Re: [PATCH v3 0/2] ARM: dts: imx7: add NAND support

[Han Xu <han.xu@nxp.com>]

On 06/01/2017 08:48 PM, Stefan Agner wrote:
> Hi Han,
>
> On 2017-06-01 14:14, Han Xu wrote:
>> On 06/01/2017 02:20 PM, Stefan Agner wrote:
>>> This are the missing device tree parts to add NAND support for i.MX 7.
>>> See previous patchset:
>>> https://emea01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flkml.org%2Flkml%2F2017%2F4%2F21%2F832&data=01%7C01%7Chan.xu%40nxp.com%7C3b9081a68c94476c4a2108d4a9235512%7C686ea1d3bc2b4c6fa92cd99c5c301635%7C0&sdata=mQ2aq5rW%2B9uADY5mSzFxk8P6bAVq%2BosPJQAi0PL9SQg%3D&reserved=0
>>>
>>> The previous version also included driver changes, which are already
>>> merged.
>>>
>>> --
>>> Stefan
>>>
>>> Changes since v2:
>>> - Only specify IMX7D_NAND_USDHC_BUS_ROOT_CLK which seems to be sufficent
>> Hi Stefan, sorry I didn't reply your last patch. I was unable to fully
>> test on i.MX7 since the work bandwidth, but the quick test shows DMA
>> cannot work WITHOUT IMX7D_NAND_ROOT_CLK on my side, I will fully check
>> it tomorrow morning and let you know the result.
> How did you test that?
>
> Since DMA can only use NAND in i.MX 7, testing is somewhat hard.
>
> Fact is, I can access DMA registers using just NAND_USDHC_BUS_CLK_ROOT
>
> mw.l 0x30388980 0x11000000 # Enable NAND_USDHC_BUS_CLK_ROOT
> mw.l 0x3038aa00 0x00000000 # Enable NAND_CLK_ROOT

NAND_ROOT_CLK offset is 0x4140 which control the CCGR20 to gate on/off 
the rawnand module, including APBH/GPMI/BCH. Without enabling it, the 
mxs-dma hangs during initialization. I guess this bit was enabled in 
some early stage.

> md.l 0x33000100 0 # Access APBH_CH0_CURCMDAR
>
> This works for me.
>
> I can *boot* from a UBIFS using this driver and Linux 4.12-rc1 with my
> patchset applied...
>
> Monitoring clocks in /sys/kernel/debug/clk/clk_summary show that
> NAND_ROOT_CLK gets turned off and back on if NAND access happens, the
> system seems stable.
>
> All that said, this patchset v3 actually does not remove the
> NAND_ROOT_CLK as intended to. Will send a v4.
>
> --
> Stefan
>
>>> - Dropped driver changes, alreay merged
>>>
>>> Changes since v1:
>>> - Make clks_count const
>>> - Introduce IS_IMX7D for i.MX 7 SoC's and make it part of GPMI_IS_MX6
>>>
>>> Stefan Agner (2):
>>>     ARM: dts: imx7: add GPMI NAND
>>>     ARM: dts: imx7-colibri: add NAND support
>>>
>>>    arch/arm/boot/dts/imx7-colibri.dtsi |  9 +++++++++
>>>    arch/arm/boot/dts/imx7s.dtsi        | 31 +++++++++++++++++++++++++++++++
>>>    2 files changed, 40 insertions(+)
>>>