[linux-yocto] [PATCH 4/6] x86 tsc_msr: Correct Silvermont reference clock values

Yong, Jonathan jonathan.yong at intel.com
Mon Jun 20 01:25:34 PDT 2016


From: Len Brown <len.brown at intel.com>

Atom processors use a 19.2 MHz crystal oscillator.

Early processors generate 100 MHz via 19.2 MHz * 26 / 5 = 99.84 MHz.

Later preocessor generate 100 MHz via 19.2 MHz * 125 / 24 = 100 MHz.

Update the Silvermont-based tables accordingly,
matching the Software Developers Manual.

Also, correct a 166 MHz entry that should have been 116 MHz,
and add a missing 80 MHz entry.

Reported-by: Stephane Gasparini <stephane.gasparini at intel.com>
Signed-off-by: Len Brown <len.brown at intel.com>
Signed-off-by: Yong, Jonathan <jonathan.yong at intel.com>
---
 arch/x86/kernel/tsc_msr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/tsc_msr.c b/arch/x86/kernel/tsc_msr.c
index 4110f72..20487e2 100644
--- a/arch/x86/kernel/tsc_msr.c
+++ b/arch/x86/kernel/tsc_msr.c
@@ -35,11 +35,11 @@ static struct freq_desc freq_desc_tables[] = {
 	/* CLV+ */
 	{ 6, 0x35, 0, { 0, 133200, 0, 0, 0, 99840, 0, 83200 } },
 	/* TNG - Intel Atom processor Z3400 series */
-	{ 6, 0x4a, 1, { 0, 99840, 133200, 0, 0, 0, 0, 0 } },
+	{ 6, 0x4a, 1, { 0, 100000, 133300, 0, 0, 0, 0, 0 } },
 	/* VLV2 - Intel Atom processor E3000, Z3600, Z3700 series */
-	{ 6, 0x37, 1, { 83200, 99840, 133200, 166400, 0, 0, 0, 0 } },
+	{ 6, 0x37, 1, { 83300, 100000, 133300, 116700, 80000, 0, 0, 0 } },
 	/* ANN - Intel Atom processor Z3500 series */
-	{ 6, 0x5a, 1, { 83200, 99840, 133200, 99840, 0, 0, 0, 0 } },
+	{ 6, 0x5a, 1, { 83300, 100000, 133300, 100000, 0, 0, 0, 0 } },
 };
 
 static int match_cpu(u8 family, u8 model)
-- 
2.7.3



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