linux-kernel - [PATCH] MIPS: Ingenic: Disable HPTLB for D0 XBurst CPUs too

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Date:   Sat, 12 Dec 2020 00:03:54 +0000
From:   Paul Cercueil <paul@...pouillou.net>
To:     Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc:     Zhou Yanjie <zhouyanjie@...o.com>,
        周琰杰 <zhouyanjie@...yeetech.com>,
        od@...c.me, linux-mips@...r.kernel.org,
        linux-kernel@...r.kernel.org, Paul Cercueil <paul@...pouillou.net>,
        stable@...r.kernel.org
Subject: [PATCH] MIPS: Ingenic: Disable HPTLB for D0 XBurst CPUs too

The JZ4760 has the HPTLB as well, but has a XBurst CPU with a D0 CPUID.

Disable the HPTLB for all XBurst CPUs with a D0 CPUID. In the case where
there is no HPTLB (e.g. for older SoCs), this won't have any side
effect.

Fixes: b02efeb05699 ("MIPS: Ingenic: Disable abandoned HPTLB function.")
Cc: <stable@...r.kernel.org> # 5.4
Signed-off-by: Paul Cercueil <paul@...pouillou.net>
---
 arch/mips/kernel/cpu-probe.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index e6853697a056..31cb9199197c 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -1830,16 +1830,17 @@ static inline void cpu_probe_ingenic(struct cpuinfo_mips *c, unsigned int cpu)
 		 */
 		case PRID_COMP_INGENIC_D0:
 			c->isa_level &= ~MIPS_CPU_ISA_M32R2;
-			break;
+			fallthrough;
 
 		/*
 		 * The config0 register in the XBurst CPUs with a processor ID of
-		 * PRID_COMP_INGENIC_D1 has an abandoned huge page tlb mode, this
-		 * mode is not compatible with the MIPS standard, it will cause
-		 * tlbmiss and into an infinite loop (line 21 in the tlb-funcs.S)
-		 * when starting the init process. After chip reset, the default
-		 * is HPTLB mode, Write 0xa9000000 to cp0 register 5 sel 4 to
-		 * switch back to VTLB mode to prevent getting stuck.
+		 * PRID_COMP_INGENIC_D0 or PRID_COMP_INGENIC_D1 has an abandoned
+		 * huge page tlb mode, this mode is not compatible with the MIPS
+		 * standard, it will cause tlbmiss and into an infinite loop
+		 * (line 21 in the tlb-funcs.S) when starting the init process.
+		 * After chip reset, the default is HPTLB mode, Write 0xa9000000
+		 * to cp0 register 5 sel 4 to switch back to VTLB mode to prevent
+		 * getting stuck.
 		 */
 		case PRID_COMP_INGENIC_D1:
 			write_c0_page_ctrl(XBURST_PAGECTRL_HPTLB_DIS);
-- 
2.29.2