drm/amd/display: Add a boot option to reduce phy ssc for HBR3

[Why]
Spread on DPREFCLK by 0.3 percent can have a negative effect on sink
when PHY SSC is also spread by 0.3 percent
[How]
Add boot option for DMU to lower PHY SSC

Reviewed-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Hansen Dsouza <Hansen.Dsouza@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>

Author: Hansen Dsouza

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

@@ -301,6 +301,7 @@ struct dmub_srv_hw_params {
 	bool disallow_phy_access;
 	bool disable_sldo_opt;
 	bool enable_non_transparent_setconfig;
+	bool lower_hbr3_phy_ssc;
 };
 
 /**

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

@@ -694,7 +694,8 @@ union dmub_fw_boot_options {
 		uint32_t ips_disable: 3; /* options to disable ips support*/
 		uint32_t ips_sequential_ono: 1; /**< 1 to enable sequential ONO IPS sequence */
 		uint32_t disable_sldo_opt: 1; /**< 1 to disable SLDO optimizations */
-		uint32_t reserved : 7; /**< reserved */
+		uint32_t lower_hbr3_phy_ssc: 1; /**< 1 to lower hbr3 phy ssc to 0.125 percent */
+		uint32_t reserved : 6; /**< reserved */
 	} bits; /**< boot bits */
 	uint32_t all; /**< 32-bit access to bits */
 };

drivers/gpu/drm/amd/display/dmub/src/dmub_dcn35.c

@@ -426,6 +426,7 @@ void dmub_dcn35_enable_dmub_boot_options(struct dmub_srv *dmub, const struct dmu
 	boot_options.bits.ips_sequential_ono = params->ips_sequential_ono;
 	boot_options.bits.disable_sldo_opt = params->disable_sldo_opt;
 	boot_options.bits.enable_non_transparent_setconfig = params->enable_non_transparent_setconfig;
+	boot_options.bits.lower_hbr3_phy_ssc = params->lower_hbr3_phy_ssc;
 
 	REG_WRITE(DMCUB_SCRATCH14, boot_options.all);
 }