Date: Thu, 1 Feb 2024 12:33:07 +0530
From: "M K, Muralidhara" <muralimk@....com>
To: Yazen Ghannam <yazen.ghannam@....com>, bp@...en8.de, tony.luck@...el.com,
 linux-edac@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, avadhut.naik@....com, john.allen@....com,
 muralidhara.mk@....com
Subject: Re: [PATCH] RAS/AMD/ATL: Add MI300 DRAM to Normalized address
 translation support

Hi Yazen,

On 1/31/2024 10:27 PM, Yazen Ghannam wrote:
> Modern 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.
> 
> Also, cache the required hardware register values during module init.
> These should not change during run time. And all UMCs should be
> programmed identically.
> 
> Signed-off-by: Yazen Ghannam <yazen.ghannam@....com>
> ---
> Notes:
> 
> This is an almost complete rewrite of the following patch:
> https://lore.kernel.org/r/20231129073521.2127403-4-muralimk@amd.com
> 
> I'd like to include Murali as co-developer, if that's okay with him,
> since this is based on his earlier work.
> 

Address translation support on MI300A is working as expected.
Please add me as codeveloped and tested-by
Muralidhara M K <muralidhara.mk@....com>


> With this patch, MI300 address translation support should be complete.
> The remaining work includes handling expanded page retirement cases.
> 
>   drivers/ras/amd/atl/internal.h |   1 +
>   drivers/ras/amd/atl/system.c   |   6 +-
>   drivers/ras/amd/atl/umc.c      | 199 ++++++++++++++++++++++++++++++++-
>   3 files changed, 204 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ras/amd/atl/internal.h b/drivers/ras/amd/atl/internal.h
> index 21d45755e5f2..5de69e0bb0f9 100644
> --- a/drivers/ras/amd/atl/internal.h
> +++ b/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);
>   
> diff --git a/drivers/ras/amd/atl/system.c b/drivers/ras/amd/atl/system.c
> index 46493ed405d6..701349e84942 100644
> --- a/drivers/ras/amd/atl/system.c
> +++ b/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();
>   }
>   
> diff --git a/drivers/ras/amd/atl/umc.c b/drivers/ras/amd/atl/umc.c
> index 7bfa21a582f0..816c2c5c683f 100644
> --- a/drivers/ras/amd/atl/umc.c
> +++ b/drivers/ras/amd/atl/umc.c
> @@ -49,6 +49,203 @@ static u8 get_coh_st_inst_id_mi300(struct atl_err *err)
>   	return i;
>   }
>   
> +static u16 internal_bitwise_xor(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 {
> +	/* Values from UMC::CH::AddrHashBank registers */
> +	struct xor_bits	bank[NUM_BANK_BITS];
> +
> +	/* Values from UMC::CH::AddrHashPC register */
> +	struct xor_bits	pc;
> +
> +	/* Value from UMC::CH::AddrHashPC2 register */
> +	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  = internal_bitwise_xor(col & addr_hash.bank[i].col_xor);
> +		temp ^= internal_bitwise_xor(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  = internal_bitwise_xor(col  & addr_hash.pc.col_xor);
> +		temp ^= internal_bitwise_xor(row  & addr_hash.pc.row_xor);
> +		temp ^= internal_bitwise_xor(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 +279,7 @@ 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",
> 
> base-commit: a7b57372e1c5c848cbe9169574f07a9ee2177a1b
> 

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