[PATCH V3 XRT Alveo 16/18] 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 <lizhih@xxxxxxxxxx>
---
 drivers/fpga/xrt/include/xleaf/calib.h |  30 ++++
 drivers/fpga/xrt/lib/xleaf/calib.c     | 226 +++++++++++++++++++++++++
 2 files changed, 256 insertions(+)
 create mode 100644 drivers/fpga/xrt/include/xleaf/calib.h
 create mode 100644 drivers/fpga/xrt/lib/xleaf/calib.c

diff --git a/drivers/fpga/xrt/include/xleaf/calib.h b/drivers/fpga/xrt/include/xleaf/calib.h
new file mode 100644
index 000000000000..f8aba4594c58
--- /dev/null
+++ b/drivers/fpga/xrt/include/xleaf/calib.h
@@ -0,0 +1,30 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Header file for XRT DDR Calibration Leaf Driver
+ *
+ * Copyright (C) 2020-2021 Xilinx, Inc.
+ *
+ * Authors:
+ *	Cheng Zhen <maxz@xxxxxxxxxx>
+ */
+
+#ifndef _XRT_CALIB_H_
+#define _XRT_CALIB_H_
+
+#include "xleaf.h"
+#include <linux/xrt/xclbin.h>
+
+/*
+ * Memory calibration driver IOCTL calls.
+ */
+enum xrt_calib_results {
+	XRT_CALIB_UNKNOWN,
+	XRT_CALIB_SUCCEEDED,
+	XRT_CALIB_FAILED,
+};
+
+enum xrt_calib_ioctl_cmd {
+	XRT_CALIB_RESULT = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
+};
+
+#endif	/* _XRT_CALIB_H_ */
diff --git a/drivers/fpga/xrt/lib/xleaf/calib.c b/drivers/fpga/xrt/lib/xleaf/calib.c
new file mode 100644
index 000000000000..fbb813636e76
--- /dev/null
+++ b/drivers/fpga/xrt/lib/xleaf/calib.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 "xclbin-helper.h"
+#include "metadata.h"
+#include "xleaf/calib.h"
+
+#define XRT_CALIB	"xrt_calib"
+
+struct calib_cache {
+	struct list_head	link;
+	const char		*ep_name;
+	char			*data;
+	u32			data_size;
+};
+
+struct calib {
+	struct platform_device	*pdev;
+	void			*calib_base;
+	struct mutex		lock; /* calibration dev lock */
+	struct list_head	cache_list;
+	u32			cache_num;
+	enum xrt_calib_results	result;
+};
+
+#define CALIB_DONE(calib)			\
+	(ioread32((calib)->calib_base) & BIT(0))
+
+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_srsr(struct calib *calib, struct platform_device *srsr_leaf)
+{
+	return -EOPNOTSUPP;
+}
+
+static int calib_calibration(struct calib *calib)
+{
+	int i;
+
+	for (i = 0; i < 20; i++) {
+		if (CALIB_DONE(calib))
+			break;
+		msleep(500);
+	}
+
+	if (i == 20) {
+		xrt_err(calib->pdev,
+			"MIG calibration timeout after bitstream download");
+		return -ETIMEDOUT;
+	}
+
+	xrt_info(calib->pdev, "took %dms", i * 500);
+	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 = evt->xe_subdev.xevt_subdev_id;
+	int instance = evt->xe_subdev.xevt_subdev_instance;
+	struct platform_device *leaf;
+	int ret;
+
+	switch (e) {
+	case XRT_EVENT_POST_CREATION: {
+		if (id == XRT_SUBDEV_SRSR) {
+			leaf = xleaf_get_leaf_by_id(pdev,
+						    XRT_SUBDEV_SRSR,
+						    instance);
+			if (!leaf) {
+				xrt_err(pdev, "does not get SRSR subdev");
+				return;
+			}
+			ret = calib_srsr(calib, leaf);
+			xleaf_put_leaf(pdev, leaf);
+			calib->result =
+				ret ? XRT_CALIB_FAILED : XRT_CALIB_SUCCEEDED;
+		} else if (id == XRT_SUBDEV_UCS) {
+			ret = calib_calibration(calib);
+			calib->result =
+				ret ? XRT_CALIB_FAILED : XRT_CALIB_SUCCEEDED;
+		}
+		break;
+	}
+	default:
+		break;
+	}
+}
+
+static int xrt_calib_remove(struct platform_device *pdev)
+{
+	struct calib *calib = platform_get_drvdata(pdev);
+
+	calib_cache_clean(calib);
+
+	if (calib->calib_base)
+		iounmap(calib->calib_base);
+
+	platform_set_drvdata(pdev, NULL);
+	devm_kfree(&pdev->dev, calib);
+
+	return 0;
+}
+
+static int xrt_calib_probe(struct platform_device *pdev)
+{
+	struct calib *calib;
+	struct resource *res;
+	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)
+		goto failed;
+
+	calib->calib_base = ioremap(res->start, res->end - res->start + 1);
+	if (!calib->calib_base) {
+		err = -EIO;
+		xrt_err(pdev, "Map iomem failed");
+		goto failed;
+	}
+
+	mutex_init(&calib->lock);
+	INIT_LIST_HEAD(&calib->cache_list);
+
+	return 0;
+
+failed:
+	xrt_calib_remove(pdev);
+	return err;
+}
+
+static int
+xrt_calib_leaf_ioctl(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_ioctl = xrt_calib_leaf_ioctl,
+	},
+};
+
+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,
+};
+
+void calib_leaf_init_fini(bool init)
+{
+	if (init)
+		xleaf_register_driver(XRT_SUBDEV_CALIB, &xrt_calib_driver, xrt_calib_endpoints);
+	else
+		xleaf_unregister_driver(XRT_SUBDEV_CALIB);
+}
-- 
2.18.4