soc/intel/baytrail: Implement POSTCAR stage

Use common code to tear down CAR.

Change-Id: I62a70ae35fe92808f180f2b5f21c5899a96c2c16
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/29930
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/intel/baytrail/Kconfig

@@ -38,6 +38,8 @@ config CPU_SPECIFIC_OPTIONS
 	select HAVE_SPI_CONSOLE_SUPPORT
 	select INTEL_GMA_ACPI
 	select INTEL_GMA_SWSMISCI
+	select POSTCAR_STAGE
+	select POSTCAR_CONSOLE
 
 config VBOOT
 	select VBOOT_STARTS_IN_ROMSTAGE

src/soc/intel/baytrail/Makefile.inc

@@ -10,6 +10,7 @@ subdirs-y += ../../../cpu/intel/turbo
 
 ramstage-y += memmap.c
 romstage-y += memmap.c
+postcar-y += memmap.c
 ramstage-y += tsc_freq.c
 romstage-y += tsc_freq.c
 smm-y += tsc_freq.c
@@ -20,6 +21,7 @@ ramstage-y += gfx.c
 ramstage-y += iosf.c
 romstage-y += iosf.c
 smm-y += iosf.c
+postcar-y += iosf.c
 ramstage-y += northcluster.c
 ramstage-y += ramstage.c
 ramstage-y += gpio.c
@@ -51,6 +53,8 @@ ramstage-y += hda.c
 # Remove as ramstage gets fleshed out
 ramstage-y += placeholders.c
 
+postcar-y += ../../../cpu/intel/car/non-evict/exit_car.S
+
 cpu_microcode_bins += 3rdparty/blobs/soc/intel/baytrail/microcode.bin
 
 CPPFLAGS_common += -Isrc/soc/intel/baytrail/include

src/soc/intel/baytrail/romstage/cache_as_ram.inc

@@ -197,95 +197,11 @@ before_romstage:
 	post_code(0x2a)
 	/* Call romstage.c main function. */
 	call	romstage_main
-	/* Save return value from romstage_main. It contains the stack to use
-	 * after cache-as-ram is torn down. It also contains the information
-	 * for setting up MTRRs. */
-	movl	%eax, %ebx
 
-	post_code(0x2b)
+	/* Should never see this postcode */
-
+	post_code(POST_DEAD_CODE)
-	/* Disable cache. */
-	movl	%cr0, %eax
-	orl	$CR0_CacheDisable, %eax
-	movl	%eax, %cr0
-
-	post_code(0x2c)
-
-	/* Disable MTRR. */
-	movl	$MTRR_DEF_TYPE_MSR, %ecx
-	rdmsr
-	andl	$(~MTRR_DEF_TYPE_EN), %eax
-	wrmsr
-
-	invd
-
-	post_code(0x2d)
-
-	/* Disable the no eviction run state */
-	movl	$NoEvictMod_MSR, %ecx
-	rdmsr
-	andl	$~2, %eax
-	wrmsr
-
-	/* Disable the no eviction mode */
-	rdmsr
-	andl	$~1, %eax
-	wrmsr
-
-	post_code(0x2e)
-
-	/* Setup stack as indicated by return value from romstage_main(). */
-	movl	%ebx, %esp
-
-	/* Get number of MTRRs. */
-	popl	%ebx
-	movl	$MTRR_PHYS_BASE(0), %ecx
-1:
-	testl	%ebx, %ebx
-	jz	1f
-
-	/* Low 32 bits of MTRR base. */
-	popl	%eax
-	/* Upper 32 bits of MTRR base. */
-	popl	%edx
-	/* Write MTRR base. */
-	wrmsr
-	inc	%ecx
-	/* Low 32 bits of MTRR mask. */
-	popl	%eax
-	/* Upper 32 bits of MTRR mask. */
-	popl	%edx
-	/* Write MTRR mask. */
-	wrmsr
-	inc	%ecx
-
-	dec	%ebx
-	jmp	1b
-1:
-	post_code(0x2f)
-
-	/* And enable cache again after setting MTRRs. */
-	movl	%cr0, %eax
-	andl	$~(CR0_CacheDisable | CR0_NoWriteThrough), %eax
-	movl	%eax, %cr0
-
-	post_code(0x30)
-
-	/* Enable MTRR. */
-	movl	$MTRR_DEF_TYPE_MSR, %ecx
-	rdmsr
-	orl	$MTRR_DEF_TYPE_EN, %eax
-	wrmsr
-
-	post_code(0x31)
-
-__main:
-	post_code(POST_PREPARE_RAMSTAGE)
-	cld			/* Clear direction flag. */
-	call	romstage_after_car
 
 .Lhlt:
-	post_code(POST_DEAD_CODE)
 	hlt
 	jmp	.Lhlt
 

src/soc/intel/baytrail/romstage/romstage.c

@@ -47,7 +47,7 @@
  * Because we can't use global variables the stack is used for allocations --
  * thus the need to call back and forth. */
 
-static void *setup_stack_and_mtrrs(void);
+static void platform_enter_postcar(void);
 
 static void program_base_addresses(void)
 {
@@ -128,7 +128,10 @@ void *asmlinkage romstage_main(unsigned long bist, uint32_t tsc_low,
 	/* Call into mainboard. */
 	mainboard_romstage_entry(&rp);
 
-	return setup_stack_and_mtrrs();
+	platform_enter_postcar();
+
+	/* We don't return here */
+	return NULL;
 }
 
 static struct chipset_power_state power_state CAR_GLOBAL;
@@ -245,7 +248,7 @@ static inline uint32_t *stack_push(u32 *stack, u32 value)
 
 /* setup_stack_and_mtrrs() determines the stack to use after
  * cache-as-ram is torn down as well as the MTRR settings to use. */
-static void *setup_stack_and_mtrrs(void)
+static void platform_enter_postcar(void)
 {
 	struct postcar_frame pcf;
 	uintptr_t top_of_ram;
@@ -267,5 +270,5 @@ static void *setup_stack_and_mtrrs(void)
 	postcar_frame_add_mtrr(&pcf, top_of_ram - 8*MiB, 16*MiB,
 			       MTRR_TYPE_WRBACK);
 
-	return postcar_commit_mtrrs(&pcf);
+	run_postcar_phase(&pcf);
 }