Re: [PATCH V3 XRT Alveo 13/18] fpga: xrt: devctl platform driver

From: Tom Rix <trix@redhat.com>
To: Lizhi Hou <lizhi.hou@xilinx.com>, linux-kernel@vger.kernel.org
Cc: Lizhi Hou <lizhih@xilinx.com>,
	linux-fpga@vger.kernel.org, maxz@xilinx.com,
	sonal.santan@xilinx.com, michal.simek@xilinx.com,
	stefanos@xilinx.com, devicetree@vger.kernel.org, mdf@kernel.org,
	robh@kernel.org, Max Zhen <max.zhen@xilinx.com>
Subject: Re: [PATCH V3 XRT Alveo 13/18] fpga: xrt: devctl platform driver
Date: Thu, 4 Mar 2021 05:39:46 -0800	[thread overview]
Message-ID: <f32d06bc-1054-eb97-cce1-9b40e9c4442b@redhat.com> (raw)
In-Reply-To: <20210218064019.29189-14-lizhih@xilinx.com>

On 2/17/21 10:40 PM, Lizhi Hou wrote:
> Add devctl driver. devctl is a type of hardware function which only has
> few registers to read or write. They are discovered by walking firmware
> metadata. A platform device node will be created for them.
>
> Signed-off-by: Sonal Santan <sonal.santan@xilinx.com>
> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
> Signed-off-by: Lizhi Hou <lizhih@xilinx.com>
> ---
>  drivers/fpga/xrt/include/xleaf/devctl.h |  43 +++++
>  drivers/fpga/xrt/lib/xleaf/devctl.c     | 206 ++++++++++++++++++++++++
>  2 files changed, 249 insertions(+)
>  create mode 100644 drivers/fpga/xrt/include/xleaf/devctl.h
>  create mode 100644 drivers/fpga/xrt/lib/xleaf/devctl.c
>
> diff --git a/drivers/fpga/xrt/include/xleaf/devctl.h b/drivers/fpga/xrt/include/xleaf/devctl.h
> new file mode 100644
> index 000000000000..96a40e066f83
> --- /dev/null
> +++ b/drivers/fpga/xrt/include/xleaf/devctl.h
> @@ -0,0 +1,43 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Header file for XRT DEVCTL Leaf Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Lizhi Hou <Lizhi.Hou@xilinx.com>
> + */
> +
> +#ifndef _XRT_DEVCTL_H_
> +#define _XRT_DEVCTL_H_
> +
> +#include "xleaf.h"
> +
> +/*
> + * DEVCTL driver IOCTL calls.
> + */
> +enum xrt_devctl_ioctl_cmd {
> +	XRT_DEVCTL_READ = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
> +	XRT_DEVCTL_WRITE,
> +};
> +
> +enum xrt_devctl_id {
> +	XRT_DEVCTL_ROM_UUID,
Assumes 0, should make this explicit and initialize to 0
> +	XRT_DEVCTL_DDR_CALIB,
> +	XRT_DEVCTL_GOLDEN_VER,
> +	XRT_DEVCTL_MAX
> +};
> +
> +struct xrt_devctl_ioctl_rw {
> +	u32	xgir_id;
> +	void	*xgir_buf;
> +	u32	xgir_len;
> +	u32	xgir_offset;
similar to other patches, the xgir_ prefix is not needed
> +};
> +
> +struct xrt_devctl_ioctl_intf_uuid {
> +	u32	xgir_uuid_num;
> +	uuid_t	*xgir_uuids;
> +};
> +
> +#endif	/* _XRT_DEVCTL_H_ */
> diff --git a/drivers/fpga/xrt/lib/xleaf/devctl.c b/drivers/fpga/xrt/lib/xleaf/devctl.c
> new file mode 100644
> index 000000000000..caf8c6569f0f
> --- /dev/null
> +++ b/drivers/fpga/xrt/lib/xleaf/devctl.c
> @@ -0,0 +1,206 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo FPGA devctl Driver
> + *
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *      Lizhi Hou<Lizhi.Hou@xilinx.com>
> + */
> +
> +#include <linux/mod_devicetable.h>
> +#include <linux/platform_device.h>
> +#include <linux/delay.h>
> +#include <linux/device.h>
> +#include <linux/io.h>
> +#include "metadata.h"
> +#include "xleaf.h"
> +#include "xleaf/devctl.h"
> +
> +#define XRT_DEVCTL "xrt_devctl"
> +
> +struct xrt_name_id {
> +	char *ep_name;
> +	int id;
> +};
> +
> +static struct xrt_name_id name_id[XRT_DEVCTL_MAX] = {
> +	{ XRT_MD_NODE_BLP_ROM, XRT_DEVCTL_ROM_UUID },
> +	{ XRT_MD_NODE_GOLDEN_VER, XRT_DEVCTL_GOLDEN_VER },
DDR_CALIB is unused ?
> +};
> +
> +struct xrt_devctl {
> +	struct platform_device	*pdev;
> +	void		__iomem *base_addrs[XRT_DEVCTL_MAX];
> +	ulong			sizes[XRT_DEVCTL_MAX];
> +};
similar to other patches, why not use regmap ?
> +
> +static int xrt_devctl_name2id(struct xrt_devctl *devctl, const char *name)
> +{
> +	int	i;
> +
> +	for (i = 0; i < XRT_DEVCTL_MAX && name_id[i].ep_name; i++) {
> +		if (!strncmp(name_id[i].ep_name, name, strlen(name_id[i].ep_name) + 1))
> +			return name_id[i].id;
> +	}
> +
> +	return -EINVAL;
> +}
> +
> +static int
> +xrt_devctl_leaf_ioctl(struct platform_device *pdev, u32 cmd, void *arg)
> +{
> +	struct xrt_devctl	*devctl;
> +	int			ret = 0;
> +
> +	devctl = platform_get_drvdata(pdev);
> +
> +	switch (cmd) {
> +	case XRT_XLEAF_EVENT:
> +		/* Does not handle any event. */
> +		break;
> +	case XRT_DEVCTL_READ: {
> +		struct xrt_devctl_ioctl_rw	*rw_arg = arg;
> +		u32				*p_src, *p_dst, i;
> +
> +		if (rw_arg->xgir_len & 0x3) {
> +			xrt_err(pdev, "invalid len %d", rw_arg->xgir_len);
> +			return -EINVAL;
> +		}
> +
> +		if (rw_arg->xgir_id >= XRT_DEVCTL_MAX) {
> +			xrt_err(pdev, "invalid id %d", rw_arg->xgir_id);
> +			return -EINVAL;
> +		}
needs a < 0 check ?
> +
> +		p_src = devctl->base_addrs[rw_arg->xgir_id];
> +		if (!p_src) {
> +			xrt_err(pdev, "io not found, id %d",
> +				rw_arg->xgir_id);
> +			return -EINVAL;
> +		}
> +		if (rw_arg->xgir_offset + rw_arg->xgir_len >
> +		    devctl->sizes[rw_arg->xgir_id]) {
> +			xrt_err(pdev, "invalid argument, off %d, len %d",
> +				rw_arg->xgir_offset, rw_arg->xgir_len);
> +			return -EINVAL;
> +		}
> +		p_dst = rw_arg->xgir_buf;
> +		for (i = 0; i < rw_arg->xgir_len / sizeof(u32); i++) {
> +			u32 val = ioread32(p_src + rw_arg->xgir_offset + i);
> +
> +			memcpy(p_dst + i, &val, sizeof(u32));
> +		}
> +		break;
> +	}

The _WRITE msg is not handled Then why have it ?

Tom

> +	default:
> +		xrt_err(pdev, "unsupported cmd %d", cmd);
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int xrt_devctl_remove(struct platform_device *pdev)
> +{
> +	struct xrt_devctl	*devctl;
> +	int			i;
> +
> +	devctl = platform_get_drvdata(pdev);
> +
> +	for (i = 0; i < XRT_DEVCTL_MAX; i++) {
> +		if (devctl->base_addrs[i])
> +			iounmap(devctl->base_addrs[i]);
> +	}
> +
> +	platform_set_drvdata(pdev, NULL);
> +	devm_kfree(&pdev->dev, devctl);
> +
> +	return 0;
> +}
> +
> +static int xrt_devctl_probe(struct platform_device *pdev)
> +{
> +	struct xrt_devctl	*devctl;
> +	int			i, id, ret = 0;
> +	struct resource		*res;
> +
> +	devctl = devm_kzalloc(&pdev->dev, sizeof(*devctl), GFP_KERNEL);
> +	if (!devctl)
> +		return -ENOMEM;
> +
> +	devctl->pdev = pdev;
> +	platform_set_drvdata(pdev, devctl);
> +
> +	xrt_info(pdev, "probing...");
> +	for (i = 0, res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	    res;
> +	    res = platform_get_resource(pdev, IORESOURCE_MEM, ++i)) {
> +		id = xrt_devctl_name2id(devctl, res->name);
> +		if (id < 0) {
> +			xrt_err(pdev, "ep %s not found", res->name);
> +			continue;
> +		}
> +		devctl->base_addrs[id] = ioremap(res->start, res->end - res->start + 1);
> +		if (!devctl->base_addrs[id]) {
> +			xrt_err(pdev, "map base failed %pR", res);
> +			ret = -EIO;
> +			goto failed;
> +		}
> +		devctl->sizes[id] = res->end - res->start + 1;
> +	}
> +
> +failed:
> +	if (ret)
> +		xrt_devctl_remove(pdev);
> +
> +	return ret;
> +}
> +
> +static struct xrt_subdev_endpoints xrt_devctl_endpoints[] = {
> +	{
> +		.xse_names = (struct xrt_subdev_ep_names[]) {
> +			/* add name if ep is in same partition */
> +			{ .ep_name = XRT_MD_NODE_BLP_ROM },
> +			{ NULL },
> +		},
> +		.xse_min_ep = 1,
> +	},
> +	{
> +		.xse_names = (struct xrt_subdev_ep_names[]) {
> +			{ .ep_name = XRT_MD_NODE_GOLDEN_VER },
> +			{ NULL },
> +		},
> +		.xse_min_ep = 1,
> +	},
> +	/* adding ep bundle generates devctl device instance */
> +	{ 0 },
> +};
> +
> +static struct xrt_subdev_drvdata xrt_devctl_data = {
> +	.xsd_dev_ops = {
> +		.xsd_ioctl = xrt_devctl_leaf_ioctl,
> +	},
> +};
> +
> +static const struct platform_device_id xrt_devctl_table[] = {
> +	{ XRT_DEVCTL, (kernel_ulong_t)&xrt_devctl_data },
> +	{ },
> +};
> +
> +static struct platform_driver xrt_devctl_driver = {
> +	.driver = {
> +		.name = XRT_DEVCTL,
> +	},
> +	.probe = xrt_devctl_probe,
> +	.remove = xrt_devctl_remove,
> +	.id_table = xrt_devctl_table,
> +};
> +
> +void devctl_leaf_init_fini(bool init)
> +{
> +	if (init)
> +		xleaf_register_driver(XRT_SUBDEV_DEVCTL, &xrt_devctl_driver, xrt_devctl_endpoints);
> +	else
> +		xleaf_unregister_driver(XRT_SUBDEV_DEVCTL);
> +}