[2/2] mtd: concat: implement _is_locked mtd operation
diff mbox series

Message ID 20190522000753.13300-2-chris.packham@alliedtelesis.co.nz
State Superseded
Delegated to: Richard Weinberger
Headers show
Series
  • [1/2] mtd: concat: refactor concat_lock/concat_unlock
Related show

Commit Message

Chris Packham May 22, 2019, 12:07 a.m. UTC
Add an implementation of the _is_locked operation for concatenated mtd
devices. As with concat_lock/concat_unlock this can simply use the
common helper and pass mtd_is_locked as the operation.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
---
 drivers/mtd/mtdconcat.c | 6 ++++++
 1 file changed, 6 insertions(+)

Comments

Richard Weinberger May 22, 2019, 8:44 p.m. UTC | #1
On Wed, May 22, 2019 at 2:08 AM Chris Packham
<chris.packham@alliedtelesis.co.nz> wrote:
>
> Add an implementation of the _is_locked operation for concatenated mtd
> devices. As with concat_lock/concat_unlock this can simply use the
> common helper and pass mtd_is_locked as the operation.
>
> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> ---
>  drivers/mtd/mtdconcat.c | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
> index 9514cd2db63c..0e919f3423af 100644
> --- a/drivers/mtd/mtdconcat.c
> +++ b/drivers/mtd/mtdconcat.c
> @@ -496,6 +496,11 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>         return __concat_xxlock(mtd, ofs, len, mtd_unlock);
>  }
>
> +static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> +{
> +       return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
> +}

Hmm, here you start abusing your own new API. :(

Did you verify that the unlock/lock-functions deal correctly with all
semantics from mtd_is_locked?
i.e. mtd_is_locked() with len = 0 returns 1 for spi-nor.
Chris Packham May 22, 2019, 9:06 p.m. UTC | #2
On 23/05/19 8:44 AM, Richard Weinberger wrote:
> On Wed, May 22, 2019 at 2:08 AM Chris Packham
> <chris.packham@alliedtelesis.co.nz> wrote:
>>
>> Add an implementation of the _is_locked operation for concatenated mtd
>> devices. As with concat_lock/concat_unlock this can simply use the
>> common helper and pass mtd_is_locked as the operation.
>>
>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>> ---
>>   drivers/mtd/mtdconcat.c | 6 ++++++
>>   1 file changed, 6 insertions(+)
>>
>> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
>> index 9514cd2db63c..0e919f3423af 100644
>> --- a/drivers/mtd/mtdconcat.c
>> +++ b/drivers/mtd/mtdconcat.c
>> @@ -496,6 +496,11 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>          return __concat_xxlock(mtd, ofs, len, mtd_unlock);
>>   }
>>
>> +static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>> +{
>> +       return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
>> +}
> 
> Hmm, here you start abusing your own new API. :(

Abusing because xxlock is a poor choice of name? I initially had a third 
copy of the logic from lock/unlock which is what lead me to do the 
cleanup first. mtd_lock(), mtd_unlock() and mtd_is_locked() all work the 
same way namely given an offset and a length either lock, unlock or 
return the status of the len/erasesz blocks at ofs.

> 
> Did you verify that the unlock/lock-functions deal correctly with all
> semantics from mtd_is_locked?
> i.e. mtd_is_locked() with len = 0 returns 1 for spi-nor.
> 

I believe so. I've only got access to a parallel NOR flash system that 
uses concatenation and that seems sane  (is mtdconcat able to work with 
spi memories?). The concat_is_locked() should just reflect what the 
underlying mtd device driver returns.
Richard Weinberger May 22, 2019, 9:26 p.m. UTC | #3
On Wed, May 22, 2019 at 11:06 PM Chris Packham
<Chris.Packham@alliedtelesis.co.nz> wrote:
>
> On 23/05/19 8:44 AM, Richard Weinberger wrote:
> > On Wed, May 22, 2019 at 2:08 AM Chris Packham
> > <chris.packham@alliedtelesis.co.nz> wrote:
> >>
> >> Add an implementation of the _is_locked operation for concatenated mtd
> >> devices. As with concat_lock/concat_unlock this can simply use the
> >> common helper and pass mtd_is_locked as the operation.
> >>
> >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> >> ---
> >>   drivers/mtd/mtdconcat.c | 6 ++++++
> >>   1 file changed, 6 insertions(+)
> >>
> >> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
> >> index 9514cd2db63c..0e919f3423af 100644
> >> --- a/drivers/mtd/mtdconcat.c
> >> +++ b/drivers/mtd/mtdconcat.c
> >> @@ -496,6 +496,11 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> >>          return __concat_xxlock(mtd, ofs, len, mtd_unlock);
> >>   }
> >>
> >> +static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> >> +{
> >> +       return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
> >> +}
> >
> > Hmm, here you start abusing your own new API. :(
>
> Abusing because xxlock is a poor choice of name? I initially had a third
> copy of the logic from lock/unlock which is what lead me to do the
> cleanup first. mtd_lock(), mtd_unlock() and mtd_is_locked() all work the
> same way namely given an offset and a length either lock, unlock or
> return the status of the len/erasesz blocks at ofs.

Well, for unlock/lock it is just a loop which applies an operation to
a given range on all submtds.
But as soon an operation returns non-zero, the loop stops and returns
that error.
This makes sense for unlock/lock.

Now you abuse this as "apply a random mtd operation to a given range".
So, giving it a proper name is the first step. Step two is figuring
for what kind
of mtd operations it makes sense and is correct.

> >
> > Did you verify that the unlock/lock-functions deal correctly with all
> > semantics from mtd_is_locked?
> > i.e. mtd_is_locked() with len = 0 returns 1 for spi-nor.
> >
>
> I believe so. I've only got access to a parallel NOR flash system that
> uses concatenation and that seems sane  (is mtdconcat able to work with
> spi memories?). The concat_is_locked() should just reflect what the
> underlying mtd device driver returns.

mtdconcat *should* work with any mtd. But I never used it much, I see
it more as legacy
code.

What happens if one submtd is locked and another not?
Does concat_is_locked() return something sane then?
I'd expect it to return true if at least one submtd is locked and 0
of no submtd is locked.

If the loop and return code handling in __concat_xxlock() can take care of that,
awesome. Then all you need is giving it a better name. :-)
Richard Weinberger May 22, 2019, 9:35 p.m. UTC | #4
On Wed, May 22, 2019 at 11:26 PM Richard Weinberger
<richard.weinberger@gmail.com> wrote:
>
> On Wed, May 22, 2019 at 11:06 PM Chris Packham
> <Chris.Packham@alliedtelesis.co.nz> wrote:
> >
> > On 23/05/19 8:44 AM, Richard Weinberger wrote:
> > > On Wed, May 22, 2019 at 2:08 AM Chris Packham
> > > <chris.packham@alliedtelesis.co.nz> wrote:
> > >>
> > >> Add an implementation of the _is_locked operation for concatenated mtd
> > >> devices. As with concat_lock/concat_unlock this can simply use the
> > >> common helper and pass mtd_is_locked as the operation.
> > >>
> > >> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
> > >> ---
> > >>   drivers/mtd/mtdconcat.c | 6 ++++++
> > >>   1 file changed, 6 insertions(+)
> > >>
> > >> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
> > >> index 9514cd2db63c..0e919f3423af 100644
> > >> --- a/drivers/mtd/mtdconcat.c
> > >> +++ b/drivers/mtd/mtdconcat.c
> > >> @@ -496,6 +496,11 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> > >>          return __concat_xxlock(mtd, ofs, len, mtd_unlock);
> > >>   }
> > >>
> > >> +static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
> > >> +{
> > >> +       return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
> > >> +}
> > >
> > > Hmm, here you start abusing your own new API. :(
> >
> > Abusing because xxlock is a poor choice of name? I initially had a third
> > copy of the logic from lock/unlock which is what lead me to do the
> > cleanup first. mtd_lock(), mtd_unlock() and mtd_is_locked() all work the
> > same way namely given an offset and a length either lock, unlock or
> > return the status of the len/erasesz blocks at ofs.
>
> Well, for unlock/lock it is just a loop which applies an operation to
> a given range on all submtds.
> But as soon an operation returns non-zero, the loop stops and returns
> that error.
> This makes sense for unlock/lock.
>
> Now you abuse this as "apply a random mtd operation to a given range".
> So, giving it a proper name is the first step. Step two is figuring
> for what kind
> of mtd operations it makes sense and is correct.
>
> > >
> > > Did you verify that the unlock/lock-functions deal correctly with all
> > > semantics from mtd_is_locked?
> > > i.e. mtd_is_locked() with len = 0 returns 1 for spi-nor.
> > >
> >
> > I believe so. I've only got access to a parallel NOR flash system that
> > uses concatenation and that seems sane  (is mtdconcat able to work with
> > spi memories?). The concat_is_locked() should just reflect what the
> > underlying mtd device driver returns.
>
> mtdconcat *should* work with any mtd. But I never used it much, I see
> it more as legacy
> code.
>
> What happens if one submtd is locked and another not?
> Does concat_is_locked() return something sane then?
> I'd expect it to return true if at least one submtd is locked and 0
> of no submtd is locked.

BTW: Meant overlapping requests. If it targets always only one submtd,
it is easy.
Chris Packham May 22, 2019, 10:16 p.m. UTC | #5
On 23/05/19 9:27 AM, Richard Weinberger wrote:
> On Wed, May 22, 2019 at 11:06 PM Chris Packham
> <Chris.Packham@alliedtelesis.co.nz> wrote:
>>
>> On 23/05/19 8:44 AM, Richard Weinberger wrote:
>>> On Wed, May 22, 2019 at 2:08 AM Chris Packham
>>> <chris.packham@alliedtelesis.co.nz> wrote:
>>>>
>>>> Add an implementation of the _is_locked operation for concatenated mtd
>>>> devices. As with concat_lock/concat_unlock this can simply use the
>>>> common helper and pass mtd_is_locked as the operation.
>>>>
>>>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>>>> ---
>>>>    drivers/mtd/mtdconcat.c | 6 ++++++
>>>>    1 file changed, 6 insertions(+)
>>>>
>>>> diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
>>>> index 9514cd2db63c..0e919f3423af 100644
>>>> --- a/drivers/mtd/mtdconcat.c
>>>> +++ b/drivers/mtd/mtdconcat.c
>>>> @@ -496,6 +496,11 @@ static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>>>           return __concat_xxlock(mtd, ofs, len, mtd_unlock);
>>>>    }
>>>>
>>>> +static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
>>>> +{
>>>> +       return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
>>>> +}
>>>
>>> Hmm, here you start abusing your own new API. :(
>>
>> Abusing because xxlock is a poor choice of name? I initially had a third
>> copy of the logic from lock/unlock which is what lead me to do the
>> cleanup first. mtd_lock(), mtd_unlock() and mtd_is_locked() all work the
>> same way namely given an offset and a length either lock, unlock or
>> return the status of the len/erasesz blocks at ofs.
> 
> Well, for unlock/lock it is just a loop which applies an operation to
> a given range on all submtds.
> But as soon an operation returns non-zero, the loop stops and returns
> that error.
> This makes sense for unlock/lock.
> 
> Now you abuse this as "apply a random mtd operation to a given range".
> So, giving it a proper name is the first step. Step two is figuring
> for what kind
> of mtd operations it makes sense and is correct.

Ah now I understand you concern. I guess the question is what is the 
right thing for MEMISLOCKED to return when consecutive blocks differ in 
lock status.

>>>
>>> Did you verify that the unlock/lock-functions deal correctly with all
>>> semantics from mtd_is_locked?
>>> i.e. mtd_is_locked() with len = 0 returns 1 for spi-nor.
>>>
>>
>> I believe so. I've only got access to a parallel NOR flash system that
>> uses concatenation and that seems sane  (is mtdconcat able to work with
>> spi memories?). The concat_is_locked() should just reflect what the
>> underlying mtd device driver returns.
> 
> mtdconcat *should* work with any mtd. But I never used it much, I see
> it more as legacy
> code.
> 
> What happens if one submtd is locked and another not?
> Does concat_is_locked() return something sane then?
> I'd expect it to return true if at least one submtd is locked and 0
> of no submtd is locked.
> 
> If the loop and return code handling in __concat_xxlock() can take care of that,
> awesome. Then all you need is giving it a better name. :-)

As implemented right now the loop will stop at the first locked block. 
So if the range starts in a unlocked block and spans into a locked one 
the return value will be 1.

Is that correct? Well do_ppb_xxlock and  do_getlockstatus_oneblock seem 
to only care about the first block (they both ignore len)? So they'd 
return 0 in the case of unlocked,locked.

stm_is_locked_sr does about the len and will return 0 if len falls 
outside the locked region or if ofs starts before the locked region.

So here's a quick breakdown

                  ppb_is_locked intelext_is_locked stm_is_locked concat
unlocked,unlocked            0                  0             0      0
locked,locked                1                  1             1      1
locked,unlocked              1                  1             0      1
unlocked,locked              0                  0             0      1

I'll try and make concat_is_locked consistent with the two cfi 
implementations.

Thanks for your feedback on this. I think the v2 series should look a 
lot better as a result.

Patch
diff mbox series

diff --git a/drivers/mtd/mtdconcat.c b/drivers/mtd/mtdconcat.c
index 9514cd2db63c..0e919f3423af 100644
--- a/drivers/mtd/mtdconcat.c
+++ b/drivers/mtd/mtdconcat.c
@@ -496,6 +496,11 @@  static int concat_unlock(struct mtd_info *mtd, loff_t ofs, uint64_t len)
 	return __concat_xxlock(mtd, ofs, len, mtd_unlock);
 }
 
+static int concat_is_locked(struct mtd_info *mtd, loff_t ofs, uint64_t len)
+{
+	return __concat_xxlock(mtd, ofs, len, mtd_is_locked);
+}
+
 static void concat_sync(struct mtd_info *mtd)
 {
 	struct mtd_concat *concat = CONCAT(mtd);
@@ -695,6 +700,7 @@  struct mtd_info *mtd_concat_create(struct mtd_info *subdev[],	/* subdevices to c
 	concat->mtd._sync = concat_sync;
 	concat->mtd._lock = concat_lock;
 	concat->mtd._unlock = concat_unlock;
+	concat->mtd._is_locked = concat_is_locked;
 	concat->mtd._suspend = concat_suspend;
 	concat->mtd._resume = concat_resume;