From 3609d2db7d26cbfda07ef4765569a0f42719c0f7 Mon Sep 17 00:00:00 2001
From: sbosse <sbosse@uni-bremen.de>
Date: Mon, 14 Oct 2024 23:08:28 +0200
Subject: [PATCH] Mon 14 Oct 23:06:38 CEST 2024

---
 kernel/device.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 176 insertions(+)
 create mode 100644 kernel/device.c

diff --git a/kernel/device.c b/kernel/device.c
new file mode 100644
index 0000000..7e2b06f
--- /dev/null
+++ b/kernel/device.c
@@ -0,0 +1,176 @@
+/*
+Copyright (C) 2016-2019 The University of Notre Dame
+This software is distributed under the GNU General Public License.
+See the file LICENSE for details.
+*/
+#include "device.h"
+#include "string.h"
+#include "page.h"
+#include "kmalloc.h"
+
+#include "kernel/stats.h"
+#include "kernel/types.h"
+#include "kernel/error.h"
+
+static struct device_driver *driver_list = 0;
+
+struct device {
+	struct device_driver *driver;
+	int refcount;
+	int unit;
+	int block_size;
+	int nblocks;
+	int multiplier;
+};
+
+void device_driver_register( struct device_driver *d )
+{
+	d->next = driver_list;
+	d->stats = (struct device_driver_stats){0};
+	driver_list = d;
+}
+
+static struct device *device_create( struct device_driver *dd, int unit, int nblocks, int block_size )
+{
+	struct device *d = kmalloc(sizeof(*d));
+	d->refcount = 1;
+	d->driver = dd;
+	d->unit = unit;
+	d->block_size = block_size;
+	d->nblocks = nblocks;
+
+/*
+If the device driver specifies a non-zero default multiplier,
+then save it in this device instance.  It gives the effect of
+multiplying the block size, typically from the 512 ATA sector
+size, up to the usual 4KB page size.  See the effect below
+in read/write.
+*/
+
+	if(dd->multiplier>0) {
+		d->multiplier = dd->multiplier;
+	} else {
+		d->multiplier = 1;
+	}
+	return d;
+}
+
+struct device *device_open( const char *name, int unit )
+{
+	int nblocks, block_size;
+	char info[64];
+
+	struct device_driver *dd = device_driver_lookup(name);
+	if (dd && dd->probe(unit,&nblocks,&block_size,info)) {
+		return device_create(dd,unit,nblocks,block_size);
+	}
+
+	return 0;
+}
+
+struct device *device_addref( struct device *d )
+{
+	d->refcount++;
+	return d;
+}
+
+int device_set_multiplier( struct device *d, int multiplier )
+{
+	if(multiplier<1 || multiplier*d->block_size>PAGE_SIZE ) {
+		return KERROR_INVALID_REQUEST;
+	}
+
+	d->multiplier = multiplier;
+
+	return 0;
+}
+
+void device_close( struct device *d )
+{
+	d->refcount--;
+	if(d->refcount<1) kfree(d);
+}
+
+int device_read(struct device *d, void *data, int size, int offset)
+{
+	int status;
+	if(d->driver->read) {
+		status = d->driver->read(d->unit,data,size*d->multiplier,offset*d->multiplier);
+		if (status) {
+			d->driver->stats.blocks_read += size*d->multiplier; // number of blocks
+		}
+		return status;
+	} else {
+		return KERROR_NOT_IMPLEMENTED;
+	}
+}
+
+int device_read_nonblock(struct device *d, void *data, int size, int offset)
+{
+	int status;
+	if(d->driver->read_nonblock) {
+		status = d->driver->read_nonblock(d->unit,data,size*d->multiplier,offset*d->multiplier);
+		if (status) {
+			d->driver->stats.blocks_read += size*d->multiplier; // number of blocks
+		}
+		return status;
+	} else {
+		return KERROR_NOT_IMPLEMENTED;
+	}
+}
+
+int device_write(struct device *d, const void *data, int size, int offset)
+{
+	int status;
+	if(d->driver->write) {
+		status = d->driver->write(d->unit,data,size*d->multiplier,offset*d->multiplier);
+		if (!status) {
+			d->driver->stats.blocks_written += size*d->multiplier;
+		}
+		return status;
+	} else {
+		return KERROR_NOT_IMPLEMENTED;
+	}
+}
+
+int device_block_size( struct device *d )
+{
+	return d->block_size*d->multiplier;
+}
+
+int device_nblocks( struct device *d )
+{
+	return d->nblocks/d->multiplier;
+}
+
+int device_unit( struct device *d )
+{
+	return d->unit;
+}
+
+const char * device_name( struct device *d )
+{
+	return d->driver->name;
+}
+
+struct device_driver * device_driver_lookup(const char *name)
+{
+	struct device_driver *dd = driver_list;
+	for(dd=driver_list; dd; dd=dd->next) {
+		if(!strcmp(dd->name, name)) {
+			break;
+		}
+	}
+	return dd;
+}
+
+void device_driver_get_stats(const char * name, struct device_driver_stats * s)
+{
+	/* Get the device driver */
+	struct device_driver *dd = device_driver_lookup(name);
+
+	/* Copy stats into struct */
+	if (dd) {
+		memcpy(s, &(dd->stats), sizeof(*s));
+	}
+}