In HWiNFO, we see support for Tccd1, Tccd3, Tccd5, and Tccd7 temperature
sensors on Zen2 based Threadripper CPUs. Checking register maps on
Threadripper 3970X confirms SMN register addresses and values for those
sensors.

Register values observed in an idle system:

0x059950: 00000000 00000abc 00000000 00000ad8
0x059960: 00000000 00000ade 00000000 00000ae4

Under load:

0x059950: 00000000 00000c02 00000000 00000c14
0x059960: 00000000 00000c30 00000000 00000c22

More analysis shows that EPYC CPUs support up to 8 CCD temperature
sensors. EPYC 7601 supports three CCD temperature sensors. Unlike
Zen2 CPUs, the register space in Zen1 CPUs supports a maximum of four
sensors, so only search for a maximum of four sensors on Zen1 CPUs.

On top of that, in thm_10_0_sh_mask.h in the Linux kernel, we find
definitions for THM_DIE{1-3}_TEMP__VALID_MASK, set to 0x00000800, as well
as matching SMN addresses. This lets us conclude that bit 11 of the
respective registers is a valid bit. With this assumption, the temperature
offset is now 49 degrees C. This conveniently matches the documented
temperature offset for Tdie, again suggesting that above registers indeed
report temperatures sensor values. Assume that bit 11 is indeed a valid
bit, and add support for the additional sensors.

With this patch applied, output from 3970X (idle) looks as follows:

k10temp-pci-00c3
Adapter: PCI adapter
Tdie:         +55.9°C
Tctl:         +55.9°C
Tccd1:        +39.8°C
Tccd3:        +43.8°C
Tccd5:        +43.8°C
Tccd7:        +44.8°C
Tested-by: Michael Larabel <michael@phoronix.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>