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authorStephen Boyd <sboyd@kernel.org>2019-04-19 13:06:58 -0700
committerStephen Boyd <sboyd@kernel.org>2019-04-19 13:06:58 -0700
commitac71e68746a3286458bb5d8792111c7bc508195f (patch)
tree74a2c387a6fdb4bf26801f60eba91db6b4037909
parent5a7efdacb9dda1c35fb414d57b3e16d520e2c0db (diff)
parent1054e4dd1cbbb7bf5cc836832648f9972134ef67 (diff)
Merge tag 'clk-fixes-for-5.1' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux into clk-fixes
Pull Allwinner clk fixes from Maxime Ripard: - Some fixes for odd cases of the NKMP clocks * tag 'clk-fixes-for-5.1' of https://git.kernel.org/pub/scm/linux/kernel/git/sunxi/linux: clk: sunxi-ng: nkmp: Explain why zero width check is needed clk: sunxi-ng: nkmp: Avoid GENMASK(-1, 0)
-rw-r--r--drivers/clk/sunxi-ng/ccu_nkmp.c24
1 files changed, 19 insertions, 5 deletions
diff --git a/drivers/clk/sunxi-ng/ccu_nkmp.c b/drivers/clk/sunxi-ng/ccu_nkmp.c
index 9b49adb20d07..cbcdf664f336 100644
--- a/drivers/clk/sunxi-ng/ccu_nkmp.c
+++ b/drivers/clk/sunxi-ng/ccu_nkmp.c
@@ -167,7 +167,7 @@ static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
struct ccu_nkmp *nkmp = hw_to_ccu_nkmp(hw);
- u32 n_mask, k_mask, m_mask, p_mask;
+ u32 n_mask = 0, k_mask = 0, m_mask = 0, p_mask = 0;
struct _ccu_nkmp _nkmp;
unsigned long flags;
u32 reg;
@@ -186,10 +186,24 @@ static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,
ccu_nkmp_find_best(parent_rate, rate, &_nkmp);
- n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1, nkmp->n.shift);
- k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1, nkmp->k.shift);
- m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1, nkmp->m.shift);
- p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1, nkmp->p.shift);
+ /*
+ * If width is 0, GENMASK() macro may not generate expected mask (0)
+ * as it falls under undefined behaviour by C standard due to shifts
+ * which are equal or greater than width of left operand. This can
+ * be easily avoided by explicitly checking if width is 0.
+ */
+ if (nkmp->n.width)
+ n_mask = GENMASK(nkmp->n.width + nkmp->n.shift - 1,
+ nkmp->n.shift);
+ if (nkmp->k.width)
+ k_mask = GENMASK(nkmp->k.width + nkmp->k.shift - 1,
+ nkmp->k.shift);
+ if (nkmp->m.width)
+ m_mask = GENMASK(nkmp->m.width + nkmp->m.shift - 1,
+ nkmp->m.shift);
+ if (nkmp->p.width)
+ p_mask = GENMASK(nkmp->p.width + nkmp->p.shift - 1,
+ nkmp->p.shift);
spin_lock_irqsave(nkmp->common.lock, flags);