drm/amd/display: Add Support for reg inbox0 for host->DMUB CMDs

[WHY]
DCN4+ supports a new register based mailbox for sending messages
from host to DMCUB. This mailbox supports 64 byte commands, which makes
it compatible with the same structure as the frame buffer based mailbox.

[HOW]
The intention for reg_inbox0 is to be slot in replacement for the frame
buffer based mailbox (Inbox1). It supports all of the required features:
- Supports all messages handled by FB Inbox1
- Supports multi command batching

Reviewed-by: Joshua Aberback <joshua.aberback@amd.com>
Signed-off-by: Dillon Varone <dillon.varone@amd.com>
Signed-off-by: Tom Chung <chiahsuan.chung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 48 insertions, 1 deletions

diff --git a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
index f84bbc033e64..1f5f4e3e49d4 100644
--- a/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
+++ b/drivers/gpu/drm/amd/display/dmub/inc/dmub_cmd.h
@@ -1332,6 +1332,16 @@ enum dmub_inbox0_command {
 #define DMUB_RB_SIZE (DMUB_RB_CMD_SIZE * DMUB_RB_MAX_ENTRY)
 
 /**
+ * Maximum number of items in the DMUB REG INBOX0 internal ringbuffer.
+ */
+#define DMUB_REG_INBOX0_RB_MAX_ENTRY 16
+
+/**
+ * Ringbuffer size in bytes.
+ */
+#define DMUB_REG_INBOX0_RB_SIZE (DMUB_RB_CMD_SIZE * DMUB_REG_INBOX0_RB_MAX_ENTRY)
+
+/**
  * REG_SET mask for reg offload.
  */
 #define REG_SET_MASK 0xFFFF
@@ -1533,7 +1543,8 @@ struct dmub_cmd_header {
 	unsigned int sub_type : 8; /**< command sub type */
 	unsigned int ret_status : 1; /**< 1 if returned data, 0 otherwise */
 	unsigned int multi_cmd_pending : 1; /**< 1 if multiple commands chained together */
-	unsigned int reserved0 : 6; /**< reserved bits */
+	unsigned int is_reg_based : 1; /**< 1 if register based mailbox cmd, 0 if FB based cmd */
+	unsigned int reserved0 : 5; /**< reserved bits */
 	unsigned int payload_bytes : 6;  /* payload excluding header - up to 60 bytes */
 	unsigned int reserved1 : 2; /**< reserved bits */
 };
@@ -5891,6 +5902,42 @@ static inline bool dmub_rb_empty(struct dmub_rb *rb)
 }
 
 /**
+ * @brief gets number of outstanding requests in the RB
+ *
+ * @param rb DMUB Ringbuffer
+ * @return true if full
+ */
+static inline uint32_t dmub_rb_num_outstanding(struct dmub_rb *rb)
+{
+	uint32_t data_count;
+
+	if (rb->wrpt >= rb->rptr)
+		data_count = rb->wrpt - rb->rptr;
+	else
+		data_count = rb->capacity - (rb->rptr - rb->wrpt);
+
+	return data_count / DMUB_RB_CMD_SIZE;
+}
+
+/**
+ * @brief gets number of free buffers in the RB
+ *
+ * @param rb DMUB Ringbuffer
+ * @return true if full
+ */
+static inline uint32_t dmub_rb_num_free(struct dmub_rb *rb)
+{
+	uint32_t data_count;
+
+	if (rb->wrpt >= rb->rptr)
+		data_count = rb->wrpt - rb->rptr;
+	else
+		data_count = rb->capacity - (rb->rptr - rb->wrpt);
+
+	return (rb->capacity - data_count) / DMUB_RB_CMD_SIZE;
+}
+
+/**
  * @brief Checks if the ringbuffer is full
  *
  * @param rb DMUB Ringbuffer