Re: [PATCH v4] vfio: platform: reset: Add Broadcom FlexRM reset module

[Anup Patel]

On Fri, Aug 11, 2017 at 12:53 AM, Alex Williamson
<alex.williamson@xxxxxxxxxx> wrote:
> On Wed,  2 Aug 2017 11:08:30 +0530
> Anup Patel <anup.patel@xxxxxxxxxxxx> 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@xxxxxxxxxxxx>
>> Reviewed-by: Oza Oza <oza.oza@xxxxxxxxxxxx>
>> Reviewed-by: Scott Branden <scott.branden@xxxxxxxxxxxx>
>> Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
>> ---
>>  drivers/vfio/platform/reset/Kconfig                |   8 ++
>>  drivers/vfio/platform/reset/Makefile               |   1 +
>>  .../vfio/platform/reset/vfio_platform_bcmflexrm.c  | 100 +++++++++++++++++++++
>>  3 files changed, 109 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..8833805 100644
>> --- a/drivers/vfio/platform/reset/Kconfig
>> +++ b/drivers/vfio/platform/reset/Kconfig
>> @@ -13,3 +13,11 @@ 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)
>> +     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..104c3c1
>> --- /dev/null
>> +++ b/drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c
>> @@ -0,0 +1,100 @@
>> +/*
>> + * 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 version 2 as
>> + * published by the Free Software Foundation.
>> + *
>> + * This program is distributed in the hope that it will be useful,
>> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
>> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
>> + * GNU General Public License for more details.
>> + *
>> + * You should have received a copy of the GNU General Public License
>> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
>> + */
>> +
>> +/*
>> + * This driver provides reset support for Broadcom FlexRM ring manager
>> + * to VFIO platform.
>> + */
>> +
>> +#include <linux/delay.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);
>> +
>> +     /* Flush ring with timeout of 1s */
>> +     timeout = 1000;
>> +     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) {
>> +             pr_warn("VFIO FlexRM shutdown timeout\n");
>> +             return -ETIMEDOUT;
>> +     }
>
>
> This doesn't work, timeout is ~0 here.

Sure, I will use "--timeout" instead of "timeout--" which will
fix the issue.

Thanks for pointing.

Regards,
Anup