Re: [PATCH v10] vfio: platform: reset: Add Broadcom FlexRM reset module

[Alex Williamson <alex.williamson-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>]

On Wed, 25 Oct 2017 11:19:21 +0530
Anup Patel <anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> wrote:

> On Tue, Oct 3, 2017 at 10:57 AM, Anup Patel <anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org> wrote:
> > This patch adds Broadcom FlexRM low-level reset for
> > VFIO platform.
> >
> > It will do the following:
> > 1. Disable/Deactivate each FlexRM ring
> > 2. Flush each FlexRM ring
> >
> > The cleanup sequence for FlexRM rings is adapted from
> > Broadcom FlexRM mailbox driver.
> >
> > Signed-off-by: Anup Patel <anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> > Reviewed-by: Oza Oza <oza.oza-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> > Reviewed-by: Scott Branden <scott.branden-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>
> > Reviewed-by: Eric Auger <eric.auger-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> > ---
> >  drivers/vfio/platform/reset/Kconfig                |   9 ++
> >  drivers/vfio/platform/reset/Makefile               |   1 +
> >  .../vfio/platform/reset/vfio_platform_bcmflexrm.c  | 113 +++++++++++++++++++++
> >  3 files changed, 123 insertions(+)
> >  create mode 100644 drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> >
> > diff --git a/drivers/vfio/platform/reset/Kconfig b/drivers/vfio/platform/reset/Kconfig
> > index 70cccc5..392e3c0 100644
> > --- a/drivers/vfio/platform/reset/Kconfig
> > +++ b/drivers/vfio/platform/reset/Kconfig
> > @@ -13,3 +13,12 @@ config VFIO_PLATFORM_AMDXGBE_RESET
> >           Enables the VFIO platform driver to handle reset for AMD XGBE
> >
> >           If you don't know what to do here, say N.
> > +
> > +config VFIO_PLATFORM_BCMFLEXRM_RESET
> > +       tristate "VFIO support for Broadcom FlexRM reset"
> > +       depends on VFIO_PLATFORM && (ARCH_BCM_IPROC || COMPILE_TEST)
> > +       default ARCH_BCM_IPROC
> > +       help
> > +         Enables the VFIO platform driver to handle reset for Broadcom FlexRM
> > +
> > +         If you don't know what to do here, say N.
> > diff --git a/drivers/vfio/platform/reset/Makefile b/drivers/vfio/platform/reset/Makefile
> > index 93f4e23..8d9874b 100644
> > --- a/drivers/vfio/platform/reset/Makefile
> > +++ b/drivers/vfio/platform/reset/Makefile
> > @@ -5,3 +5,4 @@ ccflags-y += -Idrivers/vfio/platform
> >
> >  obj-$(CONFIG_VFIO_PLATFORM_CALXEDAXGMAC_RESET) += vfio-platform-calxedaxgmac.o
> >  obj-$(CONFIG_VFIO_PLATFORM_AMDXGBE_RESET) += vfio-platform-amdxgbe.o
> > +obj-$(CONFIG_VFIO_PLATFORM_BCMFLEXRM_RESET) += vfio_platform_bcmflexrm.o
> > diff --git a/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c b/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> > new file mode 100644
> > index 0000000..d45c3be
> > --- /dev/null
> > +++ b/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
> > @@ -0,0 +1,113 @@
> > +/*
> > + * Copyright (C) 2017 Broadcom
> > + *
> > + * This program is free software; you can redistribute it and/or
> > + * modify it under the terms of the GNU General Public License as
> > + * published by the Free Software Foundation version 2.
> > + *
> > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any
> > + * kind, whether express or implied; without even the implied warranty
> > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > + * GNU General Public License for more details.
> > + */
> > +
> > +/*
> > + * This driver provides reset support for Broadcom FlexRM ring manager
> > + * to VFIO platform.
> > + */
> > +
> > +#include <linux/delay.h>
> > +#include <linux/device.h>
> > +#include <linux/init.h>
> > +#include <linux/io.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +
> > +#include "vfio_platform_private.h"
> > +
> > +/* FlexRM configuration */
> > +#define RING_REGS_SIZE                                 0x10000
> > +#define RING_VER_MAGIC                                 0x76303031
> > +
> > +/* Per-Ring register offsets */
> > +#define RING_VER                                       0x000
> > +#define RING_CONTROL                                   0x034
> > +#define RING_FLUSH_DONE                                        0x038
> > +
> > +/* Register RING_CONTROL fields */
> > +#define CONTROL_FLUSH_SHIFT                            5
> > +
> > +/* Register RING_FLUSH_DONE fields */
> > +#define FLUSH_DONE_MASK                                        0x1
> > +
> > +static int vfio_platform_bcmflexrm_shutdown(void __iomem *ring)
> > +{
> > +       unsigned int timeout;
> > +
> > +       /* Disable/inactivate ring */
> > +       writel_relaxed(0x0, ring + RING_CONTROL);
> > +
> > +       /* Set ring flush state */
> > +       timeout = 1000; /* timeout of 1s */
> > +       writel_relaxed(BIT(CONTROL_FLUSH_SHIFT), ring + RING_CONTROL);
> > +       do {
> > +               if (readl_relaxed(ring + RING_FLUSH_DONE) &
> > +                   FLUSH_DONE_MASK)
> > +                       break;
> > +               mdelay(1);
> > +       } while (--timeout);
> > +       if (!timeout)
> > +               return -ETIMEDOUT;
> > +
> > +       /* Clear ring flush state */
> > +       timeout = 1000; /* timeout of 1s */
> > +       writel_relaxed(0x0, ring + RING_CONTROL);
> > +       do {
> > +               if (!(readl_relaxed(ring + RING_FLUSH_DONE) &
> > +                     FLUSH_DONE_MASK))
> > +                       break;
> > +               mdelay(1);
> > +       } while (--timeout);
> > +       if (!timeout)
> > +               return -ETIMEDOUT;
> > +
> > +       return 0;
> > +}
> > +
> > +static int vfio_platform_bcmflexrm_reset(struct vfio_platform_device *vdev)
> > +{
> > +       void __iomem *ring;
> > +       int rc = 0, ret = 0, ring_num = 0;
> > +       struct vfio_platform_region *reg = &vdev->regions[0];
> > +
> > +       /* Map FlexRM ring registers if not mapped */
> > +       if (!reg->ioaddr) {
> > +               reg->ioaddr = ioremap_nocache(reg->addr, reg->size);
> > +               if (!reg->ioaddr)
> > +                       return -ENOMEM;
> > +       }
> > +
> > +       /* Discover and shutdown each FlexRM ring */
> > +       for (ring = reg->ioaddr;
> > +            ring < (reg->ioaddr + reg->size); ring += RING_REGS_SIZE) {
> > +               if (readl_relaxed(ring + RING_VER) == RING_VER_MAGIC) {
> > +                       rc = vfio_platform_bcmflexrm_shutdown(ring);
> > +                       if (rc) {
> > +                               dev_warn(vdev->device,
> > +                                        "FlexRM ring%d shutdown error %d\n",
> > +                                        ring_num, rc);
> > +                               ret |= rc;
> > +                       }
> > +                       ring_num++;
> > +               }
> > +       }
> > +
> > +       return ret;
> > +}
> > +
> > +module_vfio_reset_handler("brcm,iproc-flexrm-mbox",
> > +                         vfio_platform_bcmflexrm_reset);
> > +
> > +MODULE_LICENSE("GPL v2");
> > +MODULE_AUTHOR("Anup Patel <anup.patel-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>");
> > +MODULE_DESCRIPTION("Reset support for Broadcom FlexRM VFIO platform device");
> > --
> > 2.7.4
> >  
> 
> Hi All,
> 
> Any comments on this one ?

Seems ok to me and you've already got Eric's review, applied to
vfio/platform branch for v4.15.  Thanks,

Alex