From: Charles Papon <charles.papon.90@gmail.com>
Date: Fri, 1 May 2020 03:58:38 +0000 (+0530)
Subject: firmware: fw_base: Remove CSR_MTVEC update check
X-Git-Tag: v1.3~762
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=5bdf022d07f1efcf8bc1647c78a294ab2baf4c9b;p=platform%2Fkernel%2Fopensbi-spacemit.git

firmware: fw_base: Remove CSR_MTVEC update check

Remove unnecessary CSR_MTVEC read to reduce the openSBI CSR requirement.

Mux are costly in FPGA. Allowing CSR_MTVEC to be write only is usefull
for the FMax/Area of FPGA softcore.

https://github.com/SpinalHDL/opensbi.git branch mtvec

Signed-off-by: Charles Papon <charles.papon.90@gmail.com>
Reviewed-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
---

diff --git a/firmware/fw_base.S b/firmware/fw_base.S
index cc6381d..07edc74 100644
--- a/firmware/fw_base.S
+++ b/firmware/fw_base.S
@@ -400,9 +400,6 @@ _start_warm:
 	/* Setup trap handler */
 	la	a4, _trap_handler
 	csrw	CSR_MTVEC, a4
-	/* Make sure that mtvec is updated */
-1:	csrr	a5, CSR_MTVEC
-	bne	a4, a5, 1b
 
 	/* Initialize SBI runtime */
 	csrr	a0, CSR_MSCRATCH