Message-ID: <CANk1AXS-ON+Pcxtk-AY1XxH8Paw2aFBjiqhuCz7cA4cyuAQMUA@mail.gmail.com>
Date:   Thu, 1 Feb 2018 16:00:36 -0600
From:   Alan Tull <atull@...nel.org>
To:     Wu Hao <hao.wu@...el.com>
Cc:     Moritz Fischer <mdf@...nel.org>, linux-fpga@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        linux-api@...r.kernel.org, "Kang, Luwei" <luwei.kang@...el.com>,
        "Zhang, Yi Z" <yi.z.zhang@...el.com>,
        Tim Whisonant <tim.whisonant@...el.com>,
        Enno Luebbers <enno.luebbers@...el.com>,
        Shiva Rao <shiva.rao@...el.com>,
        Christopher Rauer <christopher.rauer@...el.com>,
        Xiao Guangrong <guangrong.xiao@...ux.intel.com>
Subject: Re: [PATCH v3 14/21] fpga: dfl: add fpga manager platform driver for FME

On Mon, Nov 27, 2017 at 12:42 AM, Wu Hao <hao.wu@...el.com> wrote:

Hi Hao,

A few comments below.   Besides that, looks good.

> This patch adds fpga manager driver for FPGA Management Engine (FME). It
> implements fpga_manager_ops for FPGA Partial Reconfiguration function.
>
> Signed-off-by: Tim Whisonant <tim.whisonant@...el.com>
> Signed-off-by: Enno Luebbers <enno.luebbers@...el.com>
> Signed-off-by: Shiva Rao <shiva.rao@...el.com>
> Signed-off-by: Christopher Rauer <christopher.rauer@...el.com>
> Signed-off-by: Kang Luwei <luwei.kang@...el.com>
> Signed-off-by: Xiao Guangrong <guangrong.xiao@...ux.intel.com>
> Signed-off-by: Wu Hao <hao.wu@...el.com>
> ----
> v3: rename driver to dfl-fpga-fme-mgr
>     implemented status callback for fpga manager
>     rebased due to fpga api changes
> ---
>  .../ABI/testing/sysfs-platform-fpga-dfl-fme-mgr    |   8 +
>  drivers/fpga/Kconfig                               |   6 +
>  drivers/fpga/Makefile                              |   1 +
>  drivers/fpga/fpga-dfl-fme-mgr.c                    | 318 +++++++++++++++++++++
>  drivers/fpga/fpga-dfl.h                            |  39 ++-
>  5 files changed, 371 insertions(+), 1 deletion(-)
>  create mode 100644 Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme-mgr
>  create mode 100644 drivers/fpga/fpga-dfl-fme-mgr.c
>
> diff --git a/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme-mgr b/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme-mgr
> new file mode 100644
> index 0000000..2d4f917
> --- /dev/null
> +++ b/Documentation/ABI/testing/sysfs-platform-fpga-dfl-fme-mgr
> @@ -0,0 +1,8 @@
> +What:          /sys/bus/platform/devices/fpga-dfl-fme-mgr.0/interface_id
> +Date:          November 2017
> +KernelVersion:  4.15
> +Contact:       Wu Hao <hao.wu@...el.com>
> +Description:   Read-only. It returns interface id of partial reconfiguration
> +               hardware. Userspace could use this information to check if
> +               current hardware is compatible with given image before FPGA
> +               programming.

I'm a little confused by this.  I can understand that the PR bitstream
has a dependency on the FPGA's static image, but I don't understand
the dependency of the bistream on the hardware that is used to program
the bitstream to the FPGA.

> diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
> index 57da904..0171ecb 100644
> --- a/drivers/fpga/Kconfig
> +++ b/drivers/fpga/Kconfig
> @@ -150,6 +150,12 @@ config FPGA_DFL_FME
>           FPGA platform level management features. There shall be 1 FME
>           per DFL based FPGA device.
>
> +config FPGA_DFL_FME_MGR
> +       tristate "FPGA DFL FME Manager Driver"
> +       depends on FPGA_DFL_FME
> +       help
> +         Say Y to enable FPGA Manager driver for FPGA Management Engine.
> +
>  config INTEL_FPGA_DFL_PCI
>         tristate "Intel FPGA DFL PCIe Device Driver"
>         depends on PCI && FPGA_DFL
> diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
> index cc75bb3..6378580 100644
> --- a/drivers/fpga/Makefile
> +++ b/drivers/fpga/Makefile
> @@ -31,6 +31,7 @@ obj-$(CONFIG_OF_FPGA_REGION)          += of-fpga-region.o
>  # FPGA Device Feature List Support
>  obj-$(CONFIG_FPGA_DFL)                 += fpga-dfl.o
>  obj-$(CONFIG_FPGA_DFL_FME)             += fpga-dfl-fme.o
> +obj-$(CONFIG_FPGA_DFL_FME_MGR)         += fpga-dfl-fme-mgr.o
>
>  fpga-dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
>
> diff --git a/drivers/fpga/fpga-dfl-fme-mgr.c b/drivers/fpga/fpga-dfl-fme-mgr.c
> new file mode 100644
> index 0000000..70356ce
> --- /dev/null
> +++ b/drivers/fpga/fpga-dfl-fme-mgr.c
> @@ -0,0 +1,318 @@
> +/*
> + * FPGA Manager Driver for FPGA Management Engine (FME)
> + *
> + * Copyright (C) 2017 Intel Corporation, Inc.
> + *
> + * Authors:
> + *   Kang Luwei <luwei.kang@...el.com>
> + *   Xiao Guangrong <guangrong.xiao@...ux.intel.com>
> + *   Wu Hao <hao.wu@...el.com>
> + *   Joseph Grecco <joe.grecco@...el.com>
> + *   Enno Luebbers <enno.luebbers@...el.com>
> + *   Tim Whisonant <tim.whisonant@...el.com>
> + *   Ananda Ravuri <ananda.ravuri@...el.com>
> + *   Christopher Rauer <christopher.rauer@...el.com>
> + *   Henry Mitchel <henry.mitchel@...el.com>
> + *
> + * This work is licensed under the terms of the GNU GPL version 2.
> + * SPDX-License-Identifier: GPL-2.0
> + */
> +
> +#include <linux/module.h>
> +#include <linux/iopoll.h>
> +#include <linux/fpga/fpga-mgr.h>
> +
> +#include "fpga-dfl.h"
> +#include "dfl-fme.h"
> +
> +#define PR_WAIT_TIMEOUT   8000000
> +#define PR_HOST_STATUS_IDLE    0
> +
> +struct fme_mgr_priv {
> +       void __iomem *ioaddr;
> +       u64 pr_error;
> +};
> +
> +static ssize_t interface_id_show(struct device *dev,
> +                                struct device_attribute *attr, char *buf)
> +{
> +       struct fpga_manager *mgr = dev_get_drvdata(dev);
> +       struct fme_mgr_priv *priv = mgr->priv;
> +       u64 intfc_id_l, intfc_id_h;
> +
> +       intfc_id_l = readq(priv->ioaddr + FME_PR_INTFC_ID_L);
> +       intfc_id_h = readq(priv->ioaddr + FME_PR_INTFC_ID_H);
> +
> +       return scnprintf(buf, PAGE_SIZE, "%016llx%016llx\n",
> +                       (unsigned long long)intfc_id_h,
> +                       (unsigned long long)intfc_id_l);
> +}
> +static DEVICE_ATTR_RO(interface_id);
> +
> +static const struct attribute *fme_mgr_attrs[] = {
> +       &dev_attr_interface_id.attr,
> +       NULL,
> +};
> +
> +static u64 pr_error_to_mgr_status(u64 err)
> +{
> +       u64 status = 0;
> +
> +       if (err & FME_PR_ERR_OPERATION_ERR)
> +               status |= FPGA_MGR_STATUS_OPERATION_ERR;
> +       if (err & FME_PR_ERR_CRC_ERR)
> +               status |= FPGA_MGR_STATUS_CRC_ERR;
> +       if (err & FME_PR_ERR_INCOMPATIBLE_BS)
> +               status |= FPGA_MGR_STATUS_INCOMPATIBLE_IMAGE_ERR;
> +       if (err & FME_PR_ERR_PROTOCOL_ERR)
> +               status |= FPGA_MGR_STATUS_IP_PROTOCOL_ERR;
> +       if (err & FME_PR_ERR_FIFO_OVERFLOW)
> +               status |= FPGA_MGR_STATUS_FIFO_OVERFLOW_ERR;
> +
> +       return status;
> +}
> +
> +static u64 fme_mgr_pr_error_handle(void __iomem *fme_pr)
> +{
> +       u64 pr_status, pr_error;
> +
> +       pr_status = readq(fme_pr + FME_PR_STS);
> +       if (!(pr_status & FME_PR_STS_PR_STS))
> +               return 0;
> +
> +       pr_error = readq(fme_pr + FME_PR_ERR);
> +       writeq(pr_error, fme_pr + FME_PR_ERR);
> +
> +       return pr_error;
> +}
> +
> +static int fme_mgr_write_init(struct fpga_manager *mgr,
> +                             struct fpga_image_info *info,
> +                             const char *buf, size_t count)
> +{
> +       struct device *dev = &mgr->dev;
> +       struct fme_mgr_priv *priv = mgr->priv;
> +       void __iomem *fme_pr = priv->ioaddr;
> +       u64 pr_ctrl, pr_status;
> +
> +       if (!(info->flags & FPGA_MGR_PARTIAL_RECONFIG)) {
> +               dev_err(dev, "only support partial reconfiguration.\n");

supports

> +               return -EINVAL;
> +       }
> +
> +       dev_dbg(dev, "resetting PR before initiated PR\n");
> +
> +       pr_ctrl = readq(fme_pr + FME_PR_CTRL);
> +       pr_ctrl |= FME_PR_CTRL_PR_RST;
> +       writeq(pr_ctrl, fme_pr + FME_PR_CTRL);
> +
> +       if (readq_poll_timeout(fme_pr + FME_PR_CTRL, pr_ctrl,
> +                              pr_ctrl & FME_PR_CTRL_PR_RSTACK, 1,
> +                              PR_WAIT_TIMEOUT)) {
> +               dev_err(dev, "maximum PR timeout\n");

We have two dev_err's with the same "maximum PR timeout" so the user
would not be able to see at which point the timeout occurred.

I suggest to get rid of the word 'maximum' for both.  This one could
be 'reset ack timeout" or something similar.

> +               return -ETIMEDOUT;
> +       }
> +
> +       pr_ctrl = readq(fme_pr + FME_PR_CTRL);
> +       pr_ctrl &= ~FME_PR_CTRL_PR_RST;
> +       writeq(pr_ctrl, fme_pr + FME_PR_CTRL);
> +
> +       dev_dbg(dev,
> +               "waiting for PR resource in HW to be initialized and ready\n");
> +
> +       if (readq_poll_timeout(fme_pr + FME_PR_STS, pr_status,
> +                              (pr_status & FME_PR_STS_PR_STS) ==
> +                              FME_PR_STS_PR_STS_IDLE, 1, PR_WAIT_TIMEOUT)) {
> +               dev_err(dev, "maximum PR timeout\n");

"PR_STS timeout"?  Or something better.

> +               priv->pr_error = fme_mgr_pr_error_handle(fme_pr);
> +               return -ETIMEDOUT;
> +       }
> +
> +       dev_dbg(dev, "check and clear previous PR error\n");
> +       priv->pr_error = fme_mgr_pr_error_handle(fme_pr);
> +       if (priv->pr_error)
> +               dev_dbg(dev, "previous PR error detected %llx\n",
> +                       (unsigned long long)priv->pr_error);
> +
> +       dev_dbg(dev, "set PR port ID\n");
> +
> +       pr_ctrl = readq(fme_pr + FME_PR_CTRL);
> +       pr_ctrl &= ~FME_PR_CTRL_PR_RGN_ID;
> +       pr_ctrl |= FIELD_PREP(FME_PR_CTRL_PR_RGN_ID, info->region_id);
> +       writeq(pr_ctrl, fme_pr + FME_PR_CTRL);
> +
> +       return 0;
> +}
> +
> +static int fme_mgr_write(struct fpga_manager *mgr,
> +                        const char *buf, size_t count)
> +{
> +       struct device *dev = &mgr->dev;
> +       struct fme_mgr_priv *priv = mgr->priv;
> +       void __iomem *fme_pr = priv->ioaddr;
> +       u64 pr_ctrl, pr_status, pr_data;
> +       int delay = 0, pr_credit, i = 0;
> +
> +       dev_dbg(dev, "start request\n");
> +
> +       pr_ctrl = readq(fme_pr + FME_PR_CTRL);
> +       pr_ctrl |= FME_PR_CTRL_PR_START;
> +       writeq(pr_ctrl, fme_pr + FME_PR_CTRL);
> +
> +       dev_dbg(dev, "pushing data from bitstream to HW\n");
> +
> +       pr_status = readq(fme_pr + FME_PR_STS);
> +       pr_credit = FIELD_GET(FME_PR_STS_PR_CREDIT, pr_status);
> +
> +       while (count > 0) {
> +               while (pr_credit <= 1) {
> +                       if (delay++ > PR_WAIT_TIMEOUT) {
> +                               dev_err(dev, "maximum try\n");

It looks like this is waiting for an entry in a queue and timing out
here.  Could you add a some comments for pr_credit above and this
loop?  Also a better error message, perhaps "PR credit timeout"?

> +                               return -ETIMEDOUT;
> +                       }
> +                       udelay(1);
> +
> +                       pr_status = readq(fme_pr + FME_PR_STS);
> +                       pr_credit = FIELD_GET(FME_PR_STS_PR_CREDIT, pr_status);
> +               }
> +
> +               if (count >= 4) {
> +                       pr_data = 0;
> +                       pr_data |= FIELD_PREP(FME_PR_DATA_PR_DATA_RAW,
> +                                             *(((u32 *)buf) + i));
> +                       writeq(pr_data, fme_pr + FME_PR_DATA);
> +                       count -= 4;
> +                       pr_credit--;
> +                       i++;
> +               } else {
> +                       WARN_ON(1);
> +                       return -EINVAL;
> +               }
> +       }
> +
> +       return 0;
> +}
> +
> +static int fme_mgr_write_complete(struct fpga_manager *mgr,
> +                                 struct fpga_image_info *info)
> +{
> +       struct device *dev = &mgr->dev;
> +       struct fme_mgr_priv *priv = mgr->priv;
> +       void __iomem *fme_pr = priv->ioaddr;
> +       u64 pr_ctrl;
> +
> +       pr_ctrl = readq(fme_pr + FME_PR_CTRL);
> +       pr_ctrl |= FME_PR_CTRL_PR_COMPLETE;
> +       writeq(pr_ctrl, fme_pr + FME_PR_CTRL);
> +
> +       dev_dbg(dev, "green bitstream push complete\n");
> +       dev_dbg(dev, "waiting for HW to release PR resource\n");
> +
> +       if (readq_poll_timeout(fme_pr + FME_PR_CTRL, pr_ctrl,
> +                              !(pr_ctrl & FME_PR_CTRL_PR_START), 1,
> +                              PR_WAIT_TIMEOUT)) {
> +               dev_err(dev, "maximum try.\n");

Some message specific to here also, please.

> +               return -ETIMEDOUT;
> +       }
> +
> +       dev_dbg(dev, "PR operation complete, checking status\n");
> +       priv->pr_error = fme_mgr_pr_error_handle(fme_pr);
> +       if (priv->pr_error) {
> +               dev_dbg(dev, "PR error detected %llx\n",
> +                       (unsigned long long)priv->pr_error);
> +               return -EIO;
> +       }
> +
> +       dev_dbg(dev, "PR done successfully\n");
> +
> +       return 0;
> +}
> +
> +static enum fpga_mgr_states fme_mgr_state(struct fpga_manager *mgr)
> +{
> +       return FPGA_MGR_STATE_UNKNOWN;
> +}
> +
> +static u64 fme_mgr_status(struct fpga_manager *mgr)
> +{
> +       struct fme_mgr_priv *priv = mgr->priv;
> +
> +       return pr_error_to_mgr_status(priv->pr_error);
> +}
> +
> +static const struct fpga_manager_ops fme_mgr_ops = {
> +       .write_init = fme_mgr_write_init,
> +       .write = fme_mgr_write,
> +       .write_complete = fme_mgr_write_complete,
> +       .state = fme_mgr_state,
> +       .status = fme_mgr_status,
> +};
> +
> +static int fme_mgr_probe(struct platform_device *pdev)
> +{
> +       struct device *dev = &pdev->dev;
> +       struct fme_mgr_priv *priv;
> +       struct fpga_manager *mgr;
> +       struct resource *res;
> +       int ret;
> +
> +       priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> +       if (!priv)
> +               return -ENOMEM;
> +
> +       res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +       priv->ioaddr = devm_ioremap(dev, res->start, resource_size(res));
> +       if (IS_ERR(priv->ioaddr))
> +               return PTR_ERR(priv->ioaddr);
> +
> +       ret = sysfs_create_files(&pdev->dev.kobj, fme_mgr_attrs);
> +       if (ret)
> +               return ret;
> +
> +       mgr = devm_kzalloc(dev, sizeof(*mgr), GFP_KERNEL);
> +       if (!mgr)
> +               goto sysfs_remove_exit;
> +
> +       mgr->name = "DFL FPGA Manager";
> +       mgr->mops = &fme_mgr_ops;
> +       mgr->priv = priv;
> +       mgr->parent = dev;
> +       platform_set_drvdata(pdev, mgr);
> +
> +       ret = fpga_mgr_register(mgr);
> +       if (ret) {
> +               dev_err(dev, "unable to register FPGA manager\n");
> +               goto sysfs_remove_exit;
> +       }
> +
> +       return 0;
> +
> +sysfs_remove_exit:
> +       sysfs_remove_files(&pdev->dev.kobj, fme_mgr_attrs);
> +       return ret;
> +}
> +
> +static int fme_mgr_remove(struct platform_device *pdev)
> +{
> +       struct fpga_manager *mgr = platform_get_drvdata(pdev);
> +
> +       fpga_mgr_unregister(mgr);
> +       sysfs_remove_files(&pdev->dev.kobj, fme_mgr_attrs);
> +
> +       return 0;
> +}
> +
> +static struct platform_driver fme_mgr_driver = {
> +       .driver = {
> +               .name    = FPGA_DFL_FME_MGR,
> +       },
> +       .probe   = fme_mgr_probe,
> +       .remove  = fme_mgr_remove,
> +};
> +
> +module_platform_driver(fme_mgr_driver);
> +
> +MODULE_DESCRIPTION("FPGA Manager for FPGA Management Engine");
> +MODULE_AUTHOR("Intel Corporation");
> +MODULE_LICENSE("GPL v2");
> +MODULE_ALIAS("platform:fpga-dfl-fme-mgr");
> diff --git a/drivers/fpga/fpga-dfl.h b/drivers/fpga/fpga-dfl.h
> index e5a1094..d45eb82 100644
> --- a/drivers/fpga/fpga-dfl.h
> +++ b/drivers/fpga/fpga-dfl.h
> @@ -130,7 +130,44 @@
>
>  /* FME Partial Reconfiguration Sub Feature Register Set */
>  #define FME_PR_DFH             DFH
> -#define FME_PR_SIZE            DFH_SIZE
> +#define FME_PR_CTRL            0x8
> +#define FME_PR_STS             0x10
> +#define FME_PR_DATA            0x18
> +#define FME_PR_ERR             0x20
> +#define FME_PR_INTFC_ID_H      0xA8
> +#define FME_PR_INTFC_ID_L      0xB0
> +#define FME_PR_SIZE            0xB8
> +
> +/* FME PR Control Register Bitfield */
> +#define FME_PR_CTRL_PR_RST     BIT(0)  /* Reset PR engine */
> +#define FME_PR_CTRL_PR_RSTACK  BIT(4)  /* Ack for PR engine reset */
> +#define FME_PR_CTRL_PR_RGN_ID  GENMASK_ULL(9, 7)       /* PR Region ID */
> +#define FME_PR_CTRL_PR_START   BIT(12) /* Start to request for PR service */
> +#define FME_PR_CTRL_PR_COMPLETE        BIT(13) /* PR data push complete notification */
> +
> +/* FME PR Status Register Bitfield */
> +/* Number of available entries in HW queue inside the PR engine. */
> +#define FME_PR_STS_PR_CREDIT   GENMASK_ULL(8, 0)
> +#define FME_PR_STS_PR_STS      BIT(16) /* PR operation status */
> +#define FME_PR_STS_PR_STS_IDLE 0
> +#define FME_PR_STS_PR_CTRLR_STS        GENMASK_ULL(22, 20)     /* Controller status */
> +#define FME_PR_STS_PR_HOST_STS GENMASK_ULL(27, 24)     /* PR host status */
> +
> +/* FME PR Data Register Bitfield */
> +/* PR data from the raw-binary file. */
> +#define FME_PR_DATA_PR_DATA_RAW        GENMASK_ULL(32, 0)
> +
> +/* FME PR Error Register */
> +/* Previous PR Operation errors detected. */
> +#define FME_PR_ERR_OPERATION_ERR       BIT(0)
> +/* CRC error detected. */
> +#define FME_PR_ERR_CRC_ERR             BIT(1)
> +/* Incompatible PR bitstream detected. */
> +#define FME_PR_ERR_INCOMPATIBLE_BS     BIT(2)
> +/* PR data push protocol violated. */
> +#define FME_PR_ERR_PROTOCOL_ERR                BIT(3)
> +/* PR data fifo overflow error detected */
> +#define FME_PR_ERR_FIFO_OVERFLOW       BIT(4)
>
>  /* FME HSSI Sub Feature Register Set */
>  #define FME_HSSI_DFH           DFH

I see fpga-dfl.h as enumeration code which is separate from any driver
implementation specifics other than what's required for the DFL
enumeration scheme.    These PR engine #defines should move to a .h
that is dedicated to this specific PR hardware device. If someone else
adds a different PR device to the framework, their PR driver would
also have its own .h.  Same for any other modules that aren't central
to DFL enumeration.

Thanks,
Alan

> --
> 1.8.3.1
>

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