omap4: utility function to identify the context of hw init

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>
Signed-off-by: Sandeep Paulraj <s-paulraj@ti.com>

2 files changed, 82 insertions, 1 deletions

diff --git a/arch/arm/include/asm/arch-omap4/sys_proto.h b/arch/arm/include/asm/arch-omap4/sys_proto.h
index 4fa4f4b2d..6b596b489 100644
--- a/arch/arm/include/asm/arch-omap4/sys_proto.h
+++ b/arch/arm/include/asm/arch-omap4/sys_proto.h
@@ -23,10 +23,12 @@
 
 #include <asm/arch/omap4.h>
 #include <asm/io.h>
+#include <asm/omap_common.h>
 
 struct omap_sysinfo {
 	char *board_string;
 };
+extern const struct omap_sysinfo sysinfo;
 
 void gpmc_init(void);
 void watchdog_init(void);
@@ -37,6 +39,51 @@ u32 wait_on_value(u32, u32, void *, u32);
 void sdelay(unsigned long);
 void set_pl310_ctrl_reg(u32 val);
 
-extern const struct omap_sysinfo sysinfo;
+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 at 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_SPL_BUILD
+	return OMAP_INIT_CONTEXT_SPL;
+#else
+	if (uboot_loaded_by_spl())
+		return OMAP_INIT_CONTEXT_UBOOT_AFTER_SPL;
+	else if (running_from_sdram())
+		return OMAP_INIT_CONTEXT_UBOOT_AFTER_CH;
+	else
+		return OMAP_INIT_CONTEXT_UBOOT_FROM_NOR;
+#endif
+}
 
 #endif
diff --git a/arch/arm/include/asm/omap_common.h b/arch/arm/include/asm/omap_common.h
new file mode 100644
index 000000000..d80f66507
--- /dev/null
+++ b/arch/arm/include/asm/omap_common.h
@@ -0,0 +1,34 @@
+/*
+ * (C) Copyright 2010
+ * Texas Instruments, <www.ti.com>
+ *
+ * Aneesh V <aneesh@ti.com>
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+#ifndef	_OMAP_COMMON_H_
+#define	_OMAP_COMMON_H_
+
+/* HW Init Context */
+#define OMAP_INIT_CONTEXT_SPL			0
+#define OMAP_INIT_CONTEXT_UBOOT_FROM_NOR	1
+#define OMAP_INIT_CONTEXT_UBOOT_AFTER_SPL	2
+#define OMAP_INIT_CONTEXT_UBOOT_AFTER_CH	3
+
+#endif /* _OMAP_COMMON_H_ */