[PATCH 2/2] EDAC, i10nm: Fix i10nm_edac loading failure on some servers

[Tony Luck <tony.luck@intel.com>]

From: Qiuxu Zhuo <qiuxu.zhuo@intel.com>

It failed to load the i10nm_edac driver on Ice Lake and
Tremont/Jacobsville servers if their CPU stepping >= 4 and failed
on Ice Lake-D servers from stepping 0. The root cause was that for
Ice Lake and Tremont/Jacobsville servers with CPU stepping >=4, the
offset for bus number configuration register was updated from 0xcc
to 0xd0. For Ice Lake-D servers, all the steppings use the updated
0xd0 offset.

Fix the issue by using the appropriate offset for bus number
configuration register according to the CPU model number and stepping.

Reported-by: Jerry Chen <jerry.t.chen@intel.com>
Reported-and-tested-by: Jin Wen <wen.jin@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
 drivers/edac/i10nm_base.c | 20 ++++++++++++++++----
 1 file changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/edac/i10nm_base.c b/drivers/edac/i10nm_base.c
index ba4578c6ef2b..ebb45738c11b 100644
--- a/drivers/edac/i10nm_base.c
+++ b/drivers/edac/i10nm_base.c
@@ -122,16 +122,24 @@ static int i10nm_get_all_munits(void)
 	return 0;
 }
 
-static struct res_config i10nm_cfg = {
+/* ATOM_TREMONT_D, ICELAKE_X */
+static struct res_config i10nm_cfg0 = {
 	.type			= I10NM,
 	.decs_did		= 0x3452,
 	.busno_cfg_offset	= 0xcc,
 };
 
+/* ICELAKE_D */
+static struct res_config i10nm_cfg1 = {
+	.type			= I10NM,
+	.decs_did		= 0x3452,
+	.busno_cfg_offset	= 0xd0,
+};
+
 static const struct x86_cpu_id i10nm_cpuids[] = {
-	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D,	&i10nm_cfg),
-	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,		&i10nm_cfg),
-	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,		&i10nm_cfg),
+	X86_MATCH_INTEL_FAM6_MODEL(ATOM_TREMONT_D,	&i10nm_cfg0),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_X,		&i10nm_cfg0),
+	X86_MATCH_INTEL_FAM6_MODEL(ICELAKE_D,		&i10nm_cfg1),
 	{}
 };
 MODULE_DEVICE_TABLE(x86cpu, i10nm_cpuids);
@@ -257,6 +265,10 @@ static int __init i10nm_init(void)
 		return -ENODEV;
 	cfg = (struct res_config *)id->driver_data;
 
+	/* Newer steppings have different offset for ATOM_TREMONT_D/ICELAKE_X */
+	if (boot_cpu_data.x86_stepping >= 4)
+		cfg->busno_cfg_offset = 0xd0;
+
 	rc = skx_get_hi_lo(0x09a2, off, &tolm, &tohm);
 	if (rc)
 		return rc;
-- 
2.21.1