Hello,
for learning device drivers I took 8139too.c to explore it. I disrupted the
code into several logical blocks and now I'm trying to implement my own
simplified version referring to original code from time to time. I have
rtl8139d NIC for experiments. So, by now I've acomplished the following
stages:
1) detected device
2) enable PCI device
3) memory mapped IO initialised
4) initialization of 'net_device' structure
And I'm stuck on the chip reset. Whenever I load driver and try to enable
interface (ifconfig eth1 up) my system just hangs, keyboard locks up, I
can't even use 'SysRq' shortcuts.
I figured out that problem occurs after I initialised chip, i.e. in this
routine called from 'net_device->open' method:
#define CmdTxEnb (0x04)
...
#define RxOK (0x01)
#define RxErr (0x02)
#define TxOK (0x04)
#define TxErr (0x08)
#define RxOverFlow (0x10)
#define RxUnderrun (0x20)
#define RxFIFOOver (0x40)
#define CableLen (0x2000)
#define TimeOut (0x4000)
#define SysErr (0x8000)
#define INT_MASK (RxOK | RxErr | TxOK | TxErr | RxOverFlow | \
RxUnderrun | RxFIFOOver | CableLen |
TimeOut | SysErr)
static void rtl8139_hw_start(struct net_device *dev)
{
struct rtl8139_private *tp = dev->priv;
void *ioaddr = tp->mmio_addr;
...
writeb(CmdTxEnb, ioaddr + REG_COMMAND);
writel(0x00000600, ioaddr + REG_TX_CONFIG); /* DMA burst size 1024 */
/* init TX buffer DMA addresses */
for (i = 0; i < NUM_TX_DESC; i++) {
writel(tp->tx_bufs_dma + (tp->tx_buf[i] - tp->tx_bufs), ioaddr +
REG_TX_ADDR0 + (i * 4));
}
/* enable all known interrupts by setting the interrupt mask */
writew(INT_MASK, ioaddr + REG_INTR_MASK);
netif_start_queue(dev);
return;
}
static int rtl8139_open(struct net_device *dev)
{
int retval;
struct rtl8139_private *tp = dev->priv;
...
retval = request_irq(dev->irq, rtl8139_interrupt, 0, dev->name, dev);
if (retval)
return retval;
/* Get memory for TX buffers. Memory must be DMA-able */
tp->tx_bufs = pci_alloc_consistent(tp->pci_dev, TOTAL_TX_BUF_SIZE,
&tp->tx_bufs_dma);
...
rtl8139_init_ring(dev);
rtl8139_hw_start(dev);
DPRINTK("init_ring() & hw_start() passed\n");
return;
}
rtl8139_hw_start() is really invoked and returned, since I'm getting printk
output. Commenting 'rtl8139_hw_start(dev);' out brings the interface up
succesfully, that's why I came to conclusion the problem is in chip
initialization routine.
If anybody has any clue, I'd appreciate to hear it and get advice.
Thanks in advance.
--
Roman Mashak
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