drm/amd/display: Support for DMUB AUX

[WHY]
To process AUX transactions with DMUB using inbox1 and outbox1 mail boxes.

[HOW]
1) Added inbox1 command DMUB_CMD__DP_AUX_ACCESS to issue AUX commands
   to DMUB in dc_process_dmub_aux_transfer_async(). DMUB processes AUX cmd
   with DCN and sends reply back in an outbox1 message triggering an
   outbox1 interrupt to driver.
2) In existing driver implementation, AUX commands are processed
   synchronously by configuring DCN reg. But in DMUB AUX, driver sends an
   inbox1 message and waits for a conditional variable (CV) which will be
   signaled by outbox1 ISR.
3) As the driver holds dal and dc locks while waiting for CV, the outbox1
   ISR is registered with noMutexWait set to true, which allows ISR to run
   and signal CV. This sets a constraint on ISR to not modify variables
   such as dc, dmub, etc.
4) Created dmub_outbox.c with dmub_enable_outbox_notification() to enable
   outbox1 mailbox.
5) New mailbox address ranges allocated for outbox1 of size DMUB_RB_SIZE.
   Created dmub functions for Outbox1: dmub_dcn20_setup_out_mailbox(),
   dmub_dcn20_get_outbox1_wptr() and dmub_dcn20_set_outbox1_rptr().
6) Added functions dc_stat_get_dmub_notification() and
   dmub_srv_stat_get_notification() to retrieve Outbox1 message.
7) Currently, DMUB doesn't opens DDC in AUX mode before issuing AUX
   transaction. A workaround is added in dce_aux_transfer_dmub_raw() to
   open in DDC in AUX mode for every AUX transaction.
8) Added dc debug option enable_dmub_aux_for_legacy_ddc enable/disable
   DMUB AUX. This debug option is checked dce_aux_transfer_with_retries()
   to select the method to process AUX transactions.

Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Meenakshikumar Somasundaram <meenakshikumar.somasundaram@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

1 files changed, 105 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/display/dmub/src/dmub_srv_stat.c b/drivers/gpu/drm/amd/display/dmub/src/dmub_srv_stat.c
new file mode 100644
index 000000000000..e6f3bfab33d3
--- /dev/null
+++ b/drivers/gpu/drm/amd/display/dmub/src/dmub_srv_stat.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright 2019 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * Authors: AMD
+ *
+ */
+
+#include "dmub/dmub_srv_stat.h"
+#include "dmub/inc/dmub_cmd.h"
+
+/**
+ * DOC: DMUB_SRV STAT Interface
+ *
+ * These interfaces are called without acquiring DAL and DC locks.
+ * Hence, there is limitations on whese interfaces can access. Only
+ * variables exclusively defined for these interfaces can be modified.
+ */
+
+/**
+ *****************************************************************************
+ *  Function: dmub_srv_stat_get_notification
+ *
+ *  @brief
+ *		Retrieves a dmub outbox notification, set up dmub notification
+ *		structure with message information. Also a pending bit if queue
+ *		is having more notifications
+ *
+ *  @param [in] dmub: dmub srv structure
+ *  @param [out] pnotify: dmub notification structure to be filled up
+ *
+ *  @return
+ *     dmub_status
+ *****************************************************************************
+ */
+enum dmub_status dmub_srv_stat_get_notification(struct dmub_srv *dmub,
+						struct dmub_notification *notify)
+{
+	/**
+	 * This function is called without dal and dc locks, so
+	 * we shall not modify any dmub variables, only dmub->outbox1_rb
+	 * is exempted as it is exclusively accessed by this function
+	 */
+	union dmub_rb_out_cmd cmd = {0};
+
+	if (!dmub->hw_init) {
+		notify->type = DMUB_NOTIFICATION_NO_DATA;
+		notify->pending_notification = false;
+		return DMUB_STATUS_INVALID;
+	}
+
+	/* Get write pointer which is updated by dmub */
+	dmub->outbox1_rb.wrpt = dmub->hw_funcs.get_outbox1_wptr(dmub);
+
+	if (!dmub_rb_out_front(&dmub->outbox1_rb, &cmd)) {
+		notify->type = DMUB_NOTIFICATION_NO_DATA;
+		notify->pending_notification = false;
+		return DMUB_STATUS_OK;
+	}
+
+	switch (cmd.cmd_common.header.type) {
+	case DMUB_OUT_CMD__DP_AUX_REPLY:
+		notify->type = DMUB_NOTIFICATION_AUX_REPLY;
+		notify->link_index = cmd.dp_aux_reply.control.instance;
+		notify->result = cmd.dp_aux_reply.control.result;
+		dmub_memcpy((void *)&notify->aux_reply,
+			(void *)&cmd.dp_aux_reply.reply_data, sizeof(struct aux_reply_data));
+		break;
+	default:
+		notify->type = DMUB_NOTIFICATION_NO_DATA;
+		break;
+	}
+
+	/* Pop outbox1 ringbuffer and update read pointer */
+	dmub_rb_pop_front(&dmub->outbox1_rb);
+	dmub->hw_funcs.set_outbox1_rptr(dmub, dmub->outbox1_rb.rptr);
+
+	/**
+	 * Notify dc whether dmub has a pending outbox message,
+	 * this is to avoid one more call to dmub_srv_stat_get_notification
+	 */
+	if (dmub_rb_empty(&dmub->outbox1_rb))
+		notify->pending_notification = false;
+	else
+		notify->pending_notification = true;
+
+	return DMUB_STATUS_OK;
+}