[PATCH V4 XRT Alveo 18/20] fpga: xrt: DDR calibration platform driver

[Lizhi Hou]

Add DDR calibration driver. DDR calibration is a hardware function
discovered by walking firmware metadata. A platform device node will
be created for it. Hardware provides DDR calibration status through
this function.

Signed-off-by: Sonal Santan <sonal.santan@xxxxxxxxxx>
Signed-off-by: Max Zhen <max.zhen@xxxxxxxxxx>
Signed-off-by: Lizhi Hou <lizhi.hou@xxxxxxxxxx>
---
 .../fpga/xrt/include/xleaf/ddr_calibration.h  |  28 +++
 drivers/fpga/xrt/lib/xleaf/ddr_calibration.c  | 226 ++++++++++++++++++
 2 files changed, 254 insertions(+)
 create mode 100644 drivers/fpga/xrt/include/xleaf/ddr_calibration.h
 create mode 100644 drivers/fpga/xrt/lib/xleaf/ddr_calibration.c

diff --git a/drivers/fpga/xrt/include/xleaf/ddr_calibration.h b/drivers/fpga/xrt/include/xleaf/ddr_calibration.h
new file mode 100644
index 000000000000..878740c26ca2
--- /dev/null
+++ b/drivers/fpga/xrt/include/xleaf/ddr_calibration.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Cheng Zhen <maxz@xxxxxxxxxx>
+ */
+
+#ifndef _XRT_DDR_CALIBRATION_H_
+#define _XRT_DDR_CALIBRATION_H_
+
+#include "xleaf.h"
+#include <linux/xrt/xclbin.h>
+
+/*
+ * Memory calibration driver leaf calls.
+ */
+enum xrt_calib_results {
+	XRT_CALIB_UNKNOWN = 0,
+	XRT_CALIB_SUCCEEDED,
+	XRT_CALIB_FAILED,
+};
+
+enum xrt_calib_leaf_cmd {
+	XRT_CALIB_RESULT = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
+};
+
+#endif	/* _XRT_DDR_CALIBRATION_H_ */
diff --git a/drivers/fpga/xrt/lib/xleaf/ddr_calibration.c b/drivers/fpga/xrt/lib/xleaf/ddr_calibration.c
new file mode 100644
index 000000000000..5a9fa82946cb
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/ddr_calibration.c
@@ -0,0 +1,226 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Xilinx Alveo FPGA memory calibration driver
+ *
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * memory calibration
+ *
+ * Authors:
+ *      Lizhi Hou<Lizhi.Hou@xxxxxxxxxx>
+ */
+#include <linux/delay.h>
+#include <linux/regmap.h>
+#include "xclbin-helper.h"
+#include "metadata.h"
+#include "xleaf/ddr_calibration.h"
+
+#define XRT_CALIB	"xrt_calib"
+
+#define XRT_CALIB_STATUS_REG		0
+#define XRT_CALIB_READ_RETRIES		20
+#define XRT_CALIB_READ_INTERVAL		500 /* ms */
+
+static const struct regmap_config calib_regmap_config = {
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.max_register = 0x1000,
+};
+
+struct calib_cache {
+	struct list_head	link;
+	const char		*ep_name;
+	char			*data;
+	u32			data_size;
+};
+
+struct calib {
+	struct platform_device	*pdev;
+	struct regmap		*regmap;
+	struct mutex		lock; /* calibration dev lock */
+	struct list_head	cache_list;
+	u32			cache_num;
+	enum xrt_calib_results	result;
+};
+
+static void __calib_cache_clean_nolock(struct calib *calib)
+{
+	struct calib_cache *cache, *temp;
+
+	list_for_each_entry_safe(cache, temp, &calib->cache_list, link) {
+		vfree(cache->data);
+		list_del(&cache->link);
+		vfree(cache);
+	}
+	calib->cache_num = 0;
+}
+
+static void calib_cache_clean(struct calib *calib)
+{
+	mutex_lock(&calib->lock);
+	__calib_cache_clean_nolock(calib);
+	mutex_unlock(&calib->lock);
+}
+
+static int calib_calibration(struct calib *calib)
+{
+	u32 times = XRT_CALIB_READ_RETRIES;
+	u32 status;
+	int ret;
+
+	while (times != 0) {
+		ret = regmap_read(calib->regmap, XRT_CALIB_STATUS_REG, &status);
+		if (ret) {
+			xrt_err(calib->pdev, "failed to read status reg %d", ret);
+			return ret;
+		}
+
+		if (status & BIT(0))
+			break;
+		msleep(XRT_CALIB_READ_INTERVAL);
+		times--;
+	}
+
+	if (!times) {
+		xrt_err(calib->pdev,
+			"MIG calibration timeout after bitstream download");
+		return -ETIMEDOUT;
+	}
+
+	xrt_info(calib->pdev, "took %dms", (XRT_CALIB_READ_RETRIES - times) *
+		 XRT_CALIB_READ_INTERVAL);
+	return 0;
+}
+
+static void xrt_calib_event_cb(struct platform_device *pdev, void *arg)
+{
+	struct calib *calib = platform_get_drvdata(pdev);
+	struct xrt_event *evt = (struct xrt_event *)arg;
+	enum xrt_events e = evt->xe_evt;
+	enum xrt_subdev_id id;
+	int ret;
+
+	id = evt->xe_subdev.xevt_subdev_id;
+
+	switch (e) {
+	case XRT_EVENT_POST_CREATION:
+		if (id == XRT_SUBDEV_UCS) {
+			ret = calib_calibration(calib);
+			if (ret)
+				calib->result = XRT_CALIB_FAILED;
+			else
+				calib->result = XRT_CALIB_SUCCEEDED;
+		}
+		break;
+	default:
+		xrt_dbg(pdev, "ignored event %d", e);
+		break;
+	}
+}
+
+static int xrt_calib_remove(struct platform_device *pdev)
+{
+	struct calib *calib = platform_get_drvdata(pdev);
+
+	calib_cache_clean(calib);
+
+	return 0;
+}
+
+static int xrt_calib_probe(struct platform_device *pdev)
+{
+	void __iomem *base = NULL;
+	struct resource *res;
+	struct calib *calib;
+	int err = 0;
+
+	calib = devm_kzalloc(&pdev->dev, sizeof(*calib), GFP_KERNEL);
+	if (!calib)
+		return -ENOMEM;
+
+	calib->pdev = pdev;
+	platform_set_drvdata(pdev, calib);
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		err = -EINVAL;
+		goto failed;
+	}
+
+	base = devm_ioremap_resource(&pdev->dev, res);
+	if (IS_ERR(base)) {
+		err = PTR_ERR(base);
+		goto failed;
+	}
+
+	calib->regmap = devm_regmap_init_mmio(&pdev->dev, base, &calib_regmap_config);
+	if (IS_ERR(calib->regmap)) {
+		xrt_err(pdev, "Map iomem failed");
+		err = PTR_ERR(calib->regmap);
+		goto failed;
+	}
+
+	mutex_init(&calib->lock);
+	INIT_LIST_HEAD(&calib->cache_list);
+
+	return 0;
+
+failed:
+	return err;
+}
+
+static int
+xrt_calib_leaf_call(struct platform_device *pdev, u32 cmd, void *arg)
+{
+	struct calib *calib = platform_get_drvdata(pdev);
+	int ret = 0;
+
+	switch (cmd) {
+	case XRT_XLEAF_EVENT:
+		xrt_calib_event_cb(pdev, arg);
+		break;
+	case XRT_CALIB_RESULT: {
+		enum xrt_calib_results *r = (enum xrt_calib_results *)arg;
+		*r = calib->result;
+		break;
+	}
+	default:
+		xrt_err(pdev, "unsupported cmd %d", cmd);
+		ret = -EINVAL;
+	}
+	return ret;
+}
+
+static struct xrt_subdev_endpoints xrt_calib_endpoints[] = {
+	{
+		.xse_names = (struct xrt_subdev_ep_names[]) {
+			{ .ep_name = XRT_MD_NODE_DDR_CALIB },
+			{ NULL },
+		},
+		.xse_min_ep = 1,
+	},
+	{ 0 },
+};
+
+static struct xrt_subdev_drvdata xrt_calib_data = {
+	.xsd_dev_ops = {
+		.xsd_leaf_call = xrt_calib_leaf_call,
+	},
+};
+
+static const struct platform_device_id xrt_calib_table[] = {
+	{ XRT_CALIB, (kernel_ulong_t)&xrt_calib_data },
+	{ },
+};
+
+static struct platform_driver xrt_calib_driver = {
+	.driver = {
+		.name = XRT_CALIB,
+	},
+	.probe = xrt_calib_probe,
+	.remove = xrt_calib_remove,
+	.id_table = xrt_calib_table,
+};
+
+XRT_LEAF_INIT_FINI_FUNC(XRT_SUBDEV_CALIB, calib);
-- 
2.27.0