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

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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);
+     }
+}




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