doc: README.SPL: adjust for Kbuild and Kconfig

Reflect the latest build system to doc/README.SPL. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>

doc: README.SPL: adjust for Kbuild and Kconfig
Reflect the latest build system to doc/README.SPL. Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Masahiro Yamada · Tom Rini
1 parent e8e6d2a990
Showing 1 changed file with 6 additions and 22 deletions Side-by-side Diff
doc/README.SPL
@@ -13,35 +13,30 @@
 How it works
 ------------
  
-There is a new directory $(srctree)/spl which contains only a Makefile.
-The object files are built separately for SPL and placed in this directory.
+The object files for SPL are built separately and placed in the "spl" directory.
 The final binaries which are generated are u-boot-spl, u-boot-spl.bin and
 u-boot-spl.map.
  
-During the SPL build a variable named CONFIG_SPL_BUILD is exported
-in the make environment and also appended to CPPFLAGS with -DCONFIG_SPL_BUILD.
+A config option named CONFIG_SPL_BUILD is enabled by Kconfig for SPL.
 Source files can therefore be compiled for SPL with different settings.
-ARM-based boards have previously used the option CONFIG_PRELOADER for it.
  
 For example:
  
 ifeq ($(CONFIG_SPL_BUILD),y)
-COBJS-y += board_spl.o
+obj-y += board_spl.o
 else
-COBJS-y += board.o
+obj-y += board.o
 endif
  
-COBJS-$(CONFIG_SPL_BUILD) += foo.o
+obj-$(CONFIG_SPL_BUILD) += foo.o
  
 #ifdef CONFIG_SPL_BUILD
 	foo();
 #endif
  
  
-The building of SPL images can be with:
+The building of SPL images can be enabled by CONFIG_SPL option in Kconfig.
  
-#define CONFIG_SPL 1
-
 Because SPL images normally have a different text base, one has to be
 configured by defining CONFIG_SPL_TEXT_BASE. The linker script has to be
 defined with CONFIG_SPL_LDSCRIPT.
@@ -69,17 +64,6 @@
 CONFIG_SPL_SPI_LOAD (drivers/mtd/spi/spi_spl_load.o)
 CONFIG_SPL_RAM_DEVICE (common/spl/spl.c)
 CONFIG_SPL_WATCHDOG_SUPPORT (drivers/watchdog/libwatchdog.o)
-
-Normally CPU is assumed to be the same between the SPL and normal
-u-boot build.  However it is possible to specify a different CPU for
-the SPL build for cases where the SPL is expected to run on a
-different CPU model from the main u-boot.  This is done by specifying
-an SPL CPU in boards.cfg as follows:
-
-	normal_cpu:spl_cpu
-
-This case CPU will be set to "normal_cpu" during the main u-boot
-build and "spl_cpu" during the SPL build.
  
  
 Debugging
...	...	@@ -13,35 +13,30 @@
13	13	How it works
14	14	------------
15	15
16		-There is a new directory $(srctree)/spl which contains only a Makefile.
17		-The object files are built separately for SPL and placed in this directory.
	16	+The object files for SPL are built separately and placed in the "spl" directory.
18	17	The final binaries which are generated are u-boot-spl, u-boot-spl.bin and
19	18	u-boot-spl.map.
20	19
21		-During the SPL build a variable named CONFIG_SPL_BUILD is exported
22		-in the make environment and also appended to CPPFLAGS with -DCONFIG_SPL_BUILD.
	20	+A config option named CONFIG_SPL_BUILD is enabled by Kconfig for SPL.
23	21	Source files can therefore be compiled for SPL with different settings.
24		-ARM-based boards have previously used the option CONFIG_PRELOADER for it.
25	22
26	23	For example:
27	24
28	25	ifeq ($(CONFIG_SPL_BUILD),y)
29		-COBJS-y += board_spl.o
	26	+obj-y += board_spl.o
30	27	else
31		-COBJS-y += board.o
	28	+obj-y += board.o
32	29	endif
33	30
34		-COBJS-$(CONFIG_SPL_BUILD) += foo.o
	31	+obj-$(CONFIG_SPL_BUILD) += foo.o
35	32
36	33	#ifdef CONFIG_SPL_BUILD
37	34	foo();
38	35	#endif
39	36
40	37
41		-The building of SPL images can be with:
	38	+The building of SPL images can be enabled by CONFIG_SPL option in Kconfig.
42	39
43		-#define CONFIG_SPL 1
44		-
45	40	Because SPL images normally have a different text base, one has to be
46	41	configured by defining CONFIG_SPL_TEXT_BASE. The linker script has to be
47	42	defined with CONFIG_SPL_LDSCRIPT.
...	...	@@ -69,17 +64,6 @@
69	64	CONFIG_SPL_SPI_LOAD (drivers/mtd/spi/spi_spl_load.o)
70	65	CONFIG_SPL_RAM_DEVICE (common/spl/spl.c)
71	66	CONFIG_SPL_WATCHDOG_SUPPORT (drivers/watchdog/libwatchdog.o)
72		-
73		-Normally CPU is assumed to be the same between the SPL and normal
74		-u-boot build. However it is possible to specify a different CPU for
75		-the SPL build for cases where the SPL is expected to run on a
76		-different CPU model from the main u-boot. This is done by specifying
77		-an SPL CPU in boards.cfg as follows:
78		-
79		- normal_cpu:spl_cpu
80		-
81		-This case CPU will be set to "normal_cpu" during the main u-boot
82		-build and "spl_cpu" during the SPL build.
83	67
84	68
85	69	Debugging