From 13c985c4f46a203d12974609d6bc27ebb65e98e4 Mon Sep 17 00:00:00 2001 From: Pavel Pisa Date: Wed, 31 Aug 2016 16:49:15 +0200 Subject: arm/xilinx_zynq: ensure that cache is cleaned and MMU disabled when initialization starts. The u-boot loader enables the MMU plus the data and instruction caches in some versions which results in RTEMS boot failure. Closes #2774. --- .../libbsp/arm/xilinx-zynq/startup/bspstarthooks.c | 35 ++++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstarthooks.c b/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstarthooks.c index 58f5ec63ff..5372380c24 100644 --- a/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstarthooks.c +++ b/c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstarthooks.c @@ -21,6 +21,41 @@ BSP_START_TEXT_SECTION void bsp_start_hook_0(void) { + uint32_t sctlr_val; + + sctlr_val = arm_cp15_get_control(); + + /* + * Current U-boot loader seems to start kernel image + * with I and D caches on and MMU enabled. + * If RTEMS application image finds that cache is on + * during startup then disable caches. + */ + if ( sctlr_val & (ARM_CP15_CTRL_I | ARM_CP15_CTRL_C | ARM_CP15_CTRL_M ) ) { + if ( sctlr_val & (ARM_CP15_CTRL_C | ARM_CP15_CTRL_M ) ) { + /* + * If the data cache is on then ensure that it is clean + * before switching off to be extra carefull. + */ + arm_cp15_data_cache_clean_all_levels(); + } + arm_cp15_flush_prefetch_buffer(); + sctlr_val &= ~ ( ARM_CP15_CTRL_I | ARM_CP15_CTRL_C | ARM_CP15_CTRL_M | ARM_CP15_CTRL_A ); + arm_cp15_set_control( sctlr_val ); + } + arm_cp15_instruction_cache_invalidate(); + /* + * The care should be taken there that no shared levels + * are invalidated by secondary CPUs in SMP case. + * It is not problem on Zynq because level of coherency + * is L1 only and higher level is not maintained and seen + * by CP15. So no special care to limit levels on the secondary + * are required there. + */ + arm_cp15_data_cache_invalidate_all_levels(); + arm_cp15_branch_predictor_invalidate_all(); + arm_cp15_tlb_invalidate(); + arm_cp15_flush_prefetch_buffer(); arm_a9mpcore_start_hook_0(); } -- cgit v1.2.3