Added cromdisk implementation.

bsp/drv/dev/block/Makefile.inc

@@ -1,3 +1,6 @@
 
 SRCS-$(CONFIG_RAMDISK)+=	dev/block/ramdisk.c
 SRCS-$(CONFIG_FDD)+=		dev/block/fdd.c
+SRCS-$(CONFIG_CROMDISK)+=   dev/block/cromdisk/cromdisk.c \
+                            dev/block/cromdisk/puff.c
+

bsp/drv/dev/block/cromdisk/README

@@ -0,0 +1,24 @@
+cromdisk compressed ROM disk
+----------------------------
+
+cromdisk is a simple compressed ROM block device. It uses a ROM image
+generated by an offline tool and provides random access to it; it's a drop-in
+replacement to ramdisk (although, naturally, read only).
+
+It achieves random access by individually compressing each 512 byte block.
+This means that the compression ratio isn't that great, but it's achieving
+about 2:1 in my experience, which makes it useful when ROM space is tight.
+Decompression is done using zlib's puff lightweight deflator. This isn't
+nearly as fast as true zlib, but it's only about 3kB of code.  
+
+There are no configuration options.
+
+You can't enable ramdisk and cromdisk at the same time, as they both try to
+register /dev/ram0. (Besides, raw access to the compressed data probably
+isn't useful.)
+
+
+-- 
+David Given
+dg@cowlark.com
+

bsp/drv/dev/block/cromdisk/cromdisk.c

@@ -0,0 +1,169 @@
+/*-
+ * Copyright (c) 2010, David Given
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the author nor the names of any co-contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+/*
+ * cromdisk.c - compressed ROM disk driver
+ */
+
+#include <driver.h>
+#include "puff.h"
+
+/* #define DEBUG_CROMDISK 1 */
+
+#ifdef DEBUG_CROMDISK
+#define DPRINTF(a)	printf a
+#else
+#define DPRINTF(a)
+#endif
+
+/* Block size */
+#define BSIZE		512
+
+struct cromdisk_softc {
+	device_t dev;		/* device object */
+	uint8_t* addr;      /* base address of image */
+	size_t size;		/* uncompressed image size */
+};
+
+static int cromdisk_read(device_t, char *, size_t *, int);
+static int cromdisk_probe(struct driver *);
+static int cromdisk_init(struct driver *);
+
+static struct devops cromdisk_devops = {
+	/* open */	no_open,
+	/* close */	no_close,
+	/* read */	cromdisk_read,
+	/* write */	no_write,
+	/* ioctl */	no_ioctl,
+	/* devctl */ no_devctl,
+};
+
+struct driver cromdisk_driver = {
+	/* name */	"cromdisk",
+	/* devops */ &cromdisk_devops,
+	/* devsz */	sizeof(struct cromdisk_softc),
+	/* flags */	0,
+	/* probe */	cromdisk_probe,
+	/* init */	cromdisk_init,
+	/* shutdown */	NULL,
+};
+
+static int
+cromdisk_read(device_t dev, char *buf, size_t *nbyte, int blkno)
+{
+	struct cromdisk_softc *sc = device_private(dev);
+	int offset = blkno * BSIZE;
+	uint8_t* kbuf;
+	size_t nr_read;
+
+	DPRINTF(("cromdisk_read: buf=%x nbyte=%d blkno=%x\n",
+		 buf, *nbyte, blkno));
+
+	/* Check overrun */
+	if (offset > (int)sc->size) {
+		DPRINTF(("cromdisk_read: overrun!\n"));
+		return EIO;
+	}
+	nr_read = *nbyte;
+	if (offset + nr_read > (int)sc->size)
+		nr_read = sc->size - offset;
+
+	/* Translate buffer address to kernel address */
+	if ((kbuf = kmem_map(buf, nr_read)) == NULL) {
+		return EFAULT;
+	}
+
+	/* Copy data */
+	*nbyte = nr_read;
+	while (nr_read > 0)
+	{
+		int e;
+		unsigned long destlen = nr_read;
+		uint8_t* p = sc->addr + 2 + (blkno * 4);
+		unsigned long blksize = *p++ * 2;
+		uint32_t blkoffset = p[0] | (p[1] << 8) | (p[2] << 16);
+		uint8_t* blkaddr = sc->addr + blkoffset;
+
+		sched_lock();
+		e = puff(kbuf, &destlen, blkaddr, &blksize);
+		sched_unlock();
+
+		nr_read -= BSIZE;
+		kbuf += BSIZE;
+		blkno++;
+	}
+	return 0;
+}
+
+static int
+cromdisk_probe(struct driver *self)
+{
+	struct bootinfo *bi;
+	struct physmem *phys;
+
+	machine_bootinfo(&bi);
+	phys = &bi->bootdisk;
+	if (phys->size == 0) {
+#ifdef DEBUG
+		printf("cromdisk: no bootdisk found...\n");
+#endif
+		return ENXIO;
+	}
+	return 0;
+}
+
+static int
+cromdisk_init(struct driver *self)
+{
+	struct cromdisk_softc *sc;
+	struct bootinfo *bi;
+	struct physmem *phys;
+	uint8_t* data;
+	uint16_t blocks;
+	device_t dev;
+
+	machine_bootinfo(&bi);
+	phys = &bi->bootdisk;
+	data = (uint8_t*) ptokv(phys->base);
+	blocks = data[0] | data[1]<<8;
+
+	dev = device_create(self, "ram0", D_BLK|D_PROT);
+
+	sc = device_private(dev);
+	sc->dev = dev;
+	sc->addr = (uint8_t*) data;
+	sc->size = (size_t) blocks * BSIZE;
+
+#ifdef DEBUG
+	printf("CROM disk at 0x%08x (%dK bytes compressed, %dK bytes real)\n",
+	       (u_int)sc->addr, phys->size/1024,
+	       sc->size/1024);
+#endif
+	return 0;
+}