x86: fsp: Allow remembering the location of FSP-S

[oweals/u-boot.git] / arch / x86 / cpu / start.S

diff --git a/arch/x86/cpu/start.S b/arch/x86/cpu/start.S
index 8de55a0af1de3681a360ff35fb5acf70ef878a90..01524635e9c82d9a498653605dc36d2107ea8d90 100644 (file)
--- a/arch/x86/cpu/start.S
+++ b/arch/x86/cpu/start.S
@@ -1,13 +1,24 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
 /*
  *  U-Boot - x86 Startup Code
  *
+ * This is always the first code to run from the U-Boot source. To spell it out:
+ *
+ * 1. When TPL (Tertiary Program Loader) is enabled, the boot flow is
+ * TPL->SPL->U-Boot and this file is used for TPL. Then start_from_tpl.S is used
+ * for SPL and start_from_spl.S is used for U-Boot proper.
+ *
+ * 2. When SPL (Secondary Program Loader) is enabled, but not TPL, the boot
+ * flow is SPL->U-Boot and this file is used for SPL. Then start_from_spl.S is
+ * used for U-Boot proper.
+ *
+ * 3. When neither TPL nor SPL is used, this file is used for U-Boot proper.
+ *
  * (C) Copyright 2008-2011
  * Graeme Russ, <graeme.russ@gmail.com>
  *
  * (C) Copyright 2002
  * Daniel Engström, Omicron Ceti AB, <daniel@omicron.se>
- *
- * SPDX-License-Identifier:    GPL-2.0+
  */
 
 #include <config.h>
@@ -17,8 +28,9 @@
 #include <asm/processor-flags.h>
 #include <generated/generic-asm-offsets.h>
 #include <generated/asm-offsets.h>
+#include <linux/linkage.h>
 
-.section .text
+.section .text.start
 .code32
 .globl _start
 .type _start, @function
@@ -40,9 +52,6 @@ _x86boot_start:
        movl    %eax, %cr0
        wbinvd
 
-       /* Tell 32-bit code it is being entered from an in-RAM copy */
-       movl    $GD_FLG_WARM_BOOT, %ebx
-
        /*
         * Zero the BIST (Built-In Self Test) value since we don't have it.
         * It must be 0 or the previous loader would have reported an error.
@@ -55,11 +64,7 @@ _x86boot_start:
        .align  4
        .long   0x12345678
 _start:
-       /*
-        * This is the 32-bit cold-reset entry point, coming from start16.
-        * Set %ebx to GD_FLG_COLD_BOOT to indicate this.
-        */
-       movl    $GD_FLG_COLD_BOOT, %ebx
+       /* This is the 32-bit cold-reset entry point, coming from start16 */
 
        /* Save BIST */
        movl    %eax, %ebp
@@ -97,7 +102,7 @@ early_board_init_ret:
        jmp     car_init
 .globl car_init_ret
 car_init_ret:
-#ifndef CONFIG_HAVE_FSP
+#ifdef CONFIG_USE_CAR
        /*
         * We now have CONFIG_SYS_CAR_SIZE bytes of Cache-As-RAM (or SRAM,
         * or fully initialised SDRAM - we really don't care which)
@@ -137,12 +142,13 @@ car_init_ret:
 
        /* Get address of global_data */
        mov     %fs:0, %edx
-#ifdef CONFIG_HAVE_FSP
+#if defined(CONFIG_USE_HOB) && !defined(CONFIG_USE_CAR)
        /* Store the HOB list if we have one */
        test    %esi, %esi
        jz      skip_hob
        movl    %esi, GD_HOB_LIST(%edx)
 
+#ifdef CONFIG_HAVE_FSP
        /*
         * After fsp_init() returns, the stack has already been switched to a
         * place within system memory as defined by CONFIG_FSP_TEMP_RAM_ADDR.
@@ -151,6 +157,7 @@ car_init_ret:
         */
        subl    $CONFIG_FSP_SYS_MALLOC_F_LEN, %esp
        movl    %esp, GD_MALLOC_BASE(%edx)
+#endif
 skip_hob:
 #else
        /* Store table pointer */
@@ -185,21 +192,33 @@ board_init_f_r_trampoline:
        movl    %eax, %esp
 
        /* See if we need to disable CAR */
-.weak  car_uninit
-       movl    $car_uninit, %eax
-       cmpl    $0, %eax
-       jz      1f
-
        call    car_uninit
-1:
+
        /* Re-enter U-Boot by calling board_init_f_r() */
        call    board_init_f_r
 
+#ifdef CONFIG_TPL
+.globl jump_to_spl
+.type jump_to_spl, @function
+jump_to_spl:
+       /* Reset stack to the top of CAR space */
+       movl    $(CONFIG_SYS_CAR_ADDR + CONFIG_SYS_CAR_SIZE - 4), %esp
+#ifdef CONFIG_DCACHE_RAM_MRC_VAR_SIZE
+       subl    $CONFIG_DCACHE_RAM_MRC_VAR_SIZE, %esp
+#endif
+
+       jmp     *%eax
+#endif
+
 die:
        hlt
        jmp     die
        hlt
 
+WEAK(car_uninit)
+       ret
+ENDPROC(car_uninit)
+
 blank_idt_ptr:
        .word   0               /* limit */
        .long   0               /* base */