powerpc: Increase warp SD buffer

Submitted by Sean MacLennan on Dec. 9, 2009, 5:04 a.m.

Details

Message ID 20091209000437.78794a8f@opus.seanm.ca
State Accepted, archived
Commit a18cb387e5c29be5c95cded5b5a55110bb930f5c
Delegated to: Josh Boyer
Headers show

Commit Message

Sean MacLennan Dec. 9, 2009, 5:04 a.m.
Newer revs of the FPGA have a larger SD buffer.

Signed-off-by: Sean MacLennan <smaclennan@pikatech.com>
---

Comments

Josh Boyer Dec. 9, 2009, 2:40 p.m.
On Wed, Dec 09, 2009 at 12:04:37AM -0500, Sean MacLennan wrote:
>Newer revs of the FPGA have a larger SD buffer.

How does that impact the older revisions?  You're using a cuImage with Warp,
so the device tree is bundled with that.  If you boot a new kernel with this
change to the DTS on a older board revision, will it do bad things?

josh
Sean MacLennan Dec. 9, 2009, 3:36 p.m.
On Wed, 9 Dec 2009 09:40:55 -0500
Josh Boyer <jwboyer@linux.vnet.ibm.com> wrote:

> How does that impact the older revisions?  You're using a cuImage
> with Warp, so the device tree is bundled with that.  If you boot a
> new kernel with this change to the DTS on a older board revision,
> will it do bad things?

The new SD driver takes care of that. If you use the new kernel with an
old FPGA you reserve more space than you need, but the driver will not
touch it.

And if you somehow end up with the new DTS on an older kernel, the old
SD driver will not use the space anyway since the buffer is limited to
one block.

The SD driver is not in the kernel proper because it was implemented in
the FPGA and has a non-standard interface. It requires a change to the
SD core to run. But it is GPLed, so if anybody wants to see it, just
ask.

Cheers,
    Sean
Josh Boyer Dec. 9, 2009, 3:47 p.m.
On Wed, Dec 09, 2009 at 10:36:45AM -0500, Sean MacLennan wrote:
>On Wed, 9 Dec 2009 09:40:55 -0500
>Josh Boyer <jwboyer@linux.vnet.ibm.com> wrote:
>
>> How does that impact the older revisions?  You're using a cuImage
>> with Warp, so the device tree is bundled with that.  If you boot a
>> new kernel with this change to the DTS on a older board revision,
>> will it do bad things?
>
>The new SD driver takes care of that. If you use the new kernel with an
>old FPGA you reserve more space than you need, but the driver will not
>touch it.
>
>And if you somehow end up with the new DTS on an older kernel, the old
>SD driver will not use the space anyway since the buffer is limited to
>one block.
>
>The SD driver is not in the kernel proper because it was implemented in
>the FPGA and has a non-standard interface. It requires a change to the
>SD core to run. But it is GPLed, so if anybody wants to see it, just
>ask.

OK thanks.  I figured something like that would be the case, but wanted to
verify first.

josh

Patch hide | download patch | download mbox

diff --git a/arch/powerpc/boot/dts/warp.dts b/arch/powerpc/boot/dts/warp.dts
index 31605ee..e576ee8 100644
--- a/arch/powerpc/boot/dts/warp.dts
+++ b/arch/powerpc/boot/dts/warp.dts
@@ -146,7 +146,7 @@ 
 
 				fpga@2,4000 {
 					compatible = "pika,fpga-sd";
-					reg = <0x00000002 0x00004000 0x00000A00>;
+					reg = <0x00000002 0x00004000 0x00004000>;
 				};
 
 				nor@0,0 {