cpu/intel/car: Prepare for C_ENVIRONMENT_BOOTBLOCK

Pass timestamps and BIST to romstage using the same signature
as C_ENVIRONMENT_BOOTBLOCK will.

Change-Id: Ic90da6b1b5ac3b56c69b593ba447ed8e05c8a4e2
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/30492
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

3 files changed, 25 insertions, 18 deletions

diff --git a/src/soc/intel/baytrail/include/soc/romstage.h b/src/soc/intel/baytrail/include/soc/romstage.h
index ac0f03bfdf..b65c6809a9 100644
--- a/src/soc/intel/baytrail/include/soc/romstage.h
+++ b/src/soc/intel/baytrail/include/soc/romstage.h
@@ -31,8 +31,7 @@ struct romstage_params {
 
 void mainboard_romstage_entry(struct romstage_params *params);
 void romstage_common(struct romstage_params *params);
-void *asmlinkage romstage_main(unsigned long bist, uint32_t tsc_lo,
-                                uint32_t tsc_high);
+
 void raminit(struct mrc_params *mp, int prev_sleep_state);
 void gfx_init(void);
 void tco_disable(void);
diff --git a/src/soc/intel/baytrail/romstage/cache_as_ram.inc b/src/soc/intel/baytrail/romstage/cache_as_ram.inc
index 8602237d28..4326636bfd 100644
--- a/src/soc/intel/baytrail/romstage/cache_as_ram.inc
+++ b/src/soc/intel/baytrail/romstage/cache_as_ram.inc
@@ -176,23 +176,24 @@ addrsize_set_high:
 	post_code(0x29)
 
 	/* Setup the stack. */
-	movl	$(CONFIG_DCACHE_RAM_BASE + CONFIG_DCACHE_RAM_SIZE), %eax
-	movl	%eax, %esp
+	mov	$_car_stack_end, %esp
 
-	/* Push the initial TSC value from boot block. The low 32 bits are
-	 * in mm1, and the high 32 bits are in mm2. */
+	/* Need to align stack to 16 bytes at call instruction. Account for
+	the pushes below. */
+	andl	$0xfffffff0, %esp
+	subl	$4, %esp
+
+	/* push TSC and BIST to stack */
+	movd	%mm0, %eax
+	pushl	%eax 	/* BIST */
 	movd	%mm2, %eax
-	pushl	%eax
+	pushl	%eax	/* tsc[63:32] */
 	movd	%mm1, %eax
-	pushl	%eax
-	/* Restore the BIST result. */
-	movd	%mm0, %eax
-	pushl	%eax
+	pushl	%eax 	/* tsc[31:0] */
 
-before_romstage:
+before_c_entry:
 	post_code(0x2a)
-	/* Call romstage.c main function. */
-	call	romstage_main
+	call	bootblock_c_entry_bist
 
 	/* Should never see this postcode */
 	post_code(POST_DEAD_CODE)
diff --git a/src/soc/intel/baytrail/romstage/romstage.c b/src/soc/intel/baytrail/romstage/romstage.c
index a52d3b1c2d..4b499061e9 100644
--- a/src/soc/intel/baytrail/romstage/romstage.c
+++ b/src/soc/intel/baytrail/romstage/romstage.c
@@ -17,6 +17,7 @@
 #include <arch/cpu.h>
 #include <arch/io.h>
 #include <arch/early_variables.h>
+#include <bootblock_common.h>
 #include <console/console.h>
 #include <cbmem.h>
 #include <cpu/x86/mtrr.h>
@@ -95,8 +96,7 @@ static void spi_init(void)
 }
 
 /* Entry from cache-as-ram.inc. */
-void *asmlinkage romstage_main(unsigned long bist, uint32_t tsc_low,
-			       uint32_t tsc_hi)
+static void romstage_main(uint64_t tsc, uint32_t bist)
 {
 	struct romstage_params rp = {
 		.bist = bist,
@@ -104,7 +104,7 @@ void *asmlinkage romstage_main(unsigned long bist, uint32_t tsc_low,
 	};
 
 	/* Save initial timestamp from bootblock. */
-	timestamp_init((((uint64_t)tsc_hi) << 32) | (uint64_t)tsc_low);
+	timestamp_init(tsc);
 
 	/* Save romstage begin */
 	timestamp_add_now(TS_START_ROMSTAGE);
@@ -131,7 +131,14 @@ void *asmlinkage romstage_main(unsigned long bist, uint32_t tsc_low,
 	platform_enter_postcar();
 
 	/* We don't return here */
-	return NULL;
+}
+
+/* This wrapper enables easy transition towards C_ENVIRONMENT_BOOTBLOCK,
+ * keeping changes in cache_as_ram.S easy to manage.
+ */
+asmlinkage void bootblock_c_entry_bist(uint64_t base_timestamp, uint32_t bist)
+{
+	romstage_main(base_timestamp, bist);
 }
 
 static struct chipset_power_state power_state CAR_GLOBAL;