linux-kernel - [PATCH 3/4] 44x/fsp2: tvsense workaround for dd1

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Date:   Thu, 2 Nov 2017 16:07:05 +0300
From:   Ivan Mikhaylov <ivan@...ibm.com>
To:     Alistair Popple <alistair@...ple.id.au>,
        Matt Porter <mporter@...nel.crashing.org>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Joel Stanley <joel@....id.au>,
        Paul Mackerras <paulus@...ba.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH 3/4] 44x/fsp2: tvsense workaround for dd1

* tvsense(temperature and voltage sensors) may provide
  erratic sense values which may result in parity errors
  on CMU.

Signed-off-by: Ivan Mikhaylov <ivan@...ibm.com>
---
 arch/powerpc/platforms/44x/fsp2.c |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)

diff --git a/arch/powerpc/platforms/44x/fsp2.c b/arch/powerpc/platforms/44x/fsp2.c
index 9585725..4e12490 100644
--- a/arch/powerpc/platforms/44x/fsp2.c
+++ b/arch/powerpc/platforms/44x/fsp2.c
@@ -59,6 +59,23 @@ static int __init fsp2_probe(void)
 	mtdcr(DCRN_PLB6_HD, 0xffff0000);
 	mtdcr(DCRN_PLB6_SHD, 0xffff0000);
 
+	/* TVSENSE reset is blocked (clock gated) by the POR default of the TVS
+	 * sleep config bit. As a consequence, TVSENSE will provide erratic
+	 * sensor values, which may result in spurious (parity) errors
+	 * recorded in the CMU FIR and leading to erroneous interrupt requests
+	 * once the CMU interrupt is unmasked.
+	 */
+
+	/* 1. set TVS1[UNDOZE] */
+	val = mfcmu(CMUN_TVS1);
+	val |= 0x4;
+	mtcmu(CMUN_TVS1, val);
+
+	/* 2. clear FIR[TVS] and FIR[TVSPAR] */
+	val = mfcmu(CMUN_FIR0);
+	val |= 0x30000000;
+	mtcmu(CMUN_FIR0, val);
+
 	/* L2 machine checks */
 	mtl2(L2PLBMCKEN0, 0xffffffff);
 	mtl2(L2PLBMCKEN1, 0x0000ffff);
-- 
1.7.1