From 4d4e784770b576199b18f22100689125a18bfd9a Mon Sep 17 00:00:00 2001
From: Marvin Borner
Date: Thu, 15 Apr 2021 22:47:54 +0200
Subject: Basic block/unblock

---
 kernel/features/io.c | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

(limited to 'kernel/features/io.c')

diff --git a/kernel/features/io.c b/kernel/features/io.c
index b8275f9..6042818 100644
--- a/kernel/features/io.c
+++ b/kernel/features/io.c
@@ -3,15 +3,18 @@
 #include <assert.h>
 #include <def.h>
 #include <fb.h>
+#include <interrupts.h>
 #include <io.h>
 #include <list.h>
 #include <mm.h>
+#include <proc.h>
 #include <ps2.h>
 #include <rand.h>
 #include <str.h>
 #include <timer.h>
 
 PROTECTED static struct io_dev *io_mappings[IO_MAX] = { 0 };
+PROTECTED static struct list *io_listeners[IO_MAX] = { 0 };
 
 static u8 io_type_valid(enum io_type io)
 {
@@ -75,11 +78,48 @@ res io_read(enum io_type io, void *buf, u32 offset, u32 count)
 	if (!(dev = io_get(io)) || !dev->read)
 		return -ENOENT;
 
+	if (dev->ready && !dev->ready())
+		return -EAGAIN;
+
 	return dev->read(buf, offset, count);
 }
 
+void io_block(enum io_type io, struct proc *proc, struct regs *r)
+{
+	assert(r->eax == SYS_IOREAD);
+	assert(io_type_valid(io));
+	list_add(io_listeners[io], proc);
+	proc_state(proc_current(), PROC_BLOCKED);
+	proc_yield(r);
+}
+
+void io_unblock(enum io_type io)
+{
+	struct page_dir *dir_bak;
+	memory_backup_dir(&dir_bak);
+
+	assert(io_type_valid(io));
+	struct node *iterator = io_listeners[io]->head;
+	while (iterator) {
+		struct proc *proc = iterator->data;
+		struct regs *r = &proc->regs;
+
+		memory_switch_dir(proc->page_dir);
+		r->eax = io_read(r->ebx, (void *)r->ecx, r->edx, r->esi);
+		memory_switch_dir(dir_bak);
+
+		proc_state(proc, PROC_RUNNING);
+		struct node *next = iterator->next;
+		list_remove(io_listeners[io], iterator);
+		iterator = next;
+	}
+}
+
 CLEAR void io_install(struct boot_info *boot)
 {
+	for (u32 i = 0; i < IO_MAX; i++)
+		io_listeners[i] = list_new();
+
 	ps2_detect();
 
 	u8 ps2_keyboard = ps2_keyboard_detect();
-- 
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