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MIPS: cache: optimise changing of k0 CCA mode

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Changing the Cache Coherency Algorithm (CCA) for kernel mode
requires executing from KSEG1. Thus do a jump from KSEG0 to KSEG1
before changing the CCA mode. Jump back to KSEG0 afterwards.

Signed-off-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
This commit is contained in:
Daniel Schwierzeck 2018-09-07 19:02:04 +02:00
parent 2f85c2be21
commit b838586086
1 changed files with 32 additions and 22 deletions
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54
arch/mips/lib/cache_init.S
View File

@ -84,6 +84,7 @@
10:
.set pop
.endm
/*
* mips_cache_reset - low level initialisation of the primary caches
*
@ -319,19 +320,21 @@ l1_init:
PTR_LI t0, INDEX_BASE
cache_loop t0, t1, R_IC_LINE, INDEX_STORE_TAG_I
#endif
/* Enable use of the I-cache by setting Config.K0 */
sync
mfc0 t0, CP0_CONFIG
li t1, CONFIG_SYS_MIPS_CACHE_MODE
#if __mips_isa_rev >= 2
ins t0, t1, 0, 3
#else
ori t0, t0, CONF_CM_CMASK
xori t0, t0, CONF_CM_CMASK
/*
* Enable use of the I-cache by setting Config.K0. The code for this
* must be executed from KSEG1. Jump from KSEG0 to KSEG1 to do this.
* Jump back to KSEG0 after caches are enabled and insert an
* instruction hazard barrier.
*/
PTR_LA t0, change_k0_cca
li t1, CPHYSADDR(~0)
and t0, t0, t1
PTR_LI t1, CKSEG1
or t0, t0, t1
#endif
mtc0 t0, CP0_CONFIG
li a0, CONFIG_SYS_MIPS_CACHE_MODE
jalr.hb t0
/*
* then initialize D-cache.
@ -391,16 +394,9 @@ l2_unbypass:
beqz t0, 2f
/* Change Config.K0 to a coherent CCA */
mfc0 t0, CP0_CONFIG
li t1, CONF_CM_CACHABLE_COW
#if __mips_isa_rev >= 2
ins t0, t1, 0, 3
#else
ori t0, t0, CONF_CM_CMASK
xori t0, t0, CONF_CM_CMASK
or t0, t0, t1
#endif
mtc0 t0, CP0_CONFIG
PTR_LA t0, change_k0_cca
li a0, CONF_CM_CACHABLE_COW
jalr t0
/*
* Join the coherent domain such that the caches of this core are kept
@ -421,5 +417,19 @@ l2_unbypass:
return:
/* Ensure all cache operations complete before returning */
sync
jr ra
jr R_RETURN
END(mips_cache_reset)
LEAF(change_k0_cca)
mfc0 t0, CP0_CONFIG
#if __mips_isa_rev >= 2
ins t0, a0, 0, 3
#else
xor a0, a0, t0
andi a0, a0, CONF_CM_CMASK
xor a0, a0, t0
#endif
mtc0 a0, CP0_CONFIG
jr.hb ra
END(change_k0_cca)