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linux/drivers/fpga/of-fpga-region.c
Uwe Kleine-König 8abe405a5c
fpga: of-fpga-region: Convert to platform remove callback returning void
The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Xu Yilun <yilun.xu@intel.com>
Link: https://lore.kernel.org/r/1ff30f297310bf048af567924c0fd4cb7c6c3240.1703006638.git.u.kleine-koenig@pengutronix.de
Signed-off-by: Xu Yilun <yilun.xu@linux.intel.com>
2023-12-21 22:33:04 +08:00

483 lines
12 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* FPGA Region - Device Tree support for FPGA programming under Linux
*
* Copyright (C) 2013-2016 Altera Corporation
* Copyright (C) 2017 Intel Corporation
*/
#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.h>
#include <linux/of_platform.h>
#include <linux/platform_device.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);
/**
* of_fpga_region_find - find FPGA region
* @np: device node of FPGA Region
*
* Caller will need to put_device(&region->dev) when done.
*
* Return: FPGA Region struct or NULL
*/
static struct fpga_region *of_fpga_region_find(struct device_node *np)
{
return fpga_region_class_find(NULL, np, device_match_of_node);
}
/**
* 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(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. */
br = of_parse_phandle(info->overlay, "fpga-bridges", 0);
if (br) {
of_node_put(br);
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) {
of_node_put(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);
of_node_put(br);
/* 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 - Used to check the child region info.
* @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 an FPGA region, parse the FPGA image specific
* info in the overlay and do some checking.
*
* Return:
* 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 an 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.
*
* Return: 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;
info = of_fpga_region_parse_ov(region, nd->overlay);
if (IS_ERR(info))
return PTR_ERR(info);
/* If overlay doesn't program the FPGA, accept it anyway. */
if (!info)
return 0;
if (region->info) {
dev_err(dev, "Region already has overlay applied.\n");
return -EINVAL;
}
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 an FPGA when a "firmware-name" property is
* added to an fpga-region.
*
* Return: 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,
};
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 = fpga_region_register(dev, mgr, of_fpga_region_get_bridges);
if (IS_ERR(region)) {
ret = PTR_ERR(region);
goto eprobe_mgr_put;
}
of_platform_populate(np, fpga_region_of_match, NULL, &region->dev);
platform_set_drvdata(pdev, region);
dev_info(dev, "FPGA Region probed\n");
return 0;
eprobe_mgr_put:
fpga_mgr_put(mgr);
return ret;
}
static void of_fpga_region_remove(struct platform_device *pdev)
{
struct fpga_region *region = platform_get_drvdata(pdev);
struct fpga_manager *mgr = region->mgr;
fpga_region_unregister(region);
fpga_mgr_put(mgr);
}
static struct platform_driver of_fpga_region_driver = {
.probe = of_fpga_region_probe,
.remove_new = of_fpga_region_remove,
.driver = {
.name = "of-fpga-region",
.of_match_table = of_match_ptr(fpga_region_of_match),
},
};
/**
* of_fpga_region_init - init function for fpga_region class
* Creates the fpga_region class and registers a reconfig notifier.
*
* Return: 0 on success, negative error code otherwise.
*/
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@kernel.org>");
MODULE_LICENSE("GPL v2");