Commit c216620c authored by Enrico Scholz's avatar Enrico Scholz
Browse files

onsemi: core: avoid overflow on 32 bit archs

Intermediate result of 'a * b / c' can overflow on 32 bit archs; calculate
the value by using 64 bit types
Signed-off-by: Enrico Scholz's avatarEnrico Scholz <>
parent 1b37df70
......@@ -3249,6 +3249,19 @@ static void _onsemi_calculate_div(struct onsemi_core const *onsemi,
static unsigned long _ul_mul_div(unsigned long a, unsigned long b, unsigned long c)
uint64_t res;
res = a;
res *= b;
res = div64_ul(res, c);
WARN_ON(res != (unsigned long)res);
return res;
int onsemi_calculate_pll(struct onsemi_core const *onsemi,
struct onsemi_businfo const *bus_info,
unsigned int bpp,
......@@ -3287,7 +3300,7 @@ int onsemi_calculate_pll(struct onsemi_core const *onsemi,
return rc;
freq.ext = onsemi->ext_clk_freq;
freq.vco = freq.ext * cfg.pre_pll_mul / cfg.pre_pll_div;
freq.vco = _ul_mul_div(freq.ext, cfg.pre_pll_mul, cfg.pre_pll_div);
_onsemi_calculate_div(onsemi, bus_info, freq.vco, bpp, &cfg);
Markdown is supported
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment