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armv8/fsl-layerscape: Add loop to check L3 dcache status

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Flushing L3 cache may need variable time depending upon cache line
allocation.

Coming up with a proper timeout value would be best handled by
simulations under multiple scenarios in your actual system.
>From the purely HN-F point of view, the flush would take ~15 cycles for
a clean line, and ~22 cycles for a dirty line.  For the dirty line case,
there are many variables outside the HN-F that will increase the
duration per line.  For example, a *DBIDResp from the SN-F/SBSX,
memory controller latency, SN-F/SBSX RetryAck responses, CCN ring
congestion, CCN ring hops, etc, etc.  The worst-case timeout would
have to factor in all of these variables plus the HN-F cycles for
every line in the L3, and assuming all lines are dirty

In case if L3 is not flushed properly, system behaviour will be
erratic, so remove timeout and add loop to check status of L3 cache.

System will stuck in while loop if there is some issue in L3 cache
flushing.

Signed-off-by: Udit Kumar <udit.kumar@nxp.com>
Signed-off-by: Meenakshi Aggarwal <meenakshi.aggarwal@nxp.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>
This commit is contained in:
Meenakshi Aggarwal
2019-05-28 21:37:58 +05:30
committed by Prabhakar Kushwaha
parent 85e5e21981
commit 1dff14c87d
1 changed files with 8 additions and 22 deletions
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30
arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S
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@@ -1,6 +1,7 @@
/* SPDX-License-Identifier: GPL-2.0+ */ /* SPDX-License-Identifier: GPL-2.0+ */
/* /*
* (C) Copyright 2014-2015 Freescale Semiconductor * (C) Copyright 2014-2015 Freescale Semiconductor
* Copyright 2019 NXP
* *
* Extracted from armv8/start.S * Extracted from armv8/start.S
*/ */
@@ -356,31 +357,22 @@ get_svr:
#if defined(CONFIG_SYS_FSL_HAS_CCN504) || defined(CONFIG_SYS_FSL_HAS_CCN508) #if defined(CONFIG_SYS_FSL_HAS_CCN504) || defined(CONFIG_SYS_FSL_HAS_CCN508)
hnf_pstate_poll: hnf_pstate_poll:
/* x0 has the desired status, return 0 for success, 1 for timeout /* x0 has the desired status, return only if operation succeed
* clobber x1, x2, x3, x4, x6, x7 * clobber x1, x2, x6
*/ */
mov x1, x0 mov x1, x0
mov x7, #0 /* flag for timeout */ mov w6, #8 /* HN-F node count */
mrs x3, cntpct_el0 /* read timer */
add x3, x3, #1200 /* timeout after 100 microseconds */
mov x0, #0x18 mov x0, #0x18
movk x0, #0x420, lsl #16 /* HNF0_PSTATE_STATUS */ movk x0, #0x420, lsl #16 /* HNF0_PSTATE_STATUS */
mov w6, #8 /* HN-F node count */
1: 1:
ldr x2, [x0] ldr x2, [x0]
cmp x2, x1 /* check status */ cmp x2, x1 /* check status */
b.eq 2f b.eq 2f
mrs x4, cntpct_el0 b 1b
cmp x4, x3
b.ls 1b
mov x7, #1 /* timeout */
b 3f
2: 2:
add x0, x0, #0x10000 /* move to next node */ add x0, x0, #0x10000 /* move to next node */
subs w6, w6, #1 subs w6, w6, #1
cbnz w6, 1b cbnz w6, 1b
3:
mov x0, x7
ret ret
hnf_set_pstate: hnf_set_pstate:
@@ -405,10 +397,8 @@ ENTRY(__asm_flush_l3_dcache)
/* /*
* Return status in x0 * Return status in x0
* success 0 * success 0
* timeout 1 for setting SFONLY, 2 for FAM, 3 for both
*/ */
mov x29, lr mov x29, lr
mov x8, #0
dsb sy dsb sy
mov x0, #0x1 /* HNFPSTAT_SFONLY */ mov x0, #0x1 /* HNFPSTAT_SFONLY */
@@ -416,19 +406,15 @@ ENTRY(__asm_flush_l3_dcache)
mov x0, #0x4 /* SFONLY status */ mov x0, #0x4 /* SFONLY status */
bl hnf_pstate_poll bl hnf_pstate_poll
cbz x0, 1f
mov x8, #1 /* timeout */
1:
dsb sy dsb sy
mov x0, #0x3 /* HNFPSTAT_FAM */ mov x0, #0x3 /* HNFPSTAT_FAM */
bl hnf_set_pstate bl hnf_set_pstate
mov x0, #0xc /* FAM status */ mov x0, #0xc /* FAM status */
bl hnf_pstate_poll bl hnf_pstate_poll
cbz x0, 1f
add x8, x8, #0x2 mov x0, #0
1:
mov x0, x8
mov lr, x29 mov lr, x29
ret ret
ENDPROC(__asm_flush_l3_dcache) ENDPROC(__asm_flush_l3_dcache)