+int mips32_cp0_read(struct mips_ejtag *ejtag_info, uint32_t *val, uint32_t cp0_reg, uint32_t cp0_sel)
+{
+ /**
+ * Do not make this code static, but regenerate it every time,
+ * as 5th element has to be changed to add parameters
+ */
+ uint32_t code[] = {
+ /* start: */
+ MIPS32_MTC0(15,31,0), /* move $15 to COP0 DeSave */
+ MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)), /* $15 = MIPS32_PRACC_STACK */
+ MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)),
+ MIPS32_SW(8,0,15), /* sw $8,($15) */
+ MIPS32_SW(9,0,15), /* sw $9,($15) */
+
+ /* 5 */ MIPS32_MFC0(8,0,0), /* move COP0 [cp0_reg select] to $8 */
+
+ MIPS32_LUI(9,UPPER16(MIPS32_PRACC_PARAM_OUT)), /* $11 = MIPS32_PRACC_PARAM_OUT */
+ MIPS32_ORI(9,9,LOWER16(MIPS32_PRACC_PARAM_OUT)),
+ MIPS32_SW(8,0,9), /* sw $8,0($9) */
+
+ MIPS32_LW(9,0,15), /* lw $9,($15) */
+ MIPS32_LW(8,0,15), /* lw $8,($15) */
+ MIPS32_B(NEG16(12)), /* b start */
+ MIPS32_MFC0(15,31,0), /* move COP0 DeSave to $15 */
+ };
+
+ /**
+ * Note that our input parametes cp0_reg and cp0_sel
+ * are numbers (not gprs) which make part of mfc0 instruction opcode.
+ *
+ * These are not fix, but can be different for each mips32_cp0_read() function call,
+ * and that is why we must insert them directly into opcode,
+ * i.e. we can not pass it on EJTAG microprogram stack (via param_in),
+ * and put them into the gprs later from MIPS32_PRACC_STACK
+ * because mfc0 do not use gpr as a parameter for the cp0_reg and select part,
+ * but plain (immediate) number.
+ *
+ * MIPS32_MTC0 is implemented via MIPS32_R_INST macro.
+ * In order to insert our parameters, we must change rd and funct fields.
+ */
+ code[5] |= (cp0_reg << 11) | cp0_sel; /* change rd and funct of MIPS32_R_INST macro */
+
+ /* TODO remove array */
+ uint32_t *param_out = val;
+ int retval;
+
+ retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 0, NULL, 1, param_out, 1);
+
+ return retval;
+}
+
+int mips32_cp0_write(struct mips_ejtag *ejtag_info,
+ uint32_t val, uint32_t cp0_reg, uint32_t cp0_sel)
+{
+ uint32_t code[] = {
+ /* start: */
+ MIPS32_MTC0(15,31,0), /* move $15 to COP0 DeSave */
+ MIPS32_LUI(15,UPPER16(MIPS32_PRACC_STACK)), /* $15 = MIPS32_PRACC_STACK */
+ MIPS32_ORI(15,15,LOWER16(MIPS32_PRACC_STACK)),
+ MIPS32_SW(8,0,15), /* sw $8,($15) */
+ MIPS32_SW(9,0,15), /* sw $9,($15) */
+
+ MIPS32_LUI(8,UPPER16(MIPS32_PRACC_PARAM_IN)), /* $8 = MIPS32_PRACC_PARAM_IN */
+ MIPS32_ORI(8,8,LOWER16(MIPS32_PRACC_PARAM_IN)),
+ MIPS32_LW(9,0,8), /* Load write val to $9 */
+
+ /* 8 */ MIPS32_MTC0(9,0,0), /* move $9 to COP0 [cp0_reg select] */
+
+ MIPS32_LW(9,0,15), /* lw $9,($15) */
+ MIPS32_LW(8,0,15), /* lw $8,($15) */
+ MIPS32_B(NEG16(12)), /* b start */
+ MIPS32_MFC0(15,31,0), /* move COP0 DeSave to $15 */
+ };
+
+ /**
+ * Note that MIPS32_MTC0 macro is implemented via MIPS32_R_INST macro.
+ * In order to insert our parameters, we must change rd and funct fields.
+ */
+ code[8] |= (cp0_reg << 11) | cp0_sel; /* change rd and funct fields of MIPS32_R_INST macro */
+
+ /* TODO remove array */
+ uint32_t *param_in = malloc(1 * sizeof(uint32_t));
+ int retval;
+ param_in[0] = val;
+
+ retval = mips32_pracc_exec(ejtag_info, ARRAY_SIZE(code), code, 1, param_in, 0, NULL, 1);
+
+ free(param_in);
+
+ return retval;
+}
+