arm: Keep track of the tlb size as well as its location

It may be necessary to know where the TLB area ends as well as where it
starts. This allows board code to complete a secure memory erase without
destroying the page tables.
Signed-off-by: NGabe Black <gabeblack@google.com>
Signed-off-by: NSimon Glass <sjg@chromium.org>

arch/arm/include/asm/global_data.h

@@ -73,6 +73,7 @@ typedef	struct	global_data {
 	unsigned long	reloc_off;
 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
 	unsigned long	tlb_addr;
+	unsigned long	tlb_size;
 #endif
 	const void	*fdt_blob;	/* Our device tree, NULL if none */
 	void		**jt;		/* jump table */

arch/arm/lib/board.c

@@ -348,13 +348,14 @@ void board_init_f(ulong bootflag)
 
 #if !(defined(CONFIG_SYS_ICACHE_OFF) && defined(CONFIG_SYS_DCACHE_OFF))
 	/* reserve TLB table */
-	addr -= (4096 * 4);
+	gd->tlb_size = 4096 * 4;
+	addr -= gd->tlb_size;
 
 	/* round down to next 64 kB limit */
 	addr &= ~(0x10000 - 1);
 
 	gd->tlb_addr = addr;
-	debug("TLB table at: %08lx\n", addr);
+	debug("TLB table from %08lx to %08lx\n", addr, addr + gd->tlb_size);
 #endif
 
 	/* round down to next 4 kB limit */