-----Original Message-----
From: linux-pci-owner at vger.kernel.org [mailto:linux-pci-
owner at vger.kernel.org] On Behalf Of Bjorn Helgaas
Sent: Thursday, October 22, 2015 5:36 PM
To: Gabriele Paoloni
Cc: Wangzhou (B); Bjorn Helgaas; jingoohan1 at gmail.com;
pratyush.anand at gmail.com; Arnd Bergmann; linux at arm.linux.org.uk;
thomas.petazzoni at free-electrons.com; lorenzo.pieralisi at arm.com;
james.morse at arm.com; Liviu.Dudau at arm.com; jason at lakedaemon.net;
robh at kernel.org; gabriel.fernandez at linaro.org;
Minghuan.Lian at freescale.com; linux-pci at vger.kernel.org; linux-arm-
kernel at lists.infradead.org; devicetree at vger.kernel.org; linux-
kernel at vger.kernel.org; zhangjukuo; qiuzhenfa; liudongdong (C);
qiujiang; xuwei (O); Liguozhu (Kenneth)
Subject: Re: [PATCH v11 1/6] PCI: designware: move calculation of bus
addresses to DRA7xx

Hi Gabriele,

On Thu, Oct 22, 2015 at 07:21:41AM +0000, Gabriele Paoloni wrote:

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-----Original Message-----
From: Bjorn Helgaas [mailto:helgaas at kernel.org]

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 #define	PCIECTRL_DRA7XX_CONF_PHY_CS			0x010C
 #define	LINK_UP						BIT(16)
+#define	CPU_TO_BUS_ADDR					0x0FFFFFFF

"CPU_TO_BUS_ADDR" is a very generic name.  Since you do have DRA7XX

in

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other #defines and static symbols in this file, maybe it could be

DRA7XX to

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make it obvious that it only applies here?

Ok will change to DRA7XX_CPU_TO_BUS_ADRR in v12
..

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+	if (pp->io_mod_base)
+		pp->io_mod_base &= CPU_TO_BUS_ADDR;

These are equivalent to

  pp->io_mod_base &= CPU_TO_BUS_ADDR;

(You don't need to test whether they're zero first.)

Yes agreed, will change in v12
...

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 	cfg_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,

"config");

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@@ -415,8 +411,7 @@ int dw_pcie_host_init(struct pcie_port *pp)
 			pp->io_base = range.cpu_addr;

 			/* Find the untranslated IO space address */
-			pp->io_mod_base = of_read_number(parser.range -
-							 parser.np + na, ns);
+			pp->io_mod_base = range.cpu_addr;

So apparently

  "of_read_number() == range.cpu_addr & CPU_TO_BUS_ADDR" on DRA7xx
  "of_read_number() == range.cpu_addr" everywhere else?

Yes correct

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Is that right?  Is that a valid assumption, i.e., are we assuming
anything about DTs in the field that we shouldn't?

Before I wrote a patch that was generic to accommodate intermediate

level

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of translation between PCI_addr -> BUS_addr -> CPU_addr

http://lists.infradead.org/pipermail/linux-arm-kernel/2015-

July/360922.html

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After discussion we agreed to solve it with a bitmask rather than

adding

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a field to of_pci_range to make it generic.
The bitmask only applies to DRA7xx

I haven't gotten all the way through this series yet, but don't bother
with
a v12 just for these minor changes.  I can easily fix them up when
applying
it.

Great Many Thanks for this!

Gab

Bjorn
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