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Re: [Qemu-arm] [PATCH 13/17] i.MX: Add code to emulate i.MX2 watchdog IP
From: |
Andrey Smirnov |
Subject: |
Re: [Qemu-arm] [PATCH 13/17] i.MX: Add code to emulate i.MX2 watchdog IP block |
Date: |
Mon, 9 Oct 2017 08:54:56 -0700 |
On Fri, Oct 6, 2017 at 7:22 AM, Peter Maydell <address@hidden> wrote:
> On 18 September 2017 at 20:50, Andrey Smirnov <address@hidden> wrote:
>> Add enough code to emulate i.MX2 watchdog IP block so it would be
>> possible to reboot the machine running Linux Guest.
>>
>> Cc: Peter Maydell <address@hidden>
>> Cc: address@hidden
>> Cc: address@hidden
>> Cc: address@hidden
>> Signed-off-by: Andrey Smirnov <address@hidden>
>> ---
>> hw/misc/Makefile.objs | 1 +
>> hw/misc/imx2_wdt.c | 117
>> +++++++++++++++++++++++++++++++++++++++++++++
>> include/hw/misc/imx2_wdt.h | 36 ++++++++++++++
>> 3 files changed, 154 insertions(+)
>> create mode 100644 hw/misc/imx2_wdt.c
>> create mode 100644 include/hw/misc/imx2_wdt.h
>>
>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>> index ac1be05a03..c393a93456 100644
>> --- a/hw/misc/Makefile.objs
>> +++ b/hw/misc/Makefile.objs
>> @@ -35,6 +35,7 @@ obj-$(CONFIG_IMX) += imx25_ccm.o
>> obj-$(CONFIG_IMX) += imx6_ccm.o
>> obj-$(CONFIG_IMX) += imx6_src.o
>> obj-$(CONFIG_IMX) += imx7_ccm.o
>> +obj-$(CONFIG_IMX) += imx2_wdt.o
>> obj-$(CONFIG_MILKYMIST) += milkymist-hpdmc.o
>> obj-$(CONFIG_MILKYMIST) += milkymist-pfpu.o
>> obj-$(CONFIG_MAINSTONE) += mst_fpga.o
>> diff --git a/hw/misc/imx2_wdt.c b/hw/misc/imx2_wdt.c
>> new file mode 100644
>> index 0000000000..9d97a19511
>> --- /dev/null
>> +++ b/hw/misc/imx2_wdt.c
>> @@ -0,0 +1,117 @@
>> +/*
>> + * Copyright (c) 2017, Impinj, Inc.
>> + *
>> + * i.MX2 Watchdog IP block
>> + *
>> + * Author: Andrey Smirnov <address@hidden>
>> + *
>> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
>> + * See the COPYING file in the top-level directory.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qapi/error.h"
>> +#include "qemu-common.h"
>> +#include "hw/hw.h"
>> +#include "exec/memory.h"
>> +#include "exec/address-spaces.h"
>> +#include "hw/sysbus.h"
>> +#include "qemu/log.h"
>> +#include "qemu/timer.h"
>> +#include "sysemu/sysemu.h"
>> +#include "sysemu/watchdog.h"
>> +#include "qemu/error-report.h"
>> +#include "qemu/sizes.h"
>
> That's an awful lot of includes for a very simple device. Are
> you sure they're all needed?
No, I am not sure. I'll double-check.
>
>> +
>> +#include "hw/misc/imx2_wdt.h"
>> +
>> +
>> +#define IMX2_WDT_WCR_WDA BIT(5) /* -> External Reset WDOG_B
>> */
>> +#define IMX2_WDT_WCR_SRS BIT(4) /* -> Software Reset Signal
>> */
>> +
>> +static uint64_t imx2_wdt_read(void *opaque, hwaddr addr,
>> + unsigned int size)
>> +{
>> + IMX2WdtState *s = opaque;
>> + const size_t index = addr / sizeof(s->reg[0]);
>> +
>> + if (index < ARRAY_SIZE(s->reg))
>> + return s->reg[index];
>> + else
>> + qemu_log_mask(LOG_GUEST_ERROR,
>> + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
>> +
>> + return 0xDEADBEEF;
>> +}
>> +
>> +static void imx2_wdt_write(void *opaque, hwaddr addr,
>> + uint64_t val64, unsigned int size)
>> +{
>> + uint16_t value = val64;
>> + IMX2WdtState *s = opaque;
>> + const size_t index = addr / sizeof(s->reg[0]);
>> +
>> + switch (index) {
>> + case IMX2_WDT_WCR:
>> + if (value & (IMX2_WDT_WCR_WDA | IMX2_WDT_WCR_SRS))
>> + watchdog_perform_action();
>
> Missing "break"?
>
Oops, good catch! Will fix in v2.
> Also checkpatch should tell you you need more braces.
>
Yeah, I definitely forgot to run this through checkpatch, sorry.
>> + default:
>> + qemu_log_mask(LOG_GUEST_ERROR,
>> + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr);
>> + }
>> +}
>> +
>> +static const MemoryRegionOps imx2_wdt_ops = {
>> + .read = imx2_wdt_read,
>> + .write = imx2_wdt_write,
>> + .endianness = DEVICE_NATIVE_ENDIAN,
>> + .valid = {
>> + /*
>> + * Our device would not work correctly if the guest was doing
>> + * unaligned access. This might not be a limitation on the real
>> + * device but in practice there is no reason for a guest to access
>> + * this device unaligned.
>> + */
>
> This sounds like it's perhaps a job for .impl.unaligned
> rather than .valid.unaligned ?
>
This was a snippet I copied from some already existing emulation
block, so I didn't pay too much attention. But yeah, now that you
suggested it, I think I should've used impl.valid as you suggest. Will
fix in v2.
>> + .min_access_size = 4,
>> + .max_access_size = 4,
>> + .unaligned = false,
>> + },
>> +};
>> +
>> +static void imx2_wdt_realize(DeviceState *dev, Error **errp)
>> +{
>> + IMX2WdtState *s = IMX2_WDT(dev);
>> +
>> + memory_region_init_io(&s->mmio, OBJECT(dev),
>> + &imx2_wdt_ops, s,
>> + TYPE_IMX2_WDT".mmio", SZ_64K);
>> + sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->mmio);
>> +}
>> +
>> +static void imx2_wdt_class_init(ObjectClass *klass, void *data)
>> +{
>> + DeviceClass *dc = DEVICE_CLASS(klass);
>> +
>> + dc->realize = imx2_wdt_realize;
>> +
>> + set_bit(DEVICE_CATEGORY_MISC, dc->categories);
>> +}
>> +
>> +static const TypeInfo imx2_wdt_info = {
>> + .name = TYPE_IMX2_WDT,
>> + .parent = TYPE_SYS_BUS_DEVICE,
>> + .instance_size = sizeof(IMX2WdtState),
>> + .class_init = imx2_wdt_class_init,
>> +};
>
> This device needs a reset function and vmstate description.
>
OK, will fix in v2.
Thanks
Andrey Smirnov