[U-Boot] [PATCH v6 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. This is different from PRAM
used to reserve private memory. PRAM offers memory at the top
of u-boot memory, not necessarily the real end of memory for
systems with very large DDR. Using the end of memory simplifies
MMU setup and avoid memory fragmentation.

"bdinfo" command shows gd->secure_ram value if this memory is
marked as secured.

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

---

Changes in v6:
  Move cmd_bdinfo change into this patch
  Move flag macros and comments of secure_ram into this patch

Changes in v5: None
Changes in v4: None
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 +++++++++
 common/cmd_bdinfo.c               |    6 ++++++
 include/asm-generic/global_data.h |   14 ++++++++++++++
 4 files changed, 37 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/common/cmd_bdinfo.c b/common/cmd_bdinfo.c
index adda55a..deed6d8 100644
--- a/common/cmd_bdinfo.c
+++ b/common/cmd_bdinfo.c
@@ -382,6 +382,12 @@ static int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc,
 		print_num("-> size",	bd->bi_dram[i].size);
 	}
 
+#ifdef CONFIG_SYS_MEM_RESERVE_SECURE
+	if (gd->secure_ram & MEM_RESERVE_SECURE_SECURED) {
+		print_num("Secure ram",
+			  gd->secure_ram & MEM_RESERVE_SECURE_ADDR_MASK);
+	}
+#endif
 #if defined(CONFIG_CMD_NET) && !defined(CONFIG_DM_ETH)
 	print_eths();
 #endif
diff --git a/include/asm-generic/global_data.h b/include/asm-generic/global_data.h
index d0383f3..fc10528 100644
--- a/include/asm-generic/global_data.h
+++ b/include/asm-generic/global_data.h
@@ -58,6 +58,20 @@ 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
+#define MEM_RESERVE_SECURE_SECURED	0x1
+#define MEM_RESERVE_SECURE_MAINTAINED	0x2
+#define MEM_RESERVE_SECURE_ADDR_MASK	(~0x3)
+	/*
+	 * Secure memory addr
+	 * This variable needs maintenance if the RAM base is not zero,
+	 * or if RAM splits into non-consecutive banks. It also has a
+	 * flag indicating the secure memory is marked as secure by MMU.
+	 * Flags used: 0x1 secured
+	 *             0x2 maintained
+	 */
+	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