我今天买了块tiny210v2的开发板，接了串口启动了以后看内存怎么是397M，不是512M？
请问这正常吗？
free的输出如下
total used free shared buffers
Mem: 393592 372300 21292 0 0
dmesg的输出如下
/tmp # dmesg|more
<6>[ 0.000000] Initializing cgroup subsys cpu
<5>[ 0.000000] Linux version 3.0.8-FriendlyARM (
root@friendlyarm.tzs) (gcc version 4.5.1 (ctng-1.8.1-FA) ) #1 PREEMPT Sat Oct 27 15:57:19 CST 2012
<4>[ 0.000000] CPU: ARMv7 Processor [412fc082] revision 2 (ARMv7), cr=10c53c7f
<4>[ 0.000000] CPU: VIPT nonaliasing data cache, VIPT aliasing instruction cache
<4>[ 0.000000] Machine: MINI210
<4>[ 0.000000] MINI210: S70 selected
<4>[ 0.000000] Memory policy: ECC disabled, Data cache writeback
<4>[ 0.000000] CPU S5PV210/S5PC110 (id 0x43110220)
<7>[ 0.000000] s5pv210_init_clocks: initializing clocks
<6>[ 0.000000] S3C24XX Clocks, Copyright 2004 Simtec Electronics
<7>[ 0.000000] s5pv210_setup_clocks: registering clocks
<7>[ 0.000000] s5pv210_setup_clocks: clkdiv0 = 14131440, clkdiv1 = 00000400
<7>[ 0.000000] s5pv210_setup_clocks: xtal is 24000000
<6>[ 0.000000] S5PV210: PLL settings, A=1000000000, M=667000000, E=80000000 V=54000000
<6>[ 0.000000] S5PV210: ARMCLK=1000000000, HCLKM=200000000, HCLKD=166750000
<6>[ 0.000000] HCLKP=133400000, PCLKM=100000000, PCLKD=83375000, PCLKP=66700000
<6>[ 0.000000] sclk_dmc: source is sclk_a2m (0), rate is 200000000
<6>[ 0.000000] sclk_onenand: source is hclk_dsys (1), rate is 166750000
<6>[ 0.000000] uclk1: source is mout_mpll (6), rate is 66700000
<6>[ 0.000000] uclk1: source is mout_mpll (6), rate is 66700000
<6>[ 0.000000] uclk1: source is mout_mpll (6), rate is 66700000
<6>[ 0.000000] uclk1: source is mout_mpll (6), rate is 66700000
<6>[ 0.000000] sclk_mixer: source is sclk_dac (0), rate is 54000000
<6>[ 0.000000] sclk_fimc: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_fimc: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_fimc: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_cam0: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_cam1: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_fimd: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_mmc: source is mout_epll (7), rate is 80000000
<6>[ 0.000000] sclk_mmc: source is mout_epll (7), rate is 80000000
<6>[ 0.000000] sclk_mmc: source is mout_epll (7), rate is 80000000
<6>[ 0.000000] sclk_mmc: source is mout_epll (7), rate is 80000000
<6>[ 0.000000] sclk_mfc: source is sclk_a2m (0), rate is 200000000
<6>[ 0.000000] sclk_g2d: source is sclk_a2m (0), rate is 200000000
<6>[ 0.000000] sclk_g3d: source is sclk_a2m (0), rate is 200000000
<6>[ 0.000000] sclk_csis: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_spi: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_spi: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_pwi: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] sclk_pwm: source is ext_xtal (0), rate is 24000000
<6>[ 0.000000] s5p: 36864 kbytes system memory reserved for mfc at 0x2dc00000, 0-bank base(0x2dc00000)
<6>[ 0.000000] s5p: 36864 kbytes system memory reserved for mfc at 0x3dbf5000, 1-bank base(0x3dbf5000)
<6>[ 0.000000] s5p: 6144 kbytes system memory reserved for fimc0 at 0x3d5f5000, 1-bank base(0x3d5f5000)
<6>[ 0.000000] s5p: 16 kbytes system memory reserved for fimc1 at 0x3d5f1000, 1-bank base(0x3d5f1000)
<6>[ 0.000000] s5p: 6144 kbytes system memory reserved for fimc2 at 0x3cff1000, 1-bank base(0x3cff1000)
<6>[ 0.000000] s5p: 8192 kbytes system memory reserved for jpeg at 0x2d400000, 0-bank base(0x2d400000)
<6>[ 0.000000] s5p: 13060 kbytes system memory reserved for fimd at 0x3c330000, 1-bank base(0x3c330000)
<6>[ 0.000000] s5p: 8192 kbytes system memory reserved for g2d at 0x2cc00000, 0-bank base(0x2cc00000)
<6>[ 0.000000] s5p: 1800 kbytes system memory reserved for pmem_gpu1 at 0x2ca3e000, 0-bank base(0x2ca3e000)
<7>[ 0.000000] On node 0 totalpages: 101753
<7>[ 0.000000] Normal zone: 1024 pages used for memmap
<7>[ 0.000000] Normal zone: 0 pages reserved
<7>[ 0.000000] Normal zone: 100729 pages, LIFO batch:31
<7>[ 0.000000] pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
<7>[ 0.000000] pcpu-alloc: [0] 0
<4>[ 0.000000] Built 1 zonelists in Zone order, mobility grouping on. Total pages: 100729
<5>[ 0.000000] Kernel command line: root=/dev/mtdblock4 rootfstype=yaffs2 console=ttySAC0,115200 init=/linuxrc androidboot.console=ttySAC0 skipcali=yes ctp=3 lcd=S70
<6>[ 0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
<6>[ 0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
<6>[ 0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
<6>[ 0.000000]
Memory: 202MB 195MB 0MB = 397MB total<5>[ 0.000000] Memory: 392140k/509416k available, 14872k reserved, 0K highmem
<5>[ 0.000000] Virtual kernel memory layout:
<5>[ 0.000000] vector : 0xffff0000 - 0xffff1000 ( 4 kB)
<5>[ 0.000000] fixmap : 0xfff00000 - 0xfffe0000 ( 896 kB)
<5>[ 0.000000] DMA : 0xff000000 - 0xffe00000 ( 14 MB)
<5>[ 0.000000] vmalloc : 0xe0800000 - 0xfd000000 ( 456 MB)
<5>[ 0.000000] lowmem : 0xc0000000 - 0xe0000000 ( 512 MB)
<5>[ 0.000000] modules : 0xbf000000 - 0xc0000000 ( 16 MB)
<5>[ 0.000000] .init : 0xc0008000 - 0xc0173000 (1452 kB)
<5>[ 0.000000] .text : 0xc0173000 - 0xc086d754 (7146 kB)
<5>[ 0.000000] .data : 0xc086e000 - 0xc08c6540 ( 354 kB)
<5>[ 0.000000] .bss : 0xc08c6564 - 0xc0a0b660 (1301 kB)
<6>[ 0.000000] SLUB: Genslabs=11, HWalign=64, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
<6>[ 0.000000] Preemptible hierarchical RCU implementation.
<6>[ 0.000000] NR_IRQS:393
