[PATCH V4 XRT Alveo 17/20] fpga: xrt: clock frequency counter platform driver

[Lizhi Hou]

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@xxxxxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxxxxx>
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxxxxx>
---
 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@xxxxxxxxxx>
+ */
+
+#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@xxxxxxxxxx>
+ */
+
+#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,
+};
+
+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)
+{
+	int times = XRT_CLKFREQ_READ_RETRIES;
+	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;
+	}
+
+	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;
+
+	count = snprintf(buf, 64, "%u\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_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:
+		ret = clkfreq_read(clkfreq, arg);
+		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 },
+			{ 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);
-- 
2.27.0