soc/amd/picasso: Use SMU to put system into S3

Send a message to the SMU to turn off the system power.  SMU will take
the proper final steps based on PmControl[SlpTyp].

BUG=b:153264473
TEST=verify system can enter S3

Change-Id: I3c0d98110c12963aa6fef5d176fd9acaa7ed9f26
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://chromium-review.googlesource.com/2140471
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41626
Reviewed-by: Raul Rangel <rrangel@chromium.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/amd/picasso/smihandler.c

@@ -15,6 +15,7 @@
 #include <amdblocks/acpi.h>
 #include <amdblocks/psp.h>
 #include <elog.h>
+#include <soc/smu.h>
 
 /* bits in smm_io_trap   */
 #define SMM_IO_TRAP_PORT_OFFSET		16
@@ -209,11 +210,9 @@ static void sb_slp_typ_handler(void)
 
 		psp_notify_sx_info(slp_typ);
 
-		/*
-		 * An IO cycle is required to trigger the STPCLK/STPGNT
-		 * handshake when the Pm1 write is reissued.
-		 */
-		outw(pm1cnt | SLP_EN, pm_read16(PM1_CNT_BLK));
+		smu_sx_entry(); /* Leave SlpTypeEn clear, SMU will set */
+		printk(BIOS_ERR, "Error: System did not go to sleep\n");
+
 		hlt();
 	}
 }