Re: [PATCH V5 XRT Alveo 17/20] fpga: xrt: clock frequency counter driver
From: Tom Rix
Date: Tue May 04 2021 - 10:10:21 EST
On 4/27/21 1:54 PM, Lizhi Hou wrote:
Add clock frequency counter driver. Clock frequency counter is
a hardware function discovered by walking xclbin metadata. A xrt
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>
v4 was ok, please add my Reviewed-by: line
Reviewed-by: Tom Rix <trix@xxxxxxxxxx>
---
drivers/fpga/xrt/include/xleaf/clkfreq.h | 21 +++
drivers/fpga/xrt/lib/xleaf/clkfreq.c | 223 +++++++++++++++++++++++
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..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..3d1f11152375
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/clkfreq.c
@@ -0,0 +1,223 @@
+// 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/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)->xdev, fmt "\n", ##arg)
+#define CLKFREQ_WARN(clkfreq, fmt, arg...) \
+ xrt_warn((clkfreq)->xdev, fmt "\n", ##arg)
+#define CLKFREQ_INFO(clkfreq, fmt, arg...) \
+ xrt_info((clkfreq)->xdev, fmt "\n", ##arg)
+#define CLKFREQ_DBG(clkfreq, fmt, arg...) \
+ xrt_dbg((clkfreq)->xdev, 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
+
+XRT_DEFINE_REGMAP_CONFIG(clkfreq_regmap_config);
+
+struct clkfreq {
+ struct xrt_device *xdev;
+ 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 = xrt_get_drvdata(to_xrt_dev(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 xrt_device *xdev, u32 cmd, void *arg)
+{
+ struct clkfreq *clkfreq;
+ int ret = 0;
+
+ clkfreq = xrt_get_drvdata(xdev);
+
+ 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(xdev, "unsupported cmd %d", cmd);
+ return -EINVAL;
+ }
+
+ return ret;
+}
+
+static void clkfreq_remove(struct xrt_device *xdev)
+{
+ sysfs_remove_group(&xdev->dev.kobj, &clkfreq_attr_group);
+}
+
+static int clkfreq_probe(struct xrt_device *xdev)
+{
+ struct clkfreq *clkfreq = NULL;
+ void __iomem *base = NULL;
+ struct resource *res;
+ int ret;
+
+ clkfreq = devm_kzalloc(&xdev->dev, sizeof(*clkfreq), GFP_KERNEL);
+ if (!clkfreq)
+ return -ENOMEM;
+
+ xrt_set_drvdata(xdev, clkfreq);
+ clkfreq->xdev = xdev;
+ mutex_init(&clkfreq->clkfreq_lock);
+
+ res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ ret = -EINVAL;
+ goto failed;
+ }
+ base = devm_ioremap_resource(&xdev->dev, res);
+ if (IS_ERR(base)) {
+ ret = PTR_ERR(base);
+ goto failed;
+ }
+
+ clkfreq->regmap = devm_regmap_init_mmio(&xdev->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(&xdev->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_dev_endpoints xrt_clkfreq_endpoints[] = {
+ {
+ .xse_names = (struct xrt_dev_ep_names[]) {
+ { .compat = XRT_MD_COMPAT_CLKFREQ },
+ { NULL },
+ },
+ .xse_min_ep = 1,
+ },
+ { 0 },
+};
+
+static struct xrt_driver xrt_clkfreq_driver = {
+ .driver = {
+ .name = XRT_CLKFREQ,
+ },
+ .subdev_id = XRT_SUBDEV_CLKFREQ,
+ .endpoints = xrt_clkfreq_endpoints,
+ .probe = clkfreq_probe,
+ .remove = clkfreq_remove,
+ .leaf_call = xrt_clkfreq_leaf_call,
+};
+
+XRT_LEAF_INIT_FINI_FUNC(clkfreq);