Re: [PATCH] mtd: rawnand: marvell: select target before setting up data interface

[Daniel Mack <daniel@xxxxxxxxxx>]

Hi Miquel,

On 25/3/2019 10:09 AM, Miquel Raynal wrote:
> Daniel Mack <daniel@xxxxxxxxxx> wrote on Fri, 22 Mar 2019 19:48:08
> +0100:
> 
>> Hi Miquel,
>>
>> On 22/3/2019 9:30 AM, Miquel Raynal wrote:
>>> + Richard: this is fixes materials
>>>
>>> Daniel Mack <daniel@xxxxxxxxxx> wrote on Thu, 21 Mar 2019 22:20:10
>>> +0100:
>>>   
>>>> Now that the nand drivers are responsible for selecting the target
>>>> prior to hardware access, a call to marvell_nfc_select_target() is
>>>> necessary from marvell_nfc_setup_data_interface().
>>>>
>>>> This is a regression introduced by commit b25251414f6e ("mtd:
>>>> rawnand: marvell: Stop implementing ->select_chip()").
>>>>
>>>> Fixes: b25251414f6e ("mtd: rawnand: marvell: Stop implementing ->select_chip()")
>>>> Cc: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxx>
>>>> Cc: <stable@xxxxxxxxxxxxxxx>
>>>> Signed-off-by: Daniel Mack <daniel@xxxxxxxxxx>
>>>> ---
>>>>  drivers/mtd/nand/raw/marvell_nand.c | 2 ++
>>>>  1 file changed, 2 insertions(+)
>>>>
>>>> diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
>>>> index 84283c6bb0ff..93abe5be8995 100644
>>>> --- a/drivers/mtd/nand/raw/marvell_nand.c
>>>> +++ b/drivers/mtd/nand/raw/marvell_nand.c
>>>> @@ -2325,6 +2325,8 @@ static int marvell_nfc_setup_data_interface(struct nand_chip *chip, int chipnr,
>>>>  	struct marvell_nfc_timings nfc_tmg;
>>>>  	int read_delay;
>>>>  
>>>> +	marvell_nfc_select_target(chip, chip->cur_cs);
>>>> +
>>>>  	sdr = nand_get_sdr_timings(conf);
>>>>  	if (IS_ERR(sdr))
>>>>  		return PTR_ERR(sdr);  
>>>
>>> I had a short look yesterday and this is very likely to be the root
>>> cause of the regression, thank you very much!  
>>
>> Yes it is, it fixes the regression I have reported.
>>
>> Do you want me to resend with that nit addressed you mentioned? My
>> version works well, I know that much :)
> 
> Yes please, resent with Boris' comment addressed and we'll be fine.

I tried this now, and with 'chip->cur_cs' instead of 'chipnr', the
regression is back. This function is invoked twice during boot, and in
both cases, 'chip->cur_cs' is -1, while 'chipnr' is 0. The 2nd time this
function is invoked, the 'selected_die' cache value is 0, so
marvell_nfc_select_target() bails early, which seems to be a problem.

I can't quite make sense of that yet, all I know is that calling
marvell_nfc_select_target() with -1 from
marvell_nfc_setup_data_interface() makes the driver functional again. Hmm.


Thanks,
Daniel

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