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arm/xilinx_zynq: ensure that cache is cleaned and MMU disabled when initialization starts.

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The u-boot loader enables the MMU plus the data and instruction caches
in some versions which results in RTEMS boot failure.

Closes #2774.
This commit is contained in:
Pavel Pisa
2016-08-31 16:49:15 +02:00
parent d3a428cafa
commit 22cc80783b
1 changed files with 35 additions and 0 deletions
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35
c/src/lib/libbsp/arm/xilinx-zynq/startup/bspstarthooks.c
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@@ -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();
}