drm/amd/display: Add GPINT handler interface

[Why]
The General Purpose Interrupt is used on the DMCUB to pass lightweight
commands via a register to the DMCUB.

This is limited to 32-bit command and 32-bit response.

This will be used for shutting down the firmware in a clean manner.

[How]
Add the command IDs and the data register to correctly format
the commands.

Add the interface functions to dmub_srv for sending and receiving the
commands.

Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Reviewed-by: Tony Cheng <Tony.Cheng@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dmub/inc/dmub_gpint_cmd.h

@@ -0,0 +1,68 @@
+/*
+ * 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
+ *
+ */
+
+#ifndef _DMUB_GPINT_CMD_H_
+#define _DMUB_GPINT_CMD_H_
+
+#include "dmub_types.h"
+
+/**
+ * The register format for sending a command via the GPINT.
+ */
+union dmub_gpint_data_register {
+	struct {
+		uint32_t param : 16;
+		uint32_t command_code : 12;
+		uint32_t status : 4;
+	} bits;
+	uint32_t all;
+};
+
+/**
+ * The shifts and masks below may alternatively be used to format and read
+ * the command register bits.
+ */
+
+#define DMUB_GPINT_DATA_PARAM_MASK 0xFFFF
+#define DMUB_GPINT_DATA_PARAM_SHIFT 0
+
+#define DMUB_GPINT_DATA_COMMAND_CODE_MASK 0xFFF
+#define DMUB_GPINT_DATA_COMMAND_CODE_SHIFT 16
+
+#define DMUB_GPINT_DATA_STATUS_MASK 0xF
+#define DMUB_GPINT_DATA_STATUS_SHIFT 28
+
+/*
+ * Command IDs should be treated as stable ABI.
+ * Do not reuse or modify IDs.
+ */
+
+enum dmub_gpint_command {
+	DMUB_GPINT__INVALID_COMMAND = 0,
+	DMUB_GPINT__GET_FW_VERSION = 1,
+	DMUB_GPINT__STOP_FW = 2,
+};
+
+#endif /* _DMUB_GPINT_CMD_H_ */

drivers/gpu/drm/amd/display/dmub/inc/dmub_srv.h

@@ -66,6 +66,7 @@
 
 #include "dmub_types.h"
 #include "dmub_cmd.h"
+#include "dmub_gpint_cmd.h"
 #include "dmub_rb.h"
 
 #if defined(__cplusplus)
@@ -262,6 +263,14 @@ struct dmub_srv_hw_funcs {
 	bool (*is_phy_init)(struct dmub_srv *dmub);
 
 	bool (*is_auto_load_done)(struct dmub_srv *dmub);
+
+	void (*set_gpint)(struct dmub_srv *dmub,
+			  union dmub_gpint_data_register reg);
+
+	bool (*is_gpint_acked)(struct dmub_srv *dmub,
+			       union dmub_gpint_data_register reg);
+
+	uint32_t (*get_gpint_response)(struct dmub_srv *dmub);
 };
 
 /**
@@ -516,6 +525,45 @@ enum dmub_status dmub_srv_wait_for_phy_init(struct dmub_srv *dmub,
 enum dmub_status dmub_srv_wait_for_idle(struct dmub_srv *dmub,
 					uint32_t timeout_us);
 
+/**
+ * dmub_srv_send_gpint_command() - Sends a GPINT based command.
+ * @dmub: the dmub service
+ * @command_code: the command code to send
+ * @param: the command parameter to send
+ * @timeout_us: the maximum number of microseconds to wait
+ *
+ * Sends a command via the general purpose interrupt (GPINT).
+ * Waits for the number of microseconds specified by timeout_us
+ * for the command ACK before returning.
+ *
+ * Can be called after software initialization.
+ *
+ * Return:
+ *   DMUB_STATUS_OK - success
+ *   DMUB_STATUS_TIMEOUT - wait for ACK timed out
+ *   DMUB_STATUS_INVALID - unspecified error
+ */
+enum dmub_status
+dmub_srv_send_gpint_command(struct dmub_srv *dmub,
+			    enum dmub_gpint_command command_code,
+			    uint16_t param, uint32_t timeout_us);
+
+/**
+ * dmub_srv_get_gpint_response() - Queries the GPINT response.
+ * @dmub: the dmub service
+ * @response: the response for the last GPINT
+ *
+ * Returns the response code for the last GPINT interrupt.
+ *
+ * Can be called after software initialization.
+ *
+ * Return:
+ *   DMUB_STATUS_OK - success
+ *   DMUB_STATUS_INVALID - unspecified error
+ */
+enum dmub_status dmub_srv_get_gpint_response(struct dmub_srv *dmub,
+					     uint32_t *response);
+
 #if defined(__cplusplus)
 }
 #endif

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn20.c

@@ -217,3 +217,25 @@ bool dmub_dcn20_is_supported(struct dmub_srv *dmub)
 
 	return supported;
 }
+
+void dmub_dcn20_set_gpint(struct dmub_srv *dmub,
+			  union dmub_gpint_data_register reg)
+{
+	REG_WRITE(DMCUB_GPINT_DATAIN1, reg.all);
+}
+
+bool dmub_dcn20_is_gpint_acked(struct dmub_srv *dmub,
+			       union dmub_gpint_data_register reg)
+{
+	union dmub_gpint_data_register test;
+
+	reg.bits.status = 0;
+	test.all = REG_READ(DMCUB_GPINT_DATAIN1);
+
+	return test.all == reg.all;
+}
+
+uint32_t dmub_dcn20_get_gpint_response(struct dmub_srv *dmub)
+{
+	return REG_READ(DMCUB_SCRATCH7);
+}

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn20.h

@@ -91,6 +91,7 @@ struct dmub_srv;
 	DMUB_SR(DMCUB_SCRATCH13) \
 	DMUB_SR(DMCUB_SCRATCH14) \
 	DMUB_SR(DMCUB_SCRATCH15) \
+	DMUB_SR(DMCUB_GPINT_DATAIN1) \
 	DMUB_SR(CC_DC_PIPE_DIS) \
 	DMUB_SR(MMHUBBUB_SOFT_RESET) \
 	DMUB_SR(DCN_VM_FB_LOCATION_BASE) \
@@ -183,4 +184,12 @@ bool dmub_dcn20_is_hw_init(struct dmub_srv *dmub);
 
 bool dmub_dcn20_is_supported(struct dmub_srv *dmub);
 
+void dmub_dcn20_set_gpint(struct dmub_srv *dmub,
+			  union dmub_gpint_data_register reg);
+
+bool dmub_dcn20_is_gpint_acked(struct dmub_srv *dmub,
+			       union dmub_gpint_data_register reg);
+
+uint32_t dmub_dcn20_get_gpint_response(struct dmub_srv *dmub);
+
 #endif /* _DMUB_DCN20_H_ */

drivers/gpu/drm/amd/display/dmub/src/dmub_srv.c

@@ -126,6 +126,9 @@ static bool dmub_srv_hw_setup(struct dmub_srv *dmub, enum dmub_asic asic)
 		funcs->set_inbox1_wptr = dmub_dcn20_set_inbox1_wptr;
 		funcs->is_supported = dmub_dcn20_is_supported;
 		funcs->is_hw_init = dmub_dcn20_is_hw_init;
+		funcs->set_gpint = dmub_dcn20_set_gpint;
+		funcs->is_gpint_acked = dmub_dcn20_is_gpint_acked;
+		funcs->get_gpint_response = dmub_dcn20_get_gpint_response;
 
 		if (asic == DMUB_ASIC_DCN21) {
 			dmub->regs = &dmub_srv_dcn21_regs;
@@ -522,3 +525,50 @@ enum dmub_status dmub_srv_wait_for_idle(struct dmub_srv *dmub,
 
 	return DMUB_STATUS_TIMEOUT;
 }
+
+enum dmub_status
+dmub_srv_send_gpint_command(struct dmub_srv *dmub,
+			    enum dmub_gpint_command command_code,
+			    uint16_t param, uint32_t timeout_us)
+{
+	union dmub_gpint_data_register reg;
+	uint32_t i;
+
+	if (!dmub->sw_init)
+		return DMUB_STATUS_INVALID;
+
+	if (!dmub->hw_funcs.set_gpint)
+		return DMUB_STATUS_INVALID;
+
+	if (!dmub->hw_funcs.is_gpint_acked)
+		return DMUB_STATUS_INVALID;
+
+	reg.bits.status = 1;
+	reg.bits.command_code = command_code;
+	reg.bits.param = param;
+
+	dmub->hw_funcs.set_gpint(dmub, reg);
+
+	for (i = 0; i < timeout_us; ++i) {
+		if (dmub->hw_funcs.is_gpint_acked(dmub, reg))
+			return DMUB_STATUS_OK;
+	}
+
+	return DMUB_STATUS_TIMEOUT;
+}
+
+enum dmub_status dmub_srv_get_gpint_response(struct dmub_srv *dmub,
+					     uint32_t *response)
+{
+	*response = 0;
+
+	if (!dmub->sw_init)
+		return DMUB_STATUS_INVALID;
+
+	if (!dmub->hw_funcs.get_gpint_response)
+		return DMUB_STATUS_INVALID;
+
+	*response = dmub->hw_funcs.get_gpint_response(dmub);
+
+	return DMUB_STATUS_OK;
+}