[ Upstream commit
f7b7d30158cff246667273bd2a62fc93ee0725d2 ]
If the parent clock rate is greater than unsigned long max/2 then
integer overflow happens when calculating the clock rate on 32-bit systems.
As RCG2 uses half integer dividers, the clock rate is first being
multiplied by 2 which will overflow the unsigned long max value.
Hence, replace the common pattern of doing 64-bit multiplication
and then a do_div() call with simpler mult_frac call.
Fixes:
bcd61c0f535a ("clk: qcom: Add support for root clock generators (RCGs)")
Signed-off-by: Devi Priya <quic_devipriy@quicinc.com>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Link: https://lore.kernel.org/r/20230901073640.4973-1-quic_devipriy@quicinc.com
[bjorn: Also drop unnecessary {} around single statements]
Signed-off-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
static unsigned long
calc_rate(unsigned long rate, u32 m, u32 n, u32 mode, u32 hid_div)
{
- if (hid_div) {
- rate *= 2;
- rate /= hid_div + 1;
- }
+ if (hid_div)
+ rate = mult_frac(rate, 2, hid_div + 1);
- if (mode) {
- u64 tmp = rate;
- tmp *= m;
- do_div(tmp, n);
- rate = tmp;
- }
+ if (mode)
+ rate = mult_frac(rate, m, n);
return rate;
}