Date:   Mon, 6 May 2019 15:20:13 +0530
From:   Yash Shah <yash.shah@...ive.com>
To:     James Morse <james.morse@....com>
Cc:     linux-edac@...r.kernel.org, linux-riscv@...ts.infradead.org,
        Palmer Dabbelt <palmer@...ive.com>,
        Borislav Petkov <bp@...en8.de>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        linux-kernel@...r.kernel.org, aou@...s.berkeley.edu,
        mchehab@...nel.org, Sachin Ghadi <sachin.ghadi@...ive.com>,
        davem@...emloft.net, gregkh@...uxfoundation.org,
        nicolas.ferre@...rochip.com, paulmck@...ux.ibm.com
Subject: Re: [PATCH] edac: sifive: Add EDAC platform driver for SiFive SoCs

Hi james,

On Thu, May 2, 2019 at 10:12 PM James Morse <james.morse@....com> wrote:
>
> Hi Yash,
>
> Sorry for the delay on the earlier version of this - I was trying to work out what happens
> when multiple edac drivers probe based on DT...
>
>
> On 02/05/2019 12:16, Yash Shah wrote:
> > The initial ver of EDAC driver supports:
> > - ECC event monitoring and reporting through the EDAC framework for SiFive
> >   L2 cache controller.
> >
>
> You probably don't want this bit preserved in the kernel log:
> {
>
> > This patch depends on patch
> > 'RISC-V: sifive_l2_cache: Add L2 cache controller driver for SiFive SoCs'
> > https://lkml.org/lkml/2019/5/2/309
>
> }
>
> > The EDAC driver registers for notifier events from the L2 cache controller
> > driver (arch/riscv/mm/sifive_l2_cache.c) for L2 ECC events
> >
> > Signed-off-by: Yash Shah <yash.shah@...ive.com>
> > ---
>
> (if you put it here, it gets discarded when the patch is applied)

Ok, will move it down here.

>
> Having an separately posted dependency like this is tricky, as this code can't be
> used/tested until the other bits are merged.
>
>
> >  MAINTAINERS                |   6 +++
> >  arch/riscv/Kconfig         |   1 +
> >  drivers/edac/Kconfig       |   6 +++
> >  drivers/edac/Makefile      |   1 +
> >  drivers/edac/sifive_edac.c | 121 +++++++++++++++++++++++++++++++++++++++++++++
> >  5 files changed, 135 insertions(+)
> >  create mode 100644 drivers/edac/sifive_edac.c
>
> > diff --git a/drivers/edac/sifive_edac.c b/drivers/edac/sifive_edac.c
> > new file mode 100644
> > index 0000000..eb7a9b9
> > --- /dev/null
> > +++ b/drivers/edac/sifive_edac.c
> > @@ -0,0 +1,121 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * SiFive Platform EDAC Driver
> > + *
> > + * Copyright (C) 2018-2019 SiFive, Inc.
> > + *
> > + * This driver is partially based on octeon_edac-pc.c
> > + *
> > + */
> > +#include <linux/edac.h>
> > +#include <linux/platform_device.h>
> > +#include "edac_module.h"
> > +
> > +#define DRVNAME "sifive_edac"
> > +
> > +extern int register_sifive_l2_error_notifier(struct notifier_block *nb);
> > +extern int unregister_sifive_l2_error_notifier(struct notifier_block *nb);
>
> Ideally these would live in some header file.

Will move the externs in sifive_l2_cache header file

>
>
> > +struct sifive_edac_priv {
> > +     struct notifier_block notifier;
> > +     struct edac_device_ctl_info *dci;
> > +};
> > +
> > +/**
> > + * EDAC error callback
> > + *
> > + * @event: non-zero if unrecoverable.
> > + */
> > +static
> > +int ecc_err_event(struct notifier_block *this, unsigned long event, void *ptr)
> > +{
> > +     const char *msg = (char *)ptr;
> > +     struct sifive_edac_priv *p;
> > +
> > +     p = container_of(this, struct sifive_edac_priv, notifier);
> > +
> > +     if (event)
> > +             edac_device_handle_ue(p->dci, 0, 0, msg);
> > +     else
> > +             edac_device_handle_ce(p->dci, 0, 0, msg);
>
> This would be easier to read if your SIFIVE_L2_ERR_TYPE_UE were exposed via some header file.

sure.

>
>
> > +
> > +     return NOTIFY_STOP;
>
> Your notifier register calls are EXPORT_SYMBOL()d, but Kconfig forbids building this as a
> module, so its not for this driver. If there is another user of this notifier-chain, won't
> NOTIFY_STOP here break it?
>

Yes, you are right. Will change it to NOTIFY_OK

>
> > +}
> > +
> > +static int ecc_register(struct platform_device *pdev)
> > +{
> > +     struct sifive_edac_priv *p;
> > +
> > +     p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL);
> > +     if (!p)
> > +             return -ENOMEM;
> > +
> > +     p->notifier.notifier_call = ecc_err_event;
> > +     platform_set_drvdata(pdev, p);
> > +
> > +     p->dci = edac_device_alloc_ctl_info(sizeof(*p), "sifive_ecc", 1,
>
> sizeof(*p) here is how much space in struct edac_device_ctl_info you need for private
> storage... but you never touch p->dci->pvt_info, so you aren't using it.
>
> 0?

Yes, will change it.

>
>
> > +                                         "sifive_ecc", 1, 1, NULL, 0,
> > +                                         edac_device_alloc_index());
> > +     if (IS_ERR(p->dci))
> > +             return PTR_ERR(p->dci);
> > +
> > +     p->dci->dev = &pdev->dev;
> > +     p->dci->mod_name = "Sifive ECC Manager";
> > +     p->dci->ctl_name = dev_name(&pdev->dev);
> > +     p->dci->dev_name = dev_name(&pdev->dev);
> > +
> > +     if (edac_device_add_device(p->dci)) {
> > +             dev_err(p->dci->dev, "failed to register with EDAC core\n");
> > +             goto err;
> > +     }
> > +
> > +     register_sifive_l2_error_notifier(&p->notifier);
> > +
> > +     return 0;
> > +
> > +err:
> > +     edac_device_free_ctl_info(p->dci);
> > +
> > +     return -ENXIO;
> > +}
>
> > +struct platform_device *sifive_pdev;
>
> static?

Yes, will change this too.

>
>
> > +static int __init sifive_edac_init(void)
> > +{
> > +     int ret;
> > +
> > +     sifive_pdev = platform_device_register_simple(DRVNAME, 0, NULL, 0);
> > +     if (IS_ERR(sifive_pdev))
> > +             return PTR_ERR(sifive_pdev);
> > +
> > +     ret = ecc_register(sifive_pdev);
> > +     if (ret)
> > +             platform_device_unregister(sifive_pdev);
> > +
> > +     return ret;
> > +}
> > +
> > +static void __exit sifive_edac_exit(void)
> > +{
> > +     ecc_unregister(sifive_pdev);
> > +     platform_device_unregister(sifive_pdev);
> > +}
>
> Looks good to me. I think this patch should go with its two dependencies, I'm not sure why
> it got split off...
>
> Reviewed-by: James Morse <james.morse@....com>
>

Thanks for your review.

- Yash

>
> Thanks,
>
> James

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