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[PULL 07/41] hw/timer/bcm2835: Support the timer COMPARE registers
From: |
Peter Maydell |
Subject: |
[PULL 07/41] hw/timer/bcm2835: Support the timer COMPARE registers |
Date: |
Tue, 20 Oct 2020 16:56:22 +0100 |
From: Philippe Mathieu-Daudé <f4bug@amsat.org>
This peripheral has 1 free-running timer and 4 compare registers.
Only the free-running timer is implemented. Add support the
COMPARE registers (each register is wired to an IRQ).
Reference: "BCM2835 ARM Peripherals" datasheet [*]
chapter 12 "System Timer":
The System Timer peripheral provides four 32-bit timer channels
and a single 64-bit free running counter. Each channel has an
output compare register, which is compared against the 32 least
significant bits of the free running counter values. When the
two values match, the system timer peripheral generates a signal
to indicate a match for the appropriate channel. The match signal
is then fed into the interrupt controller.
This peripheral is used since Linux 3.7, commit ee4af5696720
("ARM: bcm2835: add system timer").
[*] https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Luc Michel <luc@lmichel.fr>
Message-id: 20201010203709.3116542-4-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
include/hw/timer/bcm2835_systmr.h | 11 +++++--
hw/timer/bcm2835_systmr.c | 48 ++++++++++++++++++++-----------
hw/timer/trace-events | 6 ++--
3 files changed, 44 insertions(+), 21 deletions(-)
diff --git a/include/hw/timer/bcm2835_systmr.h
b/include/hw/timer/bcm2835_systmr.h
index f15788a78d8..bd3097d746b 100644
--- a/include/hw/timer/bcm2835_systmr.h
+++ b/include/hw/timer/bcm2835_systmr.h
@@ -11,6 +11,7 @@
#include "hw/sysbus.h"
#include "hw/irq.h"
+#include "qemu/timer.h"
#include "qom/object.h"
#define TYPE_BCM2835_SYSTIMER "bcm2835-sys-timer"
@@ -18,18 +19,24 @@ OBJECT_DECLARE_SIMPLE_TYPE(BCM2835SystemTimerState,
BCM2835_SYSTIMER)
#define BCM2835_SYSTIMER_COUNT 4
+typedef struct {
+ unsigned id;
+ QEMUTimer timer;
+ qemu_irq irq;
+ BCM2835SystemTimerState *state;
+} BCM2835SystemTimerCompare;
+
struct BCM2835SystemTimerState {
/*< private >*/
SysBusDevice parent_obj;
/*< public >*/
MemoryRegion iomem;
- qemu_irq irq;
-
struct {
uint32_t ctrl_status;
uint32_t compare[BCM2835_SYSTIMER_COUNT];
} reg;
+ BCM2835SystemTimerCompare tmr[BCM2835_SYSTIMER_COUNT];
};
#endif
diff --git a/hw/timer/bcm2835_systmr.c b/hw/timer/bcm2835_systmr.c
index b234e83824f..67669a57ff3 100644
--- a/hw/timer/bcm2835_systmr.c
+++ b/hw/timer/bcm2835_systmr.c
@@ -28,20 +28,13 @@ REG32(COMPARE1, 0x10)
REG32(COMPARE2, 0x14)
REG32(COMPARE3, 0x18)
-static void bcm2835_systmr_update_irq(BCM2835SystemTimerState *s)
+static void bcm2835_systmr_timer_expire(void *opaque)
{
- bool enable = !!s->reg.ctrl_status;
+ BCM2835SystemTimerCompare *tmr = opaque;
- trace_bcm2835_systmr_irq(enable);
- qemu_set_irq(s->irq, enable);
-}
-
-static void bcm2835_systmr_update_compare(BCM2835SystemTimerState *s,
- unsigned timer_index)
-{
- /* TODO fow now, since neither Linux nor U-boot use these timers. */
- qemu_log_mask(LOG_UNIMP, "COMPARE register %u not implemented\n",
- timer_index);
+ trace_bcm2835_systmr_timer_expired(tmr->id);
+ tmr->state->reg.ctrl_status |= 1 << tmr->id;
+ qemu_set_irq(tmr->irq, 1);
}
static uint64_t bcm2835_systmr_read(void *opaque, hwaddr offset,
@@ -75,19 +68,33 @@ static uint64_t bcm2835_systmr_read(void *opaque, hwaddr
offset,
}
static void bcm2835_systmr_write(void *opaque, hwaddr offset,
- uint64_t value, unsigned size)
+ uint64_t value64, unsigned size)
{
BCM2835SystemTimerState *s = BCM2835_SYSTIMER(opaque);
+ int index;
+ uint32_t value = value64;
+ uint32_t triggers_delay_us;
+ uint64_t now;
trace_bcm2835_systmr_write(offset, value);
switch (offset) {
case A_CTRL_STATUS:
s->reg.ctrl_status &= ~value; /* Ack */
- bcm2835_systmr_update_irq(s);
+ for (index = 0; index < ARRAY_SIZE(s->tmr); index++) {
+ if (extract32(value, index, 1)) {
+ trace_bcm2835_systmr_irq_ack(index);
+ qemu_set_irq(s->tmr[index].irq, 0);
+ }
+ }
break;
case A_COMPARE0 ... A_COMPARE3:
- s->reg.compare[(offset - A_COMPARE0) >> 2] = value;
- bcm2835_systmr_update_compare(s, (offset - A_COMPARE0) >> 2);
+ index = (offset - A_COMPARE0) >> 2;
+ s->reg.compare[index] = value;
+ now = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL);
+ /* Compare lower 32-bits of the free-running counter. */
+ triggers_delay_us = value - now;
+ trace_bcm2835_systmr_run(index, triggers_delay_us);
+ timer_mod(&s->tmr[index].timer, now + triggers_delay_us);
break;
case A_COUNTER_LOW:
case A_COUNTER_HIGH:
@@ -125,7 +132,14 @@ static void bcm2835_systmr_realize(DeviceState *dev, Error
**errp)
memory_region_init_io(&s->iomem, OBJECT(dev), &bcm2835_systmr_ops,
s, "bcm2835-sys-timer", 0x20);
sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
- sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq);
+
+ for (size_t i = 0; i < ARRAY_SIZE(s->tmr); i++) {
+ s->tmr[i].id = i;
+ s->tmr[i].state = s;
+ sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->tmr[i].irq);
+ timer_init_us(&s->tmr[i].timer, QEMU_CLOCK_VIRTUAL,
+ bcm2835_systmr_timer_expire, &s->tmr[i]);
+ }
}
static const VMStateDescription bcm2835_systmr_vmstate = {
diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index b996d992000..7a4326d9566 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -77,9 +77,11 @@ nrf51_timer_write(uint8_t timer_id, uint64_t addr, uint32_t
value, unsigned size
nrf51_timer_set_count(uint8_t timer_id, uint8_t counter_id, uint32_t value)
"timer %u counter %u count 0x%" PRIx32
# bcm2835_systmr.c
-bcm2835_systmr_irq(bool enable) "timer irq state %u"
+bcm2835_systmr_timer_expired(unsigned id) "timer #%u expired"
+bcm2835_systmr_irq_ack(unsigned id) "timer #%u acked"
bcm2835_systmr_read(uint64_t offset, uint64_t data) "timer read: offset 0x%"
PRIx64 " data 0x%" PRIx64
-bcm2835_systmr_write(uint64_t offset, uint64_t data) "timer write: offset 0x%"
PRIx64 " data 0x%" PRIx64
+bcm2835_systmr_write(uint64_t offset, uint32_t data) "timer write: offset 0x%"
PRIx64 " data 0x%" PRIx32
+bcm2835_systmr_run(unsigned id, uint64_t delay_us) "timer #%u expiring in
%"PRIu64" us"
# avr_timer16.c
avr_timer16_read(uint8_t addr, uint8_t value) "timer16 read addr:%u value:%u"
--
2.20.1
- [PULL 00/41] target-arm queue, Peter Maydell, 2020/10/20
- [PULL 01/41] target/arm: Fix SMLAD incorrect setting of Q bit, Peter Maydell, 2020/10/20
- [PULL 02/41] target/arm: AArch32 VCVT fixed-point to float is always round-to-nearest, Peter Maydell, 2020/10/20
- [PULL 03/41] hw/arm/strongarm: Fix 'time to transmit a char' unit comment, Peter Maydell, 2020/10/20
- [PULL 04/41] hw/arm: Restrict APEI tables generation to the 'virt' machine, Peter Maydell, 2020/10/20
- [PULL 05/41] hw/timer/bcm2835: Introduce BCM2835_SYSTIMER_COUNT definition, Peter Maydell, 2020/10/20
- [PULL 06/41] hw/timer/bcm2835: Rename variable holding CTRL_STATUS register, Peter Maydell, 2020/10/20
- [PULL 08/41] hw/arm/bcm2835_peripherals: Correctly wire the SYS_timer IRQs, Peter Maydell, 2020/10/20
- [PULL 07/41] hw/timer/bcm2835: Support the timer COMPARE registers,
Peter Maydell <=
- [PULL 09/41] accel/tcg: Add tlb_flush_page_bits_by_mmuidx*, Peter Maydell, 2020/10/20
- [PULL 10/41] target/arm: Use tlb_flush_page_bits_by_mmuidx*, Peter Maydell, 2020/10/20
- [PULL 12/41] loads-stores.rst: add footnote that clarifies GETPC usage, Peter Maydell, 2020/10/20
- [PULL 13/41] hw/intc/bcm2835_ic: Trace GPU/CPU IRQ handlers, Peter Maydell, 2020/10/20
- [PULL 11/41] tests/qtest: Add npcm7xx timer test, Peter Maydell, 2020/10/20
- [PULL 14/41] hw/intc/bcm2836_control: Use IRQ definitions instead of magic numbers, Peter Maydell, 2020/10/20
- [PULL 15/41] target/arm: Remove redundant mmu_idx lookup, Peter Maydell, 2020/10/20
- [PULL 16/41] target/arm: Fix reported EL for mte_check_fail, Peter Maydell, 2020/10/20
- [PULL 17/41] target/arm: Ignore HCR_EL2.ATA when {E2H,TGE} != 11, Peter Maydell, 2020/10/20
- [PULL 18/41] microbit_i2c: Fix coredump when dump-vmstate, Peter Maydell, 2020/10/20