[PATCH] staging: vchiq_arm: Add 36-bit address support

[Dan Carpenter]

On Thu, Oct 14, 2021 at 06:32:30PM -0400, Mwesigwa Guma wrote:
> Cc: Nicolas Saenz Julienne <nsaenz at kernel.org>
> Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> Cc: Stefan Wahren <stefan.wahren at i2se.com>
> Cc: Ojaswin Mujoo <ojaswin98 at gmail.com>
> Cc: Dan Carpenter <dan.carpenter at oracle.com>
> Cc: Amarjargal Gundjalam <amarjargal16 at gmail.com>
> Cc: Phil Elwell <phil at raspberrypi.com>
> Cc: bcm-kernel-feedback-list at broadcom.com
> Cc: linux-rpi-kernel at lists.infradead.org 
> Cc: linux-arm-kernel at lists.infradead.org 
> Cc: linux-staging at lists.linux.dev 
> Cc: fedora-rpi at googlegroups.com
> Cc: Joel Savitz <jsavitz at redhat.com>
> Cc: Chukpozohn Toe <ctoe at redhat.com>
> Cc: Clark Williams <clark at redhat.com>
> 

Did you intend to put this CC list here?  It goes at the end next to
the Signed-off-by line if so.  I don't feel like it's required except
maybe Phil to show he was Cc'd.

> This is a forward port of Phil Elwell's commit from the Raspberry Pi
> Linux fork described as follows [1]:

Please use the From: header to give authorship credit.

From: Phil Elwell <phil at raspberrypi.com>

Make that the first line of the email.

> 
>     Conditional on a new compatible string, change the pagelist encoding
>     such that the top 24 bits are the pfn, leaving 8 bits for run length
>     (-1), giving a 36-bit address range.
>     
>     Manage the split between addresses for the VPU and addresses for the
>     40-bit DMA controller with a dedicated DMA device pointer that on non-
>     BCM2711 platforms is the same as the main VCHIQ device. This allows
>     the VCHIQ node to stay in the usual place in the DT.
> 
> This commit enables VCHIQ device access on a Raspberry Pi 4B running the 
> mainline Linux kernel.
> 
> Tested on Fedora Linux running on a Raspberry Pi 4B.
> 
> [1]: https://github.com/raspberrypi/linux/commit/97268fd23eb8d08dc74eac5e3fd697303de26610
> 
> Signed-off-by: Mwesigwa Guma <mguma at redhat.com>

regards,
dan carpenter