fix issue #48

Per discussions in issue#48, we should leave PMP to firmware
or OS thus allowing mainline OpenSBI or different OS be loaded.

MAEE extension should also be turned off for standard compliance.

Signed-off-by: Yanfeng Liu <[email protected]>

Author: yf13

src/little/uboot/arch/riscv/cpu/k230/cpu.c

@@ -42,9 +42,8 @@ static inline void improving_cpu_performance(void)
 	csr_write(CSR_MCOR, 0x70013);
 	csr_write(CSR_MCCR2, 0xe0000009);
 	csr_write(CSR_MHCR, 0x11ff); //Enable L1 Cache
-	csr_write(CSR_MXSTATUS, 0x638000);
+	csr_write(CSR_MXSTATUS, 0x438000); /* use x438000 per issue#48 */
 	csr_write(CSR_MHINT, 0x6e30c);
-
 	csr_write(CSR_SMPEN, 0x1);
 }
 
@@ -79,9 +78,7 @@ void harts_early_init(void)
 
 	writel(0x80199805, (void*)0x91100004);
 
-	csr_write(pmpaddr0, 0x24484dff);//start addr：0x24484c00<<2=0x91213000 len=1<<9 * 8 = 4KB
-	csr_write(pmpaddr1, 0x244851ff);//start addr：0x24485000<<2=0x91214000 len=1<<9 * 8 = 4KB
-	csr_write(pmpcfg0, 0x9999);
+	/* leave PMP open per issue#48 */
 
 	//improving_cpu_performance();
 }
@@ -117,6 +114,7 @@ static int k230_boot_baremetal(struct cmd_tbl *cmdtp, int flag, int argc,
 	}
 	else
 	{
+		cleanup_before_linux(); /* same as do_go_exec() */
 		func_app_entry app_entry = (void *)(long)boot_address;
 		app_entry();
 	}