Fix code review issues: overflow protection and parameter handling

Co-authored-by: BernardXiong <1241087+BernardXiong@users.noreply.github.com>

Author: Copilot

components/drivers/clock_time/src/clock_time.c

@@ -52,8 +52,20 @@ rt_err_t rt_clock_time_device_register(struct rt_clock_time_device *dev,
         rt_uint64_t freq = dev->ops->get_freq();
         if (freq > 0)
         {
-            /* res_scale = (1e9 * RT_CLOCK_TIME_RESMUL) / freq */
-            dev->res_scale = ((1000000000ULL * RT_CLOCK_TIME_RESMUL) / freq);
+            /* res_scale = (1e9 * RT_CLOCK_TIME_RESMUL) / freq 
+             * To avoid overflow, we check if freq is very small.
+             * For freq >= 1000, this calculation is safe on 64-bit.
+             * For very small frequencies, limit the scale factor.
+             */
+            if (freq >= 1000)
+            {
+                dev->res_scale = ((1000000000ULL * RT_CLOCK_TIME_RESMUL) / freq);
+            }
+            else
+            {
+                /* For very low frequencies, calculate more carefully */
+                dev->res_scale = (1000000ULL * RT_CLOCK_TIME_RESMUL) / freq * 1000;
+            }
         }
         else
         {

components/drivers/clock_time/src/hrtimer.c

@@ -80,7 +80,17 @@ rt_weak rt_err_t rt_clock_hrtimer_settimeout(unsigned long cnt)
 static unsigned long _cnt_convert(unsigned long cnt)
 {
     unsigned long rtn   = 0;
-    unsigned long count = cnt - rt_clock_cputimer_getcnt();
+    unsigned long current_cnt = rt_clock_cputimer_getcnt();
+    
+    /* Check for overflow/underflow - if cnt is in the past or wrapped around */
+    if (cnt <= current_cnt)
+    {
+        return 0;
+    }
+    
+    unsigned long count = cnt - current_cnt;
+    
+    /* Sanity check: if count is too large, it might be a wrap-around */
     if (count > (_HRTIMER_MAX_CNT / 2))
         return 0;
 
@@ -289,7 +299,7 @@ rt_err_t rt_clock_hrtimer_control(rt_clock_hrtimer_t timer, int cmd, void *arg)
         *(unsigned long *)arg = timer->timeout_cnt;
         break;
     case RT_TIMER_CTRL_GET_FUNC:
-        arg = (void *)timer->timeout_func;
+        *(void **)arg = (void *)timer->timeout_func;
         break;
 
     case RT_TIMER_CTRL_SET_FUNC:

components/drivers/include/drivers/clock_time.h

@@ -256,6 +256,10 @@ rt_err_t rt_clock_hrtimer_detach(rt_clock_hrtimer_t timer);
  * @brief Keep errno in timer structure
  * @param timer Timer structure
  * @param err Error code to keep
+ * 
+ * Note: This function negates err when setting errno to convert RT-Thread
+ * error codes to POSIX-style errno values. This maintains compatibility
+ * with the original ktime implementation.
  */
 rt_inline void rt_clock_hrtimer_keep_errno(rt_clock_hrtimer_t timer, rt_err_t err)
 {