On 3/30/2019 6:48 AM Stephen Boyd wrote:
>Quoting nixiaoming (2019-03-29 04:46:00)
>> The _get_div function has a branch with a return value of 0
>> Add a check on the return value of _get_div to avoid divide-by-zero
>>
>> Signed-off-by: nixiaoming <nixiaom...@huawei.com>
>
>Similar questions apply here as they do on the generic divider patch you
>sent.
>
_get_div() in both files is a different function, with a divide-by-zero problem
I will organize it into a patch set later.
>> ---
>> drivers/clk/mmp/clk-mix.c | 4 ++++
>> 1 file changed, 4 insertions(+)
>>
>> diff --git a/drivers/clk/mmp/clk-mix.c b/drivers/clk/mmp/clk-mix.c
>> index 90814b2..9d152c2 100644
>> --- a/drivers/clk/mmp/clk-mix.c
>> +++ b/drivers/clk/mmp/clk-mix.c
>> @@ -245,6 +245,8 @@ static int mmp_clk_mix_determine_rate(struct clk_hw *hw,
>> div_val_max = _get_maxdiv(mix);
>> for (j = 0; j < div_val_max; j++) {
>> div = _get_div(mix, j);
>> + if (!div) /* avoid divide-by-zero */
>
>Why can't we return 1 for the divider value here?
I personally understand that an exception or skip should be thrown after
dividing by 0.
Directly modified to other values, I am not sure whether it affects the logic
My logical understanding of this code is not clear enough, I still need your
guidance.
>
>> + continue;
>> mix_rate = parent_rate / div;
>> gap = abs(mix_rate - req->rate);
>> if (!parent_best || gap < gap_best) {
>> @@ -341,6 +343,8 @@ static unsigned long mmp_clk_mix_recalc_rate(struct
>> clk_hw *hw,
>> shift = mix->reg_info.shift_div;
>>
>> div = _get_div(mix, MMP_CLK_BITS_GET_VAL(mux_div, width, shift));
>> + if (!div) /* avoid divide-by-zero */
>
>Same question.
I personally understand that an exception or skip should be thrown after
dividing by 0.
Directly modified to other values, I am not sure whether it affects the logic
My logical understanding of this code is not clear enough, I still need your
guidance.
>
>> + return -EINVAL;
>>
>> return parent_rate / div;
>> }
>
