libgloss/arc/hl/hl_gw.c

   1 /*
   2  * hl_gw.c -- Hostlink gateway, low-level hostlink functions.
   3  *
   4  * Copyright (c) 2024 Synopsys Inc.
   5  *
   6  * The authors hereby grant permission to use, copy, modify, distribute,
   7  * and license this software and its documentation for any purpose, provided
   8  * that existing copyright notices are retained in all copies and that this
   9  * notice is included verbatim in any distributions. No written agreement,
  10  * license, or royalty fee is required for any of the authorized uses.
  11  * Modifications to this software may be copyrighted by their authors
  12  * and need not follow the licensing terms described here, provided that
  13  * the new terms are clearly indicated on the first page of each file where
  14  * they apply.
  15  *
  16  */
  17
  18 #include <stdint.h>
  19 #include "hl_gw.h"
  20
  21 #define HL_VERSION 1
  22
  23
  24 /*
  25  * Maximum message size without service information,
  26  * see also HL_PAYLOAD_RESERVED.
  27  */
  28 #ifndef HL_IOCHUNK
  29   #define HL_IOCHUNK 1024
  30 #endif
  31
  32 /*
  33  * Each syscall argument have 4 bytes of service information in hostlink
  34  * protocol (2 bytes for type and 2 for size).  Here we reserve space for
  35  * 32 arguments.
  36  */
  37 #define HL_PAYLOAD_RESERVED (32 * 4)
  38
  39 /* "No message here" mark.  */
  40 #define HL_NOADDRESS 0xFFFFFFFF
  41
  42 /* Hostlink gateway structure.  */
  43 struct _hl_hdr {
  44   uint32_t version;             /* Current version is 1.  */
  45   uint32_t target2host_addr;    /* Packet address from target to host.  */
  46   uint32_t host2target_addr;    /* Packet address from host to target.  */
  47   uint32_t buf_addr;            /* Address for host to write answer.  */
  48   uint32_t payload_size;        /* Buffer size without packet header.  */
  49   uint32_t options;             /* For future use.  */
  50   uint32_t break_to_mon_addr;   /* For future use.  */
  51 } __uncached __packed;
  52
  53 /* Hostlink packet header.  */
  54 struct _hl_pkt_hdr {
  55   uint32_t packet_id;   /* Packet id.  Always set to 1 here.  */
  56   uint32_t total_size;  /* Size of packet including header.  */
  57   uint32_t priority;    /* For future use.  */
  58   uint32_t type;        /* For future use.  */
  59   uint32_t checksum;    /* For future use.  */
  60 } __uncached __packed;
  61
  62 /* Main hostlink structure.  */
  63 struct _hl {
  64   volatile struct _hl_hdr hdr; /* General hostlink information.  */
  65   /* Start of the hostlink buffer.  */
  66   volatile struct _hl_pkt_hdr pkt_hdr;
  67   volatile char payload[HL_IOCHUNK + HL_PAYLOAD_RESERVED];
  68 } __aligned (HL_MAX_DCACHE_LINE) __uncached __packed;
  69
  70
  71 /*
  72  * Main structure.  Do not rename because simulator will look for the
  73  * '__HOSTLINK__' symbol.
  74  */
  75 volatile struct _hl __HOSTLINK__ = {
  76   .hdr = {
  77     .version = 1 ,
  78     .target2host_addr = HL_NOADDRESS
  79   }
  80 };
  81
  82 /* Get hostlink payload pointer.  */
  83 volatile __uncached void *
  84 _hl_payload (void)
  85 {
  86   return (volatile __uncached void *) &__HOSTLINK__.payload[0];
  87 }
  88
  89 /* Get hostlink payload size (iochunk + reserved space).  */
  90 static uint32_t
  91 _hl_payload_size (void)
  92 {
  93   return sizeof (__HOSTLINK__.payload);
  94 }
  95
  96 /* Get used space size in the payload.  */
  97 static uint32_t
  98 _hl_payload_used (volatile __uncached void *p)
  99 {
 100   return (volatile __uncached char *) p
 101     - (volatile __uncached char *) _hl_payload ();
 102 }
 103
 104 /* Fill hostlink packet header.  */
 105 static void
 106 _hl_pkt_init (volatile __uncached struct _hl_pkt_hdr *pkt, int size)
 107 {
 108   pkt->packet_id = 1;
 109   pkt->total_size = ALIGN (size, 4) + sizeof (*pkt);
 110   pkt->priority = 0;
 111   pkt->type = 0;
 112   pkt->checksum = 0;
 113 }
 114
 115 /* Get hostlink iochunk size.  */
 116 uint32_t
 117 _hl_iochunk_size (void)
 118 {
 119   return HL_IOCHUNK;
 120 }
 121
 122 /* Get free space size in the payload.  */
 123 uint32_t
 124 _hl_payload_left (volatile __uncached void *p)
 125 {
 126   return _hl_payload_size () - _hl_payload_used (p);
 127 }
 128
 129 /* Send hostlink packet to the host.  */
 130 void
 131 _hl_send (volatile __uncached void *p)
 132 {
 133   volatile __uncached struct _hl_hdr *hdr = &__HOSTLINK__.hdr;
 134   volatile __uncached struct _hl_pkt_hdr *pkt_hdr = &__HOSTLINK__.pkt_hdr;
 135
 136   _hl_pkt_init (pkt_hdr, _hl_payload_used (p));
 137
 138 #if defined (__ARC64__)
 139   /*
 140    * Here we pass only low 4 bytes of the packet address (pkt_hdr).
 141    * The high part of the address is obtained from __HOSTLINK__ address.
 142    */
 143   hdr->buf_addr = (uintptr_t) pkt_hdr & 0xFFFFFFFF;
 144 #else
 145   hdr->buf_addr = (uint32_t) pkt_hdr;
 146 #endif
 147   hdr->payload_size = _hl_payload_size ();
 148   hdr->host2target_addr = HL_NOADDRESS;
 149   hdr->version = HL_VERSION;
 150   hdr->options = 0;
 151   hdr->break_to_mon_addr = 0;
 152
 153   /* This tells the debugger we have a command.
 154    * It is responsibility of debugger to set this back to HL_NOADDRESS
 155    * after receiving the packet.
 156    * Please note that we don't wait here because some implementations
 157    * use _hl_blockedPeek() function as a signal that we send a messege.
 158    */
 159   hdr->target2host_addr = hdr->buf_addr;
 160 }
 161
 162 /*
 163  * Wait for host response and return pointer to hostlink payload.
 164  * Symbol _hl_blockedPeek() is used by the simulator as message signal.
 165  */
 166 volatile __uncached char * __noinline
 167 _hl_blockedPeek (void)
 168 {
 169   while (__HOSTLINK__.hdr.host2target_addr == HL_NOADDRESS)
 170     {
 171       /* TODO: Timeout.  */
 172     }
 173
 174   return _hl_payload ();
 175 }
 176
 177 /* Get message from host.  */
 178 volatile __uncached char *
 179 _hl_recv (void)
 180 {
 181   return _hl_blockedPeek ();
 182 }
 183
 184 /* Mark hostlink buffer as "No message here".  */
 185 void
 186 _hl_delete (void)
 187 {
 188   __HOSTLINK__.hdr.target2host_addr = HL_NOADDRESS;
 189 }