Re: [U-Boot] [PATCH v2] smc911x driver frame alignment patch
Valentin, On 4/22/2010 10:40 PM, Valentin Yakovenkov wrote: SMSC911x chips have alignment function to allow frame payload data (which comes after 14-bytes ethernet header) to be aligned at some boundary when reading it from fifo (usually - 4 bytes boundary). This is done by inserting fake zeros bytes BEFORE actual frame data when reading from SMSC's fifo. This function controlled by RX_CFG register. There are bits that represents amount of fake bytes to be inserted. Linux uses alignment of 4 bytes. Ethernet frame header is 14 bytes long, so we need to add 2 fake bytes to get payload data aligned at 4-bytes boundary. Linux driver does this by adding IP_ALIGNMENT constant (defined at skb.h) when calculating fifo data length. All network subsystem of Linux uses this constant too when calculating different offsets. But u-boot does not use any packet data alignment, so we don't need to add anything when calculating fifo data length. Moreover, driver zeros the RX_CFG register just one line up, so chip does not insert any fake data at the beginig. So calculated data length is always bigger by 1 word. It seems that at almost every packet read we get an underflow condition at fifo and possible corruption of data. Especially at continuous transfers, such as tftp. Just after removing this magic addition, I've got tftp transfer speed as it aught to be at 100Mbps. It was really slow before. It seems that fifo underflow occurs only when using byte packing on 32-bit blackfin bus (may be because of very small delay between reads). Signed-off-by: Valentin Yakovenkovyakoven...@niistt.ru diff -r 7dc8ff189175 a/drivers/net/smc911x.c --- a/drivers/net/smc911x.c Mon Mar 29 11:08:55 2010 +0400 +++ b/drivers/net/smc911x.c Mon Apr 19 10:46:02 2010 +0400 @@ -220,7 +220,7 @@ smc911x_reg_write(dev, RX_CFG, 0); - tmplen = (pktlen + 2+ 3) / 4; + tmplen = (pktlen + 3) / 4; while (tmplen--) *data++ = pkt_data_pull(dev, RX_DATA_FIFO); -- WBR, Valentin CJSC NII STT, Russia, Smolensk http://www.niistt.ru Applied to net repo. thanks, Ben ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH v2] smc911x driver frame alignment patch
for future reference, you shouldnt put patch in the subject name ... i'm not referring to the leading [PATCH], but the trailing patch. also, i'm not sure if you're using `git send-email` because the trail of your patch is missing the --- marker: = It seems that fifo underflow occurs only when using byte packing on 32-bit blackfin bus (may be because of very small delay between reads). Signed-off-by: Valentin Yakovenkov yakoven...@niistt.ru diff -r 7dc8ff189175 a/drivers/net/smc911x.c --- a/drivers/net/smc911x.c Mon Mar 29 11:08:55 2010 +0400 = it should have been like: = It seems that fifo underflow occurs only when using byte packing on 32-bit blackfin bus (may be because of very small delay between reads). Signed-off-by: Valentin Yakovenkov yakoven...@niistt.ru --- diff -r 7dc8ff189175 a/drivers/net/smc911x.c --- a/drivers/net/smc911x.c Mon Mar 29 11:08:55 2010 +0400 = -mike signature.asc Description: This is a digitally signed message part. ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH v2] smc911x driver frame alignment patch
On Friday 23 April 2010 12:48:55 Valentin Yakovenkov wrote: I don't use git at all. We have mercurial master repo which is pulled from local SVN synced repo which is synchronized via svn with blackfin.uclinux.org. b.u.o offers git as well if that makes things easier to sync: http://blackfin.uclinux.org/git/ Is it so critical to make this patch via git? no, but it is important the patch format matches what git expects. so if you add the --- marker yourself after the s-o-b tag, that's fine. -mike signature.asc Description: This is a digitally signed message part. ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
Re: [U-Boot] [PATCH v2] smc911x driver frame alignment patch
23.04.2010 19:11, Mike Frysinger wrote: for future reference, you shouldnt put patch in the subject name ... i'm not referring to the leading [PATCH], but the trailing patch. ok, thanx also, i'm not sure if you're using `git send-email` because the trail of your patch is missing the --- marker: I don't use git at all. We have mercurial master repo which is pulled from local SVN synced repo which is synchronized via svn with blackfin.uclinux.org. This patch is a result of the hg diff smc911.x command with manually added signed-off-by line. Is it so critical to make this patch via git? -- WBR, Valentin CJSC NII STT, Russia, Smolensk http://www.niistt.ru smime.p7s Description: S/MIME Cryptographic Signature ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
[U-Boot] [PATCH v2] smc911x driver frame alignment patch
SMSC911x chips have alignment function to allow frame payload data (which comes after 14-bytes ethernet header) to be aligned at some boundary when reading it from fifo (usually - 4 bytes boundary). This is done by inserting fake zeros bytes BEFORE actual frame data when reading from SMSC's fifo. This function controlled by RX_CFG register. There are bits that represents amount of fake bytes to be inserted. Linux uses alignment of 4 bytes. Ethernet frame header is 14 bytes long, so we need to add 2 fake bytes to get payload data aligned at 4-bytes boundary. Linux driver does this by adding IP_ALIGNMENT constant (defined at skb.h) when calculating fifo data length. All network subsystem of Linux uses this constant too when calculating different offsets. But u-boot does not use any packet data alignment, so we don't need to add anything when calculating fifo data length. Moreover, driver zeros the RX_CFG register just one line up, so chip does not insert any fake data at the beginig. So calculated data length is always bigger by 1 word. It seems that at almost every packet read we get an underflow condition at fifo and possible corruption of data. Especially at continuous transfers, such as tftp. Just after removing this magic addition, I've got tftp transfer speed as it aught to be at 100Mbps. It was really slow before. It seems that fifo underflow occurs only when using byte packing on 32-bit blackfin bus (may be because of very small delay between reads). Signed-off-by: Valentin Yakovenkov yakoven...@niistt.ru diff -r 7dc8ff189175 a/drivers/net/smc911x.c --- a/drivers/net/smc911x.c Mon Mar 29 11:08:55 2010 +0400 +++ b/drivers/net/smc911x.c Mon Apr 19 10:46:02 2010 +0400 @@ -220,7 +220,7 @@ smc911x_reg_write(dev, RX_CFG, 0); - tmplen = (pktlen + 2+ 3) / 4; + tmplen = (pktlen + 3) / 4; while (tmplen--) *data++ = pkt_data_pull(dev, RX_DATA_FIFO); -- WBR, Valentin CJSC NII STT, Russia, Smolensk http://www.niistt.ru smime.p7s Description: S/MIME Cryptographic Signature ___ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
