From 7e2f263ee838378715a3fa45e67863d8a20bdc0d Mon Sep 17 00:00:00 2001
From: Alan Cox <alan@linux.intel.com>
Date: Thu, 19 Feb 2015 23:05:58 +0000
Subject: [PATCH] bank16k: first pass swap logic

Do the swap in four requests so that each I/O is one mapping in memory space
and the drivers can stay sane. Right now swap passes the process ptr and
that should probably change to the page number (or for the simpler cases
the bank is the same thing).
---
 Kernel/bank16k.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)

diff --git a/Kernel/bank16k.c b/Kernel/bank16k.c
index 6db6796c..09f7399b 100644
--- a/Kernel/bank16k.c
+++ b/Kernel/bank16k.c
@@ -155,4 +155,92 @@ uint16_t pagemap_mem_used(void)
 	return pfptr << 4;
 }
 
+#ifdef SWAPDEV
+
+/*
+ *	Swap out the memory of a process to make room
+ *	for something else. For bank16k do this as four operations
+ *	ready for when we pass page values not processes to the drivers
+ */
+
+int swapout(ptptr p)
+{
+	uint16_t page = p->p_page;
+	uint16_t blk;
+	uint16_t map;
+	uint16_t base = SWAPBASE;
+	uint16_t size = (0x4000 - SWAPBASE) >> 9;
+
+	swapproc = p;
+
+	if (page)
+		panic("%x: process already swapped!\n", p);
+#ifdef DEBUG
+	kprintf("Swapping out %x (%d)\n", p, p->p_page);
+#endif
+
+	/* Are we out of swap ? */
+	map = swapmap_alloc();
+	if (map == 0)
+		return ENOMEM;
+	blk = map * SWAP_SIZE;
+	/* Write the app (and possibly the uarea etc..) to disk */
+	for (i = 0; i < 4; i ++) {
+		swapwrite(SWAPDEV, blk, size, base);
+		base += 0x4000;
+		/* Last bank is determined by SWAP SIZE. We do the maths
+		   in 512's (0x60 = 0xC000) */
+		if (i == 3)
+			size = SWAP_SIZE - 0x60;
+		else
+			size = 0x20;
+	}
+	pagemap_free(p);
+	p->p_page = 0;
+	p->p_page2 = map;
+
+#ifdef DEBUG
+	kprintf("%x: swapout done %d\n", p, p->p_page);
+#endif
+	return 0;
+}
+
+/*
+ * Swap ourself in: must be on the swap stack when we do this
+ */
+void swapin(ptptr p)
+{
+	uint16_t blk = p->p_page2 * SWAP_SIZE;
+	uint16_t base = SWAPBASE;
+	uint16_t size = (0x4000 - SWAPBASE) >> 9;
+
+#ifdef DEBUG
+	kprintf("Swapin %x, %d\n", p, p->p_page);
+#endif
+	if (!p->p_page) {
+		kprintf("%x: nopage!\n", p);
+		return;
+	}
+
+	/* Return our swap */
+	swapmap_add(p->p_page2);
+
+	swapproc = p;		/* always ourself */
+	for (i = 0; i < 4; i ++) {
+		swapread(SWAPDEV, blk, size, base);
+		base += 0x4000;
+		/* Last bank is determined by SWAP SIZE. We do the maths
+		   in 512's (0x60 = 0xC000) */
+		if (i == 3)
+			size = SWAP_SIZE - 0x60;
+		else
+			size = 0x20;	/* 16 K */
+	}
+#ifdef DEBUG
+	kprintf("%x: swapin done %d\n", p, p->p_page);
+#endif
+}
+
+#endif
+
 #endif
-- 
2.34.1