spl: Add support for passing handoff info to U-Boot proper

There is some basic informaton that SPL normally wants to pass through to
U-Boot, such as the SDRAM size and bank information.

Mkae use of the new bloblist structure for this. Add a new 'handoff' blob
which is set up in SPL and passed to U-Boot proper. Also adda  test for
sandbox_spl that checks that this works correctly and a new 'sb' command
to show the information passed from SPL.

Reviewed-by: Tom Rini <trini@konsulko.com>
Signed-off-by: Simon Glass <sjg@chromium.org>

14 files changed, 253 insertions, 17 deletions

diff --git a/arch/powerpc/include/asm/spl.h b/arch/powerpc/include/asm/spl.h
index cd6d31c71a..60a7d37d30 100644
--- a/arch/powerpc/include/asm/spl.h
+++ b/arch/powerpc/include/asm/spl.h
@@ -8,7 +8,4 @@
 
 #define BOOT_DEVICE_NOR		1
 
-/* Linker symbols */
-extern char __bss_start[], __bss_end[];
-
 #endif
diff --git a/arch/sandbox/include/asm/handoff.h b/arch/sandbox/include/asm/handoff.h
new file mode 100644
index 0000000000..be4e7b0fae
--- /dev/null
+++ b/arch/sandbox/include/asm/handoff.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Architecture-specific SPL handoff information for sandbox
+ *
+ * Copyright 2018 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ */
+
+#ifndef __handoff_h
+#define __handoff_h
+
+#define TEST_HANDOFF_MAGIC	0x14f93c7b
+
+struct arch_spl_handoff {
+	ulong	magic;		/* Used for testing */
+};
+
+#endif
diff --git a/cmd/sb.c b/cmd/sb.c
index 6ca3361d7e..5701e03797 100644
--- a/cmd/sb.c
+++ b/cmd/sb.c
@@ -9,6 +9,23 @@
 #include <spl.h>
 #include <asm/state.h>
 
+static int do_sb_handoff(cmd_tbl_t *cmdtp, int flag, int argc,
+			 char *const argv[])
+{
+#if CONFIG_IS_ENABLED(HANDOFF)
+	if (gd->spl_handoff)
+		printf("SPL handoff magic %lx\n", gd->spl_handoff->arch.magic);
+	else
+		printf("SPL handoff info not received\n");
+
+	return 0;
+#else
+	printf("Command not supported\n");
+
+	return CMD_RET_USAGE;
+#endif
+}
+
 static int do_sb_state(cmd_tbl_t *cmdtp, int flag, int argc,
 		       char * const argv[])
 {
@@ -21,6 +38,7 @@ static int do_sb_state(cmd_tbl_t *cmdtp, int flag, int argc,
 }
 
 static cmd_tbl_t cmd_sb_sub[] = {
+	U_BOOT_CMD_MKENT(handoff, 1, 0, do_sb_handoff, "", ""),
 	U_BOOT_CMD_MKENT(state, 1, 0, do_sb_state, "", ""),
 };
 
@@ -42,5 +60,6 @@ static int do_sb(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 U_BOOT_CMD(
 	sb,	8,	1,	do_sb,
 	"Sandbox status commands",
-	"state       - Show sandbox state"
+	"handoff     - Show handoff data received from SPL\n"
+	"sb state       - Show sandbox state"
 );
diff --git a/common/board_f.c b/common/board_f.c
index 290e2b09b9..835b7247c5 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -25,6 +25,9 @@
 #include <post.h>
 #include <relocate.h>
 #include <spi.h>
+#ifdef CONFIG_SPL
+#include <spl.h>
+#endif
 #include <status_led.h>
 #include <sysreset.h>
 #include <timer.h>
@@ -286,6 +289,17 @@ static int setup_mon_len(void)
 	return 0;
 }
 
+static int setup_spl_handoff(void)
+{
+#if CONFIG_IS_ENABLED(HANDOFF)
+	gd->spl_handoff = bloblist_find(BLOBLISTT_SPL_HANDOFF,
+					sizeof(struct spl_handoff));
+	debug("Found SPL hand-off info %p\n", gd->spl_handoff);
+#endif
+
+	return 0;
+}
+
 __weak int arch_cpu_init(void)
 {
 	return 0;
@@ -845,6 +859,7 @@ static const init_fnc_t init_sequence_f[] = {
 #ifdef CONFIG_BLOBLIST
 	bloblist_init,
 #endif
+	setup_spl_handoff,
 	initf_console_record,
 #if defined(CONFIG_HAVE_FSP)
 	arch_fsp_init,
diff --git a/common/init/Makefile b/common/init/Makefile
index 4902635f53..853b56d1e5 100644
--- a/common/init/Makefile
+++ b/common/init/Makefile
@@ -5,3 +5,4 @@
 #
 
 obj-y += board_init.o
+obj-$(CONFIG_$(SPL_TPL_)HANDOFF) += handoff.o
diff --git a/common/init/handoff.c b/common/init/handoff.c
new file mode 100644
index 0000000000..e00b43e6a7
--- /dev/null
+++ b/common/init/handoff.c
@@ -0,0 +1,47 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Passing basic information from SPL to U-Boot proper
+ *
+ * Copyright 2018 Google, Inc
+ */
+
+#include <common.h>
+#include <handoff.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+void handoff_save_dram(struct spl_handoff *ho)
+{
+	ho->ram_size = gd->ram_size;
+#ifdef CONFIG_NR_DRAM_BANKS
+	{
+		struct bd_info *bd = gd->bd;
+		int i;
+
+		for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+			ho->ram_bank[i].start = bd->bi_dram[i].start;
+			ho->ram_bank[i].size = bd->bi_dram[i].size;
+		}
+	}
+#endif
+}
+
+void handoff_load_dram_size(struct spl_handoff *ho)
+{
+	gd->ram_size = ho->ram_size;
+}
+
+void handoff_load_dram_banks(struct spl_handoff *ho)
+{
+#ifdef CONFIG_NR_DRAM_BANKS
+	{
+		struct bd_info *bd = gd->bd;
+		int i;
+
+		for (i = 0; i < CONFIG_NR_DRAM_BANKS; i++) {
+			bd->bi_dram[i].start = ho->ram_bank[i].start;
+			bd->bi_dram[i].size = ho->ram_bank[i].size;
+		}
+	}
+#endif
+}
diff --git a/common/spl/Kconfig b/common/spl/Kconfig
index 32fa5758bf..0ddbffc7d1 100644
--- a/common/spl/Kconfig
+++ b/common/spl/Kconfig
@@ -25,8 +25,28 @@ config SPL_FRAMEWORK
 	  supports MMC, NAND and YMODEM and other methods loading of U-Boot
 	  and the Linux Kernel.  If unsure, say Y.
 
+config HANDOFF
+	bool "Pass hand-off information from SPL to U-Boot proper"
+	depends on BLOBLIST
+	help
+	  It is useful to be able to pass information from SPL to U-Boot
+	  proper to preserve state that is known in SPL and is needed in U-Boot.
+	  Enable this to locate the handoff information in U-Boot proper, early
+	  in boot. It is available in gd->handoff. The state state is set up
+	  in SPL (or TPL if that is being used).
+
 if SPL
 
+config SPL_HANDOFF
+	bool "Pass hand-off information from SPL to U-Boot proper"
+	depends on HANDOFF
+	default y
+	help
+	  This option enables SPL to write handoff information. This can be
+	  used to pass information like the size of SDRAM from SPL to U-Boot
+	  proper. Also SPL can receive information from TPL in the same place
+	  if that is enabled.
+
 config SPL_LDSCRIPT
 	string "Linker script for the SPL stage"
 	default "arch/$(ARCH)/cpu/u-boot-spl.lds"
@@ -867,6 +887,16 @@ config TPL
 
 if TPL
 
+config TPL_HANDOFF
+	bool "Pass hand-off information from TPL to SPL and U-Boot proper"
+	depends on HANDOFF
+	default y
+	help
+	  This option enables TPL to write handoff information. This can be
+	  used to pass information like the size of SDRAM from TPL to U-Boot
+	  proper. The information is also available to SPL if it is useful
+	  there.
+
 config TPL_BOARD_INIT
 	bool "Call board-specific initialization in TPL"
 	help
diff --git a/common/spl/spl.c b/common/spl/spl.c
index 43137105ba..35120b6efd 100644
--- a/common/spl/spl.c
+++ b/common/spl/spl.c
@@ -10,6 +10,7 @@
 #include <bloblist.h>
 #include <binman_sym.h>
 #include <dm.h>
+#include <handoff.h>
 #include <spl.h>
 #include <asm/u-boot.h>
 #include <nand.h>
@@ -45,6 +46,14 @@ static bd_t bdata __attribute__ ((section(".data")));
  */
 __weak void show_boot_progress(int val) {}
 
+#if defined(CONFIG_SPL_OS_BOOT) || CONFIG_IS_ENABLED(HANDOFF)
+/* weak, default platform-specific function to initialize dram banks */
+__weak int dram_init_banksize(void)
+{
+	return 0;
+}
+#endif
+
 /*
  * Default function to determine if u-boot or the OS should
  * be started. This implementation always returns 1.
@@ -64,14 +73,6 @@ __weak int spl_start_uboot(void)
 	return 1;
 }
 
-/* weak default platform specific function to initialize
- * dram banks
- */
-__weak int dram_init_banksize(void)
-{
-	return 0;
-}
-
 /*
  * Weak default function for arch specific zImage check. Return zero
  * and fill start and end address if image is recognized.
@@ -320,6 +321,44 @@ __weak void __noreturn jump_to_image_no_args(struct spl_image_info *spl_image)
 	image_entry();
 }
 
+#if CONFIG_IS_ENABLED(HANDOFF)
+/**
+ * Set up the SPL hand-off information
+ *
+ * This is initially empty (zero) but can be written by
+ */
+static int setup_spl_handoff(void)
+{
+	struct spl_handoff *ho;
+
+	ho = bloblist_ensure(BLOBLISTT_SPL_HANDOFF, sizeof(struct spl_handoff));
+	if (!ho)
+		return -ENOENT;
+
+	return 0;
+}
+
+static int write_spl_handoff(void)
+{
+	struct spl_handoff *ho;
+
+	ho = bloblist_find(BLOBLISTT_SPL_HANDOFF, sizeof(struct spl_handoff));
+	if (!ho)
+		return -ENOENT;
+	handoff_save_dram(ho);
+#ifdef CONFIG_SANDBOX
+	ho->arch.magic = TEST_HANDOFF_MAGIC;
+#endif
+	debug(SPL_TPL_PROMPT "Wrote SPL handoff\n");
+
+	return 0;
+}
+#else
+static inline int setup_spl_handoff(void) { return 0; }
+static inline int write_spl_handoff(void) { return 0; }
+
+#endif /* HANDOFF */
+
 static int spl_common_init(bool setup_malloc)
 {
 	int ret;
@@ -355,6 +394,15 @@ static int spl_common_init(bool setup_malloc)
 			return ret;
 		}
 	}
+	if (CONFIG_IS_ENABLED(HANDOFF)) {
+		int ret;
+
+		ret = setup_spl_handoff();
+		if (ret) {
+			puts(SPL_TPL_PROMPT "Cannot set up SPL handoff\n");
+			hang();
+		}
+	}
 	if (CONFIG_IS_ENABLED(OF_CONTROL) && !CONFIG_IS_ENABLED(OF_PLATDATA)) {
 		ret = fdtdec_setup();
 		if (ret) {
@@ -503,10 +551,6 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
 
 	spl_set_bd();
 
-#ifdef CONFIG_SPL_OS_BOOT
-	dram_init_banksize();
-#endif
-
 #if defined(CONFIG_SYS_SPL_MALLOC_START)
 	mem_malloc_init(CONFIG_SYS_SPL_MALLOC_START,
 			CONFIG_SYS_SPL_MALLOC_SIZE);
@@ -528,6 +572,9 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
 	spl_board_init();
 #endif
 
+	if (IS_ENABLED(CONFIG_SPL_OS_BOOT) || CONFIG_IS_ENABLED(HANDOFF))
+		dram_init_banksize();
+
 	bootcount_inc();
 
 	memset(&spl_image, '\0', sizeof(spl_image));
@@ -544,6 +591,12 @@ void board_init_r(gd_t *dummy1, ulong dummy2)
 	}
 
 	spl_perform_fixups(&spl_image);
+	if (CONFIG_IS_ENABLED(HANDOFF)) {
+		ret = write_spl_handoff();
+		if (ret)
+			printf(SPL_TPL_PROMPT
+			       "SPL hand-off write failed (err=%d)\n", ret);
+	}
 	if (CONFIG_IS_ENABLED(BLOBLIST)) {
 		ret = bloblist_finish();
 		if (ret)
diff --git a/configs/sandbox_spl_defconfig b/configs/sandbox_spl_defconfig
index f44e80e8c3..452a2ef4a5 100644
--- a/configs/sandbox_spl_defconfig
+++ b/configs/sandbox_spl_defconfig
@@ -22,6 +22,7 @@ CONFIG_CONSOLE_RECORD=y
 CONFIG_CONSOLE_RECORD_OUT_SIZE=0x1000
 CONFIG_SILENT_CONSOLE=y
 CONFIG_DISPLAY_BOARDINFO_LATE=y
+CONFIG_HANDOFF=y
 CONFIG_SPL_BOARD_INIT=y
 CONFIG_SPL_ENV_SUPPORT=y
 CONFIG_CMD_CPU=y
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index ccf361ed88..dffd6b2602 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -125,6 +125,9 @@ typedef struct global_data {
 #if CONFIG_IS_ENABLED(BLOBLIST)
 	struct bloblist_hdr *bloblist;	/* Bloblist information */
 	struct bloblist_hdr *new_bloblist;	/* Relocated blolist info */
+# ifdef CONFIG_SPL
+	struct spl_handoff *spl_handoff;
+# endif
 #endif
 } gd_t;
 #endif
diff --git a/include/handoff.h b/include/handoff.h
new file mode 100644
index 0000000000..aacb0f5ebf
--- /dev/null
+++ b/include/handoff.h
@@ -0,0 +1,36 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+/*
+ * Passing basic information from SPL to U-Boot proper
+ *
+ * Copyright 2018 Google, Inc
+ */
+
+#ifndef __HANDOFF_H
+#define __HANDOFF_H
+
+#if CONFIG_IS_ENABLED(HANDOFF)
+
+#include <asm/handoff.h>
+
+/**
+ * struct spl_handoff - information passed from SPL to U-Boot proper
+ *
+ * @ram_size: Value to use for gd->ram_size
+ */
+struct spl_handoff {
+	struct arch_spl_handoff arch;
+	u64 ram_size;
+#ifdef CONFIG_NR_DRAM_BANKS
+	struct {
+		u64 start;
+		u64 size;
+	} ram_bank[CONFIG_NR_DRAM_BANKS];
+#endif
+};
+
+void handoff_save_dram(struct spl_handoff *ho);
+void handoff_load_dram_size(struct spl_handoff *ho);
+void handoff_load_dram_banks(struct spl_handoff *ho);
+#endif
+
+#endif
diff --git a/include/spl.h b/include/spl.h
index 205aaff4b9..ee92832f0a 100644
--- a/include/spl.h
+++ b/include/spl.h
@@ -11,6 +11,7 @@
 /* Platform-specific defines */
 #include <linux/compiler.h>
 #include <asm/spl.h>
+#include <handoff.h>
 
 /* Value in r0 indicates we booted from U-Boot */
 #define UBOOT_NOT_LOADED_FROM_SPL	0x13578642
diff --git a/test/py/tests/test_handoff.py b/test/py/tests/test_handoff.py
new file mode 100644
index 0000000000..0ee972298c
--- /dev/null
+++ b/test/py/tests/test_handoff.py
@@ -0,0 +1,15 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2016 Google, Inc
+
+import pytest
+
+# Magic number to check that SPL handoff is working
+TEST_HANDOFF_MAGIC = 0x14f93c7b
+
+@pytest.mark.boardspec('sandbox')
+@pytest.mark.buildconfigspec('spl')
+def test_handoff(u_boot_console):
+    """Test that of-platdata can be generated and used in sandbox"""
+    cons = u_boot_console
+    response = cons.run_command('sb handoff')
+    assert ('SPL handoff magic %x' % TEST_HANDOFF_MAGIC) in response
diff --git a/test/run b/test/run
index fb8ff5da0c..cd323b0a85 100755
--- a/test/run
+++ b/test/run
@@ -19,7 +19,7 @@ run_test "sandbox" ./test/py/test.py --bd sandbox --build
 
 # Run tests which require sandbox_spl
 run_test "sandbox_spl" ./test/py/test.py --bd sandbox_spl --build \
-	-k test_ofplatdata.py
+	-k 'test_ofplatdata or test_handoff'
 
 # Run tests for the flat-device-tree version of sandbox. This is a special
 # build which does not enable CONFIG_OF_LIVE for the live device tree, so we can