27.05.2014 19:08, Alan Stern пишет:
> On Tue, 27 May 2014, Nikita Yushchenko wrote:
>
>> This access causes hang on Freescale P2020DS board (that has OHCI
>> provided by ULI 1533 chip).
>
> Which access, the read or the write?
things are a bit more complex.
If inserting printk's as below
--- a/drivers/usb/host/pci-quirks.c
+++ b/drivers/usb/host/pci-quirks.c
@@ -619,16 +619,23 @@ static void quirk_usb_handoff_ohci(struct pci_dev *pdev)
}
/* software reset of the controller, preserving HcFmInterval */
+ printk("A1\n");
fminterval = readl(base + OHCI_FMINTERVAL);
+ printk("A2\n");
writel(OHCI_HCR, base + OHCI_CMDSTATUS);
+ printk("A3\n");
/* reset requires max 10 us delay */
for (cnt = 30; cnt > 0; --cnt) { /* ... allow extra time */
+ printk("A4\n");
if ((readl(base + OHCI_CMDSTATUS) & OHCI_HCR) == 0)
break;
+ printk("A5\n");
udelay(1);
}
+ printk("A6\n");
writel(fminterval, base + OHCI_FMINTERVAL);
+ printk("A7\n");
/* Now the controller is safely in SUSPEND and nothing can wake it up */
iounmap(base);
attempt to boot (using arch/powerpc/configs/mpc85xx_smp_defconfig and deb
file built by "make p2020ds.dtb" from the same kernel tree) results in
...
A1
random: nonblocking pool is initialized
irq 26: nobody cared (try booting with the "irqpoll" option)
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.15.0-rc6-dirty #5
Call Trace:
[effe5ed0] [c000726c] show_stack+0x48/0x15c (unreliable)
[effe5f10] [c05eece4] dump_stack+0x78/0xa0
[effe5f20] [c0087acc] __report_bad_irq+0x38/0x100
[effe5f40] [c0088060] note_interrupt+0x224/0x280
[effe5f70] [c008563c] handle_irq_event_percpu+0xc8/0x178
[effe5fa0] [c0085730] handle_irq_event+0x44/0x74
[effe5fc0] [c0088f88] handle_fasteoi_irq+0xd4/0x1d0
[effe5fd0] [c0084d20] generic_handle_irq+0x30/0x50
[effe5fe0] [c00048d0] __do_irq+0x2c/0x70
[effe5ff0] [c000d9a0] call_do_irq+0x24/0x3c
[ef047d10] [c00049a0] do_IRQ+0x8c/0xf8
[ef047d30] [c000f598] ret_from_except+0x0/0x18
--- Exception: 501 at quirk_usb_early_handoff+0x794/0x85c
LR = quirk_usb_early_handoff+0x788/0x85c
[ef047e30] [c02bd66c] pci_fixup_device+0xe0/0x19c
[ef047e60] [c07d4e1c] pci_apply_final_quirks+0x60/0x13c
[ef047e90] [c0002494] do_one_initcall+0x158/0x19c
[ef047f00] [c07ba928] kernel_init_freeable+0x130/0x1e4
[ef047f30] [c0002a78] kernel_init+0x14/0x10c
[ef047f40] [c000f014] ret_from_kernel_thread+0x5c/0x64
handlers:
[<c001cc78>] fsl_pci_pme_handle
Disabling IRQ #26
A2
A3
A4
A5
A4
A5
A4
A5
A4
A5
A4
and hang.
with my patch applied, board just boots ok and works.
> It looks like you haven't read ohci_shutdown() and ohci_run() in
> drivers/usb/host/ohci-hcd.c. They both access the fminterval register,
> and this patch doesn't change them.
>
> So I don't see why this patch should make any difference to the
> system's operation.
I think problem is caused by access to OHCI regs from PCI quirks - before
driver was initialized. ULI1553 southbridge chip could be in strange state
at this point.
Nikita
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