Add a rough function to handle jumping from 32-bit SPL to 64-bit U-Boot.
This still needs work to clean it up.
Signed-off-by: Simon Glass <s...@chromium.org>
---
arch/x86/cpu/call64.S | 3 +++
arch/x86/cpu/i386/cpu.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++
arch/x86/include/asm/cpu.h | 9 +++++++
3 files changed, 77 insertions(+)
diff --git a/arch/x86/cpu/call64.S b/arch/x86/cpu/call64.S
index 08dc473..970c461 100644
--- a/arch/x86/cpu/call64.S
+++ b/arch/x86/cpu/call64.S
@@ -81,6 +81,9 @@ lret_target:
jmp *%eax /* Jump to the 64-bit target */
.data
+ .align 16
+ .globl gdt64
+gdt64:
gdt:
.word gdt_end - gdt - 1
.long gdt /* Fixed up by code above */
diff --git a/arch/x86/cpu/i386/cpu.c b/arch/x86/cpu/i386/cpu.c
index 09a5b91..ddbf367 100644
--- a/arch/x86/cpu/i386/cpu.c
+++ b/arch/x86/cpu/i386/cpu.c
@@ -503,6 +503,71 @@ int cpu_jump_to_64bit(ulong setup_base, ulong target)
return -EFAULT;
}
+/*
+ * Jump from SPL to U-Boot
+ *
+ * This function is work-in-progress with many issues to resolve.
+ *
+ * It works by setting up several regions:
+ * ptr - a place to put the code that jumps into 64-bit mode
+ * gdt - a place to put the global descriptor table
+ * pgtable - a place to put the page tables
+ *
+ * The cpu_call64() code is copied from ROM and then manually patched so that
+ * it has the correct GDT address in RAM. U-Boot is copied from ROM into
+ * its pre-relocation address. Then we jump to the cpu_call64() code in RAM,
+ * which changes to 64-bit mode and starts U-Boot.
+ */
+int cpu_jump_to_64bit_uboot(ulong target)
+{
+ typedef void (*func_t)(ulong pgtable, ulong setup_base, ulong target);
+ void target64(void);
+ uint32_t *pgtable;
+ func_t func;
+
+ /* TODO(s...@chromium.org): Find a better place for this */
+ pgtable = (uint32_t *)0x1000000;
+ if (!pgtable)
+ return -ENOMEM;
+
+ build_pagetable(pgtable);
+
+ /* TODO(s...@chromium.org): Find a better place for this */
+ char *ptr = (char *)0x3000000;
+ char *gdt = (char *)0x3100000;
+
+ extern char gdt64[];
+
+ memcpy(ptr, cpu_call64, 0x1000);
+ memcpy(gdt, gdt64, 0x100);
+
+ /*
+ * TODO(s...@chromium.org): This manually inserts the pointers into
+ * the code. Tidy this up to avoid this.
+ */
+ func = (func_t)ptr;
+ ulong ofs = (ulong)cpu_call64 - (ulong)ptr;
+ *(ulong *)(ptr + 7) = (ulong)gdt;
+ *(ulong *)(ptr + 0xc) = (ulong)gdt + 2;
+ *(ulong *)(ptr + 0x13) = (ulong)gdt;
+ *(ulong *)(ptr + 0x117 - 0xd4) -= ofs;
+
+ /*
+ * Copy U-Boot from ROM
+ * TODO(s...@chromium.org): Figure out a way to get the text base
+ * correctly here, and in the device-tree binman definition.
+ *
+ * Also consider using FIT so we get the correct image length and
+ * parameters.
+ */
+ memcpy((char *)target, (char *)0xfff00000, 0x100000);
+
+ /* Jump to U-Boot */
+ func((ulong)pgtable, 0, (ulong)target);
+
+ return -EFAULT;
+}
+
#ifdef CONFIG_SMP
static int enable_smis(struct udevice *cpu, void *unused)
{
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
index 9a8ae2a..cd55201 100644
--- a/arch/x86/include/asm/cpu.h
+++ b/arch/x86/include/asm/cpu.h
@@ -265,6 +265,15 @@ void cpu_call32(ulong code_seg32, ulong target, ulong
table);
int cpu_jump_to_64bit(ulong setup_base, ulong target);
/**
+ * cpu_jump_to_64bit_uboot() - special function to jump from SPL to U-Boot
+ *
+ * This handles calling from 32-bit SPL to 64-bit U-Boot.
+ *
+ * @target: Address of U-Boot in RAM
+ */
+int cpu_jump_to_64bit_uboot(ulong target);
+
+/**
* cpu_get_family_model() - Get the family and model for the CPU
*
* @return the CPU ID masked with 0x0fff0ff0
--
2.8.0.rc3.226.g39d4020
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