Initial import

1 files changed, 1603 insertions, 0 deletions

diff --git a/drivers/crypto/nx/nx-842.c b/drivers/crypto/nx/nx-842.c
new file mode 100644
index 000000000..887196e9b
--- /dev/null
+++ b/drivers/crypto/nx/nx-842.c
@@ -0,0 +1,1603 @@
+/*
+ * Driver for IBM Power 842 compression accelerator
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *
+ * Copyright (C) IBM Corporation, 2012
+ *
+ * Authors: Robert Jennings <rcj@linux.vnet.ibm.com>
+ *          Seth Jennings <sjenning@linux.vnet.ibm.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/nx842.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+
+#include <asm/page.h>
+#include <asm/vio.h>
+
+#include "nx_csbcpb.h" /* struct nx_csbcpb */
+
+#define MODULE_NAME "nx-compress"
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Robert Jennings <rcj@linux.vnet.ibm.com>");
+MODULE_DESCRIPTION("842 H/W Compression driver for IBM Power processors");
+
+#define SHIFT_4K 12
+#define SHIFT_64K 16
+#define SIZE_4K (1UL << SHIFT_4K)
+#define SIZE_64K (1UL << SHIFT_64K)
+
+/* IO buffer must be 128 byte aligned */
+#define IO_BUFFER_ALIGN 128
+
+struct nx842_header {
+	int blocks_nr; /* number of compressed blocks */
+	int offset; /* offset of the first block (from beginning of header) */
+	int sizes[0]; /* size of compressed blocks */
+};
+
+static inline int nx842_header_size(const struct nx842_header *hdr)
+{
+	return sizeof(struct nx842_header) +
+			hdr->blocks_nr * sizeof(hdr->sizes[0]);
+}
+
+/* Macros for fields within nx_csbcpb */
+/* Check the valid bit within the csbcpb valid field */
+#define NX842_CSBCBP_VALID_CHK(x) (x & BIT_MASK(7))
+
+/* CE macros operate on the completion_extension field bits in the csbcpb.
+ * CE0 0=full completion, 1=partial completion
+ * CE1 0=CE0 indicates completion, 1=termination (output may be modified)
+ * CE2 0=processed_bytes is source bytes, 1=processed_bytes is target bytes */
+#define NX842_CSBCPB_CE0(x)	(x & BIT_MASK(7))
+#define NX842_CSBCPB_CE1(x)	(x & BIT_MASK(6))
+#define NX842_CSBCPB_CE2(x)	(x & BIT_MASK(5))
+
+/* The NX unit accepts data only on 4K page boundaries */
+#define NX842_HW_PAGE_SHIFT	SHIFT_4K
+#define NX842_HW_PAGE_SIZE	(ASM_CONST(1) << NX842_HW_PAGE_SHIFT)
+#define NX842_HW_PAGE_MASK	(~(NX842_HW_PAGE_SIZE-1))
+
+enum nx842_status {
+	UNAVAILABLE,
+	AVAILABLE
+};
+
+struct ibm_nx842_counters {
+	atomic64_t comp_complete;
+	atomic64_t comp_failed;
+	atomic64_t decomp_complete;
+	atomic64_t decomp_failed;
+	atomic64_t swdecomp;
+	atomic64_t comp_times[32];
+	atomic64_t decomp_times[32];
+};
+
+static struct nx842_devdata {
+	struct vio_dev *vdev;
+	struct device *dev;
+	struct ibm_nx842_counters *counters;
+	unsigned int max_sg_len;
+	unsigned int max_sync_size;
+	unsigned int max_sync_sg;
+	enum nx842_status status;
+} __rcu *devdata;
+static DEFINE_SPINLOCK(devdata_mutex);
+
+#define NX842_COUNTER_INC(_x) \
+static inline void nx842_inc_##_x( \
+	const struct nx842_devdata *dev) { \
+	if (dev) \
+		atomic64_inc(&dev->counters->_x); \
+}
+NX842_COUNTER_INC(comp_complete);
+NX842_COUNTER_INC(comp_failed);
+NX842_COUNTER_INC(decomp_complete);
+NX842_COUNTER_INC(decomp_failed);
+NX842_COUNTER_INC(swdecomp);
+
+#define NX842_HIST_SLOTS 16
+
+static void ibm_nx842_incr_hist(atomic64_t *times, unsigned int time)
+{
+	int bucket = fls(time);
+
+	if (bucket)
+		bucket = min((NX842_HIST_SLOTS - 1), bucket - 1);
+
+	atomic64_inc(&times[bucket]);
+}
+
+/* NX unit operation flags */
+#define NX842_OP_COMPRESS	0x0
+#define NX842_OP_CRC		0x1
+#define NX842_OP_DECOMPRESS	0x2
+#define NX842_OP_COMPRESS_CRC   (NX842_OP_COMPRESS | NX842_OP_CRC)
+#define NX842_OP_DECOMPRESS_CRC (NX842_OP_DECOMPRESS | NX842_OP_CRC)
+#define NX842_OP_ASYNC		(1<<23)
+#define NX842_OP_NOTIFY		(1<<22)
+#define NX842_OP_NOTIFY_INT(x)	((x & 0xff)<<8)
+
+static unsigned long nx842_get_desired_dma(struct vio_dev *viodev)
+{
+	/* No use of DMA mappings within the driver. */
+	return 0;
+}
+
+struct nx842_slentry {
+	unsigned long ptr; /* Real address (use __pa()) */
+	unsigned long len;
+};
+
+/* pHyp scatterlist entry */
+struct nx842_scatterlist {
+	int entry_nr; /* number of slentries */
+	struct nx842_slentry *entries; /* ptr to array of slentries */
+};
+
+/* Does not include sizeof(entry_nr) in the size */
+static inline unsigned long nx842_get_scatterlist_size(
+				struct nx842_scatterlist *sl)
+{
+	return sl->entry_nr * sizeof(struct nx842_slentry);
+}
+
+static inline unsigned long nx842_get_pa(void *addr)
+{
+	if (is_vmalloc_addr(addr))
+		return page_to_phys(vmalloc_to_page(addr))
+		       + offset_in_page(addr);
+	else
+		return __pa(addr);
+}
+
+static int nx842_build_scatterlist(unsigned long buf, int len,
+			struct nx842_scatterlist *sl)
+{
+	unsigned long nextpage;
+	struct nx842_slentry *entry;
+
+	sl->entry_nr = 0;
+
+	entry = sl->entries;
+	while (len) {
+		entry->ptr = nx842_get_pa((void *)buf);
+		nextpage = ALIGN(buf + 1, NX842_HW_PAGE_SIZE);
+		if (nextpage < buf + len) {
+			/* we aren't at the end yet */
+			if (IS_ALIGNED(buf, NX842_HW_PAGE_SIZE))
+				/* we are in the middle (or beginning) */
+				entry->len = NX842_HW_PAGE_SIZE;
+			else
+				/* we are at the beginning */
+				entry->len = nextpage - buf;
+		} else {
+			/* at the end */
+			entry->len = len;
+		}
+
+		len -= entry->len;
+		buf += entry->len;
+		sl->entry_nr++;
+		entry++;
+	}
+
+	return 0;
+}
+
+/*
+ * Working memory for software decompression
+ */
+struct sw842_fifo {
+	union {
+		char f8[256][8];
+		char f4[512][4];
+	};
+	char f2[256][2];
+	unsigned char f84_full;
+	unsigned char f2_full;
+	unsigned char f8_count;
+	unsigned char f2_count;
+	unsigned int f4_count;
+};
+
+/*
+ * Working memory for crypto API
+ */
+struct nx842_workmem {
+	char bounce[PAGE_SIZE]; /* bounce buffer for decompression input */
+	union {
+		/* hardware working memory */
+		struct {
+			/* scatterlist */
+			char slin[SIZE_4K];
+			char slout[SIZE_4K];
+			/* coprocessor status/parameter block */
+			struct nx_csbcpb csbcpb;
+		};
+		/* software working memory */
+		struct sw842_fifo swfifo; /* software decompression fifo */
+	};
+};
+
+int nx842_get_workmem_size(void)
+{
+	return sizeof(struct nx842_workmem) + NX842_HW_PAGE_SIZE;
+}
+EXPORT_SYMBOL_GPL(nx842_get_workmem_size);
+
+int nx842_get_workmem_size_aligned(void)
+{
+	return sizeof(struct nx842_workmem);
+}
+EXPORT_SYMBOL_GPL(nx842_get_workmem_size_aligned);
+
+static int nx842_validate_result(struct device *dev,
+	struct cop_status_block *csb)
+{
+	/* The csb must be valid after returning from vio_h_cop_sync */
+	if (!NX842_CSBCBP_VALID_CHK(csb->valid)) {
+		dev_err(dev, "%s: cspcbp not valid upon completion.\n",
+				__func__);
+		dev_dbg(dev, "valid:0x%02x cs:0x%02x cc:0x%02x ce:0x%02x\n",
+				csb->valid,
+				csb->crb_seq_number,
+				csb->completion_code,
+				csb->completion_extension);
+		dev_dbg(dev, "processed_bytes:%d address:0x%016lx\n",
+				csb->processed_byte_count,
+				(unsigned long)csb->address);
+		return -EIO;
+	}
+
+	/* Check return values from the hardware in the CSB */
+	switch (csb->completion_code) {
+	case 0:	/* Completed without error */
+		break;
+	case 64: /* Target bytes > Source bytes during compression */
+	case 13: /* Output buffer too small */
+		dev_dbg(dev, "%s: Compression output larger than input\n",
+					__func__);
+		return -ENOSPC;
+	case 66: /* Input data contains an illegal template field */
+	case 67: /* Template indicates data past the end of the input stream */
+		dev_dbg(dev, "%s: Bad data for decompression (code:%d)\n",
+					__func__, csb->completion_code);
+		return -EINVAL;
+	default:
+		dev_dbg(dev, "%s: Unspecified error (code:%d)\n",
+					__func__, csb->completion_code);
+		return -EIO;
+	}
+
+	/* Hardware sanity check */
+	if (!NX842_CSBCPB_CE2(csb->completion_extension)) {
+		dev_err(dev, "%s: No error returned by hardware, but "
+				"data returned is unusable, contact support.\n"
+				"(Additional info: csbcbp->processed bytes "
+				"does not specify processed bytes for the "
+				"target buffer.)\n", __func__);
+		return -EIO;
+	}
+
+	return 0;
+}
+
+/**
+ * nx842_compress - Compress data using the 842 algorithm
+ *
+ * Compression provide by the NX842 coprocessor on IBM Power systems.
+ * The input buffer is compressed and the result is stored in the
+ * provided output buffer.
+ *
+ * Upon return from this function @outlen contains the length of the
+ * compressed data.  If there is an error then @outlen will be 0 and an
+ * error will be specified by the return code from this function.
+ *
+ * @in: Pointer to input buffer, must be page aligned
+ * @inlen: Length of input buffer, must be PAGE_SIZE
+ * @out: Pointer to output buffer
+ * @outlen: Length of output buffer
+ * @wrkmem: ptr to buffer for working memory, size determined by
+ *          nx842_get_workmem_size()
+ *
+ * Returns:
+ *   0		Success, output of length @outlen stored in the buffer at @out
+ *   -ENOMEM	Unable to allocate internal buffers
+ *   -ENOSPC	Output buffer is to small
+ *   -EMSGSIZE	XXX Difficult to describe this limitation
+ *   -EIO	Internal error
+ *   -ENODEV	Hardware unavailable
+ */
+int nx842_compress(const unsigned char *in, unsigned int inlen,
+		       unsigned char *out, unsigned int *outlen, void *wmem)
+{
+	struct nx842_header *hdr;
+	struct nx842_devdata *local_devdata;
+	struct device *dev = NULL;
+	struct nx842_workmem *workmem;
+	struct nx842_scatterlist slin, slout;
+	struct nx_csbcpb *csbcpb;
+	int ret = 0, max_sync_size, i, bytesleft, size, hdrsize;
+	unsigned long inbuf, outbuf, padding;
+	struct vio_pfo_op op = {
+		.done = NULL,
+		.handle = 0,
+		.timeout = 0,
+	};
+	unsigned long start_time = get_tb();
+
+	/*
+	 * Make sure input buffer is 64k page aligned.  This is assumed since
+	 * this driver is designed for page compression only (for now).  This
+	 * is very nice since we can now use direct DDE(s) for the input and
+	 * the alignment is guaranteed.
+	*/
+	inbuf = (unsigned long)in;
+	if (!IS_ALIGNED(inbuf, PAGE_SIZE) || inlen != PAGE_SIZE)
+		return -EINVAL;
+
+	rcu_read_lock();
+	local_devdata = rcu_dereference(devdata);
+	if (!local_devdata || !local_devdata->dev) {
+		rcu_read_unlock();
+		return -ENODEV;
+	}
+	max_sync_size = local_devdata->max_sync_size;
+	dev = local_devdata->dev;
+
+	/* Create the header */
+	hdr = (struct nx842_header *)out;
+	hdr->blocks_nr = PAGE_SIZE / max_sync_size;
+	hdrsize = nx842_header_size(hdr);
+	outbuf = (unsigned long)out + hdrsize;
+	bytesleft = *outlen - hdrsize;
+
+	/* Init scatterlist */
+	workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
+		NX842_HW_PAGE_SIZE);
+	slin.entries = (struct nx842_slentry *)workmem->slin;
+	slout.entries = (struct nx842_slentry *)workmem->slout;
+
+	/* Init operation */
+	op.flags = NX842_OP_COMPRESS;
+	csbcpb = &workmem->csbcpb;
+	memset(csbcpb, 0, sizeof(*csbcpb));
+	op.csbcpb = nx842_get_pa(csbcpb);
+	op.out = nx842_get_pa(slout.entries);
+
+	for (i = 0; i < hdr->blocks_nr; i++) {
+		/*
+		 * Aligning the output blocks to 128 bytes does waste space,
+		 * but it prevents the need for bounce buffers and memory
+		 * copies.  It also simplifies the code a lot.  In the worst
+		 * case (64k page, 4k max_sync_size), you lose up to
+		 * (128*16)/64k = ~3% the compression factor. For 64k
+		 * max_sync_size, the loss would be at most 128/64k = ~0.2%.
+		 */
+		padding = ALIGN(outbuf, IO_BUFFER_ALIGN) - outbuf;
+		outbuf += padding;
+		bytesleft -= padding;
+		if (i == 0)
+			/* save offset into first block in header */
+			hdr->offset = padding + hdrsize;
+
+		if (bytesleft <= 0) {
+			ret = -ENOSPC;
+			goto unlock;
+		}
+
+		/*
+		 * NOTE: If the default max_sync_size is changed from 4k
+		 * to 64k, remove the "likely" case below, since a
+		 * scatterlist will always be needed.
+		 */
+		if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
+			/* Create direct DDE */
+			op.in = nx842_get_pa((void *)inbuf);
+			op.inlen = max_sync_size;
+
+		} else {
+			/* Create indirect DDE (scatterlist) */
+			nx842_build_scatterlist(inbuf, max_sync_size, &slin);
+			op.in = nx842_get_pa(slin.entries);
+			op.inlen = -nx842_get_scatterlist_size(&slin);
+		}
+
+		/*
+		 * If max_sync_size != NX842_HW_PAGE_SIZE, an indirect
+		 * DDE is required for the outbuf.
+		 * If max_sync_size == NX842_HW_PAGE_SIZE, outbuf must
+		 * also be page aligned (1 in 128/4k=32 chance) in order
+		 * to use a direct DDE.
+		 * This is unlikely, just use an indirect DDE always.
+		 */
+		nx842_build_scatterlist(outbuf,
+			min(bytesleft, max_sync_size), &slout);
+		/* op.out set before loop */
+		op.outlen = -nx842_get_scatterlist_size(&slout);
+
+		/* Send request to pHyp */
+		ret = vio_h_cop_sync(local_devdata->vdev, &op);
+
+		/* Check for pHyp error */
+		if (ret) {
+			dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
+				__func__, ret, op.hcall_err);
+			ret = -EIO;
+			goto unlock;
+		}
+
+		/* Check for hardware error */
+		ret = nx842_validate_result(dev, &csbcpb->csb);
+		if (ret && ret != -ENOSPC)
+			goto unlock;
+
+		/* Handle incompressible data */
+		if (unlikely(ret == -ENOSPC)) {
+			if (bytesleft < max_sync_size) {
+				/*
+				 * Not enough space left in the output buffer
+				 * to store uncompressed block
+				 */
+				goto unlock;
+			} else {
+				/* Store incompressible block */
+				memcpy((void *)outbuf, (void *)inbuf,
+					max_sync_size);
+				hdr->sizes[i] = -max_sync_size;
+				outbuf += max_sync_size;
+				bytesleft -= max_sync_size;
+				/* Reset ret, incompressible data handled */
+				ret = 0;
+			}
+		} else {
+			/* Normal case, compression was successful */
+			size = csbcpb->csb.processed_byte_count;
+			dev_dbg(dev, "%s: processed_bytes=%d\n",
+				__func__, size);
+			hdr->sizes[i] = size;
+			outbuf += size;
+			bytesleft -= size;
+		}
+
+		inbuf += max_sync_size;
+	}
+
+	*outlen = (unsigned int)(outbuf - (unsigned long)out);
+
+unlock:
+	if (ret)
+		nx842_inc_comp_failed(local_devdata);
+	else {
+		nx842_inc_comp_complete(local_devdata);
+		ibm_nx842_incr_hist(local_devdata->counters->comp_times,
+			(get_tb() - start_time) / tb_ticks_per_usec);
+	}
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nx842_compress);
+
+static int sw842_decompress(const unsigned char *, int, unsigned char *, int *,
+			const void *);
+
+/**
+ * nx842_decompress - Decompress data using the 842 algorithm
+ *
+ * Decompression provide by the NX842 coprocessor on IBM Power systems.
+ * The input buffer is decompressed and the result is stored in the
+ * provided output buffer.  The size allocated to the output buffer is
+ * provided by the caller of this function in @outlen.  Upon return from
+ * this function @outlen contains the length of the decompressed data.
+ * If there is an error then @outlen will be 0 and an error will be
+ * specified by the return code from this function.
+ *
+ * @in: Pointer to input buffer, will use bounce buffer if not 128 byte
+ *      aligned
+ * @inlen: Length of input buffer
+ * @out: Pointer to output buffer, must be page aligned
+ * @outlen: Length of output buffer, must be PAGE_SIZE
+ * @wrkmem: ptr to buffer for working memory, size determined by
+ *          nx842_get_workmem_size()
+ *
+ * Returns:
+ *   0		Success, output of length @outlen stored in the buffer at @out
+ *   -ENODEV	Hardware decompression device is unavailable
+ *   -ENOMEM	Unable to allocate internal buffers
+ *   -ENOSPC	Output buffer is to small
+ *   -EINVAL	Bad input data encountered when attempting decompress
+ *   -EIO	Internal error
+ */
+int nx842_decompress(const unsigned char *in, unsigned int inlen,
+			 unsigned char *out, unsigned int *outlen, void *wmem)
+{
+	struct nx842_header *hdr;
+	struct nx842_devdata *local_devdata;
+	struct device *dev = NULL;
+	struct nx842_workmem *workmem;
+	struct nx842_scatterlist slin, slout;
+	struct nx_csbcpb *csbcpb;
+	int ret = 0, i, size, max_sync_size;
+	unsigned long inbuf, outbuf;
+	struct vio_pfo_op op = {
+		.done = NULL,
+		.handle = 0,
+		.timeout = 0,
+	};
+	unsigned long start_time = get_tb();
+
+	/* Ensure page alignment and size */
+	outbuf = (unsigned long)out;
+	if (!IS_ALIGNED(outbuf, PAGE_SIZE) || *outlen != PAGE_SIZE)
+		return -EINVAL;
+
+	rcu_read_lock();
+	local_devdata = rcu_dereference(devdata);
+	if (local_devdata)
+		dev = local_devdata->dev;
+
+	/* Get header */
+	hdr = (struct nx842_header *)in;
+
+	workmem = (struct nx842_workmem *)ALIGN((unsigned long)wmem,
+		NX842_HW_PAGE_SIZE);
+
+	inbuf = (unsigned long)in + hdr->offset;
+	if (likely(!IS_ALIGNED(inbuf, IO_BUFFER_ALIGN))) {
+		/* Copy block(s) into bounce buffer for alignment */
+		memcpy(workmem->bounce, in + hdr->offset, inlen - hdr->offset);
+		inbuf = (unsigned long)workmem->bounce;
+	}
+
+	/* Init scatterlist */
+	slin.entries = (struct nx842_slentry *)workmem->slin;
+	slout.entries = (struct nx842_slentry *)workmem->slout;
+
+	/* Init operation */
+	op.flags = NX842_OP_DECOMPRESS;
+	csbcpb = &workmem->csbcpb;
+	memset(csbcpb, 0, sizeof(*csbcpb));
+	op.csbcpb = nx842_get_pa(csbcpb);
+
+	/*
+	 * max_sync_size may have changed since compression,
+	 * so we can't read it from the device info. We need
+	 * to derive it from hdr->blocks_nr.
+	 */
+	max_sync_size = PAGE_SIZE / hdr->blocks_nr;
+
+	for (i = 0; i < hdr->blocks_nr; i++) {
+		/* Skip padding */
+		inbuf = ALIGN(inbuf, IO_BUFFER_ALIGN);
+
+		if (hdr->sizes[i] < 0) {
+			/* Negative sizes indicate uncompressed data blocks */
+			size = abs(hdr->sizes[i]);
+			memcpy((void *)outbuf, (void *)inbuf, size);
+			outbuf += size;
+			inbuf += size;
+			continue;
+		}
+
+		if (!dev)
+			goto sw;
+
+		/*
+		 * The better the compression, the more likely the "likely"
+		 * case becomes.
+		 */
+		if (likely((inbuf & NX842_HW_PAGE_MASK) ==
+			((inbuf + hdr->sizes[i] - 1) & NX842_HW_PAGE_MASK))) {
+			/* Create direct DDE */
+			op.in = nx842_get_pa((void *)inbuf);
+			op.inlen = hdr->sizes[i];
+		} else {
+			/* Create indirect DDE (scatterlist) */
+			nx842_build_scatterlist(inbuf, hdr->sizes[i] , &slin);
+			op.in = nx842_get_pa(slin.entries);
+			op.inlen = -nx842_get_scatterlist_size(&slin);
+		}
+
+		/*
+		 * NOTE: If the default max_sync_size is changed from 4k
+		 * to 64k, remove the "likely" case below, since a
+		 * scatterlist will always be needed.
+		 */
+		if (likely(max_sync_size == NX842_HW_PAGE_SIZE)) {
+			/* Create direct DDE */
+			op.out = nx842_get_pa((void *)outbuf);
+			op.outlen = max_sync_size;
+		} else {
+			/* Create indirect DDE (scatterlist) */
+			nx842_build_scatterlist(outbuf, max_sync_size, &slout);
+			op.out = nx842_get_pa(slout.entries);
+			op.outlen = -nx842_get_scatterlist_size(&slout);
+		}
+
+		/* Send request to pHyp */
+		ret = vio_h_cop_sync(local_devdata->vdev, &op);
+
+		/* Check for pHyp error */
+		if (ret) {
+			dev_dbg(dev, "%s: vio_h_cop_sync error (ret=%d, hret=%ld)\n",
+				__func__, ret, op.hcall_err);
+			dev = NULL;
+			goto sw;
+		}
+
+		/* Check for hardware error */
+		ret = nx842_validate_result(dev, &csbcpb->csb);
+		if (ret) {
+			dev = NULL;
+			goto sw;
+		}
+
+		/* HW decompression success */
+		inbuf += hdr->sizes[i];
+		outbuf += csbcpb->csb.processed_byte_count;
+		continue;
+
+sw:
+		/* software decompression */
+		size = max_sync_size;
+		ret = sw842_decompress(
+			(unsigned char *)inbuf, hdr->sizes[i],
+			(unsigned char *)outbuf, &size, wmem);
+		if (ret)
+			pr_debug("%s: sw842_decompress failed with %d\n",
+				__func__, ret);
+
+		if (ret) {
+			if (ret != -ENOSPC && ret != -EINVAL &&
+					ret != -EMSGSIZE)
+				ret = -EIO;
+			goto unlock;
+		}
+
+		/* SW decompression success */
+		inbuf += hdr->sizes[i];
+		outbuf += size;
+	}
+
+	*outlen = (unsigned int)(outbuf - (unsigned long)out);
+
+unlock:
+	if (ret)
+		/* decompress fail */
+		nx842_inc_decomp_failed(local_devdata);
+	else {
+		if (!dev)
+			/* software decompress */
+			nx842_inc_swdecomp(local_devdata);
+		nx842_inc_decomp_complete(local_devdata);
+		ibm_nx842_incr_hist(local_devdata->counters->decomp_times,
+			(get_tb() - start_time) / tb_ticks_per_usec);
+	}
+
+	rcu_read_unlock();
+	return ret;
+}
+EXPORT_SYMBOL_GPL(nx842_decompress);
+
+/**
+ * nx842_OF_set_defaults -- Set default (disabled) values for devdata
+ *
+ * @devdata - struct nx842_devdata to update
+ *
+ * Returns:
+ *  0 on success
+ *  -ENOENT if @devdata ptr is NULL
+ */
+static int nx842_OF_set_defaults(struct nx842_devdata *devdata)
+{
+	if (devdata) {
+		devdata->max_sync_size = 0;
+		devdata->max_sync_sg = 0;
+		devdata->max_sg_len = 0;
+		devdata->status = UNAVAILABLE;
+		return 0;
+	} else
+		return -ENOENT;
+}
+
+/**
+ * nx842_OF_upd_status -- Update the device info from OF status prop
+ *
+ * The status property indicates if the accelerator is enabled.  If the
+ * device is in the OF tree it indicates that the hardware is present.
+ * The status field indicates if the device is enabled when the status
+ * is 'okay'.  Otherwise the device driver will be disabled.
+ *
+ * @devdata - struct nx842_devdata to update
+ * @prop - struct property point containing the maxsyncop for the update
+ *
+ * Returns:
+ *  0 - Device is available
+ *  -EINVAL - Device is not available
+ */
+static int nx842_OF_upd_status(struct nx842_devdata *devdata,
+					struct property *prop) {
+	int ret = 0;
+	const char *status = (const char *)prop->value;
+
+	if (!strncmp(status, "okay", (size_t)prop->length)) {
+		devdata->status = AVAILABLE;
+	} else {
+		dev_info(devdata->dev, "%s: status '%s' is not 'okay'\n",
+				__func__, status);
+		devdata->status = UNAVAILABLE;
+	}
+
+	return ret;
+}
+
+/**
+ * nx842_OF_upd_maxsglen -- Update the device info from OF maxsglen prop
+ *
+ * Definition of the 'ibm,max-sg-len' OF property:
+ *  This field indicates the maximum byte length of a scatter list
+ *  for the platform facility. It is a single cell encoded as with encode-int.
+ *
+ * Example:
+ *  # od -x ibm,max-sg-len
+ *  0000000 0000 0ff0
+ *
+ *  In this example, the maximum byte length of a scatter list is
+ *  0x0ff0 (4,080).
+ *
+ * @devdata - struct nx842_devdata to update
+ * @prop - struct property point containing the maxsyncop for the update
+ *
+ * Returns:
+ *  0 on success
+ *  -EINVAL on failure
+ */
+static int nx842_OF_upd_maxsglen(struct nx842_devdata *devdata,
+					struct property *prop) {
+	int ret = 0;
+	const int *maxsglen = prop->value;
+
+	if (prop->length != sizeof(*maxsglen)) {
+		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sg-len property\n", __func__);
+		dev_dbg(devdata->dev, "%s: ibm,max-sg-len is %d bytes long, expected %lu bytes\n", __func__,
+				prop->length, sizeof(*maxsglen));
+		ret = -EINVAL;
+	} else {
+		devdata->max_sg_len = (unsigned int)min(*maxsglen,
+				(int)NX842_HW_PAGE_SIZE);
+	}
+
+	return ret;
+}
+
+/**
+ * nx842_OF_upd_maxsyncop -- Update the device info from OF maxsyncop prop
+ *
+ * Definition of the 'ibm,max-sync-cop' OF property:
+ *  Two series of cells.  The first series of cells represents the maximums
+ *  that can be synchronously compressed. The second series of cells
+ *  represents the maximums that can be synchronously decompressed.
+ *  1. The first cell in each series contains the count of the number of
+ *     data length, scatter list elements pairs that follow – each being
+ *     of the form
+ *    a. One cell data byte length
+ *    b. One cell total number of scatter list elements
+ *
+ * Example:
+ *  # od -x ibm,max-sync-cop
+ *  0000000 0000 0001 0000 1000 0000 01fe 0000 0001
+ *  0000020 0000 1000 0000 01fe
+ *
+ *  In this example, compression supports 0x1000 (4,096) data byte length
+ *  and 0x1fe (510) total scatter list elements.  Decompression supports
+ *  0x1000 (4,096) data byte length and 0x1f3 (510) total scatter list
+ *  elements.
+ *
+ * @devdata - struct nx842_devdata to update
+ * @prop - struct property point containing the maxsyncop for the update
+ *
+ * Returns:
+ *  0 on success
+ *  -EINVAL on failure
+ */
+static int nx842_OF_upd_maxsyncop(struct nx842_devdata *devdata,
+					struct property *prop) {
+	int ret = 0;
+	const struct maxsynccop_t {
+		int comp_elements;
+		int comp_data_limit;
+		int comp_sg_limit;
+		int decomp_elements;
+		int decomp_data_limit;
+		int decomp_sg_limit;
+	} *maxsynccop;
+
+	if (prop->length != sizeof(*maxsynccop)) {
+		dev_err(devdata->dev, "%s: unexpected format for ibm,max-sync-cop property\n", __func__);
+		dev_dbg(devdata->dev, "%s: ibm,max-sync-cop is %d bytes long, expected %lu bytes\n", __func__, prop->length,
+				sizeof(*maxsynccop));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	maxsynccop = (const struct maxsynccop_t *)prop->value;
+
+	/* Use one limit rather than separate limits for compression and
+	 * decompression. Set a maximum for this so as not to exceed the
+	 * size that the header can support and round the value down to
+	 * the hardware page size (4K) */
+	devdata->max_sync_size =
+			(unsigned int)min(maxsynccop->comp_data_limit,
+					maxsynccop->decomp_data_limit);
+
+	devdata->max_sync_size = min_t(unsigned int, devdata->max_sync_size,
+					SIZE_64K);
+
+	if (devdata->max_sync_size < SIZE_4K) {
+		dev_err(devdata->dev, "%s: hardware max data size (%u) is "
+				"less than the driver minimum, unable to use "
+				"the hardware device\n",
+				__func__, devdata->max_sync_size);
+		ret = -EINVAL;
+		goto out;
+	}
+
+	devdata->max_sync_sg = (unsigned int)min(maxsynccop->comp_sg_limit,
+						maxsynccop->decomp_sg_limit);
+	if (devdata->max_sync_sg < 1) {
+		dev_err(devdata->dev, "%s: hardware max sg size (%u) is "
+				"less than the driver minimum, unable to use "
+				"the hardware device\n",
+				__func__, devdata->max_sync_sg);
+		ret = -EINVAL;
+		goto out;
+	}
+
+out:
+	return ret;
+}
+
+/**
+ *
+ * nx842_OF_upd -- Handle OF properties updates for the device.
+ *
+ * Set all properties from the OF tree.  Optionally, a new property
+ * can be provided by the @new_prop pointer to overwrite an existing value.
+ * The device will remain disabled until all values are valid, this function
+ * will return an error for updates unless all values are valid.
+ *
+ * @new_prop: If not NULL, this property is being updated.  If NULL, update
+ *  all properties from the current values in the OF tree.
+ *
+ * Returns:
+ *  0 - Success
+ *  -ENOMEM - Could not allocate memory for new devdata structure
+ *  -EINVAL - property value not found, new_prop is not a recognized
+ *	property for the device or property value is not valid.
+ *  -ENODEV - Device is not available
+ */
+static int nx842_OF_upd(struct property *new_prop)
+{
+	struct nx842_devdata *old_devdata = NULL;
+	struct nx842_devdata *new_devdata = NULL;
+	struct device_node *of_node = NULL;
+	struct property *status = NULL;
+	struct property *maxsglen = NULL;
+	struct property *maxsyncop = NULL;
+	int ret = 0;
+	unsigned long flags;
+
+	spin_lock_irqsave(&devdata_mutex, flags);
+	old_devdata = rcu_dereference_check(devdata,
+			lockdep_is_held(&devdata_mutex));
+	if (old_devdata)
+		of_node = old_devdata->dev->of_node;
+
+	if (!old_devdata || !of_node) {
+		pr_err("%s: device is not available\n", __func__);
+		spin_unlock_irqrestore(&devdata_mutex, flags);
+		return -ENODEV;
+	}
+
+	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
+	if (!new_devdata) {
+		dev_err(old_devdata->dev, "%s: Could not allocate memory for device data\n", __func__);
+		ret = -ENOMEM;
+		goto error_out;
+	}
+
+	memcpy(new_devdata, old_devdata, sizeof(*old_devdata));
+	new_devdata->counters = old_devdata->counters;
+
+	/* Set ptrs for existing properties */
+	status = of_find_property(of_node, "status", NULL);
+	maxsglen = of_find_property(of_node, "ibm,max-sg-len", NULL);
+	maxsyncop = of_find_property(of_node, "ibm,max-sync-cop", NULL);
+	if (!status || !maxsglen || !maxsyncop) {
+		dev_err(old_devdata->dev, "%s: Could not locate device properties\n", __func__);
+		ret = -EINVAL;
+		goto error_out;
+	}
+
+	/*
+	 * If this is a property update, there are only certain properties that
+	 * we care about. Bail if it isn't in the below list
+	 */
+	if (new_prop && (strncmp(new_prop->name, "status", new_prop->length) ||
+		         strncmp(new_prop->name, "ibm,max-sg-len", new_prop->length) ||
+		         strncmp(new_prop->name, "ibm,max-sync-cop", new_prop->length)))
+		goto out;
+
+	/* Perform property updates */
+	ret = nx842_OF_upd_status(new_devdata, status);
+	if (ret)
+		goto error_out;
+
+	ret = nx842_OF_upd_maxsglen(new_devdata, maxsglen);
+	if (ret)
+		goto error_out;
+
+	ret = nx842_OF_upd_maxsyncop(new_devdata, maxsyncop);
+	if (ret)
+		goto error_out;
+
+out:
+	dev_info(old_devdata->dev, "%s: max_sync_size new:%u old:%u\n",
+			__func__, new_devdata->max_sync_size,
+			old_devdata->max_sync_size);
+	dev_info(old_devdata->dev, "%s: max_sync_sg new:%u old:%u\n",
+			__func__, new_devdata->max_sync_sg,
+			old_devdata->max_sync_sg);
+	dev_info(old_devdata->dev, "%s: max_sg_len new:%u old:%u\n",
+			__func__, new_devdata->max_sg_len,
+			old_devdata->max_sg_len);
+
+	rcu_assign_pointer(devdata, new_devdata);
+	spin_unlock_irqrestore(&devdata_mutex, flags);
+	synchronize_rcu();
+	dev_set_drvdata(new_devdata->dev, new_devdata);
+	kfree(old_devdata);
+	return 0;
+
+error_out:
+	if (new_devdata) {
+		dev_info(old_devdata->dev, "%s: device disabled\n", __func__);
+		nx842_OF_set_defaults(new_devdata);
+		rcu_assign_pointer(devdata, new_devdata);
+		spin_unlock_irqrestore(&devdata_mutex, flags);
+		synchronize_rcu();
+		dev_set_drvdata(new_devdata->dev, new_devdata);
+		kfree(old_devdata);
+	} else {
+		dev_err(old_devdata->dev, "%s: could not update driver from hardware\n", __func__);
+		spin_unlock_irqrestore(&devdata_mutex, flags);
+	}
+
+	if (!ret)
+		ret = -EINVAL;
+	return ret;
+}
+
+/**
+ * nx842_OF_notifier - Process updates to OF properties for the device
+ *
+ * @np: notifier block
+ * @action: notifier action
+ * @update: struct pSeries_reconfig_prop_update pointer if action is
+ *	PSERIES_UPDATE_PROPERTY
+ *
+ * Returns:
+ *	NOTIFY_OK on success
+ *	NOTIFY_BAD encoded with error number on failure, use
+ *		notifier_to_errno() to decode this value
+ */
+static int nx842_OF_notifier(struct notifier_block *np, unsigned long action,
+			     void *data)
+{
+	struct of_reconfig_data *upd = data;
+	struct nx842_devdata *local_devdata;
+	struct device_node *node = NULL;
+
+	rcu_read_lock();
+	local_devdata = rcu_dereference(devdata);
+	if (local_devdata)
+		node = local_devdata->dev->of_node;
+
+	if (local_devdata &&
+			action == OF_RECONFIG_UPDATE_PROPERTY &&
+			!strcmp(upd->dn->name, node->name)) {
+		rcu_read_unlock();
+		nx842_OF_upd(upd->prop);
+	} else
+		rcu_read_unlock();
+
+	return NOTIFY_OK;
+}
+
+static struct notifier_block nx842_of_nb = {
+	.notifier_call = nx842_OF_notifier,
+};
+
+#define nx842_counter_read(_name)					\
+static ssize_t nx842_##_name##_show(struct device *dev,		\
+		struct device_attribute *attr,				\
+		char *buf) {						\
+	struct nx842_devdata *local_devdata;			\
+	int p = 0;							\
+	rcu_read_lock();						\
+	local_devdata = rcu_dereference(devdata);			\
+	if (local_devdata)						\
+		p = snprintf(buf, PAGE_SIZE, "%ld\n",			\
+		       atomic64_read(&local_devdata->counters->_name));	\
+	rcu_read_unlock();						\
+	return p;							\
+}
+
+#define NX842DEV_COUNTER_ATTR_RO(_name)					\
+	nx842_counter_read(_name);					\
+	static struct device_attribute dev_attr_##_name = __ATTR(_name,	\
+						0444,			\
+						nx842_##_name##_show,\
+						NULL);
+
+NX842DEV_COUNTER_ATTR_RO(comp_complete);
+NX842DEV_COUNTER_ATTR_RO(comp_failed);
+NX842DEV_COUNTER_ATTR_RO(decomp_complete);
+NX842DEV_COUNTER_ATTR_RO(decomp_failed);
+NX842DEV_COUNTER_ATTR_RO(swdecomp);
+
+static ssize_t nx842_timehist_show(struct device *,
+		struct device_attribute *, char *);
+
+static struct device_attribute dev_attr_comp_times = __ATTR(comp_times, 0444,
+		nx842_timehist_show, NULL);
+static struct device_attribute dev_attr_decomp_times = __ATTR(decomp_times,
+		0444, nx842_timehist_show, NULL);
+
+static ssize_t nx842_timehist_show(struct device *dev,
+		struct device_attribute *attr, char *buf) {
+	char *p = buf;
+	struct nx842_devdata *local_devdata;
+	atomic64_t *times;
+	int bytes_remain = PAGE_SIZE;
+	int bytes;
+	int i;
+
+	rcu_read_lock();
+	local_devdata = rcu_dereference(devdata);
+	if (!local_devdata) {
+		rcu_read_unlock();
+		return 0;
+	}
+
+	if (attr == &dev_attr_comp_times)
+		times = local_devdata->counters->comp_times;
+	else if (attr == &dev_attr_decomp_times)
+		times = local_devdata->counters->decomp_times;
+	else {
+		rcu_read_unlock();
+		return 0;
+	}
+
+	for (i = 0; i < (NX842_HIST_SLOTS - 2); i++) {
+		bytes = snprintf(p, bytes_remain, "%u-%uus:\t%ld\n",
+			       i ? (2<<(i-1)) : 0, (2<<i)-1,
+			       atomic64_read(&times[i]));
+		bytes_remain -= bytes;
+		p += bytes;
+	}
+	/* The last bucket holds everything over
+	 * 2<<(NX842_HIST_SLOTS - 2) us */
+	bytes = snprintf(p, bytes_remain, "%uus - :\t%ld\n",
+			2<<(NX842_HIST_SLOTS - 2),
+			atomic64_read(&times[(NX842_HIST_SLOTS - 1)]));
+	p += bytes;
+
+	rcu_read_unlock();
+	return p - buf;
+}
+
+static struct attribute *nx842_sysfs_entries[] = {
+	&dev_attr_comp_complete.attr,
+	&dev_attr_comp_failed.attr,
+	&dev_attr_decomp_complete.attr,
+	&dev_attr_decomp_failed.attr,
+	&dev_attr_swdecomp.attr,
+	&dev_attr_comp_times.attr,
+	&dev_attr_decomp_times.attr,
+	NULL,
+};
+
+static struct attribute_group nx842_attribute_group = {
+	.name = NULL,		/* put in device directory */
+	.attrs = nx842_sysfs_entries,
+};
+
+static int __init nx842_probe(struct vio_dev *viodev,
+				  const struct vio_device_id *id)
+{
+	struct nx842_devdata *old_devdata, *new_devdata = NULL;
+	unsigned long flags;
+	int ret = 0;
+
+	spin_lock_irqsave(&devdata_mutex, flags);
+	old_devdata = rcu_dereference_check(devdata,
+			lockdep_is_held(&devdata_mutex));
+
+	if (old_devdata && old_devdata->vdev != NULL) {
+		dev_err(&viodev->dev, "%s: Attempt to register more than one instance of the hardware\n", __func__);
+		ret = -1;
+		goto error_unlock;
+	}
+
+	dev_set_drvdata(&viodev->dev, NULL);
+
+	new_devdata = kzalloc(sizeof(*new_devdata), GFP_NOFS);
+	if (!new_devdata) {
+		dev_err(&viodev->dev, "%s: Could not allocate memory for device data\n", __func__);
+		ret = -ENOMEM;
+		goto error_unlock;
+	}
+
+	new_devdata->counters = kzalloc(sizeof(*new_devdata->counters),
+			GFP_NOFS);
+	if (!new_devdata->counters) {
+		dev_err(&viodev->dev, "%s: Could not allocate memory for performance counters\n", __func__);
+		ret = -ENOMEM;
+		goto error_unlock;
+	}
+
+	new_devdata->vdev = viodev;
+	new_devdata->dev = &viodev->dev;
+	nx842_OF_set_defaults(new_devdata);
+
+	rcu_assign_pointer(devdata, new_devdata);
+	spin_unlock_irqrestore(&devdata_mutex, flags);
+	synchronize_rcu();
+	kfree(old_devdata);
+
+	of_reconfig_notifier_register(&nx842_of_nb);
+
+	ret = nx842_OF_upd(NULL);
+	if (ret && ret != -ENODEV) {
+		dev_err(&viodev->dev, "could not parse device tree. %d\n", ret);
+		ret = -1;
+		goto error;
+	}
+
+	rcu_read_lock();
+	dev_set_drvdata(&viodev->dev, rcu_dereference(devdata));
+	rcu_read_unlock();
+
+	if (sysfs_create_group(&viodev->dev.kobj, &nx842_attribute_group)) {
+		dev_err(&viodev->dev, "could not create sysfs device attributes\n");
+		ret = -1;
+		goto error;
+	}
+
+	return 0;
+
+error_unlock:
+	spin_unlock_irqrestore(&devdata_mutex, flags);
+	if (new_devdata)
+		kfree(new_devdata->counters);
+	kfree(new_devdata);
+error:
+	return ret;
+}
+
+static int __exit nx842_remove(struct vio_dev *viodev)
+{
+	struct nx842_devdata *old_devdata;
+	unsigned long flags;
+
+	pr_info("Removing IBM Power 842 compression device\n");
+	sysfs_remove_group(&viodev->dev.kobj, &nx842_attribute_group);
+
+	spin_lock_irqsave(&devdata_mutex, flags);
+	old_devdata = rcu_dereference_check(devdata,
+			lockdep_is_held(&devdata_mutex));
+	of_reconfig_notifier_unregister(&nx842_of_nb);
+	RCU_INIT_POINTER(devdata, NULL);
+	spin_unlock_irqrestore(&devdata_mutex, flags);
+	synchronize_rcu();
+	dev_set_drvdata(&viodev->dev, NULL);
+	if (old_devdata)
+		kfree(old_devdata->counters);
+	kfree(old_devdata);
+	return 0;
+}
+
+static struct vio_device_id nx842_driver_ids[] = {
+	{"ibm,compression-v1", "ibm,compression"},
+	{"", ""},
+};
+
+static struct vio_driver nx842_driver = {
+	.name = MODULE_NAME,
+	.probe = nx842_probe,
+	.remove = __exit_p(nx842_remove),
+	.get_desired_dma = nx842_get_desired_dma,
+	.id_table = nx842_driver_ids,
+};
+
+static int __init nx842_init(void)
+{
+	struct nx842_devdata *new_devdata;
+	pr_info("Registering IBM Power 842 compression driver\n");
+
+	RCU_INIT_POINTER(devdata, NULL);
+	new_devdata = kzalloc(sizeof(*new_devdata), GFP_KERNEL);
+	if (!new_devdata) {
+		pr_err("Could not allocate memory for device data\n");
+		return -ENOMEM;
+	}
+	new_devdata->status = UNAVAILABLE;
+	RCU_INIT_POINTER(devdata, new_devdata);
+
+	return vio_register_driver(&nx842_driver);
+}
+
+module_init(nx842_init);
+
+static void __exit nx842_exit(void)
+{
+	struct nx842_devdata *old_devdata;
+	unsigned long flags;
+
+	pr_info("Exiting IBM Power 842 compression driver\n");
+	spin_lock_irqsave(&devdata_mutex, flags);
+	old_devdata = rcu_dereference_check(devdata,
+			lockdep_is_held(&devdata_mutex));
+	RCU_INIT_POINTER(devdata, NULL);
+	spin_unlock_irqrestore(&devdata_mutex, flags);
+	synchronize_rcu();
+	if (old_devdata)
+		dev_set_drvdata(old_devdata->dev, NULL);
+	kfree(old_devdata);
+	vio_unregister_driver(&nx842_driver);
+}
+
+module_exit(nx842_exit);
+
+/*********************************
+ * 842 software decompressor
+*********************************/
+typedef int (*sw842_template_op)(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+
+static int sw842_data8(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+static int sw842_data4(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+static int sw842_data2(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+static int sw842_ptr8(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+static int sw842_ptr4(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+static int sw842_ptr2(const char **, int *, unsigned char **,
+						struct sw842_fifo *);
+
+/* special templates */
+#define SW842_TMPL_REPEAT 0x1B
+#define SW842_TMPL_ZEROS 0x1C
+#define SW842_TMPL_EOF 0x1E
+
+static sw842_template_op sw842_tmpl_ops[26][4] = {
+	{ sw842_data8, NULL}, /* 0 (00000) */
+	{ sw842_data4, sw842_data2, sw842_ptr2,  NULL},
+	{ sw842_data4, sw842_ptr2,  sw842_data2, NULL},
+	{ sw842_data4, sw842_ptr2,  sw842_ptr2,  NULL},
+	{ sw842_data4, sw842_ptr4,  NULL},
+	{ sw842_data2, sw842_ptr2,  sw842_data4, NULL},
+	{ sw842_data2, sw842_ptr2,  sw842_data2, sw842_ptr2},
+	{ sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_data2},
+	{ sw842_data2, sw842_ptr2,  sw842_ptr2,  sw842_ptr2,},
+	{ sw842_data2, sw842_ptr2,  sw842_ptr4,  NULL},
+	{ sw842_ptr2,  sw842_data2, sw842_data4, NULL}, /* 10 (01010) */
+	{ sw842_ptr2,  sw842_data4, sw842_ptr2,  NULL},
+	{ sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_data2},
+	{ sw842_ptr2,  sw842_data2, sw842_ptr2,  sw842_ptr2},
+	{ sw842_ptr2,  sw842_data2, sw842_ptr4,  NULL},
+	{ sw842_ptr2,  sw842_ptr2,  sw842_data4, NULL},
+	{ sw842_ptr2,  sw842_ptr2,  sw842_data2, sw842_ptr2},
+	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_data2},
+	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr2,  sw842_ptr2},
+	{ sw842_ptr2,  sw842_ptr2,  sw842_ptr4,  NULL},
+	{ sw842_ptr4,  sw842_data4, NULL}, /* 20 (10100) */
+	{ sw842_ptr4,  sw842_data2, sw842_ptr2,  NULL},
+	{ sw842_ptr4,  sw842_ptr2,  sw842_data2, NULL},
+	{ sw842_ptr4,  sw842_ptr2,  sw842_ptr2,  NULL},
+	{ sw842_ptr4,  sw842_ptr4,  NULL},
+	{ sw842_ptr8,  NULL}
+};
+
+/* Software decompress helpers */
+
+static uint8_t sw842_get_byte(const char *buf, int bit)
+{
+	uint8_t tmpl;
+	uint16_t tmp;
+	tmp = htons(*(uint16_t *)(buf));
+	tmp = (uint16_t)(tmp << bit);
+	tmp = ntohs(tmp);
+	memcpy(&tmpl, &tmp, 1);
+	return tmpl;
+}
+
+static uint8_t sw842_get_template(const char **buf, int *bit)
+{
+	uint8_t byte;
+	byte = sw842_get_byte(*buf, *bit);
+	byte = byte >> 3;
+	byte &= 0x1F;
+	*buf += (*bit + 5) / 8;
+	*bit = (*bit + 5) % 8;
+	return byte;
+}
+
+/* repeat_count happens to be 5-bit too (like the template) */
+static uint8_t sw842_get_repeat_count(const char **buf, int *bit)
+{
+	uint8_t byte;
+	byte = sw842_get_byte(*buf, *bit);
+	byte = byte >> 2;
+	byte &= 0x3F;
+	*buf += (*bit + 6) / 8;
+	*bit = (*bit + 6) % 8;
+	return byte;
+}
+
+static uint8_t sw842_get_ptr2(const char **buf, int *bit)
+{
+	uint8_t ptr;
+	ptr = sw842_get_byte(*buf, *bit);
+	(*buf)++;
+	return ptr;
+}
+
+static uint16_t sw842_get_ptr4(const char **buf, int *bit,
+		struct sw842_fifo *fifo)
+{
+	uint16_t ptr;
+	ptr = htons(*(uint16_t *)(*buf));
+	ptr = (uint16_t)(ptr << *bit);
+	ptr = ptr >> 7;
+	ptr &= 0x01FF;
+	*buf += (*bit + 9) / 8;
+	*bit = (*bit + 9) % 8;
+	return ptr;
+}
+
+static uint8_t sw842_get_ptr8(const char **buf, int *bit,
+		struct sw842_fifo *fifo)
+{
+	return sw842_get_ptr2(buf, bit);
+}
+
+/* Software decompress template ops */
+
+static int sw842_data8(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	int ret;
+
+	ret = sw842_data4(inbuf, inbit, outbuf, fifo);
+	if (ret)
+		return ret;
+	ret = sw842_data4(inbuf, inbit, outbuf, fifo);
+	return ret;
+}
+
+static int sw842_data4(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	int ret;
+
+	ret = sw842_data2(inbuf, inbit, outbuf, fifo);
+	if (ret)
+		return ret;
+	ret = sw842_data2(inbuf, inbit, outbuf, fifo);
+	return ret;
+}
+
+static int sw842_data2(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	**outbuf = sw842_get_byte(*inbuf, *inbit);
+	(*inbuf)++;
+	(*outbuf)++;
+	**outbuf = sw842_get_byte(*inbuf, *inbit);
+	(*inbuf)++;
+	(*outbuf)++;
+	return 0;
+}
+
+static int sw842_ptr8(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	uint8_t ptr;
+	ptr = sw842_get_ptr8(inbuf, inbit, fifo);
+	if (!fifo->f84_full && (ptr >= fifo->f8_count))
+		return 1;
+	memcpy(*outbuf, fifo->f8[ptr], 8);
+	*outbuf += 8;
+	return 0;
+}
+
+static int sw842_ptr4(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	uint16_t ptr;
+	ptr = sw842_get_ptr4(inbuf, inbit, fifo);
+	if (!fifo->f84_full && (ptr >= fifo->f4_count))
+		return 1;
+	memcpy(*outbuf, fifo->f4[ptr], 4);
+	*outbuf += 4;
+	return 0;
+}
+
+static int sw842_ptr2(const char **inbuf, int *inbit,
+		unsigned char **outbuf, struct sw842_fifo *fifo)
+{
+	uint8_t ptr;
+	ptr = sw842_get_ptr2(inbuf, inbit);
+	if (!fifo->f2_full && (ptr >= fifo->f2_count))
+		return 1;
+	memcpy(*outbuf, fifo->f2[ptr], 2);
+	*outbuf += 2;
+	return 0;
+}
+
+static void sw842_copy_to_fifo(const char *buf, struct sw842_fifo *fifo)
+{
+	unsigned char initial_f2count = fifo->f2_count;
+
+	memcpy(fifo->f8[fifo->f8_count], buf, 8);
+	fifo->f4_count += 2;
+	fifo->f8_count += 1;
+
+	if (!fifo->f84_full && fifo->f4_count >= 512) {
+		fifo->f84_full = 1;
+		fifo->f4_count /= 512;
+	}
+
+	memcpy(fifo->f2[fifo->f2_count++], buf, 2);
+	memcpy(fifo->f2[fifo->f2_count++], buf + 2, 2);
+	memcpy(fifo->f2[fifo->f2_count++], buf + 4, 2);
+	memcpy(fifo->f2[fifo->f2_count++], buf + 6, 2);
+	if (fifo->f2_count < initial_f2count)
+		fifo->f2_full = 1;
+}
+
+static int sw842_decompress(const unsigned char *src, int srclen,
+			unsigned char *dst, int *destlen,
+			const void *wrkmem)
+{
+	uint8_t tmpl;
+	const char *inbuf;
+	int inbit = 0;
+	unsigned char *outbuf, *outbuf_end, *origbuf, *prevbuf;
+	const char *inbuf_end;
+	sw842_template_op op;
+	int opindex;
+	int i, repeat_count;
+	struct sw842_fifo *fifo;
+	int ret = 0;
+
+	fifo = &((struct nx842_workmem *)(wrkmem))->swfifo;
+	memset(fifo, 0, sizeof(*fifo));
+
+	origbuf = NULL;
+	inbuf = src;
+	inbuf_end = src + srclen;
+	outbuf = dst;
+	outbuf_end = dst + *destlen;
+
+	while ((tmpl = sw842_get_template(&inbuf, &inbit)) != SW842_TMPL_EOF) {
+		if (inbuf >= inbuf_end) {
+			ret = -EINVAL;
+			goto out;
+		}
+
+		opindex = 0;
+		prevbuf = origbuf;
+		origbuf = outbuf;
+		switch (tmpl) {
+		case SW842_TMPL_REPEAT:
+			if (prevbuf == NULL) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			repeat_count = sw842_get_repeat_count(&inbuf,
+								&inbit) + 1;
+
+			/* Did the repeat count advance past the end of input */
+			if (inbuf > inbuf_end) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			for (i = 0; i < repeat_count; i++) {
+				/* Would this overflow the output buffer */
+				if ((outbuf + 8) > outbuf_end) {
+					ret = -ENOSPC;
+					goto out;
+				}
+
+				memcpy(outbuf, prevbuf, 8);
+				sw842_copy_to_fifo(outbuf, fifo);
+				outbuf += 8;
+			}
+			break;
+
+		case SW842_TMPL_ZEROS:
+			/* Would this overflow the output buffer */
+			if ((outbuf + 8) > outbuf_end) {
+				ret = -ENOSPC;
+				goto out;
+			}
+
+			memset(outbuf, 0, 8);
+			sw842_copy_to_fifo(outbuf, fifo);
+			outbuf += 8;
+			break;
+
+		default:
+			if (tmpl > 25) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			/* Does this go past the end of the input buffer */
+			if ((inbuf + 2) > inbuf_end) {
+				ret = -EINVAL;
+				goto out;
+			}
+
+			/* Would this overflow the output buffer */
+			if ((outbuf + 8) > outbuf_end) {
+				ret = -ENOSPC;
+				goto out;
+			}
+
+			while (opindex < 4 &&
+				(op = sw842_tmpl_ops[tmpl][opindex++])
+					!= NULL) {
+				ret = (*op)(&inbuf, &inbit, &outbuf, fifo);
+				if (ret) {
+					ret = -EINVAL;
+					goto out;
+				}
+				sw842_copy_to_fifo(origbuf, fifo);
+			}
+		}
+	}
+
+out:
+	if (!ret)
+		*destlen = (unsigned int)(outbuf - dst);
+	else
+		*destlen = 0;
+
+	return ret;
+}