From 02025985a1ac6b460f417e21d0ddc53a65baa0fe Mon Sep 17 00:00:00 2001
From: hinus <hinus@163.com>
Date: Tue, 6 Jul 2021 21:30:20 +0800
Subject: [PATCH] Title: Support timer in kernel. Issue:
 https://gitee.com/hinus/linux_kernel_011/issues/I3Z826 Description: Support
 timer in kernel.

---
 kernel/blk_drv/hd.c |  3 +++
 kernel/main.c       |  1 -
 kernel/sched.c      | 57 +++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/kernel/blk_drv/hd.c b/kernel/blk_drv/hd.c
index edfdb08..23b40ae 100644
--- a/kernel/blk_drv/hd.c
+++ b/kernel/blk_drv/hd.c
@@ -93,6 +93,7 @@ void hd_identity() {
     printf("HD size: %dMB\n", sectors * 512 / 1024 / 1024);
 }
 
+extern void add_timer(long jiffies, void (*fn)());
 
 int sys_setup(void * BIOS) {
     static int callable = 1;
@@ -171,6 +172,8 @@ int sys_setup(void * BIOS) {
         }
     }
 
+    add_timer(300, test_b);
+
     return 0;
 }
 
diff --git a/kernel/main.c b/kernel/main.c
index 4f6bb0e..21564b6 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -80,7 +80,6 @@ void main(void)
     move_to_user_mode();
 
     if (!fork()) {
-        test_b();
         init();
     }
 
diff --git a/kernel/sched.c b/kernel/sched.c
index 9ad225a..4541b9f 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -107,7 +107,64 @@ void wake_up(struct task_struct **p) {
     }
 }
 
+#define TIME_REQUESTS 64
+
+static struct timer_list {
+    long jiffies;
+    void (*fn)();
+    struct timer_list * next;
+} timer_list[TIME_REQUESTS], * next_timer = NULL;
+
+void add_timer(long jiffies, void (*fn)()) {
+    struct timer_list * p;
+    if (!fn)
+        return;
+    cli();
+
+    if (jiffies <= 0)
+        (fn)();
+    else {
+        for (p = timer_list ; p < timer_list + TIME_REQUESTS ; p++)
+            if (!p->fn)
+                break;
+        if (p >= timer_list + TIME_REQUESTS)
+            printk("No more time requests free");
+
+        p->fn = fn;
+        p->jiffies = jiffies;
+        p->next = next_timer;
+        next_timer = p;
+
+        if (p->next && p->jiffies < p->next->jiffies) {
+            p->next->jiffies -= p->jiffies;
+        }
+
+        while (p->next && p->next->jiffies < p->jiffies) {
+            p->jiffies -= p->next->jiffies;
+            fn = p->fn;
+            p->fn = p->next->fn;
+            p->next->fn = fn;
+            jiffies = p->jiffies;
+            p->jiffies = p->next->jiffies;
+            p->next->jiffies = jiffies;
+            p = p->next;
+        }
+    }
+    sti();
+}
+
 void do_timer(long cpl) {
+    if (next_timer) {
+        next_timer->jiffies--;
+        while (next_timer && next_timer->jiffies <= 0) {
+            void (*fn)(void);
+            fn = next_timer->fn;
+            next_timer->fn = NULL;
+            next_timer = next_timer->next;
+            (fn)();
+        }
+    }
+
     if ((--current->counter)>0) return;
     current->counter=0;
     if (!cpl) return;
-- 
Gitee