bge(4) one packet wedge

[David Christensen]

> > > Could you please answer few questions?
> > > 
> > > 1) I've found status tag is returned in status block even if 
> > > bit 9 of Misc.
> > >    Host Control Register is not set, is it ok?
> > 
> > Which controller are you using?  This bit is reserved on the 5700
> > (which didn't support tagged status mode) but all other controllers
> > should support it and all of the Broadcom drivers will always
> > enable it.
> 
> I tested it on bcm5701 & bcm5721
> 
> > 
> > > 
> > > 2) Status tag is returned in bits 0-7 of status tag field of 
> > > status block,
> > >    as long as i know it should be returned in bits 31-24, 
> is it ok?
> > 
> > Not sure what you mean by this.  If you're seeing it in bits 31-24
> > of the status block then there may be an endian issue on 
> your system.
> > Check that byte/word swapping is set correctly.
> > 
> > > 
> > > 3) If i try to return processed tag (at the end of ISR) in 
> > > Mailbox 0 register:
> > >    CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, status_tag << 24);
> > >    it would lead to disabled interrupts.
> > >    I've thought this should not happen cause in_isr bits 
> > > (0-23) are cleared.
> > 
> > Writing a non-zero value to bits 23:0 will cause the interrupt to
> > be disabled:
> > 
> > CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, 1);
> > 
> > Writing all zeros to bits 23:0 will enable interrupts.
> > 
> > CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, status_tag << 24);
> > 
> > The tag value written to bits 31:24 does not affect the interrupt
> > state.
> 
> Yes, this is i'm talking about:
> CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, 0x01000000) would lead to _disabled_
> interrupts.
> Tested on bcm5701 & bcm5721.

Here's how it's done in Linux:

static void tg3_disable_ints(struct tg3 *tp)
{
	tw32(TG3PCI_MISC_HOST_CTRL,
	     (tp->misc_host_ctrl | MISC_HOST_CTRL_MASK_PCI_INT));
	tw32_mailbox_f(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW,
0x00000001);
}

static void tg3_enable_ints(struct tg3 *tp)
{
	tp->irq_sync = 0;
	wmb();

	tw32(TG3PCI_MISC_HOST_CTRL,
	     (tp->misc_host_ctrl & ~MISC_HOST_CTRL_MASK_PCI_INT));
	tw32_mailbox_f(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW,
		       (tp->last_tag << 24));
	if (tp->tg3_flags2 & TG3_FLG2_1SHOT_MSI)
		tw32_mailbox_f(MAILBOX_INTERRUPT_0 + TG3_64BIT_REG_LOW,
			       (tp->last_tag << 24));
	tg3_cond_int(tp);
}

> 
> P.S. bcm5705 does not support tagged status mode, am i right?

No, the 5705 should support tagged status mode, only the 5788 doesn't
support it.  The 5705 and 5788 are very closely related though.

> -- 
> Oleg.