[U-Boot] [RFC PATCH v3 1/2] Reserve secure memory

[York Sun]

Secure memory is at the end of memory, separated and reserved
from OS,  tracked by gd->secure_ram. Secure memory can host
MMU tables, security monitor, etc.

Signed-off-by: York Sun <yorksun at freescale.com>

---

Changes in v3:
  Put ifdef around secure_ram
  Move defining CONFIG_SYS_MEM_RESERVE_SECURE to patch 2/2

Changes in v2:
  Do not use CONFIG_SYS_MEM_TOP_HIDE mechanism

Changes in v1:
  Initial patch.
  Depends on http://patchwork.ozlabs.org/patch/540248/

 README                            |    8 ++++++++
 common/board_f.c                  |    9 +++++++++
 include/asm-generic/global_data.h |    4 ++++
 3 files changed, 21 insertions(+)

diff --git a/README b/README
index ef8d437..61cbc82 100644
--- a/README
+++ b/README
@@ -3881,6 +3881,14 @@ Configuration Settings:
 		Scratch address used by the alternate memory test
 		You only need to set this if address zero isn't writeable
 
+- CONFIG_SYS_MEM_RESERVE_SECURE
+		If defined, the size of CONFIG_SYS_MEM_RESERVE_SECURE memory
+		is substracted from total RAM and won't be reported to OS.
+		This memory can be used as secure memory. A variable
+		gd->secure_ram is used to track the location. In systems
+		the RAM base is not zero, or RAM is divided into banks,
+		this variable needs to be recalcuated to get the address.
+
 - CONFIG_SYS_MEM_TOP_HIDE (PPC only):
 		If CONFIG_SYS_MEM_TOP_HIDE is defined in the board config header,
 		this specified memory area will get subtracted from the top
diff --git a/common/board_f.c b/common/board_f.c
index 725eb18..8061105 100644
--- a/common/board_f.c
+++ b/common/board_f.c
@@ -323,6 +323,15 @@ static int setup_dest_addr(void)
 	 * Ram is setup, size stored in gd !!
 	 */
 	debug("Ram size: %08lX\n", (ulong)gd->ram_size);
+#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
+	/* Reserve memory for secure MMU tables, and/or security monitor */
+	gd->ram_size -= CONFIG_SYS_MEM_RESERVE_SECURE;
+	/*
+	 * Record secure memory location. Need recalcuate if memory splits
+	 * into banks, or the ram base is not zero.
+	 */
+	gd->secure_ram = gd->ram_size;
+#endif
 #if defined(CONFIG_SYS_MEM_TOP_HIDE)
 	/*
 	 * Subtract specified amount of memory to hide so that it won't
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index d0383f3..8cdafd6 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -58,6 +58,10 @@ typedef struct global_data {
 
 	unsigned long relocaddr;	/* Start address of U-Boot in RAM */
 	phys_size_t ram_size;	/* RAM size */
+#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
+	/* Secure memory addr. LSB is a flag for "secured". */
+	phys_addr_t secure_ram;
+#endif
 	unsigned long mon_len;	/* monitor len */
 	unsigned long irq_sp;		/* irq stack pointer */
 	unsigned long start_addr_sp;	/* start_addr_stackpointer */
-- 
1.7.9.5