Implements USRP2 peek() command, allowing arbitrary reads from the internal

Wishbone bus.  Minor fix for USRP2 sync_to_pps() (uses correct packet type.)

Example:

>>> from gnuradio import usrp2
>>> u = usrp2.source_32fc()
>>> u.peek(0x1234, 4) # Read four bytes at offset 0x1234 (code)
(185, 244, 253, 164)
>>> 

The return value will be zero length upon error.

The read address must be 32-bit aligned, and only the lower 16 bits are
significant.  The length must be an integral multiple of 4 bytes. There is 
currently a read limit of 176 bytes per read; to change requires some additional 
firmware changes to allocate a larger reply packet.

WARNING: Trying to read from memory locations not serviced by RAM or by a
Wishbone peripheral may result in a hang requiring a USRP2 power cycle.  The
USRP2 internal memory map is documented in usrp2/firmware/lib/memory_map.h.



git-svn-id: http://gnuradio.org/svn/gnuradio/trunk@10172 221aa14e-8319-0410-a670-987f0aec2ac5

2 files changed, 43 insertions, 8 deletions

diff --git a/usrp2/firmware/apps/app_common_v2.c b/usrp2/firmware/apps/app_common_v2.c
index 9bb5e4d74..b51c3b23c 100644
--- a/usrp2/firmware/apps/app_common_v2.c
+++ b/usrp2/firmware/apps/app_common_v2.c
@@ -332,6 +332,30 @@ dboard_info_cmd(const op_generic_t *p,
 }
 
 static size_t
+peek_cmd(const op_peek_t *p,
+	 void *reply_payload, size_t reply_payload_space)
+{
+  op_generic_t *r = (op_generic_t *) reply_payload;
+
+  putstr("peek: addr="); puthex32(p->addr);
+  printf(" bytes=%u\n", p->bytes);
+
+  if (reply_payload_space < (sizeof(*r) + p->bytes)) {
+    putstr("peek: insufficient reply packet space\n");
+    return 0;			// FIXME do partial read?
+  }
+
+  r->opcode = OP_PEEK_REPLY;
+  r->len = sizeof(*r)+p->bytes;
+  r->rid = p->rid;
+  r->ok = true;
+
+  memcpy_wa(reply_payload+sizeof(*r), p->addr, p->bytes);
+
+  return r->len;
+}
+
+static size_t
 generic_reply(const op_generic_t *p,
 	      void *reply_payload, size_t reply_payload_space,
 	      bool ok)
@@ -435,6 +459,10 @@ handle_control_chan_frame(u2_eth_packet_t *pkt, size_t len)
 				sync_to_pps((op_generic_t *) payload));
       break;
 
+    case OP_PEEK:
+      subpktlen = peek_cmd((op_peek_t *)payload, reply_payload, reply_payload_space);
+      break;
+
     default:
       printf("app_common_v2: unhandled opcode = %d\n", gp->opcode);
       break;
diff --git a/usrp2/firmware/include/usrp2_eth_packet.h b/usrp2/firmware/include/usrp2_eth_packet.h
index cfff0dd08..8a9994f17 100644
--- a/usrp2/firmware/include/usrp2_eth_packet.h
+++ b/usrp2/firmware/include/usrp2_eth_packet.h
@@ -185,12 +185,8 @@ typedef struct {
 #define	OP_DBOARD_INFO_REPLY	     (OP_DBOARD_INFO | OP_REPLY_BIT)
 #define	OP_SYNC_TO_PPS               10
 #define	OP_SYNC_TO_PPS_REPLY	     (OP_SYNC_TO_PPS | OP_REPLY_BIT)
-
-
-//#define OP_WRITE_REG	         xx	// not implemented
-//#define OP_WRITE_REG_MASKED    xx
-//#define OP_READ_REG	         xx
-//#define OP_READ_REG_REPLY      xx
+#define OP_PEEK                      11
+#define OP_PEEK_REPLY                (OP_PEEK | OP_REPLY_BIT)
 
 /*
  * All subpackets are a multiple of 4 bytes long.
@@ -203,7 +199,7 @@ typedef struct {
  *
  * Used by:
  *  OP_EOP, OP_BURN_MAC_ADDR_REPLY, OP_START_RX_STREAMING_REPLY,
- *  OP_STOP_RX_REPLY, OP_DBOARD_INFO
+ *  OP_STOP_RX_REPLY, OP_DBOARD_INFO, OP_SYNC_TO_PPS
  */
 typedef struct {
   uint8_t	opcode;
@@ -380,7 +376,17 @@ typedef struct {
   u2_db_info_t	rx_db_info;
 } _AL4 op_dboard_info_reply_t;
 
-
+/*!
+ * \brief Read from Wishbone memory
+ */
+typedef struct {
+  uint8_t       opcode;
+  uint8_t	len;
+  uint8_t	rid;
+  uint8_t	mbz;
+  uint32_t      addr;
+  uint32_t      bytes;
+} _AL4 op_peek_t;
 
 /*
  * ================================================================
@@ -399,6 +405,7 @@ typedef union {
   op_config_tx_v2_t		op_config_tx_v2;
   op_config_tx_reply_v2_t	op_config_tx_reply_v2;
   op_config_mimo_t 		op_config_mimo;
+  op_peek_t                     op_peek;
 
 } u2_subpkt_t;