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Subject: Re: [PATCH V4 XRT Alveo 05/20] fpga: xrt: group platform driver
To:     Tom Rix <trix@redhat.com>, Lizhi Hou <lizhi.hou@xilinx.com>,
        <linux-kernel@vger.kernel.org>, Max Zhen <max.zhen@xilinx.com>
CC:     <linux-fpga@vger.kernel.org>, <sonal.santan@xilinx.com>,
        <yliu@xilinx.com>, <michal.simek@xilinx.com>,
        <stefanos@xilinx.com>, <devicetree@vger.kernel.org>,
        <mdf@kernel.org>, <robh@kernel.org>
References: <20210324052947.27889-1-lizhi.hou@xilinx.com>
 <20210324052947.27889-6-lizhi.hou@xilinx.com>
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From:   Max Zhen <max.zhen@xilinx.com>
Message-ID: <d69f6b53-31dc-a749-a1f5-b198561db860@xilinx.com>
Date:   Tue, 6 Apr 2021 14:42:42 -0700
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Hi Tom,


On 3/30/21 5:52 AM, Tom Rix wrote:
> On 3/23/21 10:29 PM, Lizhi Hou wrote:
>> group driver that manages life cycle of a bunch of leaf driver instances
>> and bridges them with root.
>>
>> 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>
>> ---
>>   drivers/fpga/xrt/include/group.h |  25 +++
>>   drivers/fpga/xrt/lib/group.c     | 286 +++++++++++++++++++++++++++++++
>>   2 files changed, 311 insertions(+)
>>   create mode 100644 drivers/fpga/xrt/include/group.h
>>   create mode 100644 drivers/fpga/xrt/lib/group.c
>>
>> diff --git a/drivers/fpga/xrt/include/group.h b/drivers/fpga/xrt/include/group.h
>> new file mode 100644
>> index 000000000000..09e9d03f53fe
>> --- /dev/null
>> +++ b/drivers/fpga/xrt/include/group.h
>> @@ -0,0 +1,25 @@
>> +/* SPDX-License-Identifier: GPL-2.0 */
>> +/*
>> + * Copyright (C) 2020-2021 Xilinx, Inc.
>> + *
> ok, removed generic boilerplate
>> + * Authors:
>> + *   Cheng Zhen <maxz@xilinx.com>
>> + */
>> +
>> +#ifndef _XRT_GROUP_H_
>> +#define _XRT_GROUP_H_
>> +
>> +#include "xleaf.h"
> move header to another patch


Yes, the header is moved to 04/20 patch.


>> +
>> +/*
>> + * Group driver leaf calls.
> ok
>> + */
>> +enum xrt_group_leaf_cmd {
>> +     XRT_GROUP_GET_LEAF = XRT_XLEAF_CUSTOM_BASE, /* See comments in xleaf.h */
> ok
>> +     XRT_GROUP_PUT_LEAF,
>> +     XRT_GROUP_INIT_CHILDREN,
>> +     XRT_GROUP_FINI_CHILDREN,
>> +     XRT_GROUP_TRIGGER_EVENT,
>> +};
>> +
>> +#endif       /* _XRT_GROUP_H_ */
>> diff --git a/drivers/fpga/xrt/lib/group.c b/drivers/fpga/xrt/lib/group.c
>> new file mode 100644
>> index 000000000000..7b8716569641
>> --- /dev/null
>> +++ b/drivers/fpga/xrt/lib/group.c
>> @@ -0,0 +1,286 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Xilinx Alveo FPGA Group Driver
>> + *
>> + * Copyright (C) 2020-2021 Xilinx, Inc.
>> + *
>> + * Authors:
>> + *   Cheng Zhen <maxz@xilinx.com>
>> + */
>> +
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/platform_device.h>
>> +#include "xleaf.h"
>> +#include "subdev_pool.h"
>> +#include "group.h"
>> +#include "metadata.h"
>> +#include "lib-drv.h"
>> +
>> +#define XRT_GRP "xrt_group"
>> +
>> +struct xrt_group {
>> +     struct platform_device *pdev;
>> +     struct xrt_subdev_pool leaves;
>> +     bool leaves_created;
>> +     struct mutex lock; /* lock for group */
>> +};
>> +
>> +static int xrt_grp_root_cb(struct device *dev, void *parg,
>> +                        enum xrt_root_cmd cmd, void *arg)
> ok
>> +{
>> +     int rc;
>> +     struct platform_device *pdev =
>> +             container_of(dev, struct platform_device, dev);
>> +     struct xrt_group *xg = (struct xrt_group *)parg;
>> +
>> +     switch (cmd) {
>> +     case XRT_ROOT_GET_LEAF_HOLDERS: {
>> +             struct xrt_root_get_holders *holders =
>> +                     (struct xrt_root_get_holders *)arg;
>> +             rc = xrt_subdev_pool_get_holders(&xg->leaves,
>> +                                              holders->xpigh_pdev,
>> +                                              holders->xpigh_holder_buf,
>> +                                              holders->xpigh_holder_buf_len);
>> +             break;
>> +     }
>> +     default:
>> +             /* Forward parent call to root. */
>> +             rc = xrt_subdev_root_request(pdev, cmd, arg);
>> +             break;
>> +     }
>> +
>> +     return rc;
>> +}
>> +
>> +/*
>> + * Cut subdev's dtb from group's dtb based on passed-in endpoint descriptor.
>> + * Return the subdev's dtb through dtbp, if found.
>> + */
>> +static int xrt_grp_cut_subdev_dtb(struct xrt_group *xg, struct xrt_subdev_endpoints *eps,
>> +                               char *grp_dtb, char **dtbp)
>> +{
>> +     int ret, i, ep_count = 0;
>> +     char *dtb = NULL;
>> +
>> +     ret = xrt_md_create(DEV(xg->pdev), &dtb);
>> +     if (ret)
>> +             return ret;
>> +
>> +     for (i = 0; eps->xse_names[i].ep_name || eps->xse_names[i].regmap_name; i++) {
>> +             const char *ep_name = eps->xse_names[i].ep_name;
>> +             const char *reg_name = eps->xse_names[i].regmap_name;
>> +
>> +             if (!ep_name)
>> +                     xrt_md_get_compatible_endpoint(DEV(xg->pdev), grp_dtb, reg_name, &ep_name);
>> +             if (!ep_name)
>> +                     continue;
>> +
>> +             ret = xrt_md_copy_endpoint(DEV(xg->pdev), dtb, grp_dtb, ep_name, reg_name, NULL);
>> +             if (ret)
>> +                     continue;
>> +             xrt_md_del_endpoint(DEV(xg->pdev), grp_dtb, ep_name, reg_name);
>> +             ep_count++;
>> +     }
>> +     /* Found enough endpoints, return the subdev's dtb. */
>> +     if (ep_count >= eps->xse_min_ep) {
>> +             *dtbp = dtb;
>> +             return 0;
>> +     }
>> +
>> +     /* Cleanup - Restore all endpoints that has been deleted, if any. */
>> +     if (ep_count > 0) {
>> +             xrt_md_copy_endpoint(DEV(xg->pdev), grp_dtb, dtb,
>> +                                  XRT_MD_NODE_ENDPOINTS, NULL, NULL);
>> +     }
>> +     vfree(dtb);
>> +     *dtbp = NULL;
>> +     return 0;
>> +}
>> +
>> +static int xrt_grp_create_leaves(struct xrt_group *xg)
>> +{
>> +     struct xrt_subdev_platdata *pdata = DEV_PDATA(xg->pdev);
>> +     struct xrt_subdev_endpoints *eps = NULL;
>> +     int ret = 0, failed = 0;
>> +     enum xrt_subdev_id did;
>> +     char *grp_dtb = NULL;
>> +     unsigned long mlen;
>> +
>> +     if (!pdata)
>> +             return -EINVAL;
> ok
>> +
>> +     mlen = xrt_md_size(DEV(xg->pdev), pdata->xsp_dtb);
>> +     if (mlen == XRT_MD_INVALID_LENGTH) {
>> +             xrt_err(xg->pdev, "invalid dtb, len %ld", mlen);
>> +             return -EINVAL;
>> +     }
>> +
>> +     mutex_lock(&xg->lock);
>> +
>> +     if (xg->leaves_created) {
>> +             mutex_unlock(&xg->lock);
> add a comment that this is not an error and/or error is handled elsewhere


Will do.


>> +             return -EEXIST;
>> +     }
>> +
>> +     grp_dtb = vmalloc(mlen);
>> +     if (!grp_dtb) {
>> +             mutex_unlock(&xg->lock);
>> +             return -ENOMEM;
> ok
>> +     }
>> +
>> +     /* Create all leaves based on dtb. */
>> +     xrt_info(xg->pdev, "bringing up leaves...");
>> +     memcpy(grp_dtb, pdata->xsp_dtb, mlen);
>> +     for (did = 0; did < XRT_SUBDEV_NUM; did++) {
> ok
>> +             eps = xrt_drv_get_endpoints(did);
>> +             while (eps && eps->xse_names) {
>> +                     char *dtb = NULL;
>> +
>> +                     ret = xrt_grp_cut_subdev_dtb(xg, eps, grp_dtb, &dtb);
>> +                     if (ret) {
>> +                             failed++;
>> +                             xrt_err(xg->pdev, "failed to cut subdev dtb for drv %s: %d",
>> +                                     xrt_drv_name(did), ret);
>> +                     }
>> +                     if (!dtb) {
>> +                             /*
>> +                              * No more dtb to cut or bad things happened for this instance,
>> +                              * switch to the next one.
>> +                              */
>> +                             eps++;
>> +                             continue;
>> +                     }
>> +
>> +                     /* Found a dtb for this instance, let's add it. */
>> +                     ret = xrt_subdev_pool_add(&xg->leaves, did, xrt_grp_root_cb, xg, dtb);
>> +                     if (ret < 0) {
>> +                             failed++;
>> +                             xrt_err(xg->pdev, "failed to add %s: %d", xrt_drv_name(did), ret);
> add a comment that this is not a fatal error and cleanup happens elsewhere


Will do.


Thanks,

Max


>
> Tom
>
>> +                     }
>> +                     vfree(dtb);
>> +                     /* Continue searching for the same instance from grp_dtb. */
>> +             }
>> +     }
>> +
>> +     xg->leaves_created = true;
>> +     vfree(grp_dtb);
>> +     mutex_unlock(&xg->lock);
>> +     return failed == 0 ? 0 : -ECHILD;
>> +}
>> +
>> +static void xrt_grp_remove_leaves(struct xrt_group *xg)
>> +{
>> +     mutex_lock(&xg->lock);
>> +
>> +     if (!xg->leaves_created) {
>> +             mutex_unlock(&xg->lock);
>> +             return;
>> +     }
>> +
>> +     xrt_info(xg->pdev, "tearing down leaves...");
>> +     xrt_subdev_pool_fini(&xg->leaves);
>> +     xg->leaves_created = false;
>> +
>> +     mutex_unlock(&xg->lock);
>> +}
>> +
>> +static int xrt_grp_probe(struct platform_device *pdev)
>> +{
>> +     struct xrt_group *xg;
>> +
>> +     xrt_info(pdev, "probing...");
>> +
>> +     xg = devm_kzalloc(&pdev->dev, sizeof(*xg), GFP_KERNEL);
>> +     if (!xg)
>> +             return -ENOMEM;
>> +
>> +     xg->pdev = pdev;
>> +     mutex_init(&xg->lock);
>> +     xrt_subdev_pool_init(DEV(pdev), &xg->leaves);
>> +     platform_set_drvdata(pdev, xg);
>> +
>> +     return 0;
>> +}
>> +
>> +static int xrt_grp_remove(struct platform_device *pdev)
>> +{
>> +     struct xrt_group *xg = platform_get_drvdata(pdev);
>> +
>> +     xrt_info(pdev, "leaving...");
>> +     xrt_grp_remove_leaves(xg);
>> +     return 0;
>> +}
>> +
>> +static int xrt_grp_leaf_call(struct platform_device *pdev, u32 cmd, void *arg)
>> +{
>> +     int rc = 0;
>> +     struct xrt_group *xg = platform_get_drvdata(pdev);
>> +
>> +     switch (cmd) {
>> +     case XRT_XLEAF_EVENT:
>> +             /* Simply forward to every child. */
>> +             xrt_subdev_pool_handle_event(&xg->leaves,
>> +                                          (struct xrt_event *)arg);
>> +             break;
>> +     case XRT_GROUP_GET_LEAF: {
>> +             struct xrt_root_get_leaf *get_leaf =
>> +                     (struct xrt_root_get_leaf *)arg;
>> +
>> +             rc = xrt_subdev_pool_get(&xg->leaves, get_leaf->xpigl_match_cb,
>> +                                      get_leaf->xpigl_match_arg,
>> +                                      DEV(get_leaf->xpigl_caller_pdev),
>> +                                      &get_leaf->xpigl_tgt_pdev);
>> +             break;
>> +     }
>> +     case XRT_GROUP_PUT_LEAF: {
>> +             struct xrt_root_put_leaf *put_leaf =
>> +                     (struct xrt_root_put_leaf *)arg;
>> +
>> +             rc = xrt_subdev_pool_put(&xg->leaves, put_leaf->xpipl_tgt_pdev,
>> +                                      DEV(put_leaf->xpipl_caller_pdev));
>> +             break;
>> +     }
>> +     case XRT_GROUP_INIT_CHILDREN:
>> +             rc = xrt_grp_create_leaves(xg);
>> +             break;
>> +     case XRT_GROUP_FINI_CHILDREN:
>> +             xrt_grp_remove_leaves(xg);
>> +             break;
>> +     case XRT_GROUP_TRIGGER_EVENT:
>> +             xrt_subdev_pool_trigger_event(&xg->leaves, (enum xrt_events)(uintptr_t)arg);
>> +             break;
>> +     default:
>> +             xrt_err(pdev, "unknown IOCTL cmd %d", cmd);
>> +             rc = -EINVAL;
>> +             break;
>> +     }
>> +     return rc;
>> +}
>> +
>> +static struct xrt_subdev_drvdata xrt_grp_data = {
>> +     .xsd_dev_ops = {
>> +             .xsd_leaf_call = xrt_grp_leaf_call,
>> +     },
>> +};
>> +
>> +static const struct platform_device_id xrt_grp_id_table[] = {
>> +     { XRT_GRP, (kernel_ulong_t)&xrt_grp_data },
>> +     { },
>> +};
>> +
>> +static struct platform_driver xrt_group_driver = {
>> +     .driver = {
>> +             .name    = XRT_GRP,
>> +     },
>> +     .probe   = xrt_grp_probe,
>> +     .remove  = xrt_grp_remove,
>> +     .id_table = xrt_grp_id_table,
>> +};
>> +
>> +void group_leaf_init_fini(bool init)
>> +{
>> +     if (init)
>> +             xleaf_register_driver(XRT_SUBDEV_GRP, &xrt_group_driver, NULL);
>> +     else
>> +             xleaf_unregister_driver(XRT_SUBDEV_GRP);
>> +}