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qemu-e2k/hw/watchdog/wdt_aspeed.c
Andrew Jeffery f55d613bc9 watchdog: wdt_aspeed: Add support for the reset width register 
The reset width register controls how the pulse on the SoC's WDTRST{1,2}
pins behaves. A pulse is emitted if the external reset bit is set in
WDT_CTRL. On the AST2500 WDT_RESET_WIDTH can consume magic bit patterns
to configure push-pull/open-drain and active-high/active-low
behaviours and thus needs some special handling in the write path.

As some of the capabilities depend on the SoC version a silicon-rev
property is introduced, which is used to guard version-specific
behaviour.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2017-09-04 15:21:54 +01:00

297 lines
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/*
* ASPEED Watchdog Controller
*
* Copyright (C) 2016-2017 IBM Corp.
*
* This code is licensed under the GPL version 2 or later. See the
* COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/log.h"
#include "qemu/timer.h"
#include "sysemu/watchdog.h"
#include "hw/misc/aspeed_scu.h"
#include "hw/sysbus.h"
#include "hw/watchdog/wdt_aspeed.h"
#define WDT_STATUS (0x00 / 4)
#define WDT_RELOAD_VALUE (0x04 / 4)
#define WDT_RESTART (0x08 / 4)
#define WDT_CTRL (0x0C / 4)
#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
#define WDT_CTRL_1MHZ_CLK BIT(4)
#define WDT_CTRL_WDT_EXT BIT(3)
#define WDT_CTRL_WDT_INTR BIT(2)
#define WDT_CTRL_RESET_SYSTEM BIT(1)
#define WDT_CTRL_ENABLE BIT(0)
#define WDT_RESET_WIDTH (0x18 / 4)
#define WDT_RESET_WIDTH_ACTIVE_HIGH BIT(31)
#define WDT_POLARITY_MASK (0xFF << 24)
#define WDT_ACTIVE_HIGH_MAGIC (0xA5 << 24)
#define WDT_ACTIVE_LOW_MAGIC (0x5A << 24)
#define WDT_RESET_WIDTH_PUSH_PULL BIT(30)
#define WDT_DRIVE_TYPE_MASK (0xFF << 24)
#define WDT_PUSH_PULL_MAGIC (0xA8 << 24)
#define WDT_OPEN_DRAIN_MAGIC (0x8A << 24)
#define WDT_TIMEOUT_STATUS (0x10 / 4)
#define WDT_TIMEOUT_CLEAR (0x14 / 4)
#define WDT_RESTART_MAGIC 0x4755
static bool aspeed_wdt_is_enabled(const AspeedWDTState *s)
{
return s->regs[WDT_CTRL] & WDT_CTRL_ENABLE;
}
static bool is_ast2500(const AspeedWDTState *s)
{
switch (s->silicon_rev) {
case AST2500_A0_SILICON_REV:
case AST2500_A1_SILICON_REV:
return true;
case AST2400_A0_SILICON_REV:
case AST2400_A1_SILICON_REV:
default:
break;
}
return false;
}
static uint64_t aspeed_wdt_read(void *opaque, hwaddr offset, unsigned size)
{
AspeedWDTState *s = ASPEED_WDT(opaque);
offset >>= 2;
switch (offset) {
case WDT_STATUS:
return s->regs[WDT_STATUS];
case WDT_RELOAD_VALUE:
return s->regs[WDT_RELOAD_VALUE];
case WDT_RESTART:
qemu_log_mask(LOG_GUEST_ERROR,
"%s: read from write-only reg at offset 0x%"
HWADDR_PRIx "\n", __func__, offset);
return 0;
case WDT_CTRL:
return s->regs[WDT_CTRL];
case WDT_RESET_WIDTH:
return s->regs[WDT_RESET_WIDTH];
case WDT_TIMEOUT_STATUS:
case WDT_TIMEOUT_CLEAR:
qemu_log_mask(LOG_UNIMP,
"%s: uninmplemented read at offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
return 0;
default:
qemu_log_mask(LOG_GUEST_ERROR,
"%s: Out-of-bounds read at offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
return 0;
}
}
static void aspeed_wdt_reload(AspeedWDTState *s, bool pclk)
{
uint32_t reload;
if (pclk) {
reload = muldiv64(s->regs[WDT_RELOAD_VALUE], NANOSECONDS_PER_SECOND,
s->pclk_freq);
} else {
reload = s->regs[WDT_RELOAD_VALUE] * 1000;
}
if (aspeed_wdt_is_enabled(s)) {
timer_mod(s->timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) + reload);
}
}
static void aspeed_wdt_write(void *opaque, hwaddr offset, uint64_t data,
unsigned size)
{
AspeedWDTState *s = ASPEED_WDT(opaque);
bool enable = data & WDT_CTRL_ENABLE;
offset >>= 2;
switch (offset) {
case WDT_STATUS:
qemu_log_mask(LOG_GUEST_ERROR,
"%s: write to read-only reg at offset 0x%"
HWADDR_PRIx "\n", __func__, offset);
break;
case WDT_RELOAD_VALUE:
s->regs[WDT_RELOAD_VALUE] = data;
break;
case WDT_RESTART:
if ((data & 0xFFFF) == WDT_RESTART_MAGIC) {
s->regs[WDT_STATUS] = s->regs[WDT_RELOAD_VALUE];
aspeed_wdt_reload(s, !(data & WDT_CTRL_1MHZ_CLK));
}
break;
case WDT_CTRL:
if (enable && !aspeed_wdt_is_enabled(s)) {
s->regs[WDT_CTRL] = data;
aspeed_wdt_reload(s, !(data & WDT_CTRL_1MHZ_CLK));
} else if (!enable && aspeed_wdt_is_enabled(s)) {
s->regs[WDT_CTRL] = data;
timer_del(s->timer);
}
break;
case WDT_RESET_WIDTH:
{
uint32_t property = data & WDT_POLARITY_MASK;
if (property && is_ast2500(s)) {
if (property == WDT_ACTIVE_HIGH_MAGIC) {
s->regs[WDT_RESET_WIDTH] |= WDT_RESET_WIDTH_ACTIVE_HIGH;
} else if (property == WDT_ACTIVE_LOW_MAGIC) {
s->regs[WDT_RESET_WIDTH] &= ~WDT_RESET_WIDTH_ACTIVE_HIGH;
} else if (property == WDT_PUSH_PULL_MAGIC) {
s->regs[WDT_RESET_WIDTH] |= WDT_RESET_WIDTH_PUSH_PULL;
} else if (property == WDT_OPEN_DRAIN_MAGIC) {
s->regs[WDT_RESET_WIDTH] &= ~WDT_RESET_WIDTH_PUSH_PULL;
}
}
s->regs[WDT_RESET_WIDTH] &= ~s->ext_pulse_width_mask;
s->regs[WDT_RESET_WIDTH] |= data & s->ext_pulse_width_mask;
break;
}
case WDT_TIMEOUT_STATUS:
case WDT_TIMEOUT_CLEAR:
qemu_log_mask(LOG_UNIMP,
"%s: uninmplemented write at offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
break;
default:
qemu_log_mask(LOG_GUEST_ERROR,
"%s: Out-of-bounds write at offset 0x%" HWADDR_PRIx "\n",
__func__, offset);
}
return;
}
static WatchdogTimerModel model = {
.wdt_name = TYPE_ASPEED_WDT,
.wdt_description = "Aspeed watchdog device",
};
static const VMStateDescription vmstate_aspeed_wdt = {
.name = "vmstate_aspeed_wdt",
.version_id = 0,
.minimum_version_id = 0,
.fields = (VMStateField[]) {
VMSTATE_TIMER_PTR(timer, AspeedWDTState),
VMSTATE_UINT32_ARRAY(regs, AspeedWDTState, ASPEED_WDT_REGS_MAX),
VMSTATE_END_OF_LIST()
}
};
static const MemoryRegionOps aspeed_wdt_ops = {
.read = aspeed_wdt_read,
.write = aspeed_wdt_write,
.endianness = DEVICE_LITTLE_ENDIAN,
.valid.min_access_size = 4,
.valid.max_access_size = 4,
.valid.unaligned = false,
};
static void aspeed_wdt_reset(DeviceState *dev)
{
AspeedWDTState *s = ASPEED_WDT(dev);
s->regs[WDT_STATUS] = 0x3EF1480;
s->regs[WDT_RELOAD_VALUE] = 0x03EF1480;
s->regs[WDT_RESTART] = 0;
s->regs[WDT_CTRL] = 0;
s->regs[WDT_RESET_WIDTH] = 0xFF;
timer_del(s->timer);
}
static void aspeed_wdt_timer_expired(void *dev)
{
AspeedWDTState *s = ASPEED_WDT(dev);
qemu_log_mask(CPU_LOG_RESET, "Watchdog timer expired.\n");
watchdog_perform_action();
timer_del(s->timer);
}
#define PCLK_HZ 24000000
static void aspeed_wdt_realize(DeviceState *dev, Error **errp)
{
SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
AspeedWDTState *s = ASPEED_WDT(dev);
if (!is_supported_silicon_rev(s->silicon_rev)) {
error_setg(errp, "Unknown silicon revision: 0x%" PRIx32,
s->silicon_rev);
return;
}
switch (s->silicon_rev) {
case AST2400_A0_SILICON_REV:
case AST2400_A1_SILICON_REV:
s->ext_pulse_width_mask = 0xff;
break;
case AST2500_A0_SILICON_REV:
case AST2500_A1_SILICON_REV:
s->ext_pulse_width_mask = 0xfffff;
break;
default:
g_assert_not_reached();
}
s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, aspeed_wdt_timer_expired, dev);
/* FIXME: This setting should be derived from the SCU hw strapping
* register SCU70
*/
s->pclk_freq = PCLK_HZ;
memory_region_init_io(&s->iomem, OBJECT(s), &aspeed_wdt_ops, s,
TYPE_ASPEED_WDT, ASPEED_WDT_REGS_MAX * 4);
sysbus_init_mmio(sbd, &s->iomem);
}
static Property aspeed_wdt_properties[] = {
DEFINE_PROP_UINT32("silicon-rev", AspeedWDTState, silicon_rev, 0),
DEFINE_PROP_END_OF_LIST(),
};
static void aspeed_wdt_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->realize = aspeed_wdt_realize;
dc->reset = aspeed_wdt_reset;
set_bit(DEVICE_CATEGORY_MISC, dc->categories);
dc->vmsd = &vmstate_aspeed_wdt;
dc->props = aspeed_wdt_properties;
}
static const TypeInfo aspeed_wdt_info = {
.parent = TYPE_SYS_BUS_DEVICE,
.name = TYPE_ASPEED_WDT,
.instance_size = sizeof(AspeedWDTState),
.class_init = aspeed_wdt_class_init,
};
static void wdt_aspeed_register_types(void)
{
watchdog_add_model(&model);
type_register_static(&aspeed_wdt_info);
}
type_init(wdt_aspeed_register_types)
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