HI,
On 30-01-2020 16:21, David Laight wrote:
From: Peter Zijlstra
Sent: 30 January 2020 13:43
...
+ * Bay Trail SDM MSR_FSB_FREQ frequencies simplified PLL model:
+ * 000: 100 * 5 / 6 = 83.3333 MHz
+ * 001: 100 * 1 / 1 = 100.0000 MHz
+ * 010: 100 * 4 / 3 = 133.3333 MHz
+ * 011: 100 * 7 / 6 = 116.6667 MHz
+ * 100: 100 * 4 / 5 = 80.0000 MHz
+ * Cherry Trail SDM MSR_FSB_FREQ frequencies simplified PLL model:
+ * 0000: 100 * 5 / 6 = 83.3333 MHz
+ * 0001: 100 * 1 / 1 = 100.0000 MHz
+ * 0010: 100 * 4 / 3 = 133.3333 MHz
+ * 0011: 100 * 7 / 6 = 116.6667 MHz
+ * 0100: 100 * 4 / 5 = 80.0000 MHz
+ * 0101: 100 * 14 / 15 = 93.3333 MHz
+ * 0110: 100 * 9 / 10 = 90.0000 MHz
+ * 0111: 100 * 8 / 9 = 88.8889 MHz
+ * 1000: 100 * 7 / 8 = 87.5000 MHz
+ * Merriefield (BYT MID) SDM MSR_FSB_FREQ frequencies simplified PLL model:
+ * 0001: 100 * 1 / 1 = 100.0000 MHz
+ * 0010: 100 * 4 / 3 = 133.3333 MHz
+ * Moorefield (CHT MID) SDM MSR_FSB_FREQ frequencies simplified PLL model:
+ * 0000: 100 * 5 / 6 = 83.3333 MHz
+ * 0001: 100 * 1 / 1 = 100.0000 MHz
+ * 0010: 100 * 4 / 3 = 133.3333 MHz
+ * 0011: 100 * 1 / 1 = 100.0000 MHz
Unless I'm going cross-eyed, that's 4 times the exact same table.
Apart from the very last line which duplicates 100MHz.
And the fact that some entries are missing (presumed invalid?)
for certain cpu.
If the tables are ever used for setting the frequency
then the valid range (and values?) would need to be known.
I did wonder if the 'mask' was necessary?
Are the unused bits reserved and zero?
They are reserved without having a defined value, the appear to
usually be 0 but I would rather not depend on that.
Regards,
Hans
