Re: [PATCH V5 XRT Alveo 18/20] fpga: xrt: DDR calibration driver

Tom Rix
2021-05-04T14:11:31Z

On 4/27/21 1:54 PM, Lizhi Hou wrote:
> Add DDR calibration driver. DDR calibration is a hardware function
> discovered by walking firmware metadata. A xrt device node will
> be created for it. Hardware provides DDR calibration status through
> this function.
>
> Signed-off-by: Sonal Santan <sonal.santan@xilinx.com>
> Signed-off-by: Max Zhen <max.zhen@xilinx.com>
> Signed-off-by: Lizhi Hou <lizhi.hou@xilinx.com>

v4 was ok, please add my Reviewed-by line

Reviewed-by: Tom Rix <trix@redhat.com>

> ---
> .../fpga/xrt/include/xleaf/ddr_calibration.h | 28 +++
> drivers/fpga/xrt/lib/xleaf/ddr_calibration.c | 210 ++++++++++++++++++
> 2 files changed, 238 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@xilinx.com>
> + */
> +
> +#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..36a0937c9195
> --- /dev/null
> +++ b/drivers/fpga/xrt/lib/xleaf/ddr_calibration.c
> @@ -0,0 +1,210 @@
> +// 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@xilinx.com>
> + */
> +#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 */
> +
> +XRT_DEFINE_REGMAP_CONFIG(calib_regmap_config);
> +
> +struct calib_cache {
> + struct list_head link;
> + const char *ep_name;
> + char *data;
> + u32 data_size;
> +};
> +
> +struct calib {
> + struct xrt_device *xdev;
> + 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->xdev, "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->xdev,
> + "MIG calibration timeout after bitstream download");
> + return -ETIMEDOUT;
> + }
> +
> + xrt_info(calib->xdev, "took %dms", (XRT_CALIB_READ_RETRIES - times) *
> + XRT_CALIB_READ_INTERVAL);
> + return 0;
> +}
> +
> +static void xrt_calib_event_cb(struct xrt_device *xdev, void *arg)
> +{
> + struct calib *calib = xrt_get_drvdata(xdev);
> + 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(xdev, "ignored event %d", e);
> + break;
> + }
> +}
> +
> +static void xrt_calib_remove(struct xrt_device *xdev)
> +{
> + struct calib *calib = xrt_get_drvdata(xdev);
> +
> + calib_cache_clean(calib);
> +}
> +
> +static int xrt_calib_probe(struct xrt_device *xdev)
> +{
> + void __iomem *base = NULL;
> + struct resource *res;
> + struct calib *calib;
> + int err = 0;
> +
> + calib = devm_kzalloc(&xdev->dev, sizeof(*calib), GFP_KERNEL);
> + if (!calib)
> + return -ENOMEM;
> +
> + calib->xdev = xdev;
> + xrt_set_drvdata(xdev, calib);
> +
> + res = xrt_get_resource(xdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + err = -EINVAL;
> + goto failed;
> + }
> +
> + base = devm_ioremap_resource(&xdev->dev, res);
> + if (IS_ERR(base)) {
> + err = PTR_ERR(base);
> + goto failed;
> + }
> +
> + calib->regmap = devm_regmap_init_mmio(&xdev->dev, base, &calib_regmap_config);
> + if (IS_ERR(calib->regmap)) {
> + xrt_err(xdev, "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 xrt_device *xdev, u32 cmd, void *arg)
> +{
> + struct calib *calib = xrt_get_drvdata(xdev);
> + int ret = 0;
> +
> + switch (cmd) {
> + case XRT_XLEAF_EVENT:
> + xrt_calib_event_cb(xdev, arg);
> + break;
> + case XRT_CALIB_RESULT: {
> + enum xrt_calib_results *r = (enum xrt_calib_results *)arg;
> + *r = calib->result;
> + break;
> + }
> + default:
> + xrt_err(xdev, "unsupported cmd %d", cmd);
> + ret = -EINVAL;
> + }
> + return ret;
> +}
> +
> +static struct xrt_dev_endpoints xrt_calib_endpoints[] = {
> + {
> + .xse_names = (struct xrt_dev_ep_names[]) {
> + { .ep_name = XRT_MD_NODE_DDR_CALIB },
> + { NULL },
> + },
> + .xse_min_ep = 1,
> + },
> + { 0 },
> +};
> +
> +static struct xrt_driver xrt_calib_driver = {
> + .driver = {
> + .name = XRT_CALIB,
> + },
> + .subdev_id = XRT_SUBDEV_CALIB,
> + .endpoints = xrt_calib_endpoints,
> + .probe = xrt_calib_probe,
> + .remove = xrt_calib_remove,
> + .leaf_call = xrt_calib_leaf_call,
> +};
> +
> +XRT_LEAF_INIT_FINI_FUNC(calib);