drm/amd/display: add HW i2c arbitration with dmcu

Signed-off-by: Charlene Liu <charlene.liu@amd.com>
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.c

@@ -346,6 +346,16 @@ static void release_engine(
 
 }
 
+static bool is_engine_available(struct dce_i2c_hw *dce_i2c_hw)
+{
+	unsigned int arbitrate;
+
+	REG_GET(DC_I2C_ARBITRATION, DC_I2C_REG_RW_CNTL_STATUS, &arbitrate);
+	if (arbitrate == DC_I2C_REG_RW_CNTL_STATUS_DMCU_ONLY)
+		return false;
+	return true;
+}
+
 struct dce_i2c_hw *acquire_i2c_hw_engine(
 	struct resource_pool *pool,
 	struct ddc *ddc)
@@ -368,7 +378,7 @@ struct dce_i2c_hw *acquire_i2c_hw_engine(
 	if (!dce_i2c_hw)
 		return NULL;
 
-	if (pool->i2c_hw_buffer_in_use)
+	if (pool->i2c_hw_buffer_in_use || !is_engine_available(dce_i2c_hw))
 		return NULL;
 
 	do {

drivers/gpu/drm/amd/display/dc/dce/dce_i2c_hw.h

@@ -29,7 +29,8 @@
 enum dc_i2c_status {
 	DC_I2C_STATUS__DC_I2C_STATUS_IDLE,
 	DC_I2C_STATUS__DC_I2C_STATUS_USED_BY_SW,
-	DC_I2C_STATUS__DC_I2C_STATUS_USED_BY_HW
+	DC_I2C_STATUS__DC_I2C_STATUS_USED_BY_HW,
+	DC_I2C_REG_RW_CNTL_STATUS_DMCU_ONLY = 2,
 };
 
 enum dc_i2c_arbitration {
@@ -129,7 +130,8 @@ enum {
 	I2C_SF(DC_I2C_DATA, DC_I2C_DATA, mask_sh),\
 	I2C_SF(DC_I2C_DATA, DC_I2C_INDEX, mask_sh),\
 	I2C_SF(DC_I2C_DATA, DC_I2C_INDEX_WRITE, mask_sh),\
-	I2C_SF(MICROSECOND_TIME_BASE_DIV, XTAL_REF_DIV, mask_sh)
+	I2C_SF(MICROSECOND_TIME_BASE_DIV, XTAL_REF_DIV, mask_sh),\
+	I2C_SF(DC_I2C_ARBITRATION, DC_I2C_REG_RW_CNTL_STATUS, mask_sh)
 
 #define I2C_COMMON_MASK_SH_LIST_DCE110(mask_sh)\
 	I2C_COMMON_MASK_SH_LIST_DCE_COMMON_BASE(mask_sh),\
@@ -170,6 +172,7 @@ struct dce_i2c_shift {
 	uint8_t DC_I2C_INDEX;
 	uint8_t DC_I2C_INDEX_WRITE;
 	uint8_t XTAL_REF_DIV;
+	uint8_t DC_I2C_REG_RW_CNTL_STATUS;
 };
 
 struct dce_i2c_mask {
@@ -207,6 +210,7 @@ struct dce_i2c_mask {
 	uint32_t DC_I2C_INDEX;
 	uint32_t DC_I2C_INDEX_WRITE;
 	uint32_t XTAL_REF_DIV;
+	uint32_t DC_I2C_REG_RW_CNTL_STATUS;
 };
 
 struct dce_i2c_registers {