Bug 1308355 - [PATCH] Please enable CONFIG_BCM2835 for Raspberry Pi 2
[PATCH] Please enable CONFIG_BCM2835 for Raspberry Pi 2
Status: CLOSED NEXTRELEASE
Product: Fedora
Classification: Fedora
Component: kernel (Show other bugs)
rawhide
Unspecified Unspecified
unspecified Severity unspecified
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Assigned To: Kernel Maintainer List
Peter Robinson
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Depends On:
Blocks:
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Reported: 2016-02-14 13:37 EST by Lubomir Rintel
Modified: 2016-09-21 18:03 EDT (History)
12 users (show)

See Also:
Fixed In Version: 4.8.0-0.rc7.git0.1.fc25
Doc Type: Bug Fix
Doc Text:
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Clone Of:
Environment:
Last Closed: 2016-09-21 18:03:30 EDT
Type: Bug
Regression: ---
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RHEL 7.3 requirements from Atomic Host:
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Attachments (Terms of Use)
SPEC file patch (2.10 KB, text/plain)
2016-02-14 13:37 EST, Lubomir Rintel
no flags Details

  None (edit)
Description Lubomir Rintel 2016-02-14 13:37:44 EST
Created attachment 1127044 [details]
SPEC file patch

Please enable CONFIG_BCM2835. The Raspberry Pi 2 support is now good enough to boot multi-user.

There's just a couple of nitpicks:

1.) The kernel compiled with Rawhide toolchain panicks while initializing percpu memory. This might be a GCC6 toolchain bug; I just have no other ARM7 board to verify. A build in Fedora 23 buildroot works fine.

2.) The video output is not there. Uboot doesn't set up the simplefb properly yet and the VC4 devicetree bindings have not been accepted into mainline. The serial output works fine though.

3.) The uboot loads the FDT and initrd near the top of the memory, where the kernel can't access it (since it seems to overlap the vmalloc space). The uboot fixes are pending:

http://lists.denx.de/pipermail/u-boot/2016-February/245402.html
http://git.denx.de/?p=u-boot.git;a=commit;h=89ca1000caefcfaeb06fdb9fcc8fdc09c318d26a
Comment 1 Lubomir Rintel 2016-02-14 13:39:57 EST
If it stops working here's how to debug it with earlyprintk:

-# CONFIG_DEBUG_LL is not set
+CONFIG_DEBUG_LL=y
+# CONFIG_DEBUG_BCM2835 is not set
+CONFIG_DEBUG_BCM2836=y
+CONFIG_DEBUG_LL_INCLUDE="debug/pl01x.S"
+CONFIG_DEBUG_UART_PL01X=y
+CONFIG_DEBUG_UART_PHYS=0x3f201000
+CONFIG_DEBUG_UART_VIRT=0xf0201000
+CONFIG_DEBUG_UNCOMPRESS=y
+CONFIG_UNCOMPRESS_INCLUDE="debug/uncompress.h"
+CONFIG_EARLY_PRINTK=y
+# CONFIG_SERIAL_SAMSUNG_DEBUG is not set
Comment 2 Lubomir Rintel 2016-02-14 14:16:34 EST
dmesg: http://paste.fedoraproject.org/322586/54773521/
Comment 3 Peter Robinson 2016-02-15 07:58:40 EST
I'm already working on this
Comment 4 Peter Robinson 2016-02-15 08:02:45 EST
> Please enable CONFIG_BCM2835. The Raspberry Pi 2 support is now good enough
> to boot multi-user.

"good enough" might be a problem, when this gets enabled I want decent support for video/keyboard etc because people generally don't understand serial consoles and the queries for "this doesn't work" support are overwhelming.

> 1.) The kernel compiled with Rawhide toolchain panicks while initializing
> percpu memory. This might be a GCC6 toolchain bug; I just have no other ARM7
> board to verify. A build in Fedora 23 buildroot works fine.

That's a pretty big nitpick, it's also one we're tracking in 1303147
 
> 2.) The video output is not there. Uboot doesn't set up the simplefb
> properly yet and the VC4 devicetree bindings have not been accepted into
> mainline. The serial output works fine though.

:-(

> 3.) The uboot loads the FDT and initrd near the top of the memory, where the
> kernel can't access it (since it seems to overlap the vmalloc space). The
> uboot fixes are pending:

It's an issue with a lot of boards with over 512Mb of RAM and should be fixed in u-boot, I know Stephen accepted a patch for at least the FDT for this.
Comment 5 Lubomir Rintel 2016-02-15 11:12:37 EST
(In reply to Peter Robinson from comment #4)
> > Please enable CONFIG_BCM2835. The Raspberry Pi 2 support is now good enough
> > to boot multi-user.
> 
> "good enough" might be a problem, when this gets enabled I want decent
> support for video/keyboard etc because people generally don't understand
> serial consoles and the queries for "this doesn't work" support are
> overwhelming.

Understood. Would missing out-of-box video be a blocker for enabling it in kernel? (What if Fedora didn't announce/document that Raspberry Pi is supported, but would make it possible for a remix to exist without a need for a separate kernel?)

> > 1.) The kernel compiled with Rawhide toolchain panicks while initializing
> > percpu memory. This might be a GCC6 toolchain bug; I just have no other ARM7
> > board to verify. A build in Fedora 23 buildroot works fine.
> 
> That's a pretty big nitpick, it's also one we're tracking in 1303147
>  
> > 2.) The video output is not there. Uboot doesn't set up the simplefb
> > properly yet and the VC4 devicetree bindings have not been accepted into
> > mainline. The serial output works fine though.
> 
> :-(

Would simplefb be sufficient for Fedora to enable the Raspberry Pi support? 3D doesn't really work well in Raspbian and noone seems to really mind.

> > 3.) The uboot loads the FDT and initrd near the top of the memory, where the
> > kernel can't access it (since it seems to overlap the vmalloc space). The
> > uboot fixes are pending:
> 
> It's an issue with a lot of boards with over 512Mb of RAM and should be
> fixed in u-boot, I know Stephen accepted a patch for at least the FDT for
> this.

Yes, and the initrd part got his ack too.
Comment 6 Lubomir Rintel 2016-02-26 11:43:33 EST
With the current rc2 uboot-tools the simplefb works fine (presumably due to 1382648b6be).

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