(-ENOMEM);
> -
> -	info->overlay = overlay;
> -
> -	/* Read FPGA region properties from the overlay */
> -	if (of_property_read_bool(overlay, "partial-fpga-config"))
> -		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
> -
> -	if (of_property_read_bool(overlay, "external-fpga-config"))
> -		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
> -
> -	if (of_property_read_bool(overlay, "encrypted-fpga-config"))
> -		info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
> -
> -	if (!of_property_read_string(overlay, "firmware-name",
> -				     &firmware_name)) {
> -		info->firmware_name = devm_kstrdup(dev, firmware_name,
> -						   GFP_KERNEL);
> -		if (!info->firmware_name)
> -			return ERR_PTR(-ENOMEM);
> -	}
> -
> -	of_property_read_u32(overlay, "region-unfreeze-timeout-us",
> -			     &info->enable_timeout_us);
> -
> -	of_property_read_u32(overlay, "region-freeze-timeout-us",
> -			     &info->disable_timeout_us);
> -
> -	of_property_read_u32(overlay, "config-complete-timeout-us",
> -			     &info->config_complete_timeout_us);
> -
> -	/* If overlay is not programming the FPGA, don't need FPGA image info */
> -	if (!info->firmware_name) {
> -		ret = 0;
> -		goto ret_no_info;
> -	}
> -
> -	/*
> -	 * If overlay informs us FPGA was externally programmed, specifying
> -	 * firmware here would be ambiguous.
> -	 */
> -	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
> -		dev_err(dev, "error: specified firmware and external-fpga-config");
> -		ret = -EINVAL;
> -		goto ret_no_info;
> -	}
> -
> -	return info;
> -ret_no_info:
> -	fpga_image_info_free(info);
> -	return ERR_PTR(ret);
> -}
> -
> -/**
> - * of_fpga_region_notify_pre_apply - pre-apply overlay notification
> - *
> - * @region: FPGA region that the overlay was applied to
> - * @nd: overlay notification data
> - *
> - * Called when an overlay targeted to a FPGA Region is about to be applied.
> - * Parses the overlay for properties that influence how the FPGA will be
> - * programmed and does some checking. If the checks pass, programs the FPGA.
> - * If the checks fail, overlay is rejected and does not get added to the
> - * live tree.
> - *
> - * Returns 0 for success or negative error code for failure.
> - */
> -static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
> -					   struct of_overlay_notify_data *nd)
> -{
> -	struct device *dev = &region->dev;
> -	struct fpga_image_info *info;
> -	int ret;
> -
> -	if (region->info) {
> -		dev_err(dev, "Region already has overlay applied.\n");
> -		return -EINVAL;
> -	}
> -
> -	info = of_fpga_region_parse_ov(region, nd->overlay);
> -	if (IS_ERR(info))
> -		return PTR_ERR(info);
> -
> -	if (!info)
> -		return 0;
> -
> -	region->info = info;
> -	ret = fpga_region_program_fpga(region);
> -	if (ret) {
> -		/* error; reject overlay */
> -		fpga_image_info_free(info);
> -		region->info = NULL;
> -	}
> -
> -	return ret;
> -}
> -
> -/**
> - * of_fpga_region_notify_post_remove - post-remove overlay notification
> - *
> - * @region: FPGA region that was targeted by the overlay that was removed
> - * @nd: overlay notification data
> - *
> - * Called after an overlay has been removed if the overlay's target was a
> - * FPGA region.
> - */
> -static void of_fpga_region_notify_post_remove(struct fpga_region *region,
> -					      struct of_overlay_notify_data *nd)
> -{
> -	fpga_bridges_disable(&region->bridge_list);
> -	fpga_bridges_put(&region->bridge_list);
> -	fpga_image_info_free(region->info);
> -	region->info = NULL;
> -}
> -
> -/**
> - * of_fpga_region_notify - reconfig notifier for dynamic DT changes
> - * @nb:		notifier block
> - * @action:	notifier action
> - * @arg:	reconfig data
> - *
> - * This notifier handles programming a FPGA when a "firmware-name" property is
> - * added to a fpga-region.
> - *
> - * Returns NOTIFY_OK or error if FPGA programming fails.
> - */
> -static int of_fpga_region_notify(struct notifier_block *nb,
> -				 unsigned long action, void *arg)
> -{
> -	struct of_overlay_notify_data *nd = arg;
> -	struct fpga_region *region;
> -	int ret;
> -
> -	switch (action) {
> -	case OF_OVERLAY_PRE_APPLY:
> -		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
> -		break;
> -	case OF_OVERLAY_POST_APPLY:
> -		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
> -		return NOTIFY_OK;       /* not for us */
> -	case OF_OVERLAY_PRE_REMOVE:
> -		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
> -		return NOTIFY_OK;       /* not for us */
> -	case OF_OVERLAY_POST_REMOVE:
> -		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
> -		break;
> -	default:			/* should not happen */
> -		return NOTIFY_OK;
> -	}
> -
> -	region = of_fpga_region_find(nd->target);
> -	if (!region)
> -		return NOTIFY_OK;
> -
> -	ret = 0;
> -	switch (action) {
> -	case OF_OVERLAY_PRE_APPLY:
> -		ret = of_fpga_region_notify_pre_apply(region, nd);
> -		break;
> -
> -	case OF_OVERLAY_POST_REMOVE:
> -		of_fpga_region_notify_post_remove(region, nd);
> -		break;
> -	}
> -
> -	put_device(&region->dev);
> -
> -	if (ret)
> -		return notifier_from_errno(ret);
> -
> -	return NOTIFY_OK;
> -}
> -
> -static struct notifier_block fpga_region_of_nb = {
> -	.notifier_call = of_fpga_region_notify,
> -};
> -
> int fpga_region_register(struct device *dev, struct fpga_region *region)
> {
> 	int id, ret = 0;
> @@ -576,63 +203,6 @@ int fpga_region_unregister(struct fpga_region *region)
> }
> EXPORT_SYMBOL_GPL(fpga_region_unregister);
>
> -static int of_fpga_region_probe(struct platform_device *pdev)
> -{
> -	struct device *dev = &pdev->dev;
> -	struct device_node *np = dev->of_node;
> -	struct fpga_region *region;
> -	struct fpga_manager *mgr;
> -	int ret;
> -
> -	/* Find the FPGA mgr specified by region or parent region. */
> -	mgr = of_fpga_region_get_mgr(np);
> -	if (IS_ERR(mgr))
> -		return -EPROBE_DEFER;
> -
> -	region = devm_kzalloc(dev, sizeof(*region), GFP_KERNEL);
> -	if (!region) {
> -		ret = -ENOMEM;
> -		goto eprobe_mgr_put;
> -	}
> -
> -	region->mgr = mgr;
> -
> -	/* Specify how to get bridges for this type of region. */
> -	region->get_bridges = of_fpga_region_get_bridges;
> -
> -	ret = fpga_region_register(dev, region);
> -	if (ret)
> -		goto eprobe_mgr_put;
> -
> -	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
> -
> -	dev_info(dev, "FPGA Region probed\n");
> -
> -	return 0;
> -
> -eprobe_mgr_put:
> -	fpga_mgr_put(mgr);
> -	return ret;
> -}
> -
> -static int of_fpga_region_remove(struct platform_device *pdev)
> -{
> -	struct fpga_region *region = platform_get_drvdata(pdev);
> -
> -	fpga_region_unregister(region);
> -
> -	return 0;
> -}
> -
> -static struct platform_driver of_fpga_region_driver = {
> -	.probe = of_fpga_region_probe,
> -	.remove = of_fpga_region_remove,
> -	.driver = {
> -		.name	= "fpga-region",
> -		.of_match_table = of_match_ptr(fpga_region_of_match),
> -	},
> -};
> -
> static void fpga_region_dev_release(struct device *dev)
> {
> 	struct fpga_region *region = to_fpga_region(dev);
> @@ -646,36 +216,17 @@ static void fpga_region_dev_release(struct device *dev)
>  */
> static int __init fpga_region_init(void)
> {
> -	int ret;
> -
> 	fpga_region_class = class_create(THIS_MODULE, "fpga_region");
> 	if (IS_ERR(fpga_region_class))
> 		return PTR_ERR(fpga_region_class);
>
> 	fpga_region_class->dev_release = fpga_region_dev_release;
>
> -	ret = of_overlay_notifier_register(&fpga_region_of_nb);
> -	if (ret)
> -		goto err_class;
> -
> -	ret = platform_driver_register(&of_fpga_region_driver);
> -	if (ret)
> -		goto err_plat;
> -
> 	return 0;
> -
> -err_plat:
> -	of_overlay_notifier_unregister(&fpga_region_of_nb);
> -err_class:
> -	class_destroy(fpga_region_class);
> -	ida_destroy(&fpga_region_ida);
> -	return ret;
> }
>
> static void __exit fpga_region_exit(void)
> {
> -	platform_driver_unregister(&of_fpga_region_driver);
> -	of_overlay_notifier_unregister(&fpga_region_of_nb);
> 	class_destroy(fpga_region_class);
> 	ida_destroy(&fpga_region_ida);
> }
> diff --git a/drivers/fpga/of-fpga-region.c b/drivers/fpga/of-fpga-region.c
> new file mode 100644
> index 0000000..1797057
> --- /dev/null
> +++ b/drivers/fpga/of-fpga-region.c
> @@ -0,0 +1,495 @@
> +/*
> + * FPGA Region - Device Tree support for FPGA programming under Linux
> + *
> + *  Copyright (C) 2013-2016 Altera Corporation
> + *  Copyright (C) 2017 Intel Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + *
> + * You should have received a copy of the GNU General Public License along with
> + * this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include <linux/fpga/fpga-bridge.h>
> +#include <linux/fpga/fpga-mgr.h>
> +#include <linux/fpga/fpga-region.h>
> +#include <linux/idr.h>
> +#include <linux/kernel.h>
> +#include <linux/list.h>
> +#include <linux/module.h>
> +#include <linux/of_platform.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +
> +static const struct of_device_id fpga_region_of_match[] = {
> +	{ .compatible = "fpga-region", },
> +	{},
> +};
> +MODULE_DEVICE_TABLE(of, fpga_region_of_match);
> +
> +static int fpga_region_of_node_match(struct device *dev, const void *data)
> +{
> +	return dev->of_node == data;
> +}
> +
> +/**
> + * of_fpga_region_find - find FPGA region
> + * @np: device node of FPGA Region
> + *
> + * Caller will need to put_device(&region->dev) when done.
> + *
> + * Returns FPGA Region struct or NULL
> + */
> +static struct fpga_region *of_fpga_region_find(struct device_node *np)
> +{
> +	return fpga_region_class_find(NULL, np, fpga_region_of_node_match);
> +}
> +
> +/**
> + * of_fpga_region_get_mgr - get reference for FPGA manager
> + * @np: device node of FPGA region
> + *
> + * Get FPGA Manager from "fpga-mgr" property or from ancestor region.
> + *
> + * Caller should call fpga_mgr_put() when done with manager.
> + *
> + * Return: fpga manager struct or IS_ERR() condition containing error code.
> + */
> +static struct fpga_manager *of_fpga_region_get_mgr(struct device_node *np)
> +{
> +	struct device_node  *mgr_node;
> +	struct fpga_manager *mgr;
> +
> +	of_node_get(np);
> +	while (np) {
> +		if (of_device_is_compatible(np, "fpga-region")) {
> +			mgr_node = of_parse_phandle(np, "fpga-mgr", 0);
> +			if (mgr_node) {
> +				mgr = of_fpga_mgr_get(mgr_node);
> +				of_node_put(np);
> +				return mgr;
> +			}
> +		}
> +		np = of_get_next_parent(np);
> +	}
> +	of_node_put(np);
> +
> +	return ERR_PTR(-EINVAL);
> +}
> +
> +/**
> + * of_fpga_region_get_bridges - create a list of bridges
> + * @region: FPGA region
> + *
> + * Create a list of bridges including the parent bridge and the bridges
> + * specified by "fpga-bridges" property.  Note that the
> + * fpga_bridges_enable/disable/put functions are all fine with an empty list
> + * if that happens.
> + *
> + * Caller should call fpga_bridges_put(&region->bridge_list) when
> + * done with the bridges.
> + *
> + * Return 0 for success (even if there are no bridges specified)
> + * or -EBUSY if any of the bridges are in use.
> + */
> +static int of_fpga_region_get_bridges(struct fpga_region *region)
> +{
> +	struct device *dev = &region->dev;
> +	struct device_node *region_np = dev->of_node;
> +	struct fpga_image_info *info = region->info;
> +	struct device_node *br, *np, *parent_br = NULL;
> +	int i, ret;
> +
> +	/* If parent is a bridge, add to list */
> +	ret = of_fpga_bridge_get_to_list(region_np->parent, info,
> +					 &region->bridge_list);
> +
> +	/* -EBUSY means parent is a bridge that is under use. Give up. */
> +	if (ret == -EBUSY)
> +		return ret;
> +
> +	/* Zero return code means parent was a bridge and was added to list. */
> +	if (!ret)
> +		parent_br = region_np->parent;
> +
> +	/* If overlay has a list of bridges, use it. */
> +	if (of_parse_phandle(info->overlay, "fpga-bridges", 0))
> +		np = info->overlay;
> +	else
> +		np = region_np;
> +
> +	for (i = 0; ; i++) {
> +		br = of_parse_phandle(np, "fpga-bridges", i);
> +		if (!br)
> +			break;
> +
> +		/* If parent bridge is in list, skip it. */
> +		if (br == parent_br)
> +			continue;
> +
> +		/* If node is a bridge, get it and add to list */
> +		ret = of_fpga_bridge_get_to_list(br, info,
> +						 &region->bridge_list);
> +
> +		/* If any of the bridges are in use, give up */
> +		if (ret == -EBUSY) {
> +			fpga_bridges_put(&region->bridge_list);
> +			return -EBUSY;
> +		}
> +	}
> +
> +	return 0;
> +}
> +
> +/**
> + * child_regions_with_firmware
> + * @overlay: device node of the overlay
> + *
> + * If the overlay adds child FPGA regions, they are not allowed to have
> + * firmware-name property.
> + *
> + * Return 0 for OK or -EINVAL if child FPGA region adds firmware-name.
> + */
> +static int child_regions_with_firmware(struct device_node *overlay)
> +{
> +	struct device_node *child_region;
> +	const char *child_firmware_name;
> +	int ret = 0;
> +
> +	of_node_get(overlay);
> +
> +	child_region = of_find_matching_node(overlay, fpga_region_of_match);
> +	while (child_region) {
> +		if (!of_property_read_string(child_region, "firmware-name",
> +					     &child_firmware_name)) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +		child_region = of_find_matching_node(child_region,
> +						     fpga_region_of_match);
> +	}
> +
> +	of_node_put(child_region);
> +
> +	if (ret)
> +		pr_err("firmware-name not allowed in child FPGA region: %pOF",
> +		       child_region);
> +
> +	return ret;
> +}
> +
> +/**
> + * of_fpga_region_parse_ov - parse and check overlay applied to region
> + *
> + * @region: FPGA region
> + * @overlay: overlay applied to the FPGA region
> + *
> + * Given an overlay applied to a FPGA region, parse the FPGA image specific
> + * info in the overlay and do some checking.
> + *
> + * Returns:
> + *   NULL if overlay doesn't direct us to program the FPGA.
> + *   fpga_image_info struct if there is an image to program.
> + *   error code for invalid overlay.
> + */
> +static struct fpga_image_info *of_fpga_region_parse_ov(
> +						struct fpga_region *region,
> +						struct device_node *overlay)
> +{
> +	struct device *dev = &region->dev;
> +	struct fpga_image_info *info;
> +	const char *firmware_name;
> +	int ret;
> +
> +	if (region->info) {
> +		dev_err(dev, "Region already has overlay applied.\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	/*
> +	 * Reject overlay if child FPGA Regions added in the overlay have
> +	 * firmware-name property (would mean that an FPGA region that has
> +	 * not been added to the live tree yet is doing FPGA programming).
> +	 */
> +	ret = child_regions_with_firmware(overlay);
> +	if (ret)
> +		return ERR_PTR(ret);
> +
> +	info = fpga_image_info_alloc(dev);
> +	if (!info)
> +		return ERR_PTR(-ENOMEM);
> +
> +	info->overlay = overlay;
> +
> +	/* Read FPGA region properties from the overlay */
> +	if (of_property_read_bool(overlay, "partial-fpga-config"))
> +		info->flags |= FPGA_MGR_PARTIAL_RECONFIG;
> +
> +	if (of_property_read_bool(overlay, "external-fpga-config"))
> +		info->flags |= FPGA_MGR_EXTERNAL_CONFIG;
> +
> +	if (of_property_read_bool(overlay, "encrypted-fpga-config"))
> +		info->flags |= FPGA_MGR_ENCRYPTED_BITSTREAM;
> +
> +	if (!of_property_read_string(overlay, "firmware-name",
> +				     &firmware_name)) {
> +		info->firmware_name = devm_kstrdup(dev, firmware_name,
> +						   GFP_KERNEL);
> +		if (!info->firmware_name)
> +			return ERR_PTR(-ENOMEM);
> +	}
> +
> +	of_property_read_u32(overlay, "region-unfreeze-timeout-us",
> +			     &info->enable_timeout_us);
> +
> +	of_property_read_u32(overlay, "region-freeze-timeout-us",
> +			     &info->disable_timeout_us);
> +
> +	of_property_read_u32(overlay, "config-complete-timeout-us",
> +			     &info->config_complete_timeout_us);
> +
> +	/* If overlay is not programming the FPGA, don't need FPGA image info */
> +	if (!info->firmware_name) {
> +		ret = 0;
> +		goto ret_no_info;
> +	}
> +
> +	/*
> +	 * If overlay informs us FPGA was externally programmed, specifying
> +	 * firmware here would be ambiguous.
> +	 */
> +	if (info->flags & FPGA_MGR_EXTERNAL_CONFIG) {
> +		dev_err(dev, "error: specified firmware and external-fpga-config");
> +		ret = -EINVAL;
> +		goto ret_no_info;
> +	}
> +
> +	return info;
> +ret_no_info:
> +	fpga_image_info_free(info);
> +	return ERR_PTR(ret);
> +}
> +
> +/**
> + * of_fpga_region_notify_pre_apply - pre-apply overlay notification
> + *
> + * @region: FPGA region that the overlay was applied to
> + * @nd: overlay notification data
> + *
> + * Called when an overlay targeted to a FPGA Region is about to be applied.
> + * Parses the overlay for properties that influence how the FPGA will be
> + * programmed and does some checking. If the checks pass, programs the FPGA.
> + * If the checks fail, overlay is rejected and does not get added to the
> + * live tree.
> + *
> + * Returns 0 for success or negative error code for failure.
> + */
> +static int of_fpga_region_notify_pre_apply(struct fpga_region *region,
> +					   struct of_overlay_notify_data *nd)
> +{
> +	struct device *dev = &region->dev;
> +	struct fpga_image_info *info;
> +	int ret;
> +
> +	if (region->info) {
> +		dev_err(dev, "Region already has overlay applied.\n");
> +		return -EINVAL;
> +	}
> +
> +	info = of_fpga_region_parse_ov(region, nd->overlay);
> +	if (IS_ERR(info))
> +		return PTR_ERR(info);
> +
> +	if (!info)
> +		return 0;
> +
> +	region->info = info;
> +	ret = fpga_region_program_fpga(region);
> +	if (ret) {
> +		/* error; reject overlay */
> +		fpga_image_info_free(info);
> +		region->info = NULL;
> +	}
> +
> +	return ret;
> +}
> +
> +/**
> + * of_fpga_region_notify_post_remove - post-remove overlay notification
> + *
> + * @region: FPGA region that was targeted by the overlay that was removed
> + * @nd: overlay notification data
> + *
> + * Called after an overlay has been removed if the overlay's target was a
> + * FPGA region.
> + */
> +static void of_fpga_region_notify_post_remove(struct fpga_region *region,
> +					      struct of_overlay_notify_data *nd)
> +{
> +	fpga_bridges_disable(&region->bridge_list);
> +	fpga_bridges_put(&region->bridge_list);
> +	fpga_image_info_free(region->info);
> +	region->info = NULL;
> +}
> +
> +/**
> + * of_fpga_region_notify - reconfig notifier for dynamic DT changes
> + * @nb:		notifier block
> + * @action:	notifier action
> + * @arg:	reconfig data
> + *
> + * This notifier handles programming a FPGA when a "firmware-name" property is
> + * added to a fpga-region.
> + *
> + * Returns NOTIFY_OK or error if FPGA programming fails.
> + */
> +static int of_fpga_region_notify(struct notifier_block *nb,
> +				 unsigned long action, void *arg)
> +{
> +	struct of_overlay_notify_data *nd = arg;
> +	struct fpga_region *region;
> +	int ret;
> +
> +	switch (action) {
> +	case OF_OVERLAY_PRE_APPLY:
> +		pr_debug("%s OF_OVERLAY_PRE_APPLY\n", __func__);
> +		break;
> +	case OF_OVERLAY_POST_APPLY:
> +		pr_debug("%s OF_OVERLAY_POST_APPLY\n", __func__);
> +		return NOTIFY_OK;       /* not for us */
> +	case OF_OVERLAY_PRE_REMOVE:
> +		pr_debug("%s OF_OVERLAY_PRE_REMOVE\n", __func__);
> +		return NOTIFY_OK;       /* not for us */
> +	case OF_OVERLAY_POST_REMOVE:
> +		pr_debug("%s OF_OVERLAY_POST_REMOVE\n", __func__);
> +		break;
> +	default:			/* should not happen */
> +		return NOTIFY_OK;

If this should not happen, then shouldn't an error be returned?

> +	}
> +
> +	region = of_fpga_region_find(nd->target);
> +	if (!region)
> +		return NOTIFY_OK;
> +
> +	ret = 0;
> +	switch (action) {
> +	case OF_OVERLAY_PRE_APPLY:
> +		ret = of_fpga_region_notify_pre_apply(region, nd);
> +		break;
> +
> +	case OF_OVERLAY_POST_REMOVE:
> +		of_fpga_region_notify_post_remove(region, nd);
> +		break;
> +	}
> +
> +	put_device(&region->dev);
> +
> +	if (ret)
> +		return notifier_from_errno(ret);
> +
> +	return NOTIFY_OK;
> +}
> +
> +static struct notifier_block fpga_region_of_nb = {
> +	.notifier_call = of_fpga_region_notify,
> +};
> +
> +static int of_fpga_region_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *np = dev->of_node;
> +	struct fpga_region *region;
> +	struct fpga_manager *mgr;
> +	int ret;
> +
> +	/* Find the FPGA mgr specified by region or parent region. */
> +	mgr = of_fpga_region_get_mgr(np);
> +	if (IS_ERR(mgr))
> +		return -EPROBE_DEFER;
> +
> +	region = devm_kzalloc(dev, sizeof(*region), GFP_KERNEL);
> +	if (!region) {
> +		ret = -ENOMEM;
> +		goto eprobe_mgr_put;
> +	}
> +
> +	region->mgr = mgr;
> +
> +	/* Specify how to get bridges for this type of region. */
> +	region->get_bridges = of_fpga_region_get_bridges;
> +
> +	ret = fpga_region_register(dev, region);
> +	if (ret)
> +		goto eprobe_mgr_put;
> +
> +	of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
> +
> +	dev_info(dev, "FPGA Region probed\n");
> +
> +	return 0;
> +
> +eprobe_mgr_put:
> +	fpga_mgr_put(mgr);
> +	return ret;
> +}
> +
> +static int of_fpga_region_remove(struct platform_device *pdev)
> +{
> +	struct fpga_region *region = platform_get_drvdata(pdev);
> +
> +	fpga_region_unregister(region);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver of_fpga_region_driver = {
> +	.probe = of_fpga_region_probe,
> +	.remove = of_fpga_region_remove,
> +	.driver = {
> +		.name	= "of-fpga-region",
> +		.of_match_table = of_match_ptr(fpga_region_of_match),
> +	},
> +};
> +
> +/**
> + * fpga_region_init - init function for fpga_region class
> + * Creates the fpga_region class and registers a reconfig notifier.
> + */
> +static int __init of_fpga_region_init(void)
> +{
> +	int ret;
> +
> +	ret = of_overlay_notifier_register(&fpga_region_of_nb);
> +	if (ret)
> +		return ret;
> +
> +	ret = platform_driver_register(&of_fpga_region_driver);
> +	if (ret)
> +		goto err_plat;
> +
> +	return 0;
> +
> +err_plat:
> +	of_overlay_notifier_unregister(&fpga_region_of_nb);
> +	return ret;
> +}
> +
> +static void __exit of_fpga_region_exit(void)
> +{
> +	platform_driver_unregister(&of_fpga_region_driver);
> +	of_overlay_notifier_unregister(&fpga_region_of_nb);
> +}
> +
> +subsys_initcall(of_fpga_region_init);
> +module_exit(of_fpga_region_exit);
> +
> +MODULE_DESCRIPTION("FPGA Region");
> +MODULE_AUTHOR("Alan Tull <atull@...nel.org>");
> +MODULE_LICENSE("GPL v2");
> -- 
> 2.7.4
>
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