EDAC/i10nm: Update driver to support different bus number config register offsets

The i10nm_edac driver failed to load 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: NJerry Chen <jerry.t.chen@intel.com>
Reported-and-tested-by: NJin Wen <wen.jin@intel.com>
Signed-off-by: NQiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: NTony Luck <tony.luck@intel.com>
Reviewed-by: NBorislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/linux-edac/20200427084022.GC11036@zn.tnic

drivers/edac/i10nm_base.c

@@ -122,16 +122,22 @@ static int i10nm_get_all_munits(void)
 	return 0;
 }
 
-static struct res_config i10nm_cfg = {
+static struct res_config i10nm_cfg0 = {
 	.type			= I10NM,
 	.decs_did		= 0x3452,
 	.busno_cfg_offset	= 0xcc,
 };
 
+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);
@@ -258,6 +264,10 @@ static int __init i10nm_init(void)
 
 	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;