From: gerlando.falauto@keymile•com (Gerlando Falauto)
To: linux-arm-kernel@lists•infradead.org
Subject: pci-mvebu driver on km_kirkwood
Date: Fri, 21 Feb 2014 19:18:25 +0100 [thread overview]
Message-ID: <53079871.8080801@keymile.com> (raw)
In-Reply-To: <20140221144708.48559045@skate>
Dear Thomas,
On 02/21/2014 02:47 PM, Thomas Petazzoni wrote:
> Dear Gerlando Falauto,
>
> On Fri, 21 Feb 2014 13:24:36 +0100, Gerlando Falauto wrote:
>
>> So I restored the total aperture size to 192MB.
>> I had to rework your patch a bit because:
>>
>> a) I'm running an older kernel and driver
>> b) sizes are actually 1-byte offset
>
> Hum, right. This is a bit weird, maybe I should change that, I don't
> think the mvebu-mbus driver should accept 1-byte offset sizes.
I don't know anything about this, I only know the size dumped is of the
form 0x...ffff, that's all.
>> Here's the assignment (same as before):
>>
>> pci 0000:00:01.0: BAR 8: assigned [mem 0xe0000000-0xebffffff]
>> pci 0000:01:00.0: BAR 1: assigned [mem 0xe0000000-0xe7ffffff]
>> pci 0000:01:00.0: BAR 3: assigned [mem 0xe8000000-0xe87fffff]
>> pci 0000:01:00.0: BAR 4: assigned [mem 0xe8800000-0xe8801fff]
>> pci 0000:01:00.0: BAR 0: assigned [mem 0xe8802000-0xe8802fff]
>> pci 0000:01:00.0: BAR 2: assigned [mem 0xe8803000-0xe8803fff]
>> pci 0000:01:00.0: BAR 5: assigned [mem 0xe8804000-0xe8804fff]
>>
>> And here's the output I get from:
>>
>> # cat /sys/kernel/debug/mvebu-mbus/devices
>> [00] 00000000e8000000 - 00000000ec000000 : pcie0.0 (remap 00000000e8000000)
>> [01] disabled
>> [02] disabled
>> [03] disabled
>> [04] 00000000ff000000 - 00000000ff010000 : nand
>> [05] 00000000f4000000 - 00000000f8000000 : vpcie
>> [06] 00000000fe000000 - 00000000fe010000 : dragonite
>> [07] 00000000e0000000 - 00000000e8000000 : pcie0.0
>
> This seems correct: we have two windows pointing to the same device,
> and they have consecutive addresses.
I don't know how to interpret the (remap ... ) bit, but yes, this looks
right to me as well. I just don't know why mbus window 7 gets picked
before 0, but apart from that, it looks nice.
>> I did not get to test the whole address space thoroughly, but all the
>> BARs are still accessible (mainly BAR0 which contains the control space
>> and is mapped on the "new" MBUS window, and BAR1 which is the "big"
>> one). So at least, the issues we had before are now gone.
>
> Did you check that what you read from BAR0 (which is mapped on the new
> MBUS window) is really what you expect, and not just the same thing as
> BAR1 accessible for the big window? I just want to make sure that the
> hardware indeed properly handles two windows for the same device.
Yes, there's no way the two BARs could be aliased. It's a fairly complex
FPGA design, where BAR1 is the huge address space for a PCI-to-localbus
bridge (whose connected devices are recognized correctly) and BAR0 is
the control BAR (and its registers are read and written without a problem).
>> So I'd say this looks like a very promising approach. :-)
>
> Indeed. However, I don't think this approach solves the entire problem,
> for two reasons:
>
> *) For small BARs that are not power-of-two sized, we may not want to
> consume two windows, but instead consume a little bit more address
> space. Using two windows to map a 96 KB BAR would be a waste of
> windows: using a single 128 KB window is much more efficient.
>
> *) I don't know if the algorithm to split the BAR into multiple
> windows is going to be trivial.
I see others have already replied and I pretty much agree with them.
Thanks,
Gerlando
next prev parent reply other threads:[~2014-02-21 18:18 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-10 16:15 pci-mvebu driver on km_kirkwood Gerlando Falauto
2013-07-10 16:57 ` Thomas Petazzoni
2013-07-10 17:31 ` Gerlando Falauto
2013-07-10 19:56 ` Gerlando Falauto
2013-07-11 7:03 ` Valentin Longchamp
2013-07-12 8:59 ` Thomas Petazzoni
2013-07-15 15:46 ` Valentin Longchamp
2013-07-15 19:51 ` Thomas Petazzoni
2013-07-11 14:32 ` Thomas Petazzoni
2014-02-18 17:29 ` Gerlando Falauto
2014-02-18 20:27 ` Thomas Petazzoni
2014-02-19 8:38 ` Gerlando Falauto
2014-02-19 9:26 ` Thomas Petazzoni
2014-02-19 9:39 ` Gerlando Falauto
2014-02-19 13:37 ` Thomas Petazzoni
2014-02-19 21:45 ` Bjorn Helgaas
2014-02-20 8:55 ` Thomas Petazzoni
2014-02-20 17:35 ` Jason Gunthorpe
2014-02-20 20:29 ` Thomas Petazzoni
2014-02-21 0:32 ` Jason Gunthorpe
2014-02-21 8:34 ` Thomas Petazzoni
2014-02-21 8:58 ` Gerlando Falauto
2014-02-21 9:12 ` Thomas Petazzoni
2014-02-21 9:16 ` Gerlando Falauto
2014-02-21 9:39 ` Thomas Petazzoni
2014-02-21 12:24 ` Gerlando Falauto
2014-02-21 13:47 ` Thomas Petazzoni
2014-02-21 15:05 ` Arnd Bergmann
2014-02-21 15:11 ` Thomas Petazzoni
2014-02-21 15:20 ` Arnd Bergmann
2014-02-21 15:37 ` Thomas Petazzoni
2014-02-21 16:39 ` Jason Gunthorpe
2014-02-21 17:05 ` Thomas Petazzoni
2014-02-21 17:31 ` Jason Gunthorpe
2014-02-21 18:05 ` Arnd Bergmann
2014-02-21 18:29 ` Gerlando Falauto
2014-02-21 18:18 ` Gerlando Falauto [this message]
2014-02-21 18:45 ` Thomas Petazzoni
2014-02-20 19:18 ` Bjorn Helgaas
2014-02-21 0:24 ` Jason Gunthorpe
2014-02-21 19:05 ` Bjorn Helgaas
2014-02-21 19:21 ` Thomas Petazzoni
2014-02-21 19:53 ` Benjamin Herrenschmidt
2014-02-23 3:43 ` Gavin Shan
2013-07-31 8:03 ` Thomas Petazzoni
2013-07-31 8:26 ` Gerlando Falauto
2013-07-31 9:00 ` Thomas Petazzoni
2013-07-31 20:50 ` Jason Gunthorpe
2013-08-09 14:01 ` Thierry Reding
2013-08-26 9:27 ` Gerlando Falauto
2013-08-26 12:02 ` Thierry Reding
2013-08-26 14:49 ` Gerlando Falauto
2013-08-26 19:16 ` Jason Gunthorpe
2013-11-04 14:49 ` Gerlando Falauto
2013-11-05 8:13 ` Thierry Reding
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