RAS/AMD/ATL: Add MI300 DRAM to normalized address translation support

Zen-based AMD systems report DRAM ECC errors through Unified Memory
Controller (UMC) MCA banks. The value provided in MCA_ADDR is
a "normalized" address which represents the UMC's view of its managed
memory. The normalized address must be translated to a system physical
address for software to take action.

MI300 systems, uniquely, do not provide a normalized address in MCA_ADDR
for DRAM ECC errors. Rather, the "DRAM" address is reported. This value
includes identifiers for the bank, row, column, pseudochannel and stack
of the memory location.

The DRAM address must be converted to a normalized address in order to
be further translated to a system physical address.

Add helper functions to do the DRAM to normalized translation for MI300
systems. The method is based on the fixed hardware layout of the on-chip
memory.

  [ bp: Massage commit message, decapitalize some, rename function. ]
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Co-developed-by: Muralidhara M K <muralidhara.mk@amd.com>
Signed-off-by: Muralidhara M K <muralidhara.mk@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Muralidhara M K <muralidhara.mk@amd.com>
Link: https://lore.kernel.org/r/20240131165732.88297-1-yazen.ghannam@amd.com

drivers/ras/amd/atl/internal.h

@@ -224,6 +224,7 @@ int df_indirect_read_broadcast(u16 node, u8 func, u16 reg, u32 *lo);
 
 int get_df_system_info(void);
 int determine_node_id(struct addr_ctx *ctx, u8 socket_num, u8 die_num);
+int get_addr_hash_mi300(void);
 
 int get_address_map(struct addr_ctx *ctx);
 

drivers/ras/amd/atl/system.c

@@ -124,9 +124,13 @@ static int df4_determine_df_rev(u32 reg)
 	if (reg == DF_FUNC0_ID_ZEN4_SERVER)
 		df_cfg.flags.socket_id_shift_quirk = 1;
 
-	if (reg == DF_FUNC0_ID_MI300)
+	if (reg == DF_FUNC0_ID_MI300) {
 		df_cfg.flags.heterogeneous = 1;
 
+		if (get_addr_hash_mi300())
+			return -EINVAL;
+	}
+
 	return df4_get_fabric_id_mask_registers();
 }
 

drivers/ras/amd/atl/umc.c

@@ -49,6 +49,204 @@ static u8 get_coh_st_inst_id_mi300(struct atl_err *err)
 	return i;
 }
 
+/* XOR the bits in @val. */
+static u16 bitwise_xor_bits(u16 val)
+{
+	u16 tmp = 0;
+	u8 i;
+
+	for (i = 0; i < 16; i++)
+		tmp ^= (val >> i) & 0x1;
+
+	return tmp;
+}
+
+struct xor_bits {
+	bool	xor_enable;
+	u16	col_xor;
+	u32	row_xor;
+};
+
+#define NUM_BANK_BITS	4
+
+static struct {
+	/* UMC::CH::AddrHashBank */
+	struct xor_bits	bank[NUM_BANK_BITS];
+
+	/* UMC::CH::AddrHashPC */
+	struct xor_bits	pc;
+
+	/* UMC::CH::AddrHashPC2 */
+	u8		bank_xor;
+} addr_hash;
+
+#define MI300_UMC_CH_BASE	0x90000
+#define MI300_ADDR_HASH_BANK0	(MI300_UMC_CH_BASE + 0xC8)
+#define MI300_ADDR_HASH_PC	(MI300_UMC_CH_BASE + 0xE0)
+#define MI300_ADDR_HASH_PC2	(MI300_UMC_CH_BASE + 0xE4)
+
+#define ADDR_HASH_XOR_EN	BIT(0)
+#define ADDR_HASH_COL_XOR	GENMASK(13, 1)
+#define ADDR_HASH_ROW_XOR	GENMASK(31, 14)
+#define ADDR_HASH_BANK_XOR	GENMASK(5, 0)
+
+/*
+ * Read UMC::CH::AddrHash{Bank,PC,PC2} registers to get XOR bits used
+ * for hashing. Do this during module init, since the values will not
+ * change during run time.
+ *
+ * These registers are instantiated for each UMC across each AMD Node.
+ * However, they should be identically programmed due to the fixed hardware
+ * design of MI300 systems. So read the values from Node 0 UMC 0 and keep a
+ * single global structure for simplicity.
+ */
+int get_addr_hash_mi300(void)
+{
+	u32 temp;
+	int ret;
+	u8 i;
+
+	for (i = 0; i < NUM_BANK_BITS; i++) {
+		ret = amd_smn_read(0, MI300_ADDR_HASH_BANK0 + (i * 4), &temp);
+		if (ret)
+			return ret;
+
+		addr_hash.bank[i].xor_enable = FIELD_GET(ADDR_HASH_XOR_EN,  temp);
+		addr_hash.bank[i].col_xor    = FIELD_GET(ADDR_HASH_COL_XOR, temp);
+		addr_hash.bank[i].row_xor    = FIELD_GET(ADDR_HASH_ROW_XOR, temp);
+	}
+
+	ret = amd_smn_read(0, MI300_ADDR_HASH_PC, &temp);
+	if (ret)
+		return ret;
+
+	addr_hash.pc.xor_enable = FIELD_GET(ADDR_HASH_XOR_EN,  temp);
+	addr_hash.pc.col_xor    = FIELD_GET(ADDR_HASH_COL_XOR, temp);
+	addr_hash.pc.row_xor    = FIELD_GET(ADDR_HASH_ROW_XOR, temp);
+
+	ret = amd_smn_read(0, MI300_ADDR_HASH_PC2, &temp);
+	if (ret)
+		return ret;
+
+	addr_hash.bank_xor = FIELD_GET(ADDR_HASH_BANK_XOR, temp);
+
+	return 0;
+}
+
+/*
+ * MI300 systems report a DRAM address in MCA_ADDR for DRAM ECC errors. This must
+ * be converted to the intermediate normalized address (NA) before translating to a
+ * system physical address.
+ *
+ * The DRAM address includes bank, row, and column. Also included are bits for
+ * pseudochannel (PC) and stack ID (SID).
+ *
+ * Abbreviations: (S)tack ID, (P)seudochannel, (R)ow, (B)ank, (C)olumn, (Z)ero
+ *
+ * The MCA address format is as follows:
+ *	MCA_ADDR[27:0] = {S[1:0], P[0], R[14:0], B[3:0], C[4:0], Z[0]}
+ *
+ * The normalized address format is fixed in hardware and is as follows:
+ *	NA[30:0] = {S[1:0], R[13:0], C4, B[1:0], B[3:2], C[3:2], P, C[1:0], Z[4:0]}
+ *
+ * Additionally, the PC and Bank bits may be hashed. This must be accounted for before
+ * reconstructing the normalized address.
+ */
+#define MI300_UMC_MCA_COL	GENMASK(5, 1)
+#define MI300_UMC_MCA_BANK	GENMASK(9, 6)
+#define MI300_UMC_MCA_ROW	GENMASK(24, 10)
+#define MI300_UMC_MCA_PC	BIT(25)
+#define MI300_UMC_MCA_SID	GENMASK(27, 26)
+
+#define MI300_NA_COL_1_0	GENMASK(6, 5)
+#define MI300_NA_PC		BIT(7)
+#define MI300_NA_COL_3_2	GENMASK(9, 8)
+#define MI300_NA_BANK_3_2	GENMASK(11, 10)
+#define MI300_NA_BANK_1_0	GENMASK(13, 12)
+#define MI300_NA_COL_4		BIT(14)
+#define MI300_NA_ROW		GENMASK(28, 15)
+#define MI300_NA_SID		GENMASK(30, 29)
+
+static unsigned long convert_dram_to_norm_addr_mi300(unsigned long addr)
+{
+	u16 i, col, row, bank, pc, sid, temp;
+
+	col  = FIELD_GET(MI300_UMC_MCA_COL,  addr);
+	bank = FIELD_GET(MI300_UMC_MCA_BANK, addr);
+	row  = FIELD_GET(MI300_UMC_MCA_ROW,  addr);
+	pc   = FIELD_GET(MI300_UMC_MCA_PC,   addr);
+	sid  = FIELD_GET(MI300_UMC_MCA_SID,  addr);
+
+	/* Calculate hash for each Bank bit. */
+	for (i = 0; i < NUM_BANK_BITS; i++) {
+		if (!addr_hash.bank[i].xor_enable)
+			continue;
+
+		temp  = bitwise_xor_bits(col & addr_hash.bank[i].col_xor);
+		temp ^= bitwise_xor_bits(row & addr_hash.bank[i].row_xor);
+		bank ^= temp << i;
+	}
+
+	/* Calculate hash for PC bit. */
+	if (addr_hash.pc.xor_enable) {
+		/* Bits SID[1:0] act as Bank[6:5] for PC hash, so apply them here. */
+		bank |= sid << 5;
+
+		temp  = bitwise_xor_bits(col  & addr_hash.pc.col_xor);
+		temp ^= bitwise_xor_bits(row  & addr_hash.pc.row_xor);
+		temp ^= bitwise_xor_bits(bank & addr_hash.bank_xor);
+		pc   ^= temp;
+
+		/* Drop SID bits for the sake of debug printing later. */
+		bank &= 0x1F;
+	}
+
+	/* Reconstruct the normalized address starting with NA[4:0] = 0 */
+	addr  = 0;
+
+	/* NA[6:5] = Column[1:0] */
+	temp  = col & 0x3;
+	addr |= FIELD_PREP(MI300_NA_COL_1_0, temp);
+
+	/* NA[7] = PC */
+	addr |= FIELD_PREP(MI300_NA_PC, pc);
+
+	/* NA[9:8] = Column[3:2] */
+	temp  = (col >> 2) & 0x3;
+	addr |= FIELD_PREP(MI300_NA_COL_3_2, temp);
+
+	/* NA[11:10] = Bank[3:2] */
+	temp  = (bank >> 2) & 0x3;
+	addr |= FIELD_PREP(MI300_NA_BANK_3_2, temp);
+
+	/* NA[13:12] = Bank[1:0] */
+	temp  = bank & 0x3;
+	addr |= FIELD_PREP(MI300_NA_BANK_1_0, temp);
+
+	/* NA[14] = Column[4] */
+	temp  = (col >> 4) & 0x1;
+	addr |= FIELD_PREP(MI300_NA_COL_4, temp);
+
+	/* NA[28:15] = Row[13:0] */
+	addr |= FIELD_PREP(MI300_NA_ROW, row);
+
+	/* NA[30:29] = SID[1:0] */
+	addr |= FIELD_PREP(MI300_NA_SID, sid);
+
+	pr_debug("Addr=0x%016lx", addr);
+	pr_debug("Bank=%u Row=%u Column=%u PC=%u SID=%u", bank, row, col, pc, sid);
+
+	return addr;
+}
+
+static unsigned long get_addr(unsigned long addr)
+{
+	if (df_cfg.rev == DF4p5 && df_cfg.flags.heterogeneous)
+		return convert_dram_to_norm_addr_mi300(addr);
+
+	return addr;
+}
+
 #define MCA_IPID_INST_ID_HI	GENMASK_ULL(47, 44)
 static u8 get_die_id(struct atl_err *err)
 {
@@ -82,7 +280,7 @@ unsigned long convert_umc_mca_addr_to_sys_addr(struct atl_err *err)
 {
 	u8 socket_id = topology_physical_package_id(err->cpu);
 	u8 coh_st_inst_id = get_coh_st_inst_id(err);
-	unsigned long addr = err->addr;
+	unsigned long addr = get_addr(err->addr);
 	u8 die_id = get_die_id(err);
 
 	pr_debug("socket_id=0x%x die_id=0x%x coh_st_inst_id=0x%x addr=0x%016lx",