[PATCH v4 2/2] EDAC/amd64: Add new register offset support and related changes

[Yazen Ghannam <yazen.ghannam@amd.com>]

Introduce a "family flags" bitmask that can be used to indicate any
special behavior needed on a per-family basis.

Add a flag to indicate a system uses the new register offsets introduced
with Family 19h Model 10h.

Use this flag to account for register offset changes, a new bitfield
indicating DDR5 use on a memory controller, and to set the proper number
of chip select masks.

Rework f17_addr_mask_to_cs_size() to properly handle the change in chip
select masks. And update code comments to reflect the updated Chip
Select, DIMM, and Mask relationships.

[uninitiliazed variable warning]
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
---
Link:
https://lore.kernel.org/r/20211228200615.412999-3-yazen.ghannam@amd.com

v3->v4:
* Use a single helper function for new register offsets.
* Fix an uninitialized variable warning.

v2->v3:
* Adjust variable names to explicitly show what they represent.
* Update code comment to give more detail on CS/MASK/DIMM layout.

v1->v2:
* Was patch 4 in v1.
* Change "has_ddr5" flag to "zn_regs_v2".
* Drop flag check helper function.
* Update determine_memory_type() to check bitfield for DDR5.
* Update code comments.

 drivers/edac/amd64_edac.c | 80 +++++++++++++++++++++++++++++++--------
 drivers/edac/amd64_edac.h | 14 +++++++
 2 files changed, 78 insertions(+), 16 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index 49e384207ce0..5806fe657373 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -15,6 +15,21 @@ static struct msr __percpu *msrs;
 
 static struct amd64_family_type *fam_type;
 
+static inline u32 get_umc_reg(u32 reg)
+{
+	if (!fam_type->flags.zn_regs_v2)
+		return reg;
+
+	switch (reg) {
+	case UMCCH_ADDR_CFG:		return UMCCH_ADDR_CFG_DDR5;
+	case UMCCH_ADDR_MASK_SEC:	return UMCCH_ADDR_MASK_SEC_DDR5;
+	case UMCCH_DIMM_CFG:		return UMCCH_DIMM_CFG_DDR5;
+	}
+
+	WARN_ONCE(1, "%s: unknown register 0x%x", __func__, reg);
+	return 0;
+}
+
 /* Per-node stuff */
 static struct ecc_settings **ecc_stngs;
 
@@ -1429,8 +1444,10 @@ static void __dump_misc_regs_df(struct amd64_pvt *pvt)
 		edac_dbg(1, "UMC%d x16 DIMMs present: %s\n",
 				i, (umc->dimm_cfg & BIT(7)) ? "yes" : "no");
 
-		if (umc->dram_type == MEM_LRDDR4) {
-			amd_smn_read(pvt->mc_node_id, umc_base + UMCCH_ADDR_CFG, &tmp);
+		if (umc->dram_type == MEM_LRDDR4 || umc->dram_type == MEM_LRDDR5) {
+			amd_smn_read(pvt->mc_node_id,
+				     umc_base + get_umc_reg(UMCCH_ADDR_CFG),
+				     &tmp);
 			edac_dbg(1, "UMC%d LRDIMM %dx rank multiply\n",
 					i, 1 << ((tmp >> 4) & 0x3));
 		}
@@ -1505,7 +1522,7 @@ static void prep_chip_selects(struct amd64_pvt *pvt)
 
 		for_each_umc(umc) {
 			pvt->csels[umc].b_cnt = 4;
-			pvt->csels[umc].m_cnt = 2;
+			pvt->csels[umc].m_cnt = fam_type->flags.zn_regs_v2 ? 4 : 2;
 		}
 
 	} else {
@@ -1545,7 +1562,7 @@ static void read_umc_base_mask(struct amd64_pvt *pvt)
 		}
 
 		umc_mask_reg = get_umc_base(umc) + UMCCH_ADDR_MASK;
-		umc_mask_reg_sec = get_umc_base(umc) + UMCCH_ADDR_MASK_SEC;
+		umc_mask_reg_sec = get_umc_base(umc) + get_umc_reg(UMCCH_ADDR_MASK_SEC);
 
 		for_each_chip_select_mask(cs, umc, pvt) {
 			mask = &pvt->csels[umc].csmasks[cs];
@@ -1623,12 +1640,25 @@ static void _determine_memory_type_df(struct amd64_umc *umc)
 		return;
 	}
 
-	if (umc->dimm_cfg & BIT(5))
-		umc->dram_type = MEM_LRDDR4;
-	else if (umc->dimm_cfg & BIT(4))
-		umc->dram_type = MEM_RDDR4;
-	else
-		umc->dram_type = MEM_DDR4;
+	/*
+	 * Check if the system supports the "DDR Type" field in UMC Config
+	 * and has DDR5 DIMMs in use.
+	 */
+	if (fam_type->flags.zn_regs_v2 && ((umc->umc_cfg & GENMASK(2, 0)) == 0x1)) {
+		if (umc->dimm_cfg & BIT(5))
+			umc->dram_type = MEM_LRDDR5;
+		else if (umc->dimm_cfg & BIT(4))
+			umc->dram_type = MEM_RDDR5;
+		else
+			umc->dram_type = MEM_DDR5;
+	} else {
+		if (umc->dimm_cfg & BIT(5))
+			umc->dram_type = MEM_LRDDR4;
+		else if (umc->dimm_cfg & BIT(4))
+			umc->dram_type = MEM_RDDR4;
+		else
+			umc->dram_type = MEM_DDR4;
+	}
 }
 
 static void determine_memory_type_df(struct amd64_pvt *pvt)
@@ -2170,6 +2200,7 @@ static int f17_addr_mask_to_cs_size(struct amd64_pvt *pvt, u8 umc,
 {
 	u32 addr_mask_orig, addr_mask_deinterleaved;
 	u32 msb, weight, num_zero_bits;
+	int cs_mask_nr = csrow_nr;
 	int dimm, size = 0;
 
 	/* No Chip Selects are enabled. */
@@ -2185,17 +2216,33 @@ static int f17_addr_mask_to_cs_size(struct amd64_pvt *pvt, u8 umc,
 		return size;
 
 	/*
-	 * There is one mask per DIMM, and two Chip Selects per DIMM.
-	 *	CS0 and CS1 -> DIMM0
-	 *	CS2 and CS3 -> DIMM1
+	 * Family 17h introduced systems with one mask per DIMM,
+	 * and two Chip Selects per DIMM.
+	 *
+	 *	CS0 and CS1 -> MASK0 / DIMM0
+	 *	CS2 and CS3 -> MASK1 / DIMM1
+	 *
+	 * Family 19h Model 10h introduced systems with one mask per Chip Select,
+	 * and two Chip Selects per DIMM.
+	 *
+	 *	CS0 -> MASK0 -> DIMM0
+	 *	CS1 -> MASK1 -> DIMM0
+	 *	CS2 -> MASK2 -> DIMM1
+	 *	CS3 -> MASK3 -> DIMM1
+	 *
+	 * Keep the mask number equal to the Chip Select number for newer systems,
+	 * and shift the mask number for older systems.
 	 */
 	dimm = csrow_nr >> 1;
 
+	if (!fam_type->flags.zn_regs_v2)
+		cs_mask_nr >>= 1;
+
 	/* Asymmetric dual-rank DIMM support. */
 	if ((csrow_nr & 1) && (cs_mode & CS_ODD_SECONDARY))
-		addr_mask_orig = pvt->csels[umc].csmasks_sec[dimm];
+		addr_mask_orig = pvt->csels[umc].csmasks_sec[cs_mask_nr];
 	else
-		addr_mask_orig = pvt->csels[umc].csmasks[dimm];
+		addr_mask_orig = pvt->csels[umc].csmasks[cs_mask_nr];
 
 	/*
 	 * The number of zero bits in the mask is equal to the number of bits
@@ -2951,6 +2998,7 @@ static struct amd64_family_type family_types[] = {
 		.f0_id = PCI_DEVICE_ID_AMD_19H_M10H_DF_F0,
 		.f6_id = PCI_DEVICE_ID_AMD_19H_M10H_DF_F6,
 		.max_mcs = 12,
+		.flags.zn_regs_v2 = 1,
 		.ops = {
 			.early_channel_count	= f17_early_channel_count,
 			.dbam_to_cs		= f17_addr_mask_to_cs_size,
@@ -3389,7 +3437,7 @@ static void __read_mc_regs_df(struct amd64_pvt *pvt)
 		umc_base = get_umc_base(i);
 		umc = &pvt->umc[i];
 
-		amd_smn_read(nid, umc_base + UMCCH_DIMM_CFG, &umc->dimm_cfg);
+		amd_smn_read(nid, umc_base + get_umc_reg(UMCCH_DIMM_CFG), &umc->dimm_cfg);
 		amd_smn_read(nid, umc_base + UMCCH_UMC_CFG, &umc->umc_cfg);
 		amd_smn_read(nid, umc_base + UMCCH_SDP_CTRL, &umc->sdp_ctrl);
 		amd_smn_read(nid, umc_base + UMCCH_ECC_CTRL, &umc->ecc_ctrl);
diff --git a/drivers/edac/amd64_edac.h b/drivers/edac/amd64_edac.h
index 09ad28299c57..6f8147abfa71 100644
--- a/drivers/edac/amd64_edac.h
+++ b/drivers/edac/amd64_edac.h
@@ -273,8 +273,11 @@
 #define UMCCH_BASE_ADDR_SEC		0x10
 #define UMCCH_ADDR_MASK			0x20
 #define UMCCH_ADDR_MASK_SEC		0x28
+#define UMCCH_ADDR_MASK_SEC_DDR5	0x30
 #define UMCCH_ADDR_CFG			0x30
+#define UMCCH_ADDR_CFG_DDR5		0x40
 #define UMCCH_DIMM_CFG			0x80
+#define UMCCH_DIMM_CFG_DDR5		0x90
 #define UMCCH_UMC_CFG			0x100
 #define UMCCH_SDP_CTRL			0x104
 #define UMCCH_ECC_CTRL			0x14C
@@ -483,11 +486,22 @@ struct low_ops {
 					 unsigned cs_mode, int cs_mask_nr);
 };
 
+struct amd64_family_flags {
+	/*
+	 * Indicates that the system supports the new register offsets, etc.
+	 * first introduced with Family 19h Model 10h.
+	 */
+	__u64 zn_regs_v2	: 1,
+
+	      __reserved	: 63;
+};
+
 struct amd64_family_type {
 	const char *ctl_name;
 	u16 f0_id, f1_id, f2_id, f6_id;
 	/* Maximum number of memory controllers per die/node. */
 	u8 max_mcs;
+	struct amd64_family_flags flags;
 	struct low_ops ops;
 };
 
-- 
2.25.1