> -----Original Message----- > From: Joel Stanley <joel@xxxxxxxxx> > Sent: Monday, March 1, 2021 2:44 PM > To: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>; John Wang > <wangzhiqiang.bj@xxxxxxxxxxxxx>; Yoo, Jae Hyun > <jae.hyun.yoo@xxxxxxxxx> > Cc: Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; > stable@xxxxxxxxxxxxxxx; Vernon Mauery <vernon.mauery@xxxxxxxxxxxxxxx>; > Sasha Levin <sashal@xxxxxxxxxx> > Subject: Re: [PATCH 4.19 055/247] soc: aspeed: snoop: Add clock control logic > > On Mon, 1 Mar 2021 at 16:37, Greg Kroah-Hartman > <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > > > From: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxx> > > > > [ Upstream commit 3f94cf15583be554df7aaa651b8ff8e1b68fbe51 ] > > > > If LPC SNOOP driver is registered ahead of lpc-ctrl module, LPC SNOOP > > block will be enabled without heart beating of LCLK until lpc-ctrl > > enables the LCLK. This issue causes improper handling on host > > interrupts when the host sends interrupt in that time frame. > > Then kernel eventually forcibly disables the interrupt with dumping > > stack and printing a 'nobody cared this irq' message out. > > > > To prevent this issue, all LPC sub-nodes should enable LCLK > > individually so this patch adds clock control logic into the LPC SNOOP > > driver. > > Jae, John; with this backported do we need to also provide a corresponding > device tree change for the stable tree, otherwise this driver will no longer > probe? Right. The second patch https://lore.kernel.org/linux-arm-kernel/20201208091748.1920-2-wangzhiqiang.bj@xxxxxxxxxxxxx/ John submitted should be applied to stable tree too to make this module be probed correctly. > > > > Fixes: 3772e5da4454 ("drivers/misc: Aspeed LPC snoop output using misc > > chardev") > > Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@xxxxxxxxx> > > Signed-off-by: Vernon Mauery <vernon.mauery@xxxxxxxxxxxxxxx> > > Signed-off-by: John Wang <wangzhiqiang.bj@xxxxxxxxxxxxx> > > Reviewed-by: Joel Stanley <joel@xxxxxxxxx> > > Link: > > https://lore.kernel.org/r/20201208091748.1920-1-wangzhiqiang.bj@byteda > > nce.com > > Signed-off-by: Joel Stanley <joel@xxxxxxxxx> > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> > > --- > > drivers/misc/aspeed-lpc-snoop.c | 30 +++++++++++++++++++++++++++- > -- > > 1 file changed, 27 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/misc/aspeed-lpc-snoop.c > > b/drivers/misc/aspeed-lpc-snoop.c index c10be21a1663d..b4a776bf44bc5 > > 100644 > > --- a/drivers/misc/aspeed-lpc-snoop.c > > +++ b/drivers/misc/aspeed-lpc-snoop.c > > @@ -15,6 +15,7 @@ > > */ > > > > #include <linux/bitops.h> > > +#include <linux/clk.h> > > #include <linux/interrupt.h> > > #include <linux/fs.h> > > #include <linux/kfifo.h> > > @@ -71,6 +72,7 @@ struct aspeed_lpc_snoop_channel { struct > > aspeed_lpc_snoop { > > struct regmap *regmap; > > int irq; > > + struct clk *clk; > > struct aspeed_lpc_snoop_channel chan[NUM_SNOOP_CHANNELS]; }; > > > > @@ -286,22 +288,42 @@ static int aspeed_lpc_snoop_probe(struct > platform_device *pdev) > > return -ENODEV; > > } > > > > + lpc_snoop->clk = devm_clk_get(dev, NULL); > > + if (IS_ERR(lpc_snoop->clk)) { > > + rc = PTR_ERR(lpc_snoop->clk); > > + if (rc != -EPROBE_DEFER) > > + dev_err(dev, "couldn't get clock\n"); > > + return rc; > > + } > > + rc = clk_prepare_enable(lpc_snoop->clk); > > + if (rc) { > > + dev_err(dev, "couldn't enable clock\n"); > > + return rc; > > + } > > + > > rc = aspeed_lpc_snoop_config_irq(lpc_snoop, pdev); > > if (rc) > > - return rc; > > + goto err; > > > > rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 0, port); > > if (rc) > > - return rc; > > + goto err; > > > > /* Configuration of 2nd snoop channel port is optional */ > > if (of_property_read_u32_index(dev->of_node, "snoop-ports", > > 1, &port) == 0) { > > rc = aspeed_lpc_enable_snoop(lpc_snoop, dev, 1, port); > > - if (rc) > > + if (rc) { > > aspeed_lpc_disable_snoop(lpc_snoop, 0); > > + goto err; > > + } > > } > > > > + return 0; > > + > > +err: > > + clk_disable_unprepare(lpc_snoop->clk); > > + > > return rc; > > } > > > > @@ -313,6 +335,8 @@ static int aspeed_lpc_snoop_remove(struct > platform_device *pdev) > > aspeed_lpc_disable_snoop(lpc_snoop, 0); > > aspeed_lpc_disable_snoop(lpc_snoop, 1); > > > > + clk_disable_unprepare(lpc_snoop->clk); > > + > > return 0; > > } > > > > -- > > 2.27.0 > > > > > >
