Re: [PATCH] clocksource: rtl-otto: Change driver to use __raw reads and writes

[Chris Packham]

Hi Rustam,

On 14/05/2026 06:31, Rustam Adilov wrote:
> On 2026-05-11 13:15, Rustam Adilov wrote:
>> As it stands, the driver uses ioread32 and iowrite32 for register
>> access and it works fine. However this stops working when the
>> SWAP_IO_SPACE config is enabled as this drivers expects ioread32 and
>> iowrite32 to be in native endian (that is big endian for currently
>> supported SoCs). RTL9607C is a big endian MIPS SoC that has identical
>> timer as the already supported chips but needs to have SWAP_IO_SPACE
>> to have a functioning little endian USB host.
>>
>> Fix this by replacing all instances of ioread32 and iowrite32 with
>> __raw_readl and __raw_writel variants. Since they essentially do
>> the same register access, this shouldn't affect anything on other
>> machines.
>>
>> Signed-off-by: Rustam Adilov <adilov@xxxxxxxxxxx>
>> ---
>>   drivers/clocksource/timer-rtl-otto.c | 14 +++++++-------
>>   1 file changed, 7 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/clocksource/timer-rtl-otto.c b/drivers/clocksource/timer-rtl-otto.c
>> index 6113d2fdd4de..bcb449ef0481 100644
>> --- a/drivers/clocksource/timer-rtl-otto.c
>> +++ b/drivers/clocksource/timer-rtl-otto.c
>> @@ -56,37 +56,37 @@ struct rttm_cs {
>>   /* Simple internal register functions */
>>   static inline unsigned int rttm_get_counter(void __iomem *base)
>>   {
>> -	return ioread32(base + RTTM_CNT);
>> +	return __raw_readl(base + RTTM_CNT);
>>   }
>>   
>>   static inline void rttm_set_period(void __iomem *base, unsigned int period)
>>   {
>> -	iowrite32(period, base + RTTM_DATA);
>> +	__raw_writel(period, base + RTTM_DATA);
>>   }
>>   
>>   static inline void rttm_disable_timer(void __iomem *base)
>>   {
>> -	iowrite32(0, base + RTTM_CTRL);
>> +	__raw_writel(0, base + RTTM_CTRL);
>>   }
>>   
>>   static inline void rttm_enable_timer(void __iomem *base, u32 mode, u32 divisor)
>>   {
>> -	iowrite32(RTTM_CTRL_ENABLE | mode | divisor, base + RTTM_CTRL);
>> +	__raw_writel(RTTM_CTRL_ENABLE | mode | divisor, base + RTTM_CTRL);
>>   }
>>   
>>   static inline void rttm_ack_irq(void __iomem *base)
>>   {
>> -	iowrite32(ioread32(base + RTTM_INT) | RTTM_INT_PENDING, base + RTTM_INT);
>> +	__raw_writel(__raw_readl(base + RTTM_INT) | RTTM_INT_PENDING, base + RTTM_INT);
>>   }
>>   
>>   static inline void rttm_enable_irq(void __iomem *base)
>>   {
>> -	iowrite32(RTTM_INT_ENABLE, base + RTTM_INT);
>> +	__raw_writel(RTTM_INT_ENABLE, base + RTTM_INT);
>>   }
>>   
>>   static inline void rttm_disable_irq(void __iomem *base)
>>   {
>> -	iowrite32(0, base + RTTM_INT);
>> +	__raw_writel(0, base + RTTM_INT);
>>   }
>>   
>>   /* Aggregated control functions for kernel clock framework */
> It appears the get_maintainer.pl script didn't catch the Chris Packham, presumably
> because i didn't touch the device bindings file. Added them to CC for review.

No problem.  Has --git been dropped by default from get_maintainer.pl? 
It doesn't actually help as even when explicitly using it that doesn't 
seem to get me (initial commit ignored?), it does find Markus who I've 
added to the Cc.

Reviewed-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>