U-boot用tftp命令直接烧写到NandFlash V3.0
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版本：v3.0
功能：给计数器做了清零，解决Retry count exceeded; starting again 的问题。发现的新问题，并解决了。现在可以把一个200多k的直接烧写到Nand中了。
不足：可以进一步考虑 Yaffs2文件系统的直接烧写。不过只会分析一下。
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１、定义一块tftp_nand_buffer[2048]；
２、每次store_block调用的时候，首先从tftp_nand_buffer[(tftp_nand_counter & 1) << 10]开始拷贝数据；
３、nand_write_skip_bad(nand, off, &length, buffer);
nand_write_skip_bad:
nand :
off :写入flash的位置(off + ((tftp_nand_counter-1)*1024)) //里边的off为0.
length：数据长度，为2048
buffer: 数据位置 tftp_nand_buffer
解决tftp_nand_counter清零的问题，改动如下：
diff -ru 6Ubootnand/include/net.h 7UbootTftp/include/net.h--- 6Ubootnand/include/net.h 2013-03-10 20:45:12.500500278 +0800+++ 7UbootTftp/include/net.h 2013-03-15 13:33:42.959027263 +0800@@ -54,7 +54,9 @@#include <asm/byteorder.h> /* for nton* / ntoh* stuff */-+#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP+extern ulong tftp_nand_counter ;+#endif/** The number of receive packet buffers, and the required packet buffer* alignment in memory.
diff -ru 6Ubootnand/common/cmd_net.c 7UbootTftp/common/cmd_net.c--- 6Ubootnand/common/cmd_net.c 2013-03-10 20:45:12.432500274 +0800+++ 7UbootTftp/common/cmd_net.c 2013-03-15 13:39:17.334305199 +0800@@ -159,6 +159,11 @@int size;ulong addr;+#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP+ tftp_nand_counter = 0;+#endif+ //add by kangear for tftp nand+/* pre-set load_addr */if ((s = getenv("loadaddr")) != NULL) {load_addr = simple_strtoul(s, NULL, 16);
解决Retry count exceeded; starting again 的问题，改动如下：
diff -ru 6Ubootnand/include/configs/smdk2440.h 7UbootTftp/include/configs/smdk2440.h--- 6Ubootnand/include/configs/smdk2440.h
2013-03-15 14:27:48.982175390 +0800+++ 7UbootTftp/include/configs/smdk2440.h
2013-03-15 12:29:45.197981641 +0800@@ -59,7 +59,7 @@//#define CONFIG_CS8900_BUS16
/* the Linux driver does accesses as shorts */#define CONFIG_NET_MULTI
1-#define CONFIG_NET_RETRY_COUNT 20+#define CONFIG_NET_RETRY_COUNT 100 //20 kangear for tftp to nand#define CONFIG_DRIVER_DM9000
1 /* we have a dm9000 on-board */#define CONFIG_DM9000_BASE
0x20000000#define DM9000_IO
CONFIG_DM9000_BASE@@ -76,13 +76,11 @@#define CONFIG_ASM_DEBUG 1
/* we use SERIAL 1 on SMDK2410 */#define CONFIG_SKIP_LOWLEVEL_INIT 1#define CONFIG_SKIP_RELOCATE_UBOOT 1-/*- * boot size+ * tftp 烧写到flash中*/-#define CONFIG_UBOOT_SIZE (CONFIG_ENV_ADDR-0)--+#define CONFIG_SYS_DIRECT_FLASH_TFTP 1+#define CONFIG_TFTP_BLOCKSIZE 1024
算法的优化为这样的：
diff -ru 6Ubootnand/net/tftp.c 7UbootTftp/net/tftp.c--- 6Ubootnand/net/tftp.c 2013-03-10 20:45:12.448500276 +0800+++ 7UbootTftp/net/tftp.c 2013-03-15 14:13:35.915403248 +0800@@ -9,6 +9,11 @@#include <net.h>#include "tftp.h"#include "bootp.h"+#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP+#include <nand.h>+ulong tftp_nand_counter = 0;+static u_char tftp_nand_buffer[2048];+#endif#if defined(CONFIG_CMD_NET)@@ -131,7 +136,11 @@ulong newsize = offset + len;#ifdef CONFIG_SYS_DIRECT_FLASH_TFTPint i, rc = 0;-+ int data_end_flag = 0;+ nand_info_t *nand;+ loff_t off = 0;+ size_t length;+ u_char *buffer;for (i=0; i<CONFIG_SYS_MAX_FLASH_BANKS; i++) {/* start address in flash? */if (flash_info[i].flash_id == FLASH_UNKNOWN)@@ -142,19 +151,44 @@}}- if (rc) { /* Flash is destination for this packet */- rc = flash_write ((char *)src, (ulong)(load_addr+offset), len);+ nand = &nand_info[nand_curr_device];+ off = (tftp_nand_counter-1)*1024;+ length = 2048;+ memcpy((uchar *)(tftp_nand_buffer+((tftp_nand_counter & 1) << 10)), (uchar *)src, 1024);+ //memcpy((uchar *)tftp_nand_buffer[(tftp_nand_counter & 1) << 10], (uchar *)src, 1024);+ buffer = (u_char *)tftp_nand_buffer;+ printf("\nlen = %d, tftp_nand_counter = %d", len, tftp_nand_counter);+ if(len < 1024)+ {+ data_end_flag = 1; //不足1k的。+ if (0 == tftp_nand_counter)+ tftp_nand_counter = 1;+ else if(0 == (tftp_nand_counter & 1)) //在偶数次正好结束的。+ {+ buffer = (u_char *)src;+ off = tftp_nand_counter*1024;+ }+ }+ if ( rc && ( data_end_flag || (0 != (tftp_nand_counter & 1))) ) { /* Flash is destination for this packet */+ rc = nand_write_skip_bad(nand, off, &length, buffer);+ //printf("\nhaha\n");if (rc) {flash_perror (rc);NetState = NETLOOP_FAIL;return;}+}else#endif /* CONFIG_SYS_DIRECT_FLASH_TFTP */{(void)memcpy((void *)(load_addr + offset), src, len);}++#ifdef CONFIG_SYS_DIRECT_FLASH_TFTP+ tftp_nand_counter ++;+#endif /* CONFIG_SYS_DIRECT_FLASH_TFTP */+#ifdef CONFIG_MCAST_TFTPif (Multicast)ext2_set_bit(block, Bitmap);
另外：烧写内核（4.XM）还是会出现：
len = 1024, tftp_nand_counter = 398len = 1024, tftp_nand_counter = 399Retry count exceeded; starting againdm9000 i/o: 0x20000000, id: 0x90000a46DM9000: running in 16 bit modeMAC: 00:01:02:03:04:05operating at 100M full duplex modeAbortSMDK2440 #
解决方法和上边的应该还是同样的，加大CONFIG_NET_RETRY_COUNT应该就能解决。