linux-kernel - Re: [PATCH] clk: socfpga: fix iomem pointer cast on 64-bit

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Date:   Sun, 14 Mar 2021 12:04:31 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
To:     Stephen Boyd <sboyd@...nel.org>, Dinh Nguyen <dinguyen@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Arnd Bergmann <arnd@...db.de>
Subject: Re: [PATCH] clk: socfpga: fix iomem pointer cast on 64-bit

On 13/03/2021 22:10, Stephen Boyd wrote:
> Quoting Krzysztof Kozlowski (2021-03-11 06:48:33)
>> Pointers should be cast to unsigned long instead of integer.  This fixes
>> warning when compile testing on ARM64:
>>
>>   drivers/clk/socfpga/clk-gate.c: In function ‘socfpga_clk_recalc_rate’:
>>   drivers/clk/socfpga/clk-gate.c:102:7: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
>>
>> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@...onical.com>
> 
> Any Fixes tag?

I'll add it.

> 
>> ---
>>  drivers/clk/socfpga/clk-gate.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/clk/socfpga/clk-gate.c b/drivers/clk/socfpga/clk-gate.c
>> index 43ecd507bf83..c876523d5d51 100644
>> --- a/drivers/clk/socfpga/clk-gate.c
>> +++ b/drivers/clk/socfpga/clk-gate.c
>> @@ -99,7 +99,7 @@ static unsigned long socfpga_clk_recalc_rate(struct clk_hw *hwclk,
>>                 val = readl(socfpgaclk->div_reg) >> socfpgaclk->shift;
>>                 val &= GENMASK(socfpgaclk->width - 1, 0);
>>                 /* Check for GPIO_DB_CLK by its offset */
>> -               if ((int) socfpgaclk->div_reg & SOCFPGA_GPIO_DB_CLK_OFFSET)
>> +               if ((unsigned long) socfpgaclk->div_reg & SOCFPGA_GPIO_DB_CLK_OFFSET)
> 
> Should it be uintptr_t casted instead?

Good point, thanks!

> his isn't a very great code
> pattern given the way we store information in the iomem pointer about
> which clk type it is and then have to cast the pointer and assume
> alignment. Would be nice to get rid of it but I understand.

Best regards,
Krzysztof