[U-Boot] [PATCH 1/3] imx-common: fix iomux settings

[Benoît Thébaudeau]

Hi Peng,

On Mon, Sep 21, 2015 at 3:05 AM, Peng Fan <b51431 at freescale.com> wrote:
> On Sun, Sep 20, 2015 at 05:02:58PM +0200, Benoît Thébaudeau wrote:
>>On Sun, Sep 20, 2015 at 3:02 PM, Peng Fan <b51431 at freescale.com> wrote:
>>> On Sun, Sep 20, 2015 at 01:33:20PM +0200, Benoît Thébaudeau wrote:
>>>>>> Also If still checking mux_ctrl_ofs, we have no chance to set iomux
>>>>>> for i.MX7D IOMUXC_LPSR_SW_MUX_CTL_PAD_GPIO1_IO00, because the mux_ctrl_ofs
>>>>>> for this register is 0.
>>>>
>>>>The need is clear, but then the test mechanism should be changed, not
>>>>removed. You could find a free bit in mux_ctrl_ofs or in mux_mode or
>>>>elsewhere in IOMUX_PAD (e.g. bit 63, which is currently reserved),
>>>>something like NO_PAD_CTRL, or create a reserved value other than
>>>>__NA_ for mux_ctrl_ofs/mux_mode.
>>>
>>> Stefano,
>>>
>>> There is '#define NO_PAD_CTRL             (1 << 17)' now,
>>> we can add'NO_MUX_CTRL' and 'NO_SEL_CTRL(select input)', but need to check
>>> whether the __NA__ pads are used or not now.
>>> also need a big change for the layout and related macro definition:
>>> 39  * MUX_CTRL_OFS:            0..11 (12)
>>> 40  * PAD_CTRL_OFS:           12..23 (12)
>>> 41  * SEL_INPUT_OFS:          24..35 (12)
>>> 42  * MUX_MODE + SION:        36..40  (5)
>>> 43  * PAD_CTRL + NO_PAD_CTRL: 41..58 (18)
>>> 44  * SEL_INP:                59..62  (4)
>>> 45  * reserved:                 63    (1)
>>>
>>> Can we just use the following way, since only i.mx7 has the requirement of
>>> mux_ctrl_ofs maybe at 0.
>>> if (is_soc_type(MX7)) {
>>>         __raw_writel(mux_mode, base + mux_ctrl_ofs);
>>> } else {
>>>         if (mux_ctrl_ofs)
>>>         __raw_writel(mux_mode, base + mux_ctrl_ofs);
>>> }
>>> I prefer this simple way for now, since we are at RC2 now. Later we can
>>> refactor the code using the way to provide macros NO_MUX_CTRL or NO_SEL_CTRL.
>>> What do you think?
>>
>>Maybe, but instead of NO_MUX_CTRL and the like we could also just
>>define __NA_ to (-1) instead of 0 and mask the passed values
>>appropriately in IOMUX_PAD(). This should be done for all types of
>>offsets, and __NA_ should be used everywhere instead of raw 0x000
>>values. -1 is guaranteed not to be needed by any SoC because of the
>>word alignment requirement for valid offsets. That would keep the
>>changes small.
>
> We can not just simple use __NA_ with value -1.
> see
> 70 #define IOMUX_PAD(pad_ctrl_ofs, mux_ctrl_ofs, mux_mode, sel_input_ofs,  \
> 71                 sel_input, pad_ctrl)                                    \
> 72         (((iomux_v3_cfg_t)(mux_ctrl_ofs) << MUX_CTRL_OFS_SHIFT)     |   \
> 73         ((iomux_v3_cfg_t)(mux_mode)      << MUX_MODE_SHIFT)         |   \
> 74         ((iomux_v3_cfg_t)(pad_ctrl_ofs)  << MUX_PAD_CTRL_OFS_SHIFT) |   \
> 75         ((iomux_v3_cfg_t)(pad_ctrl)      << MUX_PAD_CTRL_SHIFT)     |   \
> 76         ((iomux_v3_cfg_t)(sel_input_ofs) << MUX_SEL_INPUT_OFS_SHIFT)|   \
> 77         ((iomux_v3_cfg_t)(sel_input)     << MUX_SEL_INPUT_SHIFT))
>
> iomux_v3_cfg_t(mux_ctrl_ofs) << MUX_CTRL_OFS_SHIFT should be changed to
> `iomux_v3_cfg_t((mux_ctrl_ofs) << MUX_CTRL_OFS_SHIFT) & MUX_CTRL_OFS_MASK`,

Yes. That's why I said "mask the passed values appropriately in IOMUX_PAD()".

> in iomux-v3.c, need to test if (!(mux_ctrl_ofs & 1)) {xxxxx}.

Yes, of course.

> I am not sure whether this will incur unexpected things or not,

There's no reason.

> also
> the IOMUX_PAD with 0, but not __NA_ need to change to use __NA_.

And also, as I said, do the same for pad_ctrl_ofs and sel_input_ofs in
order to be consistent, and replace definitions like:
         MX25_PAD_CTL_GRP_DVS_MISC               = IOMUX_PAD(0x418,
0x000, 0, 0, 0, NO_PAD_CTRL),
with:
         MX25_PAD_CTL_GRP_DVS_MISC               = IOMUX_PAD(0x418,
__NA_, 0, __NA_, 0, NO_PAD_CTRL),

> So I prefer to use is_soc_type(MXC_CPU_MX7) for now.

Yes, that's OK for now. I was suggesting that as a longterm approach.
This change would be simple, but many definitions would have to be
updated.

Best regards,
Benoît