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Re: LAN9218 driver porting problem
- From: "m mariga" <ma_ariga at yahoo dot co dot jp>
- To: <ecos-discuss at ecos dot sourceware dot org>
- Date: Sat, 13 Feb 2010 10:10:13 +0900
- Subject: Re: [ECOS] LAN9218 driver porting problem
- References: <0E16609F5F8D4816B13508E3EB01DB64@masahiro>
Hello,
In danger of calling off using eCos,
again I implore you to lend me your knowledge.
I am still studying your LAN91c111 driver.
I am stuck in fatham of it. Please help me.
I tried to dump cpd->rxpacket,len,sg_len variables in lan91cxx_RxEvent,and
sg_len in lan91cxx_recv like below.
And run nc_test_slave() test program. The result dropped me deeper into the
fatham.
lan91cxx_RxEvent(struct eth_drv_sc *sc)
{
|
stat = get_reg(sc, LAN91CXX_FIFO_PORTS);
// There is an Rx Packet ready
cpd->rxpacket = 0xff & (stat >> 8);
diag_printf("rxpacket=%x\n",cpd->rxpacket);
|
stat = get_data_short(sc);
len = get_data_short(sc);
len = len - 6; // minus header/footer words
diag_printf("len=%x\n",len);
(sc->funs->eth_drv->recv)(sc, len);
}
lan91cxx_recv(struct eth_drv_sc *sc, struct eth_drv_sg *sg_list, int sg_len)
{
|
diag_printf("sg_len=%x\n",sg_len);
}
Here is part of the result.
---
connection from 172.16.1.28.1226
rxpacket=0
len=5ea
sg_len=2
rxpacket=1
len=5ea
sg_len=2
rxpacket=2
len=5ea
sg_len=2
rxpacket=0
len=5ea
sg_len=2
rxpacket=1
len=5ea
sg_len=2
rxpacket=2
len=5a
sg_len=2
rxpacket=1
len=3c
sg_len=2
rxpacket=1
len=3c
sg_len=2
rxpacket=1
len=3c
sg_len=2
rxpacket=0
len=3c
sg_len=2
rxpacket=1
len=5ea
sg_len=2
rxpacket=0
len=5ea
sg_len=2
rxpacket=2
len=5ea
sg_len=2
rxpacket=3
len=5ea
sg_len=2
rxpacket=1
len=5a
sg_len=2
rxpacket=0
len=5ea
sg_len=2
rxpacket=0
len=5ea
sg_len=2
rxpacket=1
len=5ea
sg_len=2
---
My question is,why sg_len is always 2 in spite of len being different.
I know it is too difficult for me to understand your Scatter-Gather or
something,but I need to make it work with LAN9218.
Your LAN91c111 recv routine uses sg_len in whle loop and gather data into
sg_list from DATA_FIFO.
LAN9118/9218 has RX_Status_FIFO,RX_Data_FIFO seperately. RX_Status_FIFO
tells packet length.
We know packet number from calculating data count written in RX_Status_FIFO.
I consulted LAN9118 SMSC Linux sample driver.
Its recv routine is much easier to understand.
Its operation like below.
------------> |
| <While RX_Status_FIFO!=0>
| |
| alloc new packet to skb
| //update counters
| privateData->stats.rx_packets++;
| |
| copy data into new skb packet from RX_Data_FIFO
| |
--------------
I rather I would prefer to this, instead of using enigmatic sg_len to
receive data from FIFO.
In xxx_recv routine,if I ignored sg_len and I coded like SMSC Sample(of
course I use sg_list[i].buf instead of skb),do you think will it work
properly(or permissably) ?
What if there are mismatches between sg_len and data counts written in
RX_Status_FIFO ?
Please enlighten me.
m mariga
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