On Fri, Aug 14, 2015 at 08:08:13PM +0200, Bartlomiej Zolnierkiewicz wrote:

On Friday, August 14, 2015 06:43:30 PM Russell King - ARM Linux wrote:

quoted

On Fri, Aug 14, 2015 at 07:04:23PM +0200, Bartlomiej Zolnierkiewicz wrote:

quoted

This patch disables deprecated IDE subsystem in footbridge_defconfig
(no IDE host drivers are selected in this config so there is no valid
reason to enable IDE subsystem itself).

That's actually incorrect.  I use IDE on Footbridge because it works
loads with my CY82C693 board.  I never submitted the patches which make
CY82C693 work on ARM though...

However, the CY82C693 must not be allowed to use DMA (which is why the
ATA driver can't be used) - if it does, it locks the PCI bus.  It's
a hardware incompatibility between some PCI devices and the Footbridge.

PATA driver is the same in this regard as IDE one.  They both try to
use DMA if supported by a device.  Would be great if you could fix
them (or at least PATA one) to limit your setup to PIO automatically
(please also note that you can limit libata to PIO manually these
days).

When it comes to CY82C693 there is also a leftover issue with PATA
driver that it only supports primary interface currently (BTW this is
why I left Alpha's defconfig alone for now - it uses CY82C693).  I can
look into fixing this (or assist in this work) if you are interested
in it.

Well, it looks like the PCI layer has been screwed for this for some time:

cy82c693 0000:00:06.1: IDE controller (0x1080:0xc693 rev 0x00)
Cypress_IDE 0000:00:06.1: device not available (can't reserve [io  0x0170-0x0177])
Cypress_IDE 0000:00:06.1: device not available (can't reserve [io  0x0170-0x0177])
cy82c693 0000:00:06.1: couldn't enable device
Cypress_IDE: probe of 0000:00:06.1 failed with error -22

The PCI layer forces the standard legacy ports onto the Cypress device,
and then the "primary" resources get null'd out by the long-standing
CY82C693 quirk in the ARM bios32.c.

However - the ARM quick is not what causes the above - the above looks
to be caused by the generic PCI code going wrong - it adds those
legacy resources, and nothing ever connects them to the resource tree:

000000a0-000000bf : pic2
000000c0-000000df : dma2
00000213-00000213 : ISAPnP
000002f8-000002ff : serial8250.0

which then causes pci_enable_device() to fail.

I doubt CY82C693 even works on Alpha... or any IDE interface using the
legacy IO ports...  So it may take quite a bit of work to get going
again - not something I'm going to attempt prior to the 4.3 merge
window.

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