Re: [PATCH V3 XRT Alveo 15/18] fpga: xrt: clock frequence counter platform driver

Lizhi Hou
2021-03-12T23:44:39Z

Hi Tom,

On 03/06/2021 07:25 AM, Tom Rix wrote:
> On 2/17/21 10:40 PM, Lizhi Hou wrote:
>> Add clock frequence counter driver. Clock frequence 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 frequence through clock frequence 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 <lizhih@xilinx.com>
>> ---
>> drivers/fpga/xrt/include/xleaf/clkfreq.h | 23 +++
>> drivers/fpga/xrt/lib/xleaf/clkfreq.c | 221 +++++++++++++++++++++++
>> 2 files changed, 244 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..29fc45e8a31b
>> --- /dev/null
>> +++ b/drivers/fpga/xrt/include/xleaf/clkfreq.h
>> @@ -0,0 +1,23 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Header file for XRT Clock Counter Leaf Driver
>> + *
>> + * 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 IOCTL calls.
>> + */
>> +enum xrt_clkfreq_ioctl_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..2482dd2cff47
>> --- /dev/null
>> +++ b/drivers/fpga/xrt/lib/xleaf/clkfreq.c
>> @@ -0,0 +1,221 @@
>> +// 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/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 OCL_CLKWIZ_STATUS_MASK 0xffff
>> +
>> +#define OCL_CLKWIZ_STATUS_MEASURE_START 0x1
>> +#define OCL_CLKWIZ_STATUS_MEASURE_DONE 0x2
>> +#define OCL_CLK_FREQ_COUNTER_OFFSET 0x8
>> +#define OCL_CLK_FREQ_V5_COUNTER_OFFSET 0x10
>> +#define OCL_CLK_FREQ_V5_CLK0_ENABLED 0x10000
> Similar to earlier, OCL -> XRT_CLKFREQ
>
> Use regmap
Will change this.
>
>> +
>> +struct clkfreq {
>> + struct platform_device *pdev;
>> + void __iomem *clkfreq_base;
>> + const char *clkfreq_ep_name;
>> + struct mutex clkfreq_lock; /* clock counter dev lock */
>> +};
>> +
>> +static inline u32 reg_rd(struct clkfreq *clkfreq, u32 offset)
>> +{
>> + return ioread32(clkfreq->clkfreq_base + offset);
>> +}
>> +
>> +static inline void reg_wr(struct clkfreq *clkfreq, u32 val, u32 offset)
>> +{
>> + iowrite32(val, clkfreq->clkfreq_base + offset);
>> +}
>> +
>> +static u32 clkfreq_read(struct clkfreq *clkfreq)
>> +{
> failure returns 0, it would be better if -EINVAL or similar was returned.
>
> and u32 *freq added as a function parameter
Will change this.
>
>> + u32 freq = 0, status;
>> + int times = 10;
> 10 is a config parameter, should be a #define
Sure.
>> +
>> + mutex_lock(&clkfreq->clkfreq_lock);
>> + reg_wr(clkfreq, OCL_CLKWIZ_STATUS_MEASURE_START, 0);
>> + while (times != 0) {
>> + status = reg_rd(clkfreq, 0);
>> + if ((status & OCL_CLKWIZ_STATUS_MASK) ==
>> + OCL_CLKWIZ_STATUS_MEASURE_DONE)
>> + break;
>> + mdelay(1);
>> + times--;
>> + };
>> + if (times > 0) {
> I do not like tristate setting, convert to if-else
Will change this.
>> + freq = (status & OCL_CLK_FREQ_V5_CLK0_ENABLED) ?
>> + reg_rd(clkfreq, OCL_CLK_FREQ_V5_COUNTER_OFFSET) :
>> + reg_rd(clkfreq, OCL_CLK_FREQ_COUNTER_OFFSET);
>> + }
>> + mutex_unlock(&clkfreq->clkfreq_lock);
>> +
>> + return freq;
>> +}
>> +
>> +static ssize_t freq_show(struct device *dev, struct device_attribute *attr, char *buf)
>> +{
>> + struct clkfreq *clkfreq = platform_get_drvdata(to_platform_device(dev));
>> + u32 freq;
>> + ssize_t count;
>> +
>> + freq = clkfreq_read(clkfreq);
> unchecked error
Will add check.
>> + count = snprintf(buf, 64, "%d\n", freq);
> %u
Sure.
>> +
>> + 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_ioctl(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: {
> brace not needed
Will remove.
>> + *(u32 *)arg = clkfreq_read(clkfreq);
> Unchecked error
Will add check.
>> + break;
>> + }
>> + default:
>> + xrt_err(pdev, "unsupported cmd %d", cmd);
>> + return -EINVAL;
>> + }
>> +
>> + return ret;
>> +}
>> +
>> +static int clkfreq_remove(struct platform_device *pdev)
>> +{
>> + struct clkfreq *clkfreq;
>> +
>> + clkfreq = platform_get_drvdata(pdev);
>> + if (!clkfreq) {
>> + xrt_err(pdev, "driver data is NULL");
>> + return -EINVAL;
>> + }
>> +
>> + platform_set_drvdata(pdev, NULL);
>> + devm_kfree(&pdev->dev, clkfreq);
>> +
>> + CLKFREQ_INFO(clkfreq, "successfully removed clkfreq subdev");
>> + return 0;
>> +}
>> +
>> +static int clkfreq_probe(struct platform_device *pdev)
>> +{
>> + struct clkfreq *clkfreq = 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);
>> + clkfreq->clkfreq_base = ioremap(res->start, res->end - res->start + 1);
>> + if (!clkfreq->clkfreq_base) {
>> + CLKFREQ_ERR(clkfreq, "map base %pR failed", res);
>> + ret = -EFAULT;
>> + 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:
>> + clkfreq_remove(pdev);
>> + return ret;
>> +}
>> +
>> +static struct xrt_subdev_endpoints xrt_clkfreq_endpoints[] = {
>> + {
>> + .xse_names = (struct xrt_subdev_ep_names[]) {
>> + { .regmap_name = "freq_cnt" },
> name should be closer to filename, maybe 'clock_frequency' or 'clkfreq'
'freq_cnt' is from firmware metadata. I will add #define in metadata.h.

Thanks,
Lizhi
>
> Tom
>
>> + { NULL },
>> + },
>> + .xse_min_ep = 1,
>> + },
>> + { 0 },
>> +};
>> +
>> +static struct xrt_subdev_drvdata xrt_clkfreq_data = {
>> + .xsd_dev_ops = {
>> + .xsd_ioctl = xrt_clkfreq_leaf_ioctl,
>> + },
>> +};
>> +
>> +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,
>> +};
>> +
>> +void clkfreq_leaf_init_fini(bool init)
>> +{
>> + if (init) {
>> + xleaf_register_driver(XRT_SUBDEV_CLKFREQ,
>> + &xrt_clkfreq_driver, xrt_clkfreq_endpoints);
>> + } else {
>> + xleaf_unregister_driver(XRT_SUBDEV_CLKFREQ);
>> + }
>> +}