X-Git-Url: http://git.rot13.org/?p=goodfet;a=blobdiff_plain;f=firmware%2Finclude%2Fjtagxscale.h;h=f1f17fa9401ceb1e79156d70c00d56d31f9ab6b6;hp=05d497b40653b5a35cfba79c3547d5b6b9df49c9;hb=278a9487e60fdcf3e96236580f9542c218a8c1f1;hpb=1c74a29dfb28d2b6ae468b5c516ff0f434be900f

diff --git a/firmware/include/jtagxscale.h b/firmware/include/jtagxscale.h
index 05d497b..f1f17fa 100644
--- a/firmware/include/jtagxscale.h
+++ b/firmware/include/jtagxscale.h
@@ -1,11 +1,84 @@
-/*! \file jtagxscale.h
+/*! 
+  \file jtagxscale.h
   \author Dave Huseby <huseby at linuxprogrammer.org>
-  \brief Intel XScale JTAG command verbs
+  \brief Intel XScale JTAG
 */
 
+/* NOTE: I heavily cribbed from the ARM7TDMI jtag implementation. Credit where
+ * credit is due. */
+
+/* 
+ * Utility Macros 
+ */
+
+/* XTT (LED TCK TOCK) toggles the CLK line while turning on/off the LED */
+#define XTT             CLRTCK;PLEDOUT^=PLEDPIN;SETTCK;PLEDOUT^=PLEDPIN;
+
+/* RUN_TEST_IDLE gets us into run-test-idle from anywhere in the TAP FSM */
+#define RUN_TEST_IDLE   SETTMS;XTT;XTT;XTT;XTT;XTT;XTT;XTT;XTT;CLRTMS;XTT;
+
+/* SHIFT_IR gets us into the "Shift IR" state from the run-test-idle state */
+#define SHIFT_IR        SETTMS;XTT;XTT;CLRTMS;XTT;XTT;
+
+/* SHIFT_DIR gets us into the "Shift DR" state from the run-test-idle state */
+#define SHIFT_DR        SETTMS;XTT;CLRTMS;XTT;XTT;
+
+
+/*
+ * XScale 5-bit JTAG Commands
+ */
+
+/* On the XScale chip, the TDI pin is connected to the MSB of the IR and the 
+ * TDO is connected to the LSB.  That means we have to shift these commands 
+ * in from LSB to MSB order. */
+
+/* 01000 - High Z
+ * The highz instruction floats all three-stateable output and in/out pins. 
+ * Also, when this instruction is active, the Bypass register is connected 
+ * between TDI and TDO. This register can be accessed via the JTAG Test-Access 
+ * Port throughout the device operation. Access to the Bypass register can also 
+ * be obtained with the bypass instruction. */
+#define XSCALE_IR_HIGHZ             0x08
+
+/* 11110 - Get ID Code
+ * The idcode instruction is used in conjunction with the device identification 
+ * register. It connects the identification register between TDI and TDO in the 
+ * Shift_DR state. When selected, idcode parallel-loads the hard-wired 
+ * identification code (32 bits) on TDO into the identification register on the 
+ * rising edge of TCK in the Capture_DR state. Note: The device identification 
+ * register is not altered by data being shifted in on TDI.*/
+#define XSCALE_IR_IDCODE            0x1E
+
+/* 11111 - Bypass
+ * The bypass instruction selects the Bypass register between TDI and TDO pins 
+ * while in SHIFT_DR state, effectively bypassing the processor’s test logic. 
+ * 02 is captured in the CAPTURE_DR state. While this instruction is in effect, 
+ * all other test data registers have no effect on the operation of the system. 
+ * Test data registers with both test and system functionality perform their 
+ * system functions when this instruction is selected. */
+#define XSCALE_IR_BYPASS            0x1F
 
 /*
- * TODO: specify the standard Intel XScale IR, TCB control and device specific
- * values.
+ * GoodFET Commands from the Client
  */
 
+/* Get CHIP ID */
+#define XSCALE_GET_CHIP_ID          0xF1
+
+
+/*
+ * Public Interface
+ */
+
+/* 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);
+
+/* this handles shifting in the IDCODE instruction and shifting the result
+ * out the TDO and return it. */
+unsigned long jtag_xscale_idcode();
+
+