GenWQE Character device and DDCB queue

The GenWQE card itself provides access to a generic work queue into
which the work can be put, which should be executed, e.g. compression
or decompression request, or whatever the card was configured to do.

Each request comes with a set of input data (ASV) and will produce some
output data (ASIV). The request will also contain a sequence number,
some timestamps and a command code/subcode plus some fields for hardware-/
software-interaction.

A request can contain references to blocks of memory. Since the card
requires DMA-addresses of that memory, the driver provides two ways to
solve that task:
  1) The drivers mmap() will allocate some DMAable memory for the user.
     The driver has a lookup table such that the virtual userspace
     address can properly be replaced and checked.
  2) The user allocates memory and the driver will pin/unpin that
     memory and setup a scatter gatherlist with matching DMA addresses.

Currently work requests are synchronous.
Signed-off-by: Frank Haverkamp <haver@linux.vnet.ibm.com>
Co-authors: Joerg-Stephan Vogt <jsvogt@de.ibm.com>,
            Michael Jung <MIJUNG@de.ibm.com>,
            Michael Ruettger <michael@ibmra.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/genwqe/card_ddcb.h

+#ifndef __CARD_DDCB_H__
+#define __CARD_DDCB_H__
+
+/**
+ * IBM Accelerator Family 'GenWQE'
+ *
+ * (C) Copyright IBM Corp. 2013
+ *
+ * Author: Frank Haverkamp <haver@linux.vnet.ibm.com>
+ * Author: Joerg-Stephan Vogt <jsvogt@de.ibm.com>
+ * Author: Michael Jung <mijung@de.ibm.com>
+ * Author: Michael Ruettger <michael@ibmra.de>
+ *
+ * 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, 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.
+ */
+
+#include <linux/types.h>
+#include <asm/byteorder.h>
+
+#include "genwqe_driver.h"
+#include "card_base.h"
+
+/**
+ * struct ddcb - Device Driver Control Block DDCB
+ * @hsi:        Hardware software interlock
+ * @shi:        Software hardware interlock. Hsi and shi are used to interlock
+ *              software and hardware activities. We are using a compare and
+ *              swap operation to ensure that there are no races when
+ *              activating new DDCBs on the queue, or when we need to
+ *              purge a DDCB from a running queue.
+ * @acfunc:     Accelerator function addresses a unit within the chip
+ * @cmd:        Command to work on
+ * @cmdopts_16: Options for the command
+ * @asiv:       Input data
+ * @asv:        Output data
+ *
+ * The DDCB data format is big endian. Multiple consequtive DDBCs form
+ * a DDCB queue.
+ */
+#define ASIV_LENGTH		104 /* Old specification without ATS field */
+#define ASIV_LENGTH_ATS		96  /* New specification with ATS field */
+#define ASV_LENGTH		64
+
+struct ddcb {
+	union {
+		__be32 icrc_hsi_shi_32;	/* iCRC, Hardware/SW interlock */
+		struct {
+			__be16	icrc_16;
+			u8	hsi;
+			u8	shi;
+		};
+	};
+	u8  pre;		/* Preamble */
+	u8  xdir;		/* Execution Directives */
+	__be16 seqnum_16;	/* Sequence Number */
+
+	u8  acfunc;		/* Accelerator Function.. */
+	u8  cmd;		/* Command. */
+	__be16 cmdopts_16;	/* Command Options */
+	u8  sur;		/* Status Update Rate */
+	u8  psp;		/* Protection Section Pointer */
+	__be16 rsvd_0e_16;	/* Reserved invariant */
+
+	__be64 fwiv_64;		/* Firmware Invariant. */
+
+	union {
+		struct {
+			__be64 ats_64;  /* Address Translation Spec */
+			u8     asiv[ASIV_LENGTH_ATS]; /* New ASIV */
+		} n;
+		u8  __asiv[ASIV_LENGTH];	/* obsolete */
+	};
+	u8     asv[ASV_LENGTH];	/* Appl Spec Variant */
+
+	__be16 rsvd_c0_16;	/* Reserved Variant */
+	__be16 vcrc_16;		/* Variant CRC */
+	__be32 rsvd_32;		/* Reserved unprotected */
+
+	__be64 deque_ts_64;	/* Deque Time Stamp. */
+
+	__be16 retc_16;		/* Return Code */
+	__be16 attn_16;		/* Attention/Extended Error Codes */
+	__be32 progress_32;	/* Progress indicator. */
+
+	__be64 cmplt_ts_64;	/* Completion Time Stamp. */
+
+	/* The following layout matches the new service layer format */
+	__be32 ibdc_32;		/* Inbound Data Count  (* 256) */
+	__be32 obdc_32;		/* Outbound Data Count (* 256) */
+
+	__be64 rsvd_SLH_64;	/* Reserved for hardware */
+	union {			/* private data for driver */
+		u8	priv[8];
+		__be64	priv_64;
+	};
+	__be64 disp_ts_64;	/* Dispatch TimeStamp */
+} __attribute__((__packed__));
+
+/* CRC polynomials for DDCB */
+#define CRC16_POLYNOMIAL	0x1021
+
+/*
+ * SHI: Software to Hardware Interlock
+ *   This 1 byte field is written by software to interlock the
+ *   movement of one queue entry to another with the hardware in the
+ *   chip.
+ */
+#define DDCB_SHI_INTR		0x04 /* Bit 2 */
+#define DDCB_SHI_PURGE		0x02 /* Bit 1 */
+#define DDCB_SHI_NEXT		0x01 /* Bit 0 */
+
+/*
+ * HSI: Hardware to Software interlock
+ * This 1 byte field is written by hardware to interlock the movement
+ * of one queue entry to another with the software in the chip.
+ */
+#define DDCB_HSI_COMPLETED	0x40 /* Bit 6 */
+#define DDCB_HSI_FETCHED	0x04 /* Bit 2 */
+
+/*
+ * Accessing HSI/SHI is done 32-bit wide
+ *   Normally 16-bit access would work too, but on some platforms the
+ *   16 compare and swap operation is not supported. Therefore
+ *   switching to 32-bit such that those platforms will work too.
+ *
+ *                                         iCRC HSI/SHI
+ */
+#define DDCB_INTR_BE32		cpu_to_be32(0x00000004)
+#define DDCB_PURGE_BE32		cpu_to_be32(0x00000002)
+#define DDCB_NEXT_BE32		cpu_to_be32(0x00000001)
+#define DDCB_COMPLETED_BE32	cpu_to_be32(0x00004000)
+#define DDCB_FETCHED_BE32	cpu_to_be32(0x00000400)
+
+/* Definitions of DDCB presets */
+#define DDCB_PRESET_PRE		0x80
+#define ICRC_LENGTH(n)		((n) + 8 + 8 + 8)  /* used ASIV + hdr fields */
+#define VCRC_LENGTH(n)		((n))		   /* used ASV */
+
+/*
+ * Genwqe Scatter Gather list
+ *   Each element has up to 8 entries.
+ *   The chaining element is element 0 cause of prefetching needs.
+ */
+
+/*
+ * 0b0110 Chained descriptor. The descriptor is describing the next
+ * descriptor list.
+ */
+#define SG_CHAINED		(0x6)
+
+/*
+ * 0b0010 First entry of a descriptor list. Start from a Buffer-Empty
+ * condition.
+ */
+#define SG_DATA			(0x2)
+
+/*
+ * 0b0000 Early terminator. This is the last entry on the list
+ * irregardless of the length indicated.
+ */
+#define SG_END_LIST		(0x0)
+
+/**
+ * struct sglist - Scatter gather list
+ * @target_addr:       Either a dma addr of memory to work on or a
+ *                     dma addr or a subsequent sglist block.
+ * @len:               Length of the data block.
+ * @flags:             See above.
+ *
+ * Depending on the command the GenWQE card can use a scatter gather
+ * list to describe the memory it works on. Always 8 sg_entry's form
+ * a block.
+ */
+struct sg_entry {
+	__be64 target_addr;
+	__be32 len;
+	__be32 flags;
+};
+
+#endif /* __CARD_DDCB_H__ */