git: eb08efb821fd - stable/13 - amdtemp: Fix missing 49 degree offset on current EPYC CPUs

The branch stable/13 has been updated by mhorne:

URL: https://cgit.FreeBSD.org/src/commit/?id=eb08efb821fd7d3ee599d65c704fb88c28c57842

commit eb08efb821fd7d3ee599d65c704fb88c28c57842
Author:     Val Packett <val@packett.cool>
AuthorDate: 2023-06-17 16:29:53 +0000
Commit:     Mitchell Horne <mhorne@FreeBSD.org>
CommitDate: 2023-07-07 19:20:50 +0000

    amdtemp: Fix missing 49 degree offset on current EPYC CPUs
    
    On an EPYC 7313P, the temperature reported by amdtemp was off, because
    the offset was not applied. Turns out it needs to be applied with one
    more condition: https://lkml.org/lkml/2023/4/13/1095
    
    Reviewed by:    mhorne
    Tested by:      mike.jakubik@gmail.com
    MFC after:      1 week
    Sponsored by:   https://www.patreon.com/valpackett
    Pull Request:   https://github.com/freebsd/freebsd-src/pull/754
    
    (cherry picked from commit c1cbabe8ae5702a1e54d62401fe3b58a84fcb3e4)
---
 sys/dev/amdtemp/amdtemp.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/sys/dev/amdtemp/amdtemp.c b/sys/dev/amdtemp/amdtemp.c
index 493f619c0427..238ae572d096 100644
--- a/sys/dev/amdtemp/amdtemp.c
+++ b/sys/dev/amdtemp/amdtemp.c
@@ -165,6 +165,12 @@ static const struct amdtemp_product {
  */
 #define	AMDTEMP_17H_CUR_TMP		0x59800
 #define	AMDTEMP_17H_CUR_TMP_RANGE_SEL	(1u << 19)
+/*
+ * Bits 16-17, when set, mean that CUR_TMP is read-write. When it is, the
+ * 49 degree offset should apply as well. This was revealed in a Linux
+ * patch from an AMD employee.
+ */
+#define	AMDTEMP_17H_CUR_TMP_TJ_SEL	((1u << 17) | (1u << 16))
 /*
  * The following register set was discovered experimentally by Ondrej Čerman
  * and collaborators, but is not (yet) documented in a PPR/OSRR (other than
@@ -732,7 +738,8 @@ amdtemp_decode_fam17h_tctl(int32_t sc_offset, uint32_t val)
 {
 	bool minus49;
 
-	minus49 = ((val & AMDTEMP_17H_CUR_TMP_RANGE_SEL) != 0);
+	minus49 = ((val & AMDTEMP_17H_CUR_TMP_RANGE_SEL) != 0)
+	    || ((val & AMDTEMP_17H_CUR_TMP_TJ_SEL) == AMDTEMP_17H_CUR_TMP_TJ_SEL);
 	return (amdtemp_decode_fam10h_to_17h(sc_offset,
 	    val >> AMDTEMP_REPTMP10H_CURTMP_SHIFT, minus49));
 }