ARM: hw_breakpoint: Check function for OS Save and Restore mechanism
v7 debug introduced OS Save and Restore mechanism. On a v7 debug SinglePower system, i.e a system without a separate core and debug power domain, which does not support external debug over powerdown, it is implementation defined whether OS Save and Restore is implemented. v7.1 debug requires OS Save and Restore mechanism. v6 debug and v6.1 debug do not implement it. A new global variable bool has_ossr is introduced and is determined in arch_hw_breakpoint_init() like debug_arch or the number of BRPs/WRPs. The logic how to check if OS Save and Restore is supported has changed with this patch. In reset_ctrl_regs() a mask consisting of OSLM[1] (OSLSR.3) and OSLM[0] (OSLSR.0) was used to check if the system supports OS Save and Restore. In the new function core_has_os_save_restore() only OSLM[0] is used. It is not necessary to check OSLM[1] too since it is v7.1 debug specific and v7.1 debug requires OS Save and Restore and thus OS Lock. Signed-off-by: NDietmar Eggemann <dietmar.eggemann@arm.com> Signed-off-by: NWill Deacon <will.deacon@arm.com>
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