SOFT_SCRATCH
I915_WRITE(SOFT_SCRATCH(0), 0);
I915_WRITE(SOFT_SCRATCH(1 + i), params[i]);
val = I915_READ(SOFT_SCRATCH(15));
I915_WRITE(SOFT_SCRATCH(15), val & ~msg);
guc->send_regs.base = i915_mmio_reg_offset(SOFT_SCRATCH(0));