From 8503474ca0279af90b6ffb452456235b7f5dcbd1 Mon Sep 17 00:00:00 2001
From: Roy Chan <roy.chan@amd.com>
Date: Sun, 23 Jan 2022 13:20:09 -0500
Subject: drm/amd/display: Support synchronized indirect reg access
Git-commit: 5f2c1192eba42f6926253a1f2c9b18da05b3c31f
Patch-mainline: v5.18-rc1
References: jsc#PED-1166 jsc#PED-1168 jsc#PED-1170 jsc#PED-1218 jsc#PED-1220 jsc#PED-1222 jsc#PED-1223 jsc#PED-1225

[Why]
indirect register index/data pair may be used by multi-threads.  when it
happens, it would cause register access issue that is hard to trace.

[How]
Using cgs service, which provide a sync indirect reg access api.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Reviewed-by: Aric Cyr <Aric.Cyr@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Roy Chan <roy.chan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Acked-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/amd/display/dc/dc_helper.c    | 60 +++++++++++++++++++
 .../gpu/drm/amd/display/dc/inc/reg_helper.h   | 34 +++++++++++
 2 files changed, 94 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_helper.c b/drivers/gpu/drm/amd/display/dc/dc_helper.c
index ab6bc5d79012..f43cce16bb6c 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_helper.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_helper.c
@@ -588,6 +588,66 @@ uint32_t generic_indirect_reg_update_ex(const struct dc_context *ctx,
 	return reg_val;
 }
 
+
+uint32_t generic_indirect_reg_update_ex_sync(const struct dc_context *ctx,
+		uint32_t index, uint32_t reg_val, int n,
+		uint8_t shift1, uint32_t mask1, uint32_t field_value1,
+		...)
+{
+	uint32_t shift, mask, field_value;
+	int i = 1;
+
+	va_list ap;
+
+	va_start(ap, field_value1);
+
+	reg_val = set_reg_field_value_ex(reg_val, field_value1, mask1, shift1);
+
+	while (i < n) {
+		shift = va_arg(ap, uint32_t);
+		mask = va_arg(ap, uint32_t);
+		field_value = va_arg(ap, uint32_t);
+
+		reg_val = set_reg_field_value_ex(reg_val, field_value, mask, shift);
+		i++;
+	}
+
+	dm_write_index_reg(ctx, CGS_IND_REG__PCIE, index, reg_val);
+	va_end(ap);
+
+	return reg_val;
+}
+
+uint32_t generic_indirect_reg_get_sync(const struct dc_context *ctx,
+		uint32_t index, int n,
+		uint8_t shift1, uint32_t mask1, uint32_t *field_value1,
+		...)
+{
+	uint32_t shift, mask, *field_value;
+	uint32_t value = 0;
+	int i = 1;
+
+	va_list ap;
+
+	va_start(ap, field_value1);
+
+	value = dm_read_index_reg(ctx, CGS_IND_REG__PCIE, index);
+	*field_value1 = get_reg_field_value_ex(value, mask1, shift1);
+
+	while (i < n) {
+		shift = va_arg(ap, uint32_t);
+		mask = va_arg(ap, uint32_t);
+		field_value = va_arg(ap, uint32_t *);
+
+		*field_value = get_reg_field_value_ex(value, mask, shift);
+		i++;
+	}
+
+	va_end(ap);
+
+	return value;
+}
+
 void reg_sequence_start_gather(const struct dc_context *ctx)
 {
 	/* if reg sequence is supported and enabled, set flag to
diff --git a/drivers/gpu/drm/amd/display/dc/inc/reg_helper.h b/drivers/gpu/drm/amd/display/dc/inc/reg_helper.h
index 2470405e996b..a402df225a76 100644
--- a/drivers/gpu/drm/amd/display/dc/inc/reg_helper.h
+++ b/drivers/gpu/drm/amd/display/dc/inc/reg_helper.h
@@ -498,6 +498,40 @@ uint32_t generic_indirect_reg_update_ex(const struct dc_context *ctx,
 		uint8_t shift1, uint32_t mask1, uint32_t field_value1,
 		...);
 
+/* indirect register access
+ * underlying implementation determines which index/data pair to be used
+ * in a synchronous way
+ */
+#define IX_REG_SET_N_SYNC(index, n, initial_val, ...)	\
+		generic_indirect_reg_update_ex_sync(CTX, \
+				IND_REG(index), \
+				initial_val, \
+				n, __VA_ARGS__)
+
+#define IX_REG_SET_2_SYNC(index, init_value, f1, v1, f2, v2)	\
+		IX_REG_SET_N_SYNC(index, 2, init_value, \
+				FN(reg, f1), v1,\
+				FN(reg, f2), v2)
+
+#define IX_REG_GET_N_SYNC(index, n, ...) \
+		generic_indirect_reg_get_sync(CTX, \
+				IND_REG(index), \
+				n, __VA_ARGS__)
+
+#define IX_REG_GET_SYNC(index, field, val) \
+		IX_REG_GET_N_SYNC(index, 1, \
+				FN(data_reg_name, field), val)
+
+uint32_t generic_indirect_reg_get_sync(const struct dc_context *ctx,
+		uint32_t index, int n,
+		uint8_t shift1, uint32_t mask1, uint32_t *field_value1,
+		...);
+
+uint32_t generic_indirect_reg_update_ex_sync(const struct dc_context *ctx,
+		uint32_t index, uint32_t reg_val, int n,
+		uint8_t shift1, uint32_t mask1, uint32_t field_value1,
+		...);
+
 /* register offload macros
  *
  * instead of MMIO to register directly, in some cases we want
-- 
2.38.1