Re: [RFC PATCH v4 3/4] fpga: add fake FPGA region

[Marco Pagani]

On 2023-04-20 20:38, Xu Yilun wrote:
> On 2023-04-17 at 14:23:07 +0200, Marco Pagani wrote:
>> Add fake FPGA region platform driver with support functions. This
>> module is part of the KUnit tests for the FPGA subsystem.
>>
>> Signed-off-by: Marco Pagani <marpagan@xxxxxxxxxx>
>> ---
>>  drivers/fpga/tests/fake-fpga-region.c | 259 ++++++++++++++++++++++++++
>>  drivers/fpga/tests/fake-fpga-region.h |  40 ++++
>>  2 files changed, 299 insertions(+)
>>  create mode 100644 drivers/fpga/tests/fake-fpga-region.c
>>  create mode 100644 drivers/fpga/tests/fake-fpga-region.h
>>
>> diff --git a/drivers/fpga/tests/fake-fpga-region.c b/drivers/fpga/tests/fake-fpga-region.c
>> new file mode 100644
>> index 000000000000..b23ae5e94fe6
>> --- /dev/null
>> +++ b/drivers/fpga/tests/fake-fpga-region.c
>> @@ -0,0 +1,259 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Driver for the fake FPGA region
>> + *
>> + * Copyright (C) 2023 Red Hat, Inc.
>> + *
>> + * Author: Marco Pagani <marpagan@xxxxxxxxxx>
>> + */
>> +
>> +#include <linux/device.h>
>> +#include <linux/list.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/fpga/fpga-region.h>
>> +#include <linux/fpga/fpga-bridge.h>
>> +#include <kunit/test.h>
>> +
>> +#include "fake-fpga-region.h"
>> +
>> +#define FAKE_FPGA_REGION_DEV_NAME	"fake_fpga_region"
>> +
>> +struct fake_region_priv {
>> +	int id;
>> +	struct kunit *test;
>> +	struct list_head bridge_list;
>> +};
>> +
>> +struct bridge_elem {
>> +	struct fpga_bridge *bridge;
>> +	struct list_head node;
>> +};
>> +
>> +struct fake_region_data {
>> +	struct fpga_manager *mgr;
>> +	struct kunit *test;
>> +};
>> +
>> +/**
>> + * fake_fpga_region_register() - register a fake FPGA region.
>> + * @mgr: associated FPGA manager.
>> + * @parent: parent device.
>> + * @test: KUnit test context object.
>> + *
>> + * Return: pointer to a new fake FPGA region on success, an ERR_PTR() encoded
>> + * error code on failure.
>> + */
>> +struct fake_fpga_region *
>> +fake_fpga_region_register(struct fpga_manager *mgr, struct device *parent,
>> +			  struct kunit *test)
>> +{
>> +	struct fake_fpga_region *region_ctx;
>> +	struct fake_region_data pdata;
>> +	struct fake_region_priv *priv;
>> +	int ret;
>> +
>> +	region_ctx = kzalloc(sizeof(*region_ctx), GFP_KERNEL);
>> +	if (!region_ctx) {
>> +		ret = -ENOMEM;
>> +		goto err_mem;
>> +	}
>> +
>> +	region_ctx->pdev = platform_device_alloc(FAKE_FPGA_REGION_DEV_NAME,
>> +						 PLATFORM_DEVID_AUTO);
>> +	if (!region_ctx->pdev) {
>> +		pr_err("Fake FPGA region device allocation failed\n");
>> +		ret = -ENOMEM;
>> +		goto err_mem;
>> +	}
>> +
>> +	pdata.mgr = mgr;
>> +	pdata.test = test;
>> +	platform_device_add_data(region_ctx->pdev, &pdata, sizeof(pdata));
>> +
>> +	region_ctx->pdev->dev.parent = parent;
>> +	ret = platform_device_add(region_ctx->pdev);
>> +	if (ret) {
>> +		pr_err("Fake FPGA region device add failed\n");
>> +		goto err_pdev;
>> +	}
>> +
>> +	region_ctx->region = platform_get_drvdata(region_ctx->pdev);
>> +
>> +	if (test) {
>> +		priv = region_ctx->region->priv;
>> +		kunit_info(test, "Fake FPGA region %d registered\n", priv->id);
>> +	}
>> +
>> +	return region_ctx;
>> +
>> +err_pdev:
>> +	platform_device_put(region_ctx->pdev);
>> +	kfree(region_ctx);
>> +err_mem:
>> +	return ERR_PTR(ret);
>> +}
>> +EXPORT_SYMBOL_GPL(fake_fpga_region_register);
>> +
>> +/**
>> + * fake_fpga_region_unregister() - unregister a fake FPGA region.
>> + * @region_ctx: fake FPGA region context data structure.
>> + */
>> +void fake_fpga_region_unregister(struct fake_fpga_region *region_ctx)
>> +{
>> +	struct fake_region_priv *priv;
>> +	struct kunit *test;
>> +	int id;
>> +
>> +	if (!region_ctx)
>> +		return;
>> +
>> +	priv = region_ctx->region->priv;
>> +	test = priv->test;
>> +	id = priv->id;
>> +
>> +	if (region_ctx->pdev) {
>> +		platform_device_unregister(region_ctx->pdev);
>> +		if (test)
>> +			kunit_info(test, "Fake FPGA region %d unregistered\n", id);
>> +	}
>> +
>> +	kfree(region_ctx);
>> +}
>> +EXPORT_SYMBOL_GPL(fake_fpga_region_unregister);
>> +
>> +/**
>> + * fake_fpga_region_add_bridge() - add a bridge to a fake FPGA region.
>> + * @region_ctx: fake FPGA region context data structure.
>> + * @bridge: FPGA bridge.
>> + *
>> + * Return: 0 if registration succeeded, an error code otherwise.
>> + */
>> +int fake_fpga_region_add_bridge(struct fake_fpga_region *region_ctx,
>> +				struct fpga_bridge *bridge)
>> +{
>> +	struct fake_region_priv *priv;
>> +	struct bridge_elem *elem;
>> +
>> +	priv = region_ctx->region->priv;
>> +
>> +	elem = devm_kzalloc(&region_ctx->pdev->dev, sizeof(*elem), GFP_KERNEL);
>> +	if (!elem)
>> +		return -ENOMEM;
>> +
>> +	/* Add bridge to the list of bridges in the private context */
>> +	elem->bridge = bridge;
>> +	list_add(&elem->node, &priv->bridge_list);
>> +
>> +	if (priv->test)
>> +		kunit_info(priv->test, "Bridge added to fake FPGA region %d\n",
>> +			   priv->id);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(fake_fpga_region_add_bridge);
> 
> To move these exported functions out of fake driver, could we also provide
> the bridge list in platform_data?
> 
> Thanks,
> Yilun

I feel that the function for adding bridges to the fake region should belong
to the region driver itself rather than the fpga-test module. However, I can
certainly include the bridge list also in platform_data.

Thanks,
Marco


> 
>> +
>> +int fake_fpga_region_program(struct fake_fpga_region *region_ctx)
>> +{
>> +	int ret;
>> +
>> +	ret = fpga_region_program_fpga(region_ctx->region);
>> +
>> +	/* fpga_region_program_fpga() already puts the bridges in case of errors */
>> +	if (!ret)
>> +		fpga_bridges_put(&region_ctx->region->bridge_list);
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(fake_fpga_region_program);
>> +
>> +static int fake_region_get_bridges(struct fpga_region *region)
>> +{
>> +	struct fake_region_priv *priv;
>> +	struct bridge_elem *elem;
>> +	int ret;
>> +
>> +	priv = region->priv;
>> +
>> +	/* Copy the list of bridges from the private context to the region */
>> +	list_for_each_entry(elem, &priv->bridge_list, node) {
>> +		ret = fpga_bridge_get_to_list(elem->bridge->dev.parent,
>> +					      region->info,
>> +					      &region->bridge_list);
>> +		if (ret)
>> +			break;
>> +	}
>> +
>> +	return ret;
>> +}
>> +
>> +static int fake_fpga_region_probe(struct platform_device *pdev)
>> +{
>> +	struct device *dev;
>> +	struct fpga_region *region;
>> +	struct fpga_manager *mgr;
>> +	struct fake_region_data *pdata;
>> +	struct fake_region_priv *priv;
>> +	struct fpga_region_info info;
>> +	static int id_count;
>> +
>> +	dev = &pdev->dev;
>> +	pdata = dev_get_platdata(dev);
>> +
>> +	if (!pdata) {
>> +		dev_err(&pdev->dev, "Missing platform data\n");
>> +		return -EINVAL;
>> +	}
>> +
>> +	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>> +	if (!priv)
>> +		return -ENOMEM;
>> +
>> +	mgr = fpga_mgr_get(pdata->mgr->dev.parent);
>> +	if (IS_ERR(mgr))
>> +		return PTR_ERR(mgr);
>> +
>> +	INIT_LIST_HEAD(&priv->bridge_list);
>> +	priv->id = id_count++;
>> +	priv->test = pdata->test;
>> +
>> +	memset(&info, 0, sizeof(info));
>> +	info.priv = priv;
>> +	info.mgr = mgr;
>> +	info.get_bridges = fake_region_get_bridges;
>> +
>> +	region = fpga_region_register_full(dev, &info);
>> +	if (IS_ERR(region)) {
>> +		fpga_mgr_put(mgr);
>> +		return PTR_ERR(region);
>> +	}
>> +
>> +	platform_set_drvdata(pdev, region);
>> +
>> +	return 0;
>> +}
>> +
>> +static int fake_fpga_region_remove(struct platform_device *pdev)
>> +{
>> +	struct fpga_region *region = platform_get_drvdata(pdev);
>> +	struct fpga_manager *mgr = region->mgr;
>> +
>> +	fpga_mgr_put(mgr);
>> +	fpga_region_unregister(region);
>> +
>> +	return 0;
>> +}
>> +
>> +static struct platform_driver fake_fpga_region_drv = {
>> +	.driver = {
>> +		.name = FAKE_FPGA_REGION_DEV_NAME
>> +	},
>> +	.probe = fake_fpga_region_probe,
>> +	.remove = fake_fpga_region_remove,
>> +};
>> +
>> +module_platform_driver(fake_fpga_region_drv);
>> +
>> +MODULE_AUTHOR("Marco Pagani <marpagan@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Fake FPGA Bridge");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/fpga/tests/fake-fpga-region.h b/drivers/fpga/tests/fake-fpga-region.h
>> new file mode 100644
>> index 000000000000..976982c192bc
>> --- /dev/null
>> +++ b/drivers/fpga/tests/fake-fpga-region.h
>> @@ -0,0 +1,40 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Header file for the fake FPGA region
>> + *
>> + * Copyright (C) 2023 Red Hat, Inc.
>> + *
>> + * Author: Marco Pagani <marpagan@xxxxxxxxxx>
>> + */
>> +
>> +#ifndef __FPGA_FAKE_RGN_H
>> +#define __FPGA_FAKE_RGN_H
>> +
>> +#include <linux/platform_device.h>
>> +#include <kunit/test.h>
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/fpga/fpga-bridge.h>
>> +
>> +/**
>> + * struct fake_fpga_region - fake FPGA region context data structure
>> + *
>> + * @region: FPGA region.
>> + * @pdev: platform device of the FPGA region.
>> + */
>> +struct fake_fpga_region {
>> +	struct fpga_region *region;
>> +	struct platform_device *pdev;
>> +};
>> +
>> +struct fake_fpga_region *
>> +fake_fpga_region_register(struct fpga_manager *mgr, struct device *parent,
>> +			  struct kunit *test);
>> +
>> +int fake_fpga_region_add_bridge(struct fake_fpga_region *region_ctx,
>> +				struct fpga_bridge *bridge);
>> +
>> +int fake_fpga_region_program(struct fake_fpga_region *region_ctx);
>> +
>> +void fake_fpga_region_unregister(struct fake_fpga_region *region_ctx);
>> +
>> +#endif /* __FPGA_FAKE_RGN_H */
>> -- 
>> 2.39.2
>>
>