RE: Purpose of pci_remap_iospace

From: Bharat Kumar Gogada <bharat.kumar.gogada@xilinx.com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Bjorn Helgaas <bhelgaas@google.com>,
	"Liviu.Dudau@arm.com" <Liviu.Dudau@arm.com>,
	nofooter <nofooter@xilinx.com>,
	"thomas.petazzoni@free-electrons.com" 
	<thomas.petazzoni@free-electrons.com>
Subject: RE: Purpose of pci_remap_iospace
Date: Thu, 14 Jul 2016 15:05:40 +0000	[thread overview]
Message-ID: <8520D5D51A55D047800579B094147198258B8FC3@XAP-PVEXMBX01.xlnx.xilinx.com> (raw)
In-Reply-To: <20160714145624.GB30657@red-moon>

> On Thu, Jul 14, 2016 at 01:32:13PM +0000, Bharat Kumar Gogada wrote:
>
> [...]
>
> > Hi Lorenzo,
> >
> > I missed something in my device tree now I corrected it.
> >
> > ranges = <0x01000000 0x00000000 0xe0000000 0x00000000 0xe0000000 0
> 0x00010000   //io
>
> You have not missed anything, you changed the PCI bus address at which
> your host bridge responds to IO space and it must match your configuration.
> At what PCI bus address your host bridge maps IO space ?
>
> >                      0x02000000 0x00000000 0xe0100000 0x00000000
> > 0xe0100000 0 0x0ef00000>; //non prefetchabe memory
> >
> > [    2.389498] nwl-pcie fd0e0000.pcie: Link is UP
> > [    2.389541] PCI host bridge /amba/pcie@fd0e0000 ranges:
> > [    2.389558]   No bus range found for /amba/pcie@fd0e0000, using [bus
> 00-ff]
> > [    2.389583]    IO 0xe0000000..0xe000ffff -> 0xe0000000
> > [    2.389624]   MEM 0xe0100000..0xeeffffff -> 0xe0100000
> > [    2.389803] nwl-pcie fd0e0000.pcie: PCI host bridge to bus 0000:00
> > [    2.389822] pci_bus 0000:00: root bus resource [bus 00-ff]
> > [    2.389839] pci_bus 0000:00: root bus resource [io  0x0000-0xffff] (bus
> address [0xe0000000-0xe000ffff])
> > [    2.389863] pci_bus 0000:00: root bus resource [mem 0xe0100000-
> 0xeeffffff]
> > [    2.390094] pci 0000:00:00.0: cannot attach to SMMU, is it on the same
> bus?
> > [    2.390110] iommu: Adding device 0000:00:00.0 to group 1
> > [    2.390274] pci 0000:01:00.0: reg 0x20: initial BAR value 0x00000000 invalid
> > [    2.390481] pci 0000:01:00.0: cannot attach to SMMU, is it on the same
> bus?
> > [    2.390496] iommu: Adding device 0000:01:00.0 to group 1
> > [    2.390533] in pci_bridge_check_ranges io 101
> > [    2.390545] in pci_bridge_check_ranges io 2 101
> > [    2.390575] pci 0000:00:00.0: BAR 8: assigned [mem 0xe0100000-
> 0xe02fffff]
> > [    2.390592] pci 0000:00:00.0: BAR 7: assigned [io  0x1000-0x1fff]
> > [    2.390609] pci 0000:00:00.0: BAR 6: assigned [mem 0xe0300000-
> 0xe03007ff pref]
> > [    2.390636] pci 0000:01:00.0: BAR 0: assigned [mem 0xe0100000-0xe01fffff
> 64bit]
> > [    2.390669] pci 0000:01:00.0: BAR 2: assigned [mem 0xe0200000-0xe02fffff
> 64bit]
> > [    2.390702] pci 0000:01:00.0: BAR 4: assigned [io  0x1000-0x103f]
> > [    2.390721] pci 0000:00:00.0: PCI bridge to [bus 01-0c]
> > [    2.390785] pci 0000:00:00.0:   bridge window [io  0x1000-0x1fff]
> > [    2.390823] pci 0000:00:00.0:   bridge window [mem 0xe0100000-
> 0xe02fffff]
> >
Thanks a lot Loenzo for your kind and clear explanation, I will dig through hardware and correct my device tree.

>From above log why IO space is allocated as only 4k even though I'm allocating 64k through device tree ?

Regards,
Bharat

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