linux-kernel - Re: [PATCH 1/4] PCI: refactor io size calculation code

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Message-ID: <4DA2FFB6.3040209@gaisler.com>
Date:	Mon, 11 Apr 2011 15:18:46 +0200
From:	Daniel Hellstrom <daniel@...sler.com>
To:	Ram Pai <linuxram@...ibm.com>
CC:	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	Clemens Ladisch <clemens@...isch.de>,
	Yinghai Lu <yinghai@...nel.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Kristoffer Glembo <kristoffer@...sler.com>, daniel@...sler.com
Subject: Re: [PATCH 1/4] PCI: refactor io size calculation code

>
>
>refactor  code  that  calculates  the  io  size in pbus_size_io()
>and pbus_mem_io() into separate functions.
>
>Signed-off-by: Ram Pai <linuxram@...xxxxxxx>
>---
> drivers/pci/setup-bus.c |   66 ++++++++++++++++++++++++++++++-----------------
> 1 files changed, 42 insertions(+), 24 deletions(-)
>
>diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
>index 66cb8f4..2121215 100644
>--- a/drivers/pci/setup-bus.c
>+++ b/drivers/pci/setup-bus.c
>@@ -404,6 +404,43 @@ static struct resource *find_free_bus_resource(struct pci_bus *bus, unsigned lon
> 	return NULL;
> }
>
...

>+
>+static resource_size_t calculate_memsize(resource_size_t size,
>+		resource_size_t min_size,
>+		resource_size_t size1,
>+		resource_size_t old_size,
>+		resource_size_t align)
>+{
>+	if (size < min_size)
>+		size = min_size;
>+	if (old_size == 1 )
>+		old_size = 0;
>+	if (size < old_size)
>+		size = old_size;
>+	size = ALIGN(size + size1, align);
>+	return size;
>+}
>+
> /* Sizing the IO windows of the PCI-PCI bridge is trivial,
>    since these windows have 4K granularity and the IO ranges
>    of non-bridge PCI devices are limited to 256 bytes.
>
>  
>
...

>@@ -516,14 +542,6 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> 			mem64_mask &= r->flags & IORESOURCE_MEM_64;
> 		}
> 	}
>-	if (size < min_size)
>-		size = min_size;
>-	old_size = resource_size(b_res);
>-	if (old_size == 1)
>-		old_size = 0;
>-	if (size < old_size)
>-		size = old_size;
>-
> 	align = 0;
> 	min_align = 0;
> 	for (order = 0; order <= max_order; order++) {
>@@ -537,7 +555,7 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
> 			min_align = align1 >> 1;
> 		align += aligns[order];
> 	}
>-	size = ALIGN(size, min_align);
>+	size = calculate_memsize(size, min_size, 0, resource_size(b_res), align);
>  
>
On my SPARC32/LEON4 PCI system I get overlapped areas, double mapped 
resources. Some BARs on PCIBUS0 are in the same non-prefetchable memory 
range as the secondary bus PCIBUS1. Changing align to min_align in the 
above call to calculate_memsize() fixes the problem, and the memory 
allocation is the same as with 2.6.36.4 kernel.

I belive this is just a typo.

Best Regards,
Daniel Hellstrom
Aeroflex Gaisler

> 	if (!size) {
> 		if (b_res->start || b_res->end)
> 			dev_info(&bus->self->dev, "disabling bridge window "
>-- 
>1.6.5.2
>
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