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Subject: Re: [PATCH V4 XRT Alveo 17/20] fpga: xrt: clock frequency counter
 platform driver
To:     Lizhi Hou <lizhi.hou@xilinx.com>, linux-kernel@vger.kernel.org
Cc:     linux-fpga@vger.kernel.org, maxz@xilinx.com,
        sonal.santan@xilinx.com, yliu@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>
References: <20210324052947.27889-1-lizhi.hou@xilinx.com>
 <20210324052947.27889-18-lizhi.hou@xilinx.com>
From:   Tom Rix <trix@redhat.com>
Message-ID: <ee717a18-bfec-6962-39cd-2efb223d577b@redhat.com>
Date:   Tue, 6 Apr 2021 13:32:04 -0700
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On 3/23/21 10:29 PM, Lizhi Hou wrote:
> Add clock frequency counter driver. Clock frequency counter is
> a hardware function discovered by walking xclbin metadata. A platform
> device node will be created for it. Other part of driver can read the
> actual clock frequency through clock frequency counter driver.
>
> Signed-off-by: Sonal Santan <sonal.santan@xilinx.com>
> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@xilinx.com>
> ---
>   drivers/fpga/xrt/include/xleaf/clkfreq.h |  21 ++
>   drivers/fpga/xrt/lib/xleaf/clkfreq.c     | 240 +++++++++++++++++++++++
>   2 files changed, 261 insertions(+)
>   create mode 100644 drivers/fpga/xrt/include/xleaf/clkfreq.h
>   create mode 100644 drivers/fpga/xrt/lib/xleaf/clkfreq.c
>
> diff --git a/drivers/fpga/xrt/include/xleaf/clkfreq.h b/drivers/fpga/xrt/include/xleaf/clkfreq.h
> new file mode 100644
> index 000000000000..005441d5df78
> --- /dev/null
> +++ b/drivers/fpga/xrt/include/xleaf/clkfreq.h
> @@ -0,0 +1,21 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (C) 2020-2021 Xilinx, Inc.
> + *
> + * Authors:
> + *	Lizhi Hou <Lizhi.Hou@xilinx.com>
> + */
> +
> +#ifndef _XRT_CLKFREQ_H_
> +#define _XRT_CLKFREQ_H_
> +
> +#include "xleaf.h"
> +
> +/*
> + * CLKFREQ driver leaf calls.
> + */
> +enum xrt_clkfreq_leaf_cmd {
> +	XRT_CLKFREQ_READ = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
> +};
> +
> +#endif	/* _XRT_CLKFREQ_H_ */
> diff --git a/drivers/fpga/xrt/lib/xleaf/clkfreq.c b/drivers/fpga/xrt/lib/xleaf/clkfreq.c
> new file mode 100644
> index 000000000000..49473adde3fd
> --- /dev/null
> +++ b/drivers/fpga/xrt/lib/xleaf/clkfreq.c
> @@ -0,0 +1,240 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Xilinx Alveo FPGA Clock Frequency Counter 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/regmap.h>
> +#include <linux/io.h>
> +#include "metadata.h"
> +#include "xleaf.h"
> +#include "xleaf/clkfreq.h"
> +
> +#define CLKFREQ_ERR(clkfreq, fmt, arg...)   \
> +	xrt_err((clkfreq)->pdev, fmt "\n", ##arg)
> +#define CLKFREQ_WARN(clkfreq, fmt, arg...)  \
> +	xrt_warn((clkfreq)->pdev, fmt "\n", ##arg)
> +#define CLKFREQ_INFO(clkfreq, fmt, arg...)  \
> +	xrt_info((clkfreq)->pdev, fmt "\n", ##arg)
> +#define CLKFREQ_DBG(clkfreq, fmt, arg...)   \
> +	xrt_dbg((clkfreq)->pdev, fmt "\n", ##arg)
> +
> +#define XRT_CLKFREQ		"xrt_clkfreq"
> +
> +#define XRT_CLKFREQ_CONTROL_STATUS_MASK		0xffff
> +
> +#define XRT_CLKFREQ_CONTROL_START	0x1
> +#define XRT_CLKFREQ_CONTROL_DONE	0x2
> +#define XRT_CLKFREQ_V5_CLK0_ENABLED	0x10000
> +
> +#define XRT_CLKFREQ_CONTROL_REG		0
> +#define XRT_CLKFREQ_COUNT_REG		0x8
> +#define XRT_CLKFREQ_V5_COUNT_REG	0x10
> +
> +#define XRT_CLKFREQ_READ_RETRIES	10
> +
> +static const struct regmap_config clkfreq_regmap_config = {
> +	.reg_bits = 32,
> +	.val_bits = 32,
> +	.reg_stride = 4,
> +	.max_register = 0x1000,
ok
> +};
> +
> +struct clkfreq {
> +	struct platform_device	*pdev;
> +	struct regmap		*regmap;
> +	const char		*clkfreq_ep_name;
> +	struct mutex		clkfreq_lock; /* clock counter dev lock */
> +};
> +
> +static int clkfreq_read(struct clkfreq *clkfreq, u32 *freq)
ok
> +{
> +	int times = XRT_CLKFREQ_READ_RETRIES;
ok
> +	u32 status;
> +	int ret;
> +
> +	*freq = 0;
> +	mutex_lock(&clkfreq->clkfreq_lock);
> +	ret = regmap_write(clkfreq->regmap, XRT_CLKFREQ_CONTROL_REG, XRT_CLKFREQ_CONTROL_START);
> +	if (ret) {
> +		CLKFREQ_INFO(clkfreq, "write start to control reg failed %d", ret);
> +		goto failed;
> +	}
> +	while (times != 0) {
> +		ret = regmap_read(clkfreq->regmap, XRT_CLKFREQ_CONTROL_REG, &status);
> +		if (ret) {
> +			CLKFREQ_INFO(clkfreq, "read control reg failed %d", ret);
> +			goto failed;
> +		}
> +		if ((status & XRT_CLKFREQ_CONTROL_STATUS_MASK) == XRT_CLKFREQ_CONTROL_DONE)
> +			break;
> +		mdelay(1);
> +		times--;
> +	};
> +
> +	if (!times) {
> +		ret = -ETIMEDOUT;
> +		goto failed;
> +	}
> +
> +	if (status & XRT_CLKFREQ_V5_CLK0_ENABLED)
> +		ret = regmap_read(clkfreq->regmap, XRT_CLKFREQ_V5_COUNT_REG, freq);
> +	else
> +		ret = regmap_read(clkfreq->regmap, XRT_CLKFREQ_COUNT_REG, freq);
> +	if (ret) {
> +		CLKFREQ_INFO(clkfreq, "read count failed %d", ret);
> +		goto failed;
> +	}
ok
> +
> +	mutex_unlock(&clkfreq->clkfreq_lock);
> +
> +	return 0;
> +
> +failed:
> +	mutex_unlock(&clkfreq->clkfreq_lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t freq_show(struct device *dev, struct device_attribute *attr, char *buf)
> +{
> +	struct clkfreq *clkfreq = platform_get_drvdata(to_platform_device(dev));
> +	ssize_t count;
> +	u32 freq;
> +
> +	if (clkfreq_read(clkfreq, &freq))
> +		return -EINVAL;
ok
> +
> +	count = snprintf(buf, 64, "%u\n", freq);
ok
> +
> +	return count;
> +}
> +static DEVICE_ATTR_RO(freq);
> +
> +static struct attribute *clkfreq_attrs[] = {
> +	&dev_attr_freq.attr,
> +	NULL,
> +};
> +
> +static struct attribute_group clkfreq_attr_group = {
> +	.attrs = clkfreq_attrs,
> +};
> +
> +static int
> +xrt_clkfreq_leaf_call(struct platform_device *pdev, u32 cmd, void *arg)
> +{
> +	struct clkfreq *clkfreq;
> +	int ret = 0;
> +
> +	clkfreq = platform_get_drvdata(pdev);
> +
> +	switch (cmd) {
> +	case XRT_XLEAF_EVENT:
> +		/* Does not handle any event. */
> +		break;
> +	case XRT_CLKFREQ_READ:
ok
> +		ret = clkfreq_read(clkfreq, arg);
ok
> +		break;
> +	default:
> +		xrt_err(pdev, "unsupported cmd %d", cmd);
> +		return -EINVAL;
> +	}
> +
> +	return ret;
> +}
> +
> +static int clkfreq_remove(struct platform_device *pdev)
> +{
> +	sysfs_remove_group(&pdev->dev.kobj, &clkfreq_attr_group);
> +
> +	return 0;
> +}
> +
> +static int clkfreq_probe(struct platform_device *pdev)
> +{
> +	struct clkfreq *clkfreq = NULL;
> +	void __iomem *base = NULL;
> +	struct resource *res;
> +	int ret;
> +
> +	clkfreq = devm_kzalloc(&pdev->dev, sizeof(*clkfreq), GFP_KERNEL);
> +	if (!clkfreq)
> +		return -ENOMEM;
> +
> +	platform_set_drvdata(pdev, clkfreq);
> +	clkfreq->pdev = pdev;
> +	mutex_init(&clkfreq->clkfreq_lock);
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	if (!res) {
> +		ret = -EINVAL;
> +		goto failed;
> +	}
> +	base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(base)) {
> +		ret = PTR_ERR(base);
> +		goto failed;
> +	}
> +
> +	clkfreq->regmap = devm_regmap_init_mmio(&pdev->dev, base, &clkfreq_regmap_config);
> +	if (IS_ERR(clkfreq->regmap)) {
> +		CLKFREQ_ERR(clkfreq, "regmap %pR failed", res);
> +		ret = PTR_ERR(clkfreq->regmap);
> +		goto failed;
> +	}
> +	clkfreq->clkfreq_ep_name = res->name;
> +
> +	ret = sysfs_create_group(&pdev->dev.kobj, &clkfreq_attr_group);
> +	if (ret) {
> +		CLKFREQ_ERR(clkfreq, "create clkfreq attrs failed: %d", ret);
> +		goto failed;
> +	}
> +
> +	CLKFREQ_INFO(clkfreq, "successfully initialized clkfreq subdev");
> +
> +	return 0;
> +
> +failed:
> +	return ret;
> +}
> +
> +static struct xrt_subdev_endpoints xrt_clkfreq_endpoints[] = {
> +	{
> +		.xse_names = (struct xrt_subdev_ep_names[]) {
> +			{ .regmap_name = XRT_MD_REGMAP_CLKFREQ },

ok

Looks good to me

Reviewed-by: Tom Rix <trix@redhat.com>

> +			{ NULL },
> +		},
> +		.xse_min_ep = 1,
> +	},
> +	{ 0 },
> +};
> +
> +static struct xrt_subdev_drvdata xrt_clkfreq_data = {
> +	.xsd_dev_ops = {
> +		.xsd_leaf_call = xrt_clkfreq_leaf_call,
> +	},
> +};
> +
> +static const struct platform_device_id xrt_clkfreq_table[] = {
> +	{ XRT_CLKFREQ, (kernel_ulong_t)&xrt_clkfreq_data },
> +	{ },
> +};
> +
> +static struct platform_driver xrt_clkfreq_driver = {
> +	.driver = {
> +		.name = XRT_CLKFREQ,
> +	},
> +	.probe = clkfreq_probe,
> +	.remove = clkfreq_remove,
> +	.id_table = xrt_clkfreq_table,
> +};
> +
> +XRT_LEAF_INIT_FINI_FUNC(XRT_SUBDEV_CLKFREQ, clkfreq);