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From:   Alan Tull <atull@kernel.org>
Date:   Thu, 5 Apr 2018 13:45:07 -0500
Message-ID: <CANk1AXRbYZDyguNfdE+n6Y2CwJFgqzZmQ0x-PiAa+kjqUUrB6g@mail.gmail.com>
Subject: Re: [PATCH v4 16/24] fpga: dfl: add fpga manager platform driver for FME
To:     Wu Hao <hao.wu@intel.com>
Cc:     Moritz Fischer <mdf@kernel.org>, linux-fpga@vger.kernel.org,
        linux-kernel <linux-kernel@vger.kernel.org>,
        linux-api@vger.kernel.org, "Kang, Luwei" <luwei.kang@intel.com>,
        "Zhang, Yi Z" <yi.z.zhang@intel.com>,
        Tim Whisonant <tim.whisonant@intel.com>,
        Enno Luebbers <enno.luebbers@intel.com>,
        Shiva Rao <shiva.rao@intel.com>,
        Christopher Rauer <christopher.rauer@intel.com>,
        Xiao Guangrong <guangrong.xiao@linux.intel.com>
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Sender: linux-kernel-owner@vger.kernel.org
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On Thu, Mar 22, 2018 at 1:07 AM, Wu Hao <hao.wu@intel.com> wrote:
> On Wed, Mar 21, 2018 at 09:55:52AM -0700, Moritz Fischer wrote:
>> On Wed, Mar 21, 2018 at 10:50:01AM +0800, Wu Hao wrote:
>> > On Tue, Mar 20, 2018 at 03:32:34PM -0500, Alan Tull wrote:
>> > > On Tue, Feb 13, 2018 at 3:24 AM, Wu Hao <hao.wu@intel.com> wrote:
>> > >
>> > > Hi Hao,
>> > >
>> > > Elsewhere we discussed moving #defines used only in this driver either
>> > > to this .c file or to a similarly named .h file.  A couple minor
>> > > things below.
>> >
>> > Hi Alan,
>> >
>> > Yes, I will move those #defines into a similarly named .h file.
>> >
>> > >
>> > > > 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@intel.com>
>> > > > Signed-off-by: Enno Luebbers <enno.luebbers@intel.com>
>> > > > Signed-off-by: Shiva Rao <shiva.rao@intel.com>
>> > > > Signed-off-by: Christopher Rauer <christopher.rauer@intel.com>
>> > > > Signed-off-by: Kang Luwei <luwei.kang@intel.com>
>> > > > Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
>> > > > Signed-off-by: Wu Hao <hao.wu@intel.com>
>> > > > ---
>> > > > v3: rename driver to dfl-fpga-fme-mgr
>> > > >     implemented status callback for fpga manager
>> > > >     rebased due to fpga api changes
>> > > > v4: rename to dfl-fme-mgr, and fix SPDX license issue
>> > > >     add pr_credit comments and improve dev_err message
>> > > >     remove interface_id sysfs interface
>> > > >     include dfl-fme-pr.h instead of dfl.h
>> > > > ---
>> > > >  drivers/fpga/Kconfig       |   6 +
>> > > >  drivers/fpga/Makefile      |   1 +
>> > > >  drivers/fpga/dfl-fme-mgr.c | 290 +++++++++++++++++++++++++++++++++++++++++++++
>> > > >  3 files changed, 297 insertions(+)
>> > > >  create mode 100644 drivers/fpga/dfl-fme-mgr.c
>> > > >
>> > > > diff --git a/drivers/fpga/Kconfig b/drivers/fpga/Kconfig
>> > > > index 103d5e2..89f76e8 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 FPGA_DFL_PCI
>> > > >         tristate "FPGA Device Feature List (DFL) PCIe Device Driver"
>> > > >         depends on PCI && FPGA_DFL
>> > > > diff --git a/drivers/fpga/Makefile b/drivers/fpga/Makefile
>> > > > index 3c44fc9..f82814a 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)                 += dfl.o
>> > > >  obj-$(CONFIG_FPGA_DFL_FME)             += dfl-fme.o
>> > > > +obj-$(CONFIG_FPGA_DFL_FME_MGR)         += dfl-fme-mgr.o
>> > > >
>> > > >  dfl-fme-objs := dfl-fme-main.o dfl-fme-pr.o
>> > > >
>> > > > diff --git a/drivers/fpga/dfl-fme-mgr.c b/drivers/fpga/dfl-fme-mgr.c
>> > > > new file mode 100644
>> > > > index 0000000..2f92c29
>> > > > --- /dev/null
>> > > > +++ b/drivers/fpga/dfl-fme-mgr.c
>> > > > @@ -0,0 +1,290 @@
>> > > > +// SPDX-License-Identifier: GPL-2.0
>> > > > +/*
>> > > > + * FPGA Manager Driver for FPGA Management Engine (FME)
>> > > > + *
>> > > > + * Copyright (C) 2017 Intel Corporation, Inc.
>> > > > + *
>> > > > + * Authors:
>> > > > + *   Kang Luwei <luwei.kang@intel.com>
>> > > > + *   Xiao Guangrong <guangrong.xiao@linux.intel.com>
>> > > > + *   Wu Hao <hao.wu@intel.com>
>> > > > + *   Joseph Grecco <joe.grecco@intel.com>
>> > > > + *   Enno Luebbers <enno.luebbers@intel.com>
>> > > > + *   Tim Whisonant <tim.whisonant@intel.com>
>> > > > + *   Ananda Ravuri <ananda.ravuri@intel.com>
>> > > > + *   Christopher Rauer <christopher.rauer@intel.com>
>> > > > + *   Henry Mitchel <henry.mitchel@intel.com>
>> > > > + */
>> > > > +
>> > > > +#include <linux/bitfield.h>
>> > > > +#include <linux/module.h>
>> > > > +#include <linux/iopoll.h>
>> > > > +#include <linux/fpga/fpga-mgr.h>
>> > > > +
>> > > > +#include "dfl-fme-pr.h"
>> > > > +
>> > > > +#define PR_WAIT_TIMEOUT   8000000
>> > > > +#define PR_HOST_STATUS_IDLE    0
>> > > > +
>> > > > +struct fme_mgr_priv {
>> > > > +       void __iomem *ioaddr;
>> > > > +       u64 pr_error;
>> > > > +};
>> > > > +
>> > > > +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 supports partial reconfiguration.\n");
>> > > > +               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, "PR Reset ACK timeout\n");
>> > > > +               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, "PR Status timeout\n");
>> > > > +               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");
>> > > > +
>> > > > +       /*
>> > > > +        * driver can push data to PR hardware using PR_DATA register once HW
>> > > > +        * has enough pr_credit (> 1), pr_credit reduces one for every 32bit
>> > > > +        * pr data write to PR_DATA register. If pr_credit <= 1, driver needs
>> > > > +        * to wait for enough pr_credit from hardware by polling.
>> > > > +        */
>> > > > +       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, "PR_CREDIT timeout\n");
>> > > > +                               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;
>> > > > +               }

Where there's an if..else that has a 'return' on one of its branch, it
can become an 'if' without the 'else'.  This is strongly preferred in
the kernel.  Trying to avoid indention where possible.  So this
becomes

if (count < 4) {
        WARN_ON(1);
        return -EINVAL;
}

pr_data = 0;
so on...

Alan

>> > > > +       }
>> > > > +
>> > > > +       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, "PR Completion ACK timeout.\n");
>> > > > +               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));
>> > >
>> > > How about using devm_ioremap_resourc(dev, res) here instead?
>> >
>> > Actually the register region has already been mapped in lower level driver
>> > (e.g pci) so I think we don't have to map the second time here. I plan to
>> > add some code to pass the ioaddr via the platform data, and check if valid
>> > ioaddr from the platform data firstly in this probe function. If no pdata
>> > or no valid ioaddr, then go with devm_ioremap_resource. :)
>>
>> If you end up sharing register spaces between drivers is regmap / syscon
>> maybe a good idea?
>
> Hi Moritz,
>
> Thanks for the comments. I tried the regmap_mmio before but it failed to use
> regmap_read and regmap_write for register access. It requires to use writeq /
> readq for 64bit registers on the hardware, but regmap_read and regmap_write
> only accepts unsigned int value as input parameter. So I only replaced the
> bitfields struct/union with macro.
>
> Thanks
> Hao
>
>> >
>> > >
>> > > > +       if (IS_ERR(priv->ioaddr))
>> > > > +               return PTR_ERR(priv->ioaddr);
>> > > > +
>> > > > +       mgr = devm_kzalloc(dev, sizeof(*mgr), GFP_KERNEL);
>> > > > +       if (!mgr)
>> > > > +               return -ENOMEM;
>> > > > +
>> > > > +       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");
>> > > > +
>> > > > +       return ret;
>> > >
>> > > You can probably just do "return fpga_mgr_register(mgr);" here.
>> >
>> > Yes, it looks better, I will fix it. Thanks a lot for the review.
>> >
>> > Hao
>> >
>> > >
>> > > Thanks,
>> > > Alan
>> > >
>> > > > +}
>> > > > +
>> > > > +static int fme_mgr_remove(struct platform_device *pdev)
>> > > > +{
>> > > > +       struct fpga_manager *mgr = platform_get_drvdata(pdev);
>> > > > +
>> > > > +       fpga_mgr_unregister(mgr);
>> > > > +
>> > > > +       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 DFL FPGA Management Engine");
>> > > > +MODULE_AUTHOR("Intel Corporation");
>> > > > +MODULE_LICENSE("GPL v2");
>> > > > +MODULE_ALIAS("platform:dfl-fme-mgr");
>> > > > --
>> > > > 2.7.4
>> > > >
>>
>> Cheers,
>> Moritz
>> --
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