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From: Marek Vasut <marek.vasut@gmail.com>
To: Andrew Murray <andrew.murray@arm.com>
Cc: Simon Horman <horms@verge.net.au>,
	linux-pci@vger.kernel.org,
	Marek Vasut <marek.vasut+renesas@gmail.com>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
	Wolfram Sang <wsa@the-dreams.de>,
	linux-renesas-soc@vger.kernel.org
Subject: Re: [PATCH V3 2/3] PCI: rcar: Do not abort on too many inbound dma-ranges
Date: Sat, 26 Oct 2019 20:03:12 +0200
Message-ID: <fef9502f-d51c-b922-afb3-8891267ae6c3@gmail.com> (raw)
In-Reply-To: <20191021101805.GM47056@e119886-lin.cambridge.arm.com>

On 10/21/19 12:18 PM, Andrew Murray wrote:
[...]
>>>> In case the "dma-ranges" DT property contains either too many ranges
>>>> or the range start address is unaligned in such a way that populating
>>>> the range into the controller requires multiple entries, a situation
>>>> may occur where all ranges cannot be loaded into the controller.
>>>>
>>>> Currently, the driver refuses to probe in such a situation. Relax this
>>>> behavior, load as many ranges as possible and warn if some ranges do
>>>> not fit anymore.
>>>
>>> What is the motivation for relaxing this?
>>
>> U-Boot can fill the ranges in properly now, the list would be longer in
>> such a case and the driver would fail to probe (because the list is
>> longer than what the hardware can support).
> 
> Is this the U-Boot patch you refer to:
> 
> https://patchwork.ozlabs.org/patch/1129436/

Yes.

> As pci_set_region is called with the same address for PCI and CPU memory
> this implies there is a 1:1 mapping - therefore I don't see a need for
> multiple mappings for each DRAM bank. (Also if this controller has a
> 32 bit limitation, shouldn't this code limit the addresses before calling
> pci_set_region?).
It would certainly be helpful to know about this dma-ranges detail
earlier, this whole thing could've been avoided. Now all I can do is get
that patch reverted for the next U-Boot release.

But this still leaves me with one open question -- how do I figure out
what to program into the PCI controller inbound windows, so that the
controller correctly filters inbound transfers which are targetting
nonexisting memory ?

-- 
Best regards,
Marek Vasut

  reply index

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-09 17:57 [PATCH V3 1/3] PCI: rcar: Move the inbound index check marek.vasut
2019-08-09 17:57 ` [PATCH V3 2/3] PCI: rcar: Do not abort on too many inbound dma-ranges marek.vasut
2019-08-16 13:23   ` Simon Horman
2019-08-16 13:28     ` Marek Vasut
2019-08-16 13:38       ` Simon Horman
2019-08-16 17:41         ` Marek Vasut
2019-10-21 10:18       ` Andrew Murray
2019-10-26 18:03         ` Marek Vasut [this message]
2019-10-26 20:36           ` Andrew Murray
2019-10-26 21:06             ` Andrew Murray
2019-11-06 23:37             ` Marek Vasut
2019-11-07 14:19               ` Andrew Murray
2019-11-16 15:48                 ` Marek Vasut
2019-11-18 18:42                   ` Robin Murphy
2019-10-16 15:00   ` Lorenzo Pieralisi
2019-10-16 15:10     ` Marek Vasut
2019-10-16 15:26       ` Lorenzo Pieralisi
2019-10-16 15:29         ` Marek Vasut
2019-10-16 16:18           ` Lorenzo Pieralisi
2019-10-16 18:12             ` Rob Herring
2019-10-16 18:17               ` Marek Vasut
2019-10-16 20:25                 ` Rob Herring
2019-10-16 21:15                   ` Marek Vasut
2019-10-16 22:26                     ` Rob Herring
2019-10-16 22:33                       ` Marek Vasut
2019-10-17  7:06                         ` Geert Uytterhoeven
2019-10-17 10:55                           ` Marek Vasut
2019-10-17 13:06                             ` Robin Murphy
2019-10-17 14:00                               ` Marek Vasut
2019-10-17 14:36                                 ` Rob Herring
2019-10-17 15:01                                   ` Marek Vasut
2019-10-18  9:53                                     ` Lorenzo Pieralisi
2019-10-18 12:22                                       ` Marek Vasut
2019-10-18 12:53                                         ` Robin Murphy
2019-10-18 14:26                                           ` Marek Vasut
2019-10-18 15:44                                             ` Robin Murphy
2019-10-18 16:44                                               ` Marek Vasut
2019-10-18 17:35                                                 ` Robin Murphy
2019-10-18 18:44                                                   ` Marek Vasut
2019-10-21  8:32                                                     ` Geert Uytterhoeven
2019-11-19 12:10                                                     ` Robin Murphy
2019-10-18 10:06                         ` Andrew Murray
2019-10-18 10:17                           ` Geert Uytterhoeven
2019-10-18 11:40                             ` Andrew Murray
2019-08-09 17:57 ` [PATCH V3 3/3] PCI: rcar: Recalculate inbound range alignment for each controller entry marek.vasut
2019-10-21 10:39   ` Andrew Murray
2019-08-16 10:52 ` [PATCH V3 1/3] PCI: rcar: Move the inbound index check Lorenzo Pieralisi
2019-08-16 10:59   ` Marek Vasut
2019-08-16 11:10     ` Lorenzo Pieralisi
2019-10-15 20:14 ` Marek Vasut
2019-10-21 10:11 ` Andrew Murray

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