From: Lucjan Bryndza <lbryndza.oss@icloud.com>

The current implementation of timers does not work properly
even in basic functionality. A counter configured to report
an interrupt every 10ms reports the first interrupts after a
few seconds.  There are also no properly implemented count up an
count down modes. This commit fixes bugs with interrupt
reporting and implements the basic modes of the counter's
time-base block.

Add update CR function

Signed-off-by: Lucjan Bryndza <lbryndza.oss@icloud.com>
---
 hw/timer/stm32f2xx_timer.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/timer/stm32f2xx_timer.c b/hw/timer/stm32f2xx_timer.c
index 1b3fa5da2c..96cf189933 100644
--- a/hw/timer/stm32f2xx_timer.c
+++ b/hw/timer/stm32f2xx_timer.c
@@ -214,6 +214,16 @@ static void stm32f2xx_update_cr1(STM32F2XXTimerState *s, uint64_t value)
     ptimer_transaction_commit(s->timer);
     DB_PRINT("write cr1 = %x\n", s->tim_cr1);
 }
+
+static void stm32f2xx_update_sr(STM32F2XXTimerState *s, uint64_t value)
+{
+    s->tim_sr ^= (value ^ 0xFFFF);
+    s->tim_sr &= 0x1eFF;
+    ptimer_transaction_begin(s->timer);
+    stm32f2xx_timer_update_uif(s, s->tim_sr & 0x1);
+    ptimer_transaction_commit(s->timer);
+    DB_PRINT("write sr = %x\n", s->tim_sr);
+}
 static void stm32f2xx_timer_write(void *opaque, hwaddr offset,
                         uint64_t val64, unsigned size)
 {
-- 
2.38.5