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

[Lizhi Hou]

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@xxxxxxxxxx>
> > Signed-off-by: Max Zhen <max.zhen@xxxxxxxxxx>
> > Signed-off-by: Lizhi Hou <lizhih@xxxxxxxxxx>
> > ---
> >   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@xxxxxxxxxx>
> > + */
> > +
> > +#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@xxxxxxxxxx>
> > + */
> > +
> > +#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);
> > +     }
> > +}