On Wed, 2 Dec 2020 at 05:16, John Wang <wangzhiqiang...@bytedance.com> wrote: > > From: Jae Hyun Yoo <jae.hyun....@intel.com> > > 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. > > Signed-off-by: Jae Hyun Yoo <jae.hyun....@intel.com> > Signed-off-by: Vernon Mauery <vernon.mau...@linux.intel.com> > Signed-off-by: John Wang <wangzhiqiang...@bytedance.com>
Reviewed-by: Joel Stanley <j...@jms.id.au> Thanks for sending these John. It is an excellent idea to upstream fixes that have been developed. I assume we will have the same issue for all devices that use the LPC bus? eg. vuart, bt, kcs, lpc2ahb? It looks like only the lpc-ctrl (lpc2ahb) does this so far: git grep -l clk drivers/soc/aspeed/aspeed-p2a-ctrl.c drivers/soc/aspeed/aspeed-lpc-ctrl.c drivers/char/ipmi/kcs_bmc_aspeed.c drivers/char/ipmi/bt-bmc.c drivers/soc/aspeed/aspeed-lpc-ctrl.c > --- > drivers/soc/aspeed/aspeed-lpc-snoop.c | 30 ++++++++++++++++++++++++--- > 1 file changed, 27 insertions(+), 3 deletions(-) > > diff --git a/drivers/soc/aspeed/aspeed-lpc-snoop.c > b/drivers/soc/aspeed/aspeed-lpc-snoop.c > index 682ba0eb4eba..20acac6342ef 100644 > --- a/drivers/soc/aspeed/aspeed-lpc-snoop.c > +++ b/drivers/soc/aspeed/aspeed-lpc-snoop.c > @@ -11,6 +11,7 @@ > */ > > #include <linux/bitops.h> > +#include <linux/clk.h> > #include <linux/interrupt.h> > #include <linux/fs.h> > #include <linux/kfifo.h> > @@ -67,6 +68,7 @@ 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]; > }; > > @@ -282,22 +284,42 @@ 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; > } > > @@ -309,6 +331,8 @@ 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; > } > > -- > 2.25.1 >