On Mon, 2016-10-31 at 10:08 +0800, James Liao wrote:

On Mon, 2016-10-31 at 01:08 +0100, Matthias Brugger wrote:

quoted

Hi James,

On 10/20/2016 10:56 AM, James Liao wrote:

quoted

Some power domain comsumers may init before module_init.
So the power domain provider (scpsys) need to be initialized
earlier too.

Take an example for our IOMMU (M4U) and SMI. SMI is a bridge
between IOMMU and multimedia HW. SMI is responsible to
enable/disable iommu and help transfer data for each multimedia
HW. Both of them have to wait until the power and clocks are
enabled.

So scpsys driver should be initialized before SMI, and SMI should
be initialized before IOMMU, and then init IOMMU consumers
(display/vdec/venc/camera etc.).

IOMMU is subsys_init by default. So we need to init scpsys driver
before subsys_init.

Signed-off-by: James Liao <redacted>
Reviewed-by: Kevin Hilman <khilman@baylibre.com>
---

I didn't applied this patch for now.
I answered you in v7 of this series [1]. I would prefer to see if we can 
fix that otherwise.

Would be great if you or Yong could provide some feedback.

Hi, Matthias,
  Yong had verified your propose and it seems didn't work[1].
But I'm looking at the recently merged device link patches[2], it maybe
could help with the probe sequence issue.

If we set the iommu client as the smi larb's device consumer of
device_link with the DL_DEV_PROBING flags, it will be wait for smi
larb's probe done. But I'm not test that solution yet, need to do a bit
more test to verify this.

thanks.

[1]
https://lists.linuxfoundation.org/pipermail/iommu/2016-July/018034.html
[2]https://www.mail-archive.com/linux-kernel at vger.kernel.org/msg1261311.html

quoted

Thanks,
Matthias

[1] https://patchwork.kernel.org/patch/9397405/

quoted

 drivers/soc/mediatek/mtk-scpsys.c | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
index fa9ee69..dd7a07d 100644
--- a/drivers/soc/mediatek/mtk-scpsys.c
+++ b/drivers/soc/mediatek/mtk-scpsys.c

@@ -613,4 +613,21 @@ static int scpsys_probe(struct platform_device *pdev)
 		.of_match_table = of_match_ptr(of_scpsys_match_tbl),
 	},

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