drm/amdgpu: Match against exact bootloader status

On PSP v13.x ASICs, boot loader will set only the MSB to 1 and clear the
least significant bits for any command submission. Hence match against
the exact register value, otherwise a register value of all 0xFFs also
could falsely indicate that boot loader is ready. Also, from PSP v13.0.6
and newer, bits[7:0] will be used to indicate command error status.
Signed-off-by: Lijo Lazar <lijo.lazar@amd.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdgpu/psp_v13_0.c

@@ -137,14 +137,15 @@ static int psp_v13_0_wait_for_bootloader(struct psp_context *psp)
 	int ret;
 	int retry_loop;
 
+	/* Wait for bootloader to signify that it is ready having bit 31 of
+	 * C2PMSG_35 set to 1. All other bits are expected to be cleared.
+	 * If there is an error in processing command, bits[7:0] will be set.
+	 * This is applicable for PSP v13.0.6 and newer.
+	 */
 	for (retry_loop = 0; retry_loop < 10; retry_loop++) {
-		/* Wait for bootloader to signify that is
-		    ready having bit 31 of C2PMSG_35 set to 1 */
-		ret = psp_wait_for(psp,
-				   SOC15_REG_OFFSET(MP0, 0, regMP0_SMN_C2PMSG_35),
-				   0x80000000,
-				   0x80000000,
-				   false);
+		ret = psp_wait_for(
+			psp, SOC15_REG_OFFSET(MP0, 0, regMP0_SMN_C2PMSG_35),
+			0x80000000, 0xffffffff, false);
 
 		if (ret == 0)
 			return 0;