X-Git-Url: http://git.rot13.org/?p=goodfet;a=blobdiff_plain;f=firmware%2Fapps%2Fjtag%2Fjtagxscale.c;h=bbf9b9b20cf6fa53ecb20b9fee1b5d04c8ed485c;hp=ffe169cea642999419b7e3be3fde15c194fab408;hb=5fb0341d348e101b30794945a6c91546e25e8e7b;hpb=b6ef3f8c96ad4f9a457e1a7e61a39ea452fbbd66

diff --git a/firmware/apps/jtag/jtagxscale.c b/firmware/apps/jtag/jtagxscale.c
index ffe169c..bbf9b9b 100644
--- a/firmware/apps/jtag/jtagxscale.c
+++ b/firmware/apps/jtag/jtagxscale.c
@@ -1,24 +1,219 @@
-/*! \file jtagxscale.c
+/*! 
+  \file jtagxscale.c
   \author Dave Huseby <dave@linuxprogrammer.org>
-  \brief Intel XScale JTAG (32-bit)
+  \brief Intel XScale JTAG
 */
 
 #include "platform.h"
 #include "command.h"
 #include "jtag.h"
+#include "jtagxscale.h"
 
-//! Handles XScale JTAG commands.  Forwards others to JTAG.
-void xscalehandle(unsigned char app,
-                  unsigned char verb,
-                  unsigned long len)
+#define JTAGXSCALE_APP
+
+/* Handles XScale JTAG commands.  Forwards others to JTAG. */
+void jtag_xscale_handle_fn( uint8_t const app,
+							uint8_t const verb,
+							uint32_t const len);
+
+// define the jtag xscale app's app_t
+app_t const jtagxscale_app = {
+
+	/* app number */
+	JTAGXSCALE,
+
+	/* handle fn */
+	jtag_xscale_handle_fn,
+
+	/* name */
+	"JTAG XScale",
+
+	/* desc */
+	"\tThe JTAG Xscale app extends the JTAG app adding support\n"
+	"\tfor JTAG'ing Intel XScale devices.\n"
+};
+
+
+/* From the Intel XScale Core Developer's Manual:
+ *
+ * The Intel XScale® core provides test features compatible with IEEE Standard
+ * Test Access Port and Boundary Scan Architecture (IEEE Std. 1149.1). These 
+ * features include a TAP controller, a 5 or 7 bit instruction register, and 
+ * test data registers to support software debug. The size of the instruction 
+ * register depends on which variant of the Intel XScale® core is being used.
+ * This can be found out by examining the CoreGen field of Coprocessor 15, ID 
+ * Register (bits 15:13). (See Table 7-4, "ID Register" on page 7-81 for more 
+ * details.) A CoreGen value of 0x1 means the JTAG instruction register size 
+ * is 5 bits and a CoreGen value of 0x2 means the JTAG instruction register 
+ * size is 7 bits.
+ *
+ */
+
+/* NOTE: I heavily cribbed from the ARM7TDMI jtag implementation. Credit where
+ * credit is due. */
+
+/* this handles shifting arbitrary length bit strings into the instruction
+ * register and clocking out bits while leaving the JTAG state machine in a
+ * known state. it also handle bit swapping. */
+unsigned long jtag_xscale_shift_n(unsigned long word,
+                                  unsigned char nbits,
+                                  unsigned char flags)
+{
+    unsigned int bit;
+    unsigned long high = 1;
+    unsigned long mask;
+
+    for (bit = (nbits - 1) / 8; bit > 0; bit--)
+        high <<= 8;
+    
+    high <<= ((nbits - 1) % 8);
+
+    mask = high - 1;
+
+    if (flags & LSB) 
+    {
+        /* clock the bits into the IR from LSB to MSB order */
+        for (bit = nbits; bit > 0; bit--) 
+        {
+            /* write MOSI on trailing edge of previous clock */
+            if (word & 1)
+            {
+                SETMOSI;
+            }
+            else
+            {
+                CLRMOSI;
+            }
+            word >>= 1;
+
+            if (bit == 1 && !(flags & NOEND))
+                SETTMS; /* TMS high on last bit to exit. */
+
+            /* tick tock the clock line */
+            XTT;
+
+            /* read MISO on trailing edge */
+            if (READMISO)
+            {
+                word += (high);
+            }
+        }
+    } 
+    else 
+    {
+        /* clock the bits into the IR from MSB to LSB order */
+        for (bit = nbits; bit > 0; bit--) 
+        {
+            /* write MOSI on trailing edge of previous clock */
+            if (word & high)
+            {
+                SETMOSI;
+            }
+            else
+            {
+                CLRMOSI;
+            }
+            word = (word & mask) << 1;
+
+            if (bit == 1 && !(flags & NOEND))
+                SETTMS;//TMS high on last bit to exit.
+
+            /* tick tock the clock line */
+            XTT;
+
+            /* read MISO on trailing edge */
+            word |= (READMISO);
+        }
+    }
+
+    SETMOSI;
+
+    if (!(flags & NOEND))
+    {
+        /* exit state */
+        XTT;
+
+        /* update state */
+        if (!(flags & NORETIDLE))
+        {
+            CLRTMS;
+            XTT;
+        }
+    }
+
+    return word;
+}
+
+
+/* this handles shifting in the IDCODE instruction and shifting the result
+ * out the TDO and return it. */
+unsigned long jtag_xscale_idcode()
+{
+    /* NOTE: this assumes that we're in the run-test-idle state */
+
+    /* get into the shift-ir state */
+    SHIFT_IR;
+
+    /* shift the ID code instruction into the IR and return to run-test-idle */
+    jtag_xscale_shift_n(XSCALE_IR_IDCODE, 5, LSB);
+
+    /* get into the shift-dr state */
+    SHIFT_DR;
+
+    /* now clock out the 32 bit ID code and return back to run-test-idle */
+    return jtag_xscale_shift_n(0, 32, LSB);
+}
+
+/* Handles XScale JTAG commands.  Forwards others to JTAG. */
+void jtag_xscale_handle_fn( uint8_t const app,
+							uint8_t const verb,
+							uint32_t const len)
 {    
     switch(verb) 
     {
+        /*
+         * Standard Commands
+         */
+        case SETUP:
+
+            /* set up the pin I/O for JTAG */
+            jtagsetup();
+
+            /* reset to run-test-idle state */
+            RUN_TEST_IDLE;
+
+            /* send back OK */
+            txdata(app, OK, 0);
+
+            break;
+
         case START:
         case STOP:
         case PEEK:
         case POKE:
+        case READ:
+        case WRITE:
         default:
-            jtaghandle(app,verb,len);
+ 
+            /* send back OK */
+            txdata(app, OK, 0);
+
+            break;
+
+        /*
+         * XScale Commands
+         */
+        case XSCALE_GET_CHIP_ID:
+
+            /* reset to run-test-idle state */
+            RUN_TEST_IDLE;
+
+            /* put the ID code in the data buffer */
+            cmddatalong[0] = jtag_xscale_idcode();
+
+            /* send it back to the client */
+            txdata(app,verb,4);
+
+            break;
     }
 }