armv8: Add global variable resv_ram

Use gd->arch.resv_ram to track reserved memory allocation.

Signed-off-by: York Sun <york.sun@nxp.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/arm/cpu/armv8/fsl-layerscape/Kconfig

@@ -277,6 +277,16 @@ config SYS_FSL_SDHC_CLK_DIV
 	  clock, in another word SDHC_clk = Platform_clk / this_divider.
 endmenu
 
+config RESV_RAM
+	bool
+	help
+	  Reserve memory from the top, tracked by gd->arch.resv_ram. This
+	  reserved RAM can be used by special driver that resides in memory
+	  after U-Boot exits. It's up to implementation to allocate and allow
+	  access to this reserved memory. For example, the reserved RAM can
+	  be at the high end of physical memory. The reserve RAM may be
+	  excluded from memory bank(s) passed to OS, or marked as reserved.
+
 config SYS_FSL_ERRATUM_A008336
 	bool
 

arch/arm/include/asm/global_data.h

@@ -59,6 +59,13 @@ struct arch_global_data {
 	phys_addr_t secure_ram;
 	unsigned long tlb_allocated;
 #endif
+#ifdef CONFIG_RESV_RAM
+	/*
+	 * Reserved RAM for memory resident, eg. Management Complex (MC)
+	 * driver which continues to run after U-Boot exits.
+	 */
+	phys_addr_t resv_ram;
+#endif
 
 #ifdef CONFIG_ARCH_OMAP2
 	u32 omap_boot_device;

cmd/bdinfo.c

@@ -392,6 +392,10 @@ static int do_bdinfo(cmd_tbl_t *cmdtp, int flag, int argc,
 			  gd->arch.secure_ram & MEM_RESERVE_SECURE_ADDR_MASK);
 	}
 #endif
+#ifdef CONFIG_RESV_RAM
+	if (gd->arch.resv_ram)
+		print_num("Reserved ram", gd->arch.resv_ram);
+#endif
 #if defined(CONFIG_CMD_NET) && !defined(CONFIG_DM_ETH)
 	print_eths();
 #endif