Question about DBCR0 initialization for 440

John Linn John.Linn at
Wed Apr 15 06:33:10 EST 2009

The kernel does not initialize the PPC440 DBCR0 register. This prevents
(among other things) the use of software breakpoints with GDB.  I
realize that boot loaders probably do initialize this but we run a lot
without a boot loader and so do our customers.


The file, head_fsl_booke.S, does initialize the register for the
freescale specific code (as shown at the end of the message).


We are needing this also for Xilinx.  What's the best method to
incorporate this, is it possible to add to head_44x.S?





#if !defined(CONFIG_BDI_SWITCH)


             * The Abatron BDI JTAG debugger does not tolerate others

             * mucking with the debug registers.


            lis     r2,DBCR0_IDM at h

            mtspr   SPRN_DBCR0,r2


            /* clear any residual debug events */

            li      r2,-1

            mtspr   SPRN_DBSR,r2



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