From: Dong Aisheng aisheng.dong@nxp.com
[ Upstream commit ba5f9fa0ca85a6137fa35efd3a1256d8bb6bc5ff ]
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, Anson fixes this by checking whether restore is actually needed when resume.
Signed-off-by: Dong Aisheng aisheng.dong@nxp.com Signed-off-by: Anson Huang Anson.Huang@nxp.com Signed-off-by: Jassi Brar jaswinder.singh@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 9d6f0217077b2..478308fb82cc6 100644 --- a/drivers/mailbox/imx-mailbox.c +++ b/drivers/mailbox/imx-mailbox.c @@ -66,6 +66,8 @@ struct imx_mu_priv { struct clk *clk; int irq;
+ u32 xcr; + bool side_b; };
@@ -558,12 +560,45 @@ 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); + + return 0; +} + +static const struct dev_pm_ops imx_mu_pm_ops = { + SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(imx_mu_suspend_noirq, + imx_mu_resume_noirq) +}; + static struct platform_driver imx_mu_driver = { .probe = imx_mu_probe, .remove = imx_mu_remove, .driver = { .name = "imx_mu", .of_match_table = imx_mu_dt_ids, + .pm = &imx_mu_pm_ops, }, }; module_platform_driver(imx_mu_driver);