Re: [PATCH v2] console: console: Complete exception handling in newport_probe()

[Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>]

On 4/23/20 5:05 PM, Andy Shevchenko wrote:
> On Thu, Apr 23, 2020 at 5:55 PM Bartlomiej Zolnierkiewicz
> <b.zolnierkie@samsung.com> wrote:
> 
>>> +     if (err)
>>> +             iounmap((void *)npregs);
>>
>> Looks OK but while you are at it, could you please also add missing
>> release_mem_region() on error and on device removal:
>>
>>         newport_addr = dev->resource.start + 0xF0000;
>>         if (!request_mem_region(newport_addr, 0x10000, "Newport"))
>>                 return -ENODEV;
>>
>>         npregs = (struct newport_regs *)/* ioremap cannot fail */
>>                 ioremap(newport_addr, sizeof(struct newport_regs));
>>         console_lock();
>>         err = do_take_over_console(&newport_con, 0, MAX_NR_CONSOLES - 1, 1);
>>         console_unlock();
>>         return err;
>> }
>>
>> static void newport_remove(struct gio_device *dev)
>> {
>>         give_up_console(&newport_con);
>>         iounmap((void *)npregs);
>> }
>>
>> ?
> 
> Don't you think that proper solution is rather switch to memremap()?

Doesn't seem to be a case here (used memory region in uncached).

On MIPS (this is MIPS-only driver):

...
#define ioremap(offset, size)						\
	__ioremap_mode((offset), (size), _CACHE_UNCACHED)
#define ioremap_uc		ioremap
...

While memremap() is only for cacheable memory:

...
 * memremap() - remap an iomem_resource as cacheable memory
 * @offset: iomem resource start address
 * @size: size of remap
 * @flags: any of MEMREMAP_WB, MEMREMAP_WT, MEMREMAP_WC,
 *		  MEMREMAP_ENC, MEMREMAP_DEC
...


>>>       return err;
>>>  }
> 
 
Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics