Messages in this thread | | | From | Anson Huang <> | Subject | RE: [PATCH] mailbox: imx: Add context save/restore for suspend/resume | Date | Fri, 24 Apr 2020 02:32:55 +0000 |
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> Subject: RE: [PATCH] mailbox: imx: Add context save/restore for > suspend/resume > > > From: Anson Huang <Anson.Huang@nxp.com> > > Sent: Friday, April 24, 2020 7:01 AM > > > > For "mem" mode suspend on i.MX8 SoCs, MU settings could be lost > > because its power is off, so save/restore is needed for MU settings during > suspend/resume. > > However, the restore can ONLY be done when MU settings are actually > > lost, for the scenario of settings NOT lost in "freeze" mode suspend, > > since there could be still IPC going on multiple CPUs, restoring the > > MU settings could overwrite the TIE by mistake and cause system > > freeze, so need to make sure ONLY restore the MU settings when it is > powered off. > > > > Signed-off-by: Anson Huang <Anson.Huang@nxp.com> > > As mentioned before, we'd better keep the original author. > > > --- > > drivers/mailbox/imx-mailbox.c | 35 > > +++++++++++++++++++++++++++++++++++ > > 1 file changed, 35 insertions(+) > > > > diff --git a/drivers/mailbox/imx-mailbox.c > > b/drivers/mailbox/imx-mailbox.c index 97bf0ac..b53cf63 100644 > > --- a/drivers/mailbox/imx-mailbox.c > > +++ b/drivers/mailbox/imx-mailbox.c > > @@ -67,6 +67,8 @@ struct imx_mu_priv { > > struct clk *clk; > > int irq; > > > > + u32 xcr; > > + > > bool side_b; > > }; > > > > @@ -583,12 +585,45 @@ static const struct of_device_id imx_mu_dt_ids[] > > = { }; MODULE_DEVICE_TABLE(of, imx_mu_dt_ids); > > > > +static int imx_mu_suspend_noirq(struct device *dev) { > > + struct imx_mu_priv *priv = dev_get_drvdata(dev); > > + > > + priv->xcr = imx_mu_read(priv, priv->dcfg->xCR); > > + > > + return 0; > > +} > > + > > +static int imx_mu_resume_noirq(struct device *dev) { > > + struct imx_mu_priv *priv = dev_get_drvdata(dev); > > + > > + /* > > + * ONLY restore MU when context lost, the TIE could > > + * be set during noirq resume as there is MU data > > + * communication going on, and restore the saved > > + * value will overwrite the TIE and cause MU data > > + * send failed, may lead to system freeze. This issue > > + * is observed by testing freeze mode suspend. > > + */ > > + if (!imx_mu_read(priv, priv->dcfg->xCR)) > > + imx_mu_write(priv, priv->xcr, priv->dcfg->xCR); > > This could be separate patch if it aims to fix a specific corner case.
This is NOT corner case, it can be reproduced with our imx_5.4.y very easily, and this issue cause me many days to debug...Also cause Clark's effort to help test it a lot for many days...
I do NOT think it makes sense to first send out your patch with bug for review, And then add another patch to fix it. 1 patch is enough for this feature.
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