[PATCH v2 27/31] EDAC/amd64: Update CS ID calculation to match reference code

[Yazen Ghannam]

Redo the current CS ID calculations to match the reference code. Helper
functions are introduced that will be expanded for future DF versions.

Use u16 type for dst_fabric_id and component_id_mask values to
accommodate larger bitfields in future DF versions.

Signed-off-by: Yazen Ghannam <yazen.ghannam@xxxxxxx>
---
Link:
https://lkml.kernel.org/r/20210507190140.18854-24-Yazen.Ghannam@xxxxxxx

v1->v2:
* Moved from arch/x86 to EDAC.
* Added functions to data_fabric_ops.

 drivers/edac/amd64_edac.c | 52 ++++++++++++++++++++++++++-------------
 1 file changed, 35 insertions(+), 17 deletions(-)

diff --git a/drivers/edac/amd64_edac.c b/drivers/edac/amd64_edac.c
index fa8046e2b055..fc2cd288df0f 100644
--- a/drivers/edac/amd64_edac.c
+++ b/drivers/edac/amd64_edac.c
@@ -1112,6 +1112,8 @@ struct addr_ctx {
 
 struct data_fabric_ops {
 	u64 (*get_hi_addr_offset)(struct addr_ctx *ctx);
+	u16 (*get_dst_fabric_id)(struct addr_ctx *ctx);
+	u16 (*get_component_id_mask)(struct addr_ctx *ctx);
 	u8 (*get_die_id_shift)(struct addr_ctx *ctx);
 	u8 (*get_socket_id_shift)(struct addr_ctx *ctx);
 	int (*get_intlv_mode)(struct addr_ctx *ctx);
@@ -1230,6 +1232,16 @@ static u8 get_socket_id_shift_df2(struct addr_ctx *ctx)
 	return (ctx->reg_fab_id_mask0 >> 28) & 0xF;
 }
 
+static u16 get_dst_fabric_id_df2(struct addr_ctx *ctx)
+{
+	return ctx->reg_limit_addr & 0xFF;
+}
+
+static u16 get_component_id_mask_df2(struct addr_ctx *ctx)
+{
+	return (~(ctx->socket_id_mask | ctx->die_id_mask)) & 0xFF;
+}
+
 struct data_fabric_ops df2_ops = {
 	.get_hi_addr_offset		=	&get_hi_addr_offset_df2,
 	.get_intlv_mode			=	&get_intlv_mode_df2,
@@ -1239,6 +1251,8 @@ struct data_fabric_ops df2_ops = {
 	.get_masks			=	&get_masks_df2,
 	.get_die_id_shift		=	&get_die_id_shift_df2,
 	.get_socket_id_shift		=	&get_socket_id_shift_df2,
+	.get_dst_fabric_id		=	&get_dst_fabric_id_df2,
+	.get_component_id_mask		=	&get_component_id_mask_df2,
 };
 
 struct data_fabric_ops *df_ops;
@@ -1339,38 +1353,42 @@ static void get_intlv_num_chan(struct addr_ctx *ctx)
 	}
 }
 
-static int calculate_cs_id(struct addr_ctx *ctx)
+static u8 calc_level_bits(u8 id, u8 level_mask, u8 shift, u8 mask, u8 num_bits)
 {
-	u8 die_id_bit = 0, sock_id_bit, cs_mask = 0;
+	return (((id & level_mask) >> shift) & mask) << num_bits;
+}
 
-	/* If interleaved over more than 1 channel: */
-	if (ctx->intlv_num_chan) {
-		die_id_bit = ctx->intlv_num_chan;
-		cs_mask	   = (1 << die_id_bit) - 1;
-		ctx->cs_id = ctx->cs_fabric_id & cs_mask;
-	}
+static int calculate_cs_id(struct addr_ctx *ctx)
+{
+	u16 dst_fabric_id = df_ops->get_dst_fabric_id(ctx);
+	u16 mask, num_intlv_bits = ctx->intlv_num_chan;
 
-	/* Return early if no die interleaving and no socket interleaving. */
-	if (!(ctx->intlv_num_dies || ctx->intlv_num_sockets))
-		return 0;
+	mask = df_ops->get_component_id_mask(ctx);
+	ctx->cs_id = (ctx->cs_fabric_id & mask) - (dst_fabric_id & mask);
 
-	sock_id_bit = die_id_bit;
+	mask = (1 << num_intlv_bits) - 1;
+	ctx->cs_id &= mask;
 
 	/* If interleaved over more than 1 die: */
 	if (ctx->intlv_num_dies) {
 		u8 die_id_shift = df_ops->get_die_id_shift(ctx);
 
-		sock_id_bit  = die_id_bit + ctx->intlv_num_dies;
-		ctx->cs_id |= ((ctx->cs_fabric_id & ctx->die_id_mask)
-				>> die_id_shift) << die_id_bit;
+		mask = (1 << ctx->intlv_num_dies) - 1;
+
+		ctx->cs_id |= calc_level_bits(ctx->cs_fabric_id, ctx->die_id_mask,
+					      die_id_shift, mask, num_intlv_bits);
+
+		num_intlv_bits += ctx->intlv_num_dies;
 	}
 
 	/* If interleaved over more than 1 socket: */
 	if (ctx->intlv_num_sockets) {
 		u8 socket_id_shift = df_ops->get_socket_id_shift(ctx);
 
-		ctx->cs_id |= ((ctx->cs_fabric_id & ctx->socket_id_mask)
-				>> socket_id_shift) << sock_id_bit;
+		mask = (1 << ctx->intlv_num_sockets) - 1;
+
+		ctx->cs_id |= calc_level_bits(ctx->cs_fabric_id, ctx->socket_id_mask,
+					      socket_id_shift, mask, num_intlv_bits);
 	}
 
 	return 0;
-- 
2.25.1