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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Dilip Kota <eswara.kota@linux.intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.8 189/232] x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC
Date:   Thu, 20 Aug 2020 11:20:40 +0200
Message-Id: <20200820091621.948589440@linuxfoundation.org>
In-Reply-To: <20200820091612.692383444@linuxfoundation.org>
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From: Dilip Kota <eswara.kota@linux.intel.com>

[ Upstream commit 7d98585860d845e36ee612832a5ff021f201dbaf ]

Frequency descriptor of Lightning Mountain SoC doesn't have all the
frequency entries so resulting in the below failure causing a kernel hang:

    Error MSR_FSB_FREQ index 15 is unknown
    tsc: Fast TSC calibration failed

So, add all the frequency entries in the Lightning Mountain SoC frequency
descriptor.

Fixes: 0cc5359d8fd45 ("x86/cpu: Update init data for new Airmont CPU model")
Fixes: 812c2d7506fd ("x86/tsc_msr: Use named struct initializers")
Signed-off-by: Dilip Kota <eswara.kota@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/211c643ae217604b46cbec43a2c0423946dc7d2d.1596440057.git.eswara.kota@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/x86/kernel/tsc_msr.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index 4fec6f3a1858b..a654a9b4b77c0 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -133,10 +133,15 @@ static const struct freq_desc freq_desc_ann = {
 	.mask = 0x0f,
 };
 
-/* 24 MHz crystal? : 24 * 13 / 4 = 78 MHz */
+/*
+ * 24 MHz crystal? : 24 * 13 / 4 = 78 MHz
+ * Frequency step for Lightning Mountain SoC is fixed to 78 MHz,
+ * so all the frequency entries are 78000.
+ */
 static const struct freq_desc freq_desc_lgm = {
 	.use_msr_plat = true,
-	.freqs = { 78000, 78000, 78000, 78000, 78000, 78000, 78000, 78000 },
+	.freqs = { 78000, 78000, 78000, 78000, 78000, 78000, 78000, 78000,
+		   78000, 78000, 78000, 78000, 78000, 78000, 78000, 78000 },
 	.mask = 0x0f,
 };
 
-- 
2.25.1