libpayload: arm64: Keep instruction cache enabled at all times

This patch makes libpayload enable the instruction cache as the very
first thing, which is similar to how we treat it in coreboot. It also
prevents the icache from being disabled again during mmu_disable() as
part of the two-stage page table setup in post_sysinfo_scan_mmu_setup().
It replaces the existing mmu_disable() implementation with the assembly
version from coreboot which handles certain edge cases better (see
CB:27238 for details).

The SCTLR flag definitions in libpayload seem to have still been
copy&pasted from arm32, so replace with the actual arm64 defintions from
coreboot.

Change-Id: Ifdbec34f0875ecc69fedcbea5c20e943379a3d2d
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/38908
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>

1 files changed, 0 insertions, 24 deletions

diff --git a/payloads/libpayload/arch/arm64/mmu.c b/payloads/libpayload/arch/arm64/mmu.c
index d1dd5b0147..3a5e04db6c 100644
--- a/payloads/libpayload/arch/arm64/mmu.c
+++ b/payloads/libpayload/arch/arm64/mmu.c
@@ -304,30 +304,6 @@ static uint32_t is_mmu_enabled(void)
 }
 
 /*
- * Func: mmu_disable
- * Desc: Invalidate caches and disable mmu
- */
-void mmu_disable(void)
-{
-	uint32_t sctlr;
-
-	sctlr = raw_read_sctlr_el2();
-	sctlr &= ~(SCTLR_C | SCTLR_M | SCTLR_I);
-
-	tlbiall_el2();
-	dcache_clean_invalidate_all();
-
-	dsb();
-	isb();
-
-	raw_write_sctlr_el2(sctlr);
-
-	dcache_clean_invalidate_all();
-	dsb();
-	isb();
-}
-
-/*
  * Func: mmu_enable
  * Desc: Initialize MAIR, TCR, TTBR and enable MMU by setting appropriate bits
  * in SCTLR