[PATCH AUTOSEL 5.4 161/330] clk: imx: Fix division by zero warning on pfdv2

Sasha Levin
2020-09-18T02:04:35Z

From: Anson Huang <Anson.Huang@nxp.com>

[ Upstream commit 28b2f82e0383e27476be8a5e13d2aea07ebeb275 ]

Fix below division by zero warning:

[ 3.176443] Division by zero in kernel.
[ 3.181809] CPU: 0 PID: 88 Comm: kworker/0:2 Not tainted 5.3.0-rc2-next-20190730-63758-ge08da51-dirty #124
[ 3.191817] Hardware name: Freescale i.MX7ULP (Device Tree)
[ 3.197821] Workqueue: events dbs_work_handler
[ 3.202849] [<c01127d8>] (unwind_backtrace) from [<c010cd80>] (show_stack+0x10/0x14)
[ 3.211058] [<c010cd80>] (show_stack) from [<c0c77e68>] (dump_stack+0xd8/0x110)
[ 3.218820] [<c0c77e68>] (dump_stack) from [<c0c753c0>] (Ldiv0_64+0x8/0x18)
[ 3.226263] [<c0c753c0>] (Ldiv0_64) from [<c05984b4>] (clk_pfdv2_set_rate+0x54/0xac)
[ 3.234487] [<c05984b4>] (clk_pfdv2_set_rate) from [<c059192c>] (clk_change_rate+0x1a4/0x698)
[ 3.243468] [<c059192c>] (clk_change_rate) from [<c0591a08>] (clk_change_rate+0x280/0x698)
[ 3.252180] [<c0591a08>] (clk_change_rate) from [<c0591fc0>] (clk_core_set_rate_nolock+0x1a0/0x278)
[ 3.261679] [<c0591fc0>] (clk_core_set_rate_nolock) from [<c05920c8>] (clk_set_rate+0x30/0x64)
[ 3.270743] [<c05920c8>] (clk_set_rate) from [<c089cb88>] (imx7ulp_set_target+0x184/0x2a4)
[ 3.279501] [<c089cb88>] (imx7ulp_set_target) from [<c0896358>] (__cpufreq_driver_target+0x188/0x514)
[ 3.289196] [<c0896358>] (__cpufreq_driver_target) from [<c0899b0c>] (od_dbs_update+0x130/0x15c)
[ 3.298438] [<c0899b0c>] (od_dbs_update) from [<c089a5d0>] (dbs_work_handler+0x2c/0x5c)
[ 3.306914] [<c089a5d0>] (dbs_work_handler) from [<c0156858>] (process_one_work+0x2ac/0x704)
[ 3.315826] [<c0156858>] (process_one_work) from [<c0156cdc>] (worker_thread+0x2c/0x574)
[ 3.324404] [<c0156cdc>] (worker_thread) from [<c015cfe8>] (kthread+0x134/0x148)
[ 3.332278] [<c015cfe8>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20)
[ 3.339858] Exception stack(0xe82d5fb0 to 0xe82d5ff8)
[ 3.345314] 5fa0: 00000000 00000000 00000000 00000000
[ 3.353926] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[ 3.362519] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/clk/imx/clk-pfdv2.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/drivers/clk/imx/clk-pfdv2.c b/drivers/clk/imx/clk-pfdv2.c
index a03bbed662c6b..2a46b9b61b466 100644
--- a/drivers/clk/imx/clk-pfdv2.c
+++ b/drivers/clk/imx/clk-pfdv2.c
@@ -139,6 +139,12 @@ static int clk_pfdv2_set_rate(struct clk_hw *hw, unsigned long rate,
u32 val;
u8 frac;

+ if (!rate)
+ return -EINVAL;
+
+ /* PFD can NOT change rate without gating */
+ WARN_ON(clk_pfdv2_is_enabled(hw));
+
tmp = tmp * 18 + rate / 2;
do_div(tmp, rate);
frac = tmp;
--
2.25.1