[PATCH 07/11] mfd: bcm2835-pm: Add support for BCM2711

[Peter Robinson]

Hi Stefan,

On Tue, May 31, 2022 at 6:27 PM Stefan Wahren <stefan.wahren at i2se.com> wrote:
>
> Hi Peter,
>
> Am 31.05.22 um 17:08 schrieb Peter Robinson:
> > On Sun, May 15, 2022 at 9:21 PM Stefan Wahren <stefan.wahren at i2se.com> wrote:
> >> In BCM2711 the new RPiVid ASB took over V3D. The old ASB is still present
> >> with the ISP and H264 bits, and V3D is in the same place in the new ASB
> >> as the old one.
> >>
> >> As per the devicetree bindings, BCM2711 will provide both the old and
> >> new ASB resources, so get both of them and pass them into
> >> 'bcm2835-power,' which will take care of selecting which one to use
> >> accordingly.
> >>
> >> Since the RPiVid ASB's resources were being provided prior to formalizing
> >> the bindings[1], also support the old firmwares that didn't use
> > I'm guessing this [1] is referring to "[1] See: 7dbe8c62ceeb ("ARM:
> > dts: Add minimal Raspberry Pi 4 support")" referred to in the original
> > patch [1] that Nicolas did, was there a reason to drop the
> > details/changelog here?
> Oops, the link accidently get lost.
> > The decision not to use bits makes sense I
> > believe.
> Yes, i think the new version is more elegant.
> >
> > [1] https://patchwork.kernel.org/project/linux-arm-kernel/patch/20220213225646.67761-8-pbrobinson@gmail.com/
> >
> >> 'reg-names.'
> >>
> >> Signed-off-by: Stefan Wahren <stefan.wahren at i2se.com>
> >> ---
> >>   drivers/mfd/bcm2835-pm.c       | 18 ++++++++++++++++++
> >>   include/linux/mfd/bcm2835-pm.h |  1 +
> >>   2 files changed, 19 insertions(+)
> >>
> >> diff --git a/drivers/mfd/bcm2835-pm.c b/drivers/mfd/bcm2835-pm.c
> >> index 1656d786993a..da110767c6a4 100644
> >> --- a/drivers/mfd/bcm2835-pm.c
> >> +++ b/drivers/mfd/bcm2835-pm.c
> >> @@ -28,6 +28,8 @@ static const struct mfd_cell bcm2835_power_devs[] = {
> >>   static int bcm2835_pm_get_pdata(struct platform_device *pdev,
> >>                                  struct bcm2835_pm *pm)
> >>   {
> >> +       bool is_bcm2711 = of_device_is_compatible(pm->dev->of_node, "brcm,bcm2711-pm");
> >> +
> >>          /* If no 'reg-names' property is found we can assume we're using old
> >>           * firmware.
> >>           */
> >> @@ -39,6 +41,7 @@ static int bcm2835_pm_get_pdata(struct platform_device *pdev,
> >>                          return PTR_ERR(pm->base);
> >>
> >>                  pm->asb = devm_platform_ioremap_resource(pdev, 1);
> >> +               pm->rpivid_asb = devm_platform_ioremap_resource(pdev, 2);
> > Shouldn't we check if is_bcm2711 before we assign rpivid_asb above?
> Yes, make sense.
> >
> >>          } else {
> >>                  struct resource *res;
> >>
> >> @@ -50,11 +53,25 @@ static int bcm2835_pm_get_pdata(struct platform_device *pdev,
> >>                                                      "asb");
> >>                  if (res)
> >>                          pm->asb = devm_ioremap_resource(&pdev->dev, res);
> >> +
> >> +               res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
> >> +                                                   "rpivid_asb");
> >> +               if (res)
> >> +                       pm->rpivid_asb = devm_ioremap_resource(&pdev->dev,
> >> +                                                               res);
> >>          }
> >>
> >>          if (IS_ERR(pm->asb))
> >>                  pm->asb = NULL;
> >>
> >> +       if (IS_ERR(pm->rpivid_asb))
> >> +               pm->rpivid_asb = NULL;
> >> +
> >> +       if (pm->rpivid_asb && !is_bcm2711) {
> >> +               dev_err(pm->dev, "RPiVid ASB support only present in BCM2711\n");
> > Should we ever get into this situation? If it's an older get RPi I'm
> > guessing pm->rpivid_asb should have been set to NULL from the error
> > above.
> I think this was a warning for older BCM2711 downstream DT files which
> had rpivid_asb register but no BCM2711 compatible.

Based on the history I remember that makes sense, but the warning is a
bit misleading in the context given it would actually be a 2711. Is it
purely a DT check or is does the version of VC firmware come into play
here too, I seem to remember firmware was used to make some things
work on older OSes in the early days of RPi4 (although it's hard to
tell exactly what was done, and I've tried to forget).

> >> +               return -EINVAL;
> >> +       }
> >> +
> >>          return 0;
> >>   }
> >>
> >> @@ -95,6 +112,7 @@ static int bcm2835_pm_probe(struct platform_device *pdev)
> >>   static const struct of_device_id bcm2835_pm_of_match[] = {
> >>          { .compatible = "brcm,bcm2835-pm-wdt", },
> >>          { .compatible = "brcm,bcm2835-pm", },
> >> +       { .compatible = "brcm,bcm2711-pm", },
> >>          {},
> >>   };
> >>   MODULE_DEVICE_TABLE(of, bcm2835_pm_of_match);
> >> diff --git a/include/linux/mfd/bcm2835-pm.h b/include/linux/mfd/bcm2835-pm.h
> >> index ed37dc40e82a..f70a810c55f7 100644
> >> --- a/include/linux/mfd/bcm2835-pm.h
> >> +++ b/include/linux/mfd/bcm2835-pm.h
> >> @@ -9,6 +9,7 @@ struct bcm2835_pm {
> >>          struct device *dev;
> >>          void __iomem *base;
> >>          void __iomem *asb;
> >> +       void __iomem *rpivid_asb;
> >>   };
> >>
> >>   #endif /* BCM2835_MFD_PM_H */
> >> --
> >> 2.25.1
> >>
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