linux-kernel - [PATCH] ARM: exynos: update l2c_aux

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Message-Id: <b29f34870380093e6268c11d3033033d6def61b7.1585756648.git.guillaume.tucker@collabora.com>
Date:   Wed,  1 Apr 2020 17:08:03 +0100
From:   Guillaume Tucker <guillaume.tucker@...labora.com>
To:     Russell King <linux@...linux.org.uk>,
        Kukjin Kim <kgene@...nel.org>,
        Krzysztof Kozlowski <krzk@...nel.org>
Cc:     linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...labora.com
Subject: [PATCH] ARM: exynos: update l2c_aux_mask to fix alert message

Allow setting the number of cycles for RAM reads in the pl310 cache
controller L2 auxiliary control register mask (bits 0-2) since it
needs to be changed in software.  This only affects exynos4210 and
exynos4412 as they use the pl310 cache controller.

With the mask used until now, the following warnings were generated,
the 2nd one being a pr_alert():

  L2C: platform modifies aux control register: 0x02070000 -> 0x3e470001
  L2C: platform provided aux values permit register corruption.

This latency cycles value has always been set in software in spite of
the warnings.  Keep it this way but clear the alert message about
register corruption to acknowledge it is a valid thing to do.

Tested on exynos4412-odroid-x2.

Signed-off-by: Guillaume Tucker <guillaume.tucker@...labora.com>
Reported-by: "kernelci.org bot" <bot@...nelci.org>
---
 arch/arm/mach-exynos/exynos.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
index 7a8d1555db40..ed1bba49210d 100644
--- a/arch/arm/mach-exynos/exynos.c
+++ b/arch/arm/mach-exynos/exynos.c
@@ -194,7 +194,7 @@ static void __init exynos_dt_fixup(void)

 DT_MACHINE_START(EXYNOS_DT, "Samsung Exynos (Flattened Device Tree)")
 	.l2c_aux_val	= 0x3c400001,
-	.l2c_aux_mask	= 0xc20fffff,
+	.l2c_aux_mask	= 0xc20ffff8,
 	.smp		= smp_ops(exynos_smp_ops),
 	.map_io		= exynos_init_io,
 	.init_early	= exynos_firmware_init,
-- 
2.20.1