[PATCH 4.14 075/185] ASoC: rsnd: dont call clk_get_rate() under atomic context

From: Greg Kroah-Hartman
Date: Thu Oct 03 2019 - 12:09:35 EST


From: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>

[ Upstream commit 06e8f5c842f2dbb232897ba967ea7b422745c271 ]

ADG is using clk_get_rate() under atomic context, thus, we might
have scheduling issue.
To avoid this issue, we need to get/keep clk rate under
non atomic context.

We need to handle ADG as special device at Renesas Sound driver.
>From SW point of view, we want to impletent it as
rsnd_mod_ops :: prepare, but it makes code just complicate.

To avoid complicated code/patch, this patch adds new clk_rate[] array,
and keep clk IN rate when rsnd_adg_clk_enable() was called.

Reported-by: Leon Kong <Leon.KONG@xxxxxxxxxxxx>
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@xxxxxxxxxxx>
Tested-by: Leon Kong <Leon.KONG@xxxxxxxxxxxx>
Link: https://lore.kernel.org/r/87v9vb0xkp.wl-kuninori.morimoto.gx@xxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
sound/soc/sh/rcar/adg.c | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)

diff --git a/sound/soc/sh/rcar/adg.c b/sound/soc/sh/rcar/adg.c
index eb7879bcc6a79..686401bcd1f53 100644
--- a/sound/soc/sh/rcar/adg.c
+++ b/sound/soc/sh/rcar/adg.c
@@ -33,6 +33,7 @@ struct rsnd_adg {
struct clk *clkout[CLKOUTMAX];
struct clk_onecell_data onecell;
struct rsnd_mod mod;
+ int clk_rate[CLKMAX];
u32 flags;
u32 ckr;
u32 rbga;
@@ -110,9 +111,9 @@ static void __rsnd_adg_get_timesel_ratio(struct rsnd_priv *priv,
unsigned int val, en;
unsigned int min, diff;
unsigned int sel_rate[] = {
- clk_get_rate(adg->clk[CLKA]), /* 0000: CLKA */
- clk_get_rate(adg->clk[CLKB]), /* 0001: CLKB */
- clk_get_rate(adg->clk[CLKC]), /* 0010: CLKC */
+ adg->clk_rate[CLKA], /* 0000: CLKA */
+ adg->clk_rate[CLKB], /* 0001: CLKB */
+ adg->clk_rate[CLKC], /* 0010: CLKC */
adg->rbga_rate_for_441khz, /* 0011: RBGA */
adg->rbgb_rate_for_48khz, /* 0100: RBGB */
};
@@ -328,7 +329,7 @@ int rsnd_adg_clk_query(struct rsnd_priv *priv, unsigned int rate)
* AUDIO_CLKA/AUDIO_CLKB/AUDIO_CLKC/AUDIO_CLKI.
*/
for_each_rsnd_clk(clk, adg, i) {
- if (rate == clk_get_rate(clk))
+ if (rate == adg->clk_rate[i])
return sel_table[i];
}

@@ -394,10 +395,18 @@ void rsnd_adg_clk_control(struct rsnd_priv *priv, int enable)

for_each_rsnd_clk(clk, adg, i) {
ret = 0;
- if (enable)
+ if (enable) {
ret = clk_prepare_enable(clk);
- else
+
+ /*
+ * We shouldn't use clk_get_rate() under
+ * atomic context. Let's keep it when
+ * rsnd_adg_clk_enable() was called
+ */
+ adg->clk_rate[i] = clk_get_rate(adg->clk[i]);
+ } else {
clk_disable_unprepare(clk);
+ }

if (ret < 0)
dev_warn(dev, "can't use clk %d\n", i);
--
2.20.1