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

[Lizhi Hou]

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
+
+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)
+{
+	u32 freq = 0, status;
+	int times = 10;
+
+	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) {
+		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);
+	count = snprintf(buf, 64, "%d\n", freq);
+
+	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: {
+		*(u32 *)arg = clkfreq_read(clkfreq);
+		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" },
+			{ 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);
+	}
+}
-- 
2.18.4