[PATCH 5.7 161/204] x86/tsr: Fix tsc frequency enumeration bug on Lightning Mountain SoC

Greg Kroah-Hartman
2020-08-20T12:52:47Z

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