source: rtems/c/src/lib/libbsp/sparc/shared/include/grspw_pkt.h @ 9cb7e5d

/*
 *  GRSPW/GRSPW2 SpaceWire Kernel Library Interface
 *
 *  COPYRIGHT (c) 2011
 *  Cobham Gaisler AB
 *
 *  The license and distribution terms for this file may be
 *  found in the file LICENSE in this distribution or at
 *  http://www.rtems.org/license/LICENSE.
 */

#ifndef __GRSPW_PKT_H__
#define __GRSPW_PKT_H__

struct grspw_pkt;

/* Maximum number of GRSPW devices supported by driver */
#define GRSPW_MAX 32

/* Weak overridable variable the user can use to define the worker-task
 * priority (0..255) or to disable (-1) the creation of the worker-task
 * and the message queue to save space */
extern int grspw_work_task_priority;

#ifndef GRSPW_PKT_FLAGS
#define GRSPW_PKT_FLAGS
/*** TX Packet flags ***/

/* Enable IRQ generation */
#define TXPKT_FLAG_IE 0x0040

/* Enable Header CRC generation (if CRC is available in HW)
 * Header CRC will be appended (one byte at end of header)
 */
#define TXPKT_FLAG_HCRC 0x0100

/* Enable Data CRC generation (if CRC is available in HW)
 * Data CRC will be appended (one byte at end of packet)
 */
#define TXPKT_FLAG_DCRC 0x0200

/* Control how many bytes the beginning of the Header 
 * the CRC should not be calculated for */
#define TXPKT_FLAG_NOCRC_MASK 0x0000000f
#define TXPKT_FLAG_NOCRC_LEN0 0x00000000
#define TXPKT_FLAG_NOCRC_LEN1 0x00000001
#define TXPKT_FLAG_NOCRC_LEN2 0x00000002
#define TXPKT_FLAG_NOCRC_LEN3 0x00000003
#define TXPKT_FLAG_NOCRC_LEN4 0x00000004
#define TXPKT_FLAG_NOCRC_LEN5 0x00000005
#define TXPKT_FLAG_NOCRC_LEN6 0x00000006
#define TXPKT_FLAG_NOCRC_LEN7 0x00000007
#define TXPKT_FLAG_NOCRC_LEN8 0x00000008
#define TXPKT_FLAG_NOCRC_LEN9 0x00000009
#define TXPKT_FLAG_NOCRC_LENa 0x0000000a
#define TXPKT_FLAG_NOCRC_LENb 0x0000000b
#define TXPKT_FLAG_NOCRC_LENc 0x0000000c
#define TXPKT_FLAG_NOCRC_LENd 0x0000000d
#define TXPKT_FLAG_NOCRC_LENe 0x0000000e
#define TXPKT_FLAG_NOCRC_LENf 0x0000000f

#define TXPKT_FLAG_INPUT_MASK (TXPKT_FLAG_NOCRC_MASK | TXPKT_FLAG_IE | \
                                TXPKT_FLAG_HCRC | TXPKT_FLAG_DCRC)

/* Marks if packet was transmitted or not */
#define TXPKT_FLAG_TX 0x4000

/* Link Error */
#define TXPKT_FLAG_LINKERR 0x8000

#define TXPKT_FLAG_OUTPUT_MASK (TXPKT_FLAG_TX | TXPKT_FLAG_LINKERR)

/*** RX Packet Flags ***/

/* Enable IRQ generation */
#define RXPKT_FLAG_IE 0x0010

#define RXPKT_FLAG_INPUT_MASK (RXPKT_FLAG_IE)

/* Packet was truncated */
#define RXPKT_FLAG_TRUNK 0x0800
/* Data CRC error (only valid if RMAP CRC is enabled) */
#define RXPKT_FLAG_DCRC 0x0400
/* Header CRC error (only valid if RMAP CRC is enabled) */
#define RXPKT_FLAG_HCRC 0x0200
/* Error in End-of-Packet */
#define RXPKT_FLAG_EEOP 0x0100
/* Marks if packet was recevied or not */
#define RXPKT_FLAG_RX 0x8000

#define RXPKT_FLAG_OUTPUT_MASK (RXPKT_FLAG_TRUNK | RXPKT_FLAG_DCRC | \
                                RXPKT_FLAG_HCRC | RXPKT_FLAG_EEOP)

/*** General packet flag options ***/

/* Translate Hdr and/or Payload address */
#define PKT_FLAG_TR_DATA 0x1000
#define PKT_FLAG_TR_HDR 0x2000
/* All General options */
#define PKT_FLAG_MASK 0x3000

#endif
/* GRSPW RX/TX Packet structure.
 *
 * - For RX the 'hdr' and 'hlen' fields are not used, they are not written
 *   by driver.
 *
 * - The 'pkt_id' field is untouched by driver, it is intended for packet
 *   numbering or user-custom data.
 *
 * - The last packet in a list must have 'next' set to NULL.
 *
 * - data and hdr pointers are written without modification to hardware,
 *   this means that caller must do address translation to hardware
 *   address itself.
 *
 * - the 'flags' field are interpreted differently depending on transfer
 *   type (RX/TX). See XXPKT_FLAG_* options above.
 */
struct grspw_pkt {
        struct grspw_pkt *next;
        unsigned int pkt_id;    /* User assigned ID */
        unsigned short flags;   /* RX/TX Options */
        unsigned char reserved; /* Reserved, must be zero */
        unsigned char hlen;     /* Length of Header Buffer */
        unsigned int dlen;      /* Length of Data Buffer */
        void *data;     /* 4-byte or byte aligned depends on HW */
        void *hdr;      /* 4-byte or byte aligned depends on HW */
};

/* GRSPW SpaceWire Packet List */
struct grspw_list {
        struct grspw_pkt *head;
        struct grspw_pkt *tail;
};

/* SpaceWire Link State */
typedef enum {
        SPW_LS_ERRRST = 0,
        SPW_LS_ERRWAIT = 1,
        SPW_LS_READY = 2,
        SPW_LS_CONNECTING = 3,
        SPW_LS_STARTED = 4,
        SPW_LS_RUN = 5
} spw_link_state_t;

/* Address Configuration */
struct grspw_addr_config {
        /* Ignore address field and put all received packets to first
         * DMA channel.
         */
        int promiscuous;

        /* Default Node Address and Mask */
        unsigned char def_addr;
        unsigned char def_mask;
        /* DMA Channel custom Node Address and Mask */
        struct {
                char node_en;                   /* Enable Separate Addr */
                unsigned char node_addr;        /* Node address */
                unsigned char node_mask;        /* Node address mask */
        } dma_nacfg[4];
};

/* Hardware Support in GRSPW Core */
struct grspw_hw_sup {
        char    rmap;           /* If RMAP in HW is available */
        char    rmap_crc;       /* If RMAP CRC is available */
        char    rx_unalign;     /* RX unaligned (byte boundary) access allowed*/
        char    nports;         /* Number of Ports (1 or 2) */
        char    ndma_chans;     /* Number of DMA Channels (1..4) */
        char    strip_adr;      /* Hardware can strip ADR from packet data */
        char    strip_pid;      /* Hardware can strip PID from packet data */
        int     hw_version;     /* GRSPW Hardware Version */
        char    reserved[2];
        char    irq;            /* SpW Distributed Interrupt available if 1 */
        char    irq_num;        /* Number of interrupts that can be generated */
        char    itmr_width;     /* SpW Intr. ISR timers bit width. 0=no timer */
};

struct grspw_core_stats {
        int irq_cnt;
        int err_credit;
        int err_eeop;
        int err_addr;
        int err_parity;
        int err_disconnect;
        int err_escape;
        int err_wsync; /* only in GRSPW1 */
};

/* grspw_link_ctrl() options */
#define LINKOPTS_ENABLE         0x0000
#define LINKOPTS_DISABLE        0x0001
#define LINKOPTS_START          0x0002
#define LINKOPTS_AUTOSTART      0x0004
#define LINKOPTS_DIS_ONERR      0x0008  /* Disable DMA transmitter on link error
                                         * Controls LE bit in DMACTRL register.
                                         */
#define LINKOPTS_DIS_ON_CE      0x0020000/* Disable Link on Credit error */
#define LINKOPTS_DIS_ON_ER      0x0040000/* Disable Link on Escape error */
#define LINKOPTS_DIS_ON_DE      0x0080000/* Disable Link on Disconnect error */
#define LINKOPTS_DIS_ON_PE      0x0100000/* Disable Link on Parity error */
#define LINKOPTS_DIS_ON_WE      0x0400000/* Disable Link on write synchonization
                                          * error (GRSPW1 only)
                                          */
#define LINKOPTS_DIS_ON_EE      0x1000000/* Disable Link on Early EOP/EEP error*/

/*#define LINKOPTS_TICK_OUT_IRQ 0x0100*//* Enable Tick-out IRQ */
#define LINKOPTS_EIRQ           0x0200  /* Enable Error Link IRQ */

#define LINKOPTS_MASK           0x15e020f/* All above options */
#define LINKOPTS_MASK_DIS_ON    0x15e0000/* All disable link on error options
                                          * On a certain error the link disable
                                          * bit will be written and the work
                                          * task will call dma_stop() for all
                                          * channels.
                                          */

#define LINKSTS_CE              0x002   /* Credit error */
#define LINKSTS_ER              0x004   /* Escape error */
#define LINKSTS_DE              0x008   /* Disconnect error */
#define LINKSTS_PE              0x010   /* Parity error */
#define LINKSTS_WE              0x040   /* Write synchonization error (GRSPW1 only) */
#define LINKSTS_IA              0x080   /* Invalid address */
#define LINKSTS_EE              0x100   /* Early EOP/EEP */
#define LINKSTS_MASK            0x1de


/* grspw_tc_ctrl() options */
#define TCOPTS_EN_RXIRQ 0x0001  /* Tick-Out IRQ */
#define TCOPTS_EN_TX    0x0004
#define TCOPTS_EN_RX    0x0008

/* grspw_ic_ctrl() options:
 * Corresponds code duplicatingly to GRSPW_CTRL_XX_BIT defines
 */
#define ICOPTS_INTNUM           (0x1f << 27)
#define ICOPTS_EN_SPWIRQ_ON_EE  (1 << 24)
#define ICOPTS_EN_SPWIRQ_ON_IA  (1 << 23)
#define ICOPTS_EN_PRIO          (1 << 22)
#define ICOPTS_EN_TIMEOUTIRQ    (1 << 20)
#define ICOPTS_EN_ACKIRQ        (1 << 19)
#define ICOPTS_EN_TICKOUTIRQ    (1 << 18)
#define ICOPTS_EN_RX            (1 << 17)
#define ICOPTS_EN_TX            (1 << 16)
#define ICOPTS_BASEIRQ          (0x1f << 8)
#define ICOPTS_EN_FLAGFILTER    (1 << 0) /* NOTE: Not in icctrl. CTRL.bit12 */

/* grspw_ic_rlisr() and grspw_ic_rlintack()  */
#define ICRELOAD_EN             (1 << 31)
#define ICRELOAD_MASK           0x7fffffff

/* grspw_rmap_ctrl() options */
#define RMAPOPTS_EN_RMAP        0x0001
#define RMAPOPTS_EN_BUF         0x0002

/* grspw_dma_config.flags options */
#define DMAFLAG_NO_SPILL        0x0001  /* See HW doc DMA-CTRL NS bit */
#define DMAFLAG_RESV1           0x0002  /* HAS NO EFFECT */
#define DMAFLAG_STRIP_ADR       0x0004  /* See HW doc DMA-CTRL SA bit */
#define DMAFLAG_STRIP_PID       0x0008  /* See HW doc DMA-CTRL SP bit */
#define DMAFLAG_RESV2           0x0010  /* HAS NO EFFECT */
#define DMAFLAG_MASK    (DMAFLAG_NO_SPILL|DMAFLAG_STRIP_ADR|DMAFLAG_STRIP_PID)

struct grspw_dma_config {
        int flags;

        int rxmaxlen;           /* RX Max Packet Length */
        int rx_irq_en_cnt;      /* Enable RX IRQ every cnt descriptors */
        int tx_irq_en_cnt;      /* Enable TX IRQ every cnt descriptors */
};

/* Statistics per DMA channel */
struct grspw_dma_stats {
        /* IRQ Statistics */
        int irq_cnt;            /* Number of DMA IRQs generated by channel */

        /* Descriptor Statistics */
        int tx_pkts;            /* Number of Transmitted packets */
        int tx_err_link;        /* Number of Transmitted packets with Link Error*/
        int rx_pkts;            /* Number of Received packets */
        int rx_err_trunk;       /* Number of Received Truncated packets */
        int rx_err_endpkt;      /* Number of Received packets with bad ending */

        /* Diagnostics to help developers sizing their number buffers to avoid
         * out-of-buffers or other phenomenons.
         */
        int send_cnt_min;       /* Minimum number of packets in TX SEND Q */
        int send_cnt_max;       /* Maximum number of packets in TX SEND Q */
        int tx_sched_cnt_min;   /* Minimum number of packets in TX SCHED Q */
        int tx_sched_cnt_max;   /* Maximum number of packets in TX SCHED Q */
        int sent_cnt_max;       /* Maximum number of packets in TX SENT Q */
        int tx_work_cnt;        /* Times the work thread processed TX BDs */
        int tx_work_enabled;    /* No. RX BDs enabled by work thread */

        int ready_cnt_min;      /* Minimum number of packets in RX READY Q */
        int ready_cnt_max;      /* Maximum number of packets in RX READY Q */
        int rx_sched_cnt_min;   /* Minimum number of packets in RX SCHED Q */
        int rx_sched_cnt_max;   /* Maximum number of packets in RX SCHED Q */
        int recv_cnt_max;       /* Maximum number of packets in RX RECV Q */
        int rx_work_cnt;        /* Times the work thread processed RX BDs */
        int rx_work_enabled;    /* No. RX BDs enabled by work thread */
};

extern void grspw_initialize_user(
        /* Callback every time a GRSPW device is found. Args: DeviceIndex */
        void *(*devfound)(int),
        /* Callback every time a GRSPW device is removed. Args:
         * int   = DeviceIndex
         * void* = Return Value from devfound()
         */
        void (*devremove)(int,void*)
        );
extern int grspw_dev_count(void);
extern void *grspw_open(int dev_no);
extern void grspw_close(void *d);
extern void grspw_hw_support(void *d, struct grspw_hw_sup *hw);
extern void grspw_stats_read(void *d, struct grspw_core_stats *sts);
extern void grspw_stats_clr(void *d);

/* Set and Read current node address configuration. The dma_nacfg[N] field
 * represents the configuration for DMA Channel N.
 *
 * Set cfg->promiscous to -1 in order to only read current configuration.
 */
extern void grspw_addr_ctrl(void *d, struct grspw_addr_config *cfg);

/*** Link Control interface ***/
/* Read Link State */
extern spw_link_state_t grspw_link_state(void *d);
/* options [in/out]: set to -1 to only read current config
 *
 * CLKDIV register contain:
 *  bits 7..0  : Clock Div RUN (only run-state)
 *  bits 15..8 : Clock Div During Startup (all link states except run-state)
 */
extern void grspw_link_ctrl(void *d, int *options, int *stscfg, int *clkdiv);
/* Read the current value of the status register */
extern unsigned int grspw_link_status(void *d);
/* Clear bits in the status register */
extern void grspw_link_status_clr(void *d, unsigned int clearmask);

/*** Time Code Interface ***/
/* Generate Tick-In (increment Time Counter, Send Time Code) */
extern void grspw_tc_tx(void *d);
/* Control Timcode settings of core */
extern void grspw_tc_ctrl(void *d, int *options);
/* Assign ISR Function to TimeCode RX IRQ */
extern void grspw_tc_isr(void *d, void (*tcisr)(void *data, int tc), void *data);
/* Read/Write TCTRL and TIMECNT. Write if not -1, always read current value
 * TCTRL   = bits 7 and 6
 * TIMECNT = bits 5 to 0
 */
extern void grspw_tc_time(void *d, int *time);

/*** Interrupt-code Interface ***/
struct spwpkt_ic_config {
        unsigned int tomask;
        unsigned int aamask;
        unsigned int scaler;
        unsigned int isr_reload;
        unsigned int ack_reload;
};
/* Function Interrupt-Code ISR callback prototype. Called when respective
 * interrupt handling option has been enabled by grspw_ic_ctrl(), the
 * arguments rxirq, rxack and intto are read from the registers of the
 * GRSPW core read by the GRSPW ISR, they are individually valid only when
 * repective handling been turned on.
 *
 * data    - Custom data provided by user
 * rxirq   - Interrupt-Code Recevie register of the GRSPW core read by ISR
 *           (only defined if IQ bit enabled through grspw_ic_ctrl())
 * rxack   - Interrupt-Ack-Code Recevie register of the GRSPW core read by ISR
 *           (only defined if AQ bit enabled through grspw_ic_ctrl())
 * intto   - Interrupt Tick-out Recevie register of the GRSPW core read by ISR
 *           (only defined if TQ bit enabled through grspw_ic_ctrl()) 
 */
typedef void (*spwpkt_ic_isr_t)(void *data, unsigned int rxirq,
                                unsigned int rxack, unsigned int intto);
/* Control Interrupt-code settings of core
 * Write if 'options' not pointing to -1, always read current value
 */
extern void grspw_ic_ctrl(void *d, unsigned int *options);
/* Write (rw&1 == 1) configuration parameters to registers and/or,
 * Read  (rw&2 == 1) configuration parameters from registers, in that sequence.
 */
extern void grspw_ic_config(void *d, int rw, struct spwpkt_ic_config *cfg);
/* Read or Write Interrupt-code status registers.
 * If pointer argument *ptr == 0 then only read, if *ptr != 0 then only write.
 * If *ptr is NULL no operation.
 */
extern void grspw_ic_sts(void *d, unsigned int *rxirq, unsigned int *rxack,
                        unsigned int *intto);
/* Generate Tick-In for the given Interrupt-code
 * Returns zero on success and non-zero on failure
 *
 * Interrupt code bits (ic):
 * Bit 5 - ACK if 1
 * Bits 4-0 Interrupt-code number
 */
extern int grspw_ic_tickin(void *d, int ic);
/* Assign handler function to Interrupt-code timeout IRQ */
extern void grspw_ic_isr(void *d, spwpkt_ic_isr_t handler, void *data);

/*** RMAP Control Interface ***/
/* Set (not -1) and/or read RMAP options. */
extern int grspw_rmap_ctrl(void *d, int *options, int *dstkey);
extern void grspw_rmap_support(void *d, char *rmap, char *rmap_crc);

/*** SpW Port Control Interface ***/

/* Select port, if
 * -1=The current selected port is returned
 * 0=Port 0
 * 1=Port 1
 * Other positive values=Both Port0 and Port1
 */
extern int grspw_port_ctrl(void *d, int *port);
/* Returns Number ports available in hardware */
extern int grspw_port_count(void *d);
/* Returns the current active port */
extern int grspw_port_active(void *d);

/*** DMA Interface ***/
extern void *grspw_dma_open(void *d, int chan_no);
extern void grspw_dma_close(void *c);

extern int grspw_dma_start(void *c);
extern void grspw_dma_stop(void *c);

/* Schedule List of packets for transmission at some point in
 * future.
 *
 * 1. Move transmitted packets to SENT List (SCHED->SENT)
 * 2. Add the requested packets to the SEND List (USER->SEND)
 * 3. Schedule as many packets as possible for transmission (SEND->SCHED)
 *
 * Call this function with pkts=NULL to just do step 1 and 3. This may be
 * required in Polling-mode.
 *
 * The above steps 1 and 3 may be skipped by setting 'opts':
 *  bit0 = 1: Skip Step 1.
 *  bit1 = 1: Skip Step 3.
 * Skipping both step 1 and 3 may be usefull when IRQ is enabled, then
 * the work queue will be totaly responsible for handling descriptors.
 *
 * The fastest solution in retreiving sent TX packets and sending new frames
 * is to call:
 *  A. grspw_dma_tx_reclaim(opts=0)
 *  B. grspw_dma_tx_send(opts=1)
 *
 * NOTE: the TXPKT_FLAG_TX flag must not be set.
 *
 * Return Code
 *  -1   Error
 *  0    Successfully added pkts to send/sched list
 *  1    DMA stopped. No operation.
 */
extern int grspw_dma_tx_send(void *c, int opts, struct grspw_list *pkts, int count);

/* Reclaim TX packet buffers that has previously been scheduled for transmission
 * with grspw_dma_tx_send().
 *
 * 1. Move transmitted packets to SENT List (SCHED->SENT)
 * 2. Move all SENT List to pkts list (SENT->USER)
 * 3. Schedule as many packets as possible for transmission (SEND->SCHED)
 *
 * The above steps 1 may be skipped by setting 'opts':
 *  bit0 = 1: Skip Step 1.
 *  bit1 = 1: Skip Step 3.
 *
 * The fastest solution in retreiving sent TX packets and sending new frames
 * is to call:
 *  A. grspw_dma_tx_reclaim(opts=2) (Skip step 3)
 *  B. grspw_dma_tx_send(opts=1) (Skip step 1)
 *
 * Return Code
 *  -1   Error
 *  0    Successful. pkts list filled with all packets from sent list
 *  1    Same as 0, but indicates that DMA stopped
 */
extern int grspw_dma_tx_reclaim(void *c, int opts, struct grspw_list *pkts, int *count);

/* Get current number of Packets in respective TX Queue. */
extern void grspw_dma_tx_count(void *c, int *send, int *sched, int *sent);

#define GRSPW_OP_AND 0
#define GRSPW_OP_OR 1
/* Block until send_cnt or fewer packets are Queued in "Send and Scheduled" Q,
 * op (AND or OR), sent_cnt or more packet "have been sent" (Sent Q) condition
 * is met.
 * If a link error occurs and the Stop on Link error is defined, this function
 * will also return to caller.
 * The timeout argument is used to return after timeout ticks, regardless of
 * the other conditions. If timeout is zero, the function will wait forever
 * until the condition is satisfied.
 *
 * NOTE: if IRQ of TX descriptors are not enabled conditions are never
 *       checked, this may hang infinitely unless a timeout has been specified
 *
 * Return Code
 *  -1   Error
 *  0    Returing to caller because specified conditions are now fullfilled
 *  1    DMA stopped
 *  2    Timeout, conditions are not met
 *  3    Another task is already waiting. Service is Busy.
 */
extern int grspw_dma_tx_wait(void *c, int send_cnt, int op, int sent_cnt, int timeout);

/* Get received RX packet buffers that has previously been scheduled for 
 * reception with grspw_dma_rx_prepare().
 *
 * 1. Move Scheduled packets to RECV List (SCHED->RECV)
 * 2. Move all RECV packet to the callers list (RECV->USER)
 * 3. Schedule as many free packet buffers as possible (READY->SCHED)
 *
 * The above steps 1 may be skipped by setting 'opts':
 *  bit0 = 1: Skip Step 1.
 *  bit1 = 1: Skip Step 3.
 *
 * The fastest solution in retreiving received RX packets and preparing new
 * packet buffers for future receive, is to call:
 *  A. grspw_dma_rx_recv(opts=2, &recvlist) (Skip step 3)
 *  B. grspw_dma_rx_prepare(opts=1, &freelist) (Skip step 1)
 *
 * Return Code
 *  -1   Error
 *  0    Successfully filled pkts list with packets from recv list.
 *  1    DMA stopped
 */
extern int grspw_dma_rx_recv(void *c, int opts, struct grspw_list *pkts, int *count);

/* Add more RX packet buffers for future for reception. The received packets
 * can later be read out with grspw_dma_rx_recv().
 *
 * 1. Move Received packets to RECV List (SCHED->RECV)
 * 2. Add the "free/ready" packet buffers to the READY List (USER->READY)
 * 3. Schedule as many packets as possible (READY->SCHED)
 *
 * The above steps 1 may be skipped by setting 'opts':
 *  bit0 = 1: Skip Step 1.
 *  bit1 = 1: Skip Step 3.
 *
 * The fastest solution in retreiving received RX packets and preparing new
 * packet buffers for future receive, is to call:
 *  A. grspw_dma_rx_recv(opts=2, &recvlist) (Skip step 3)
 *  B. grspw_dma_rx_prepare(opts=1, &freelist) (Skip step 1)
 *
 * Return Code
 *  -1   Error
 *  0    Successfully added packet buffers from pkt list into the ready queue
 *  1    DMA stopped
 */
extern int grspw_dma_rx_prepare(void *c, int opts, struct grspw_list *pkts, int count);

/* Get current number of Packets in respective RX Queue. */
extern void grspw_dma_rx_count(void *c, int *ready, int *sched, int *recv);

/* Block until recv_cnt or more packets are Queued in RECV Q, op (AND or OR), 
 * ready_cnt or fewer packet buffers are available in the "READY and Scheduled" Q,
 * condition is met.
 * If a link error occurs and the Stop on Link error is defined, this function
 * will also return to caller, however with an error.
 * The timeout argument is used to return after timeout ticks, regardless of
 * the other conditions. If timeout is zero, the function will wait forever
 * until the condition is satisfied.
 *
 * NOTE: if IRQ of RX descriptors are not enabled conditions are never
 *       checked, this may hang infinitely unless a timeout has been specified
 *
 * Return Code
 *  -1   Error
 *  0    Returing to caller because specified conditions are now fullfilled
 *  1    DMA stopped
 *  2    Timeout, conditions are not met
 *  3    Another task is already waiting. Service is Busy.
 */
extern int grspw_dma_rx_wait(void *c, int recv_cnt, int op, int ready_cnt, int timeout);

extern int grspw_dma_config(void *c, struct grspw_dma_config *cfg);
extern void grspw_dma_config_read(void *c, struct grspw_dma_config *cfg);

extern void grspw_dma_stats_read(void *c, struct grspw_dma_stats *sts);
extern void grspw_dma_stats_clr(void *c);

/* Register GRSPW packet driver to Driver Manager */
void grspw2_register_drv (void);

/*** GRSPW SpaceWire Packet List Handling Routines ***/

static inline void grspw_list_clr(struct grspw_list *list)
{
        list->head = NULL;
        list->tail = NULL;
}

static inline int grspw_list_is_empty(struct grspw_list *list)
{
        return (list->head == NULL);
}

/* Return Number of entries in list */
static inline int grspw_list_cnt(struct grspw_list *list)
{
        struct grspw_pkt *lastpkt = NULL, *pkt = list->head;
        int cnt = 0;
        while ( pkt ) {
                cnt++;
                lastpkt = pkt;
                pkt = pkt->next;
        }
        if ( lastpkt && (list->tail != lastpkt) )
                return -1;
        return cnt;
}

static inline void
grspw_list_append(struct grspw_list *list, struct grspw_pkt *pkt)
{
        pkt->next = NULL;
        if ( list->tail == NULL ) {
                list->head = pkt;
        } else {
                list->tail->next = pkt;
        }
        list->tail = pkt;
}

static inline void 
grspw_list_prepend(struct grspw_list *list, struct grspw_pkt *pkt)
{
        pkt->next = list->head;
        if ( list->head == NULL ) {
                list->tail = pkt;
        }
        list->head = pkt;
}

static inline void
grspw_list_append_list(struct grspw_list *list, struct grspw_list *alist)
{
        alist->tail->next = NULL;
        if ( list->tail == NULL ) {
                list->head = alist->head;
        } else {
                list->tail->next = alist->head;
        }
        list->tail = alist->tail;
}

static inline void
grspw_list_prepend_list(struct grspw_list *list, struct grspw_list *alist)
{
        if ( list->head == NULL ) {
                list->tail = alist->tail;
                alist->tail->next = NULL;
        } else {
                alist->tail->next = list->head;
        }
        list->head = alist->head;
}

/* Remove dlist (delete-list) from head of list */
static inline void
grspw_list_remove_head_list(struct grspw_list *list, struct grspw_list *dlist)
{
        list->head = dlist->tail->next;
        if ( list->head == NULL ) {
                list->tail = NULL;
        }
        dlist->tail->next = NULL;
}

/* Take A number of entries from head of list 'list' and put the entires
 * to rlist (result list).
 */
static inline int
grspw_list_take_head_list(struct grspw_list *list, struct grspw_list *rlist, int max)
{
        int cnt;
        struct grspw_pkt *pkt, *last;

        pkt = list->head;

        if ( (max < 1) || (pkt == NULL) ) {
                grspw_list_clr(rlist);
                return 0;
        }

        cnt = 0;
        rlist->head = pkt;
        last = pkt;
        while ((cnt < max) && pkt) {
                last = pkt;
                pkt = pkt->next;
                cnt++;
        }
        rlist->tail = last;
        grspw_list_remove_head_list(list, rlist);
        return cnt;
}

#endif