[U-Boot] [PATCH 12/22] omap4: utility function to identify the context of hw init

Aneesh V
2011-02-28T11:46:21Z

The basic hardware init of OMAP4(s_init()) can happen in 4
different contexts:
1. SPL running from SRAM
2. U-Boot running from FLASH
3. Non-XIP U-Boot loaded to SDRAM by SPL
4. Non-XIP U-Boot loaded to SDRAM by ROM code using the
Configuration Header feature

What level of hw initialization gets done depends on this
context. Add a utility function to find this context.

Signed-off-by: Aneesh V <aneesh@ti.com>
---
arch/arm/include/asm/arch-omap4/sys_proto.h | 47 +++++++++++++++++++++++++++
arch/arm/include/asm/omap_common.h | 6 +++
2 files changed, 53 insertions(+), 0 deletions(-)

diff --git a/arch/arm/include/asm/arch-omap4/sys_proto.h b/arch/arm/include/asm/arch-omap4/sys_proto.h
index ce86b36..19da2e1 100644
--- a/arch/arm/include/asm/arch-omap4/sys_proto.h
+++ b/arch/arm/include/asm/arch-omap4/sys_proto.h
@@ -38,6 +38,53 @@ void sr32(void *, u32, u32, u32);
u32 wait_on_value(u32, u32, void *, u32);
void sdelay(unsigned long);

+static inline u32 running_from_sdram(void)
+{
+ u32 pc;
+ asm volatile ("mov %0, pc" : "=r" (pc));
+ return ((pc >= OMAP44XX_DRAM_ADDR_SPACE_START) &&
+ (pc < OMAP44XX_DRAM_ADDR_SPACE_END));
+}
+
+static inline u8 uboot_loaded_by_spl(void)
+{
+ /*
+ * Configuration Header is not supported yet, so u-boot init running
+ * from SDRAM implies that it was loaded by SPL. When this situation
+ * changes one of these approaches could be taken:
+ * i. Pass a magic from SPL to U-Boot and U-Boot save it at a known
+ * location.
+ * ii. Check the OPP. CH can support only 50% OPP while SPL initializes
+ * the DPLLs@100% OPP.
+ */
+ return running_from_sdram();
+}
+/*
+ * The basic hardware init of OMAP(s_init()) can happen in 4
+ * different contexts:
+ * 1. SPL running from SRAM
+ * 2. U-Boot running from FLASH
+ * 3. Non-XIP U-Boot loaded to SDRAM by SPL
+ * 4. Non-XIP U-Boot loaded to SDRAM by ROM code using the
+ * Configuration Header feature
+ *
+ * This function finds this context.
+ * Defining as inline may help in compiling out unused functions in SPL
+ */
+static inline u32 omap4_hw_init_context(void)
+{
+#ifdef CONFIG_PRELOADER
+ return OMAP_INIT_CONTEXT_SPL;
+#else
+ if (uboot_loaded_by_spl())
+ return OMAP_INIT_CONTEXT_UBOOT_LOADED_BY_SPL;
+ else if (running_from_sdram())
+ return OMAP_INIT_CONTEXT_UBOOT_LOADED_BY_CH;
+ else
+ return OMAP_INIT_CONTEXT_XIP_UBOOT;
+#endif
+}
+
extern const struct omap_sysinfo sysinfo;

#endif
diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h
index 95116f4..50247af 100644
--- a/arch/arm/include/asm/omap_common.h
+++ b/arch/arm/include/asm/omap_common.h
@@ -65,6 +65,12 @@
/* Magic number passed from SPL to U-Boot */
#define OMAP_SPL_TO_UBOOT_MAGIC_NUMBER 0xDEADBEEF

+/* HW Init Context */
+#define OMAP_INIT_CONTEXT_SPL 0
+#define OMAP_INIT_CONTEXT_XIP_UBOOT 1
+#define OMAP_INIT_CONTEXT_UBOOT_LOADED_BY_SPL 2
+#define OMAP_INIT_CONTEXT_UBOOT_LOADED_BY_CH 3
+
u32 omap_boot_device(void);
u32 omap_boot_mode(void);
void preloader_console_init(void);
--
1.7.0.4