On 6/3/2024 2:37 AM, Caleb Connolly wrote:
Hi Deepak, On 03/06/2024 09:36, Deepak Kumar Singh wrote:There are certain usecases which require glink interrupt to be wakeup capable. For example if handset is in sleep state and usb charger is plugged in, dsp wakes up and sends glink interrupt to host for glink pmic channel communication. Glink is suppose to wakeup host processor completely for further glink data handling. IRQF_NO_SUSPEND does not gurantee complete wakeup, system may again enter sleep after interrupt handling and glink data may not be handled by pmic client driver. To ensure data handling by client configure glink smem device as wakeup source and attach glink interrupt as wakeup irq. Remove IRQF_NO_SUSPEND flag as it is no longer required.I'm not sure I agree with this approach, glink is used for lots of things -- like QRTR, where the sensor DSP and modem may also need to wake the system up (e.g. for "wake on pickup" on mobile, or for incoming calls/sms).Configuring this to always wake up the system fully will result in a lot of spurious wakeups for arbitrary modem notifications (e.g. signal strength changes) if userspace hasn't properly configured these (something ModemManager currently lacks support for).IRQF_NO_SUSPEND is presumably necessary to keep the DSPs happy? iirc downstream Qualcomm kernels have historically taken this approach to avoid spurious wakeups.
To give some more context, until recently the GLINK interrupt was managed and requested in the GLINK native layer. Any type of interrupt configuration would affect all of the links. The interrupt is now being requested at the transport layer (smem/rpm), so it has a little more fine grain control.
In downstream, we had switched to IRQF_NO_SUSPEND because there were a couple of cases where glink communication with rpm was needed during the suspend path. Having the interrupt configured as wake capable conflicted with the use case.
The general expectation from the DSPs is that if it is important enough to send, then it should be important enough to wake the APPS subsystem. We've always had to work around the fact we were using IRQF_NO_SUSPEND in downstream.
I proposed an alternative approach some time back that would allow the wakeup to be configured on a per-channel basis.https://lore.kernel.org/linux-arm-msm/20230117142414.983946-1-caleb.connolly@xxxxxxxxxx/ > Back then Bjorn proposed using some socket specific mechanism to handlethis for QRTR, but given this is now a common issue for multiple glink channels, maybe it's something we could revisit.Requiring the wakeup be enabled by userspace clearly doesn't make sense for your proposed usecase, perhaps there's a way to configure this on a per-channel basis in-kernel (maybe as the rpmsg API?).
This alternative approach seems reasonable to me as well. I think the only drawback I see with this approach is non-data traffic may stall. The glink protocol traffic not tied to a TX_DATA command, such as intent requests, wouldn't wake the system even if the channel is configured to be wake capable.
Thanks, Chris
Thanks and regards,Signed-off-by: Deepak Kumar Singh <quic_deesin@xxxxxxxxxxx> --- drivers/rpmsg/qcom_glink_smem.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)diff --git a/drivers/rpmsg/qcom_glink_smem.c b/drivers/rpmsg/qcom_glink_smem.cindex 7a982c60a8dd..f1b553efab13 100644 --- a/drivers/rpmsg/qcom_glink_smem.c +++ b/drivers/rpmsg/qcom_glink_smem.c @@ -22,6 +22,7 @@ #include <linux/regmap.h> #include <linux/workqueue.h> #include <linux/list.h> +#include <linux/pm_wakeirq.h> #include <linux/rpmsg/qcom_glink.h>@@ -306,8 +307,7 @@ struct qcom_glink_smem *qcom_glink_smem_register(struct device *parent,smem->irq = of_irq_get(smem->dev.of_node, 0); ret = devm_request_irq(&smem->dev, smem->irq, qcom_glink_smem_intr, - IRQF_NO_SUSPEND | IRQF_NO_AUTOEN, - "glink-smem", smem); + IRQF_NO_AUTOEN, "glink-smem", smem); if (ret) { dev_err(&smem->dev, "failed to request IRQ\n"); goto err_put_dev;@@ -346,6 +346,8 @@ struct qcom_glink_smem *qcom_glink_smem_register(struct device *parent,smem->glink = glink; + device_init_wakeup(dev, true); + dev_pm_set_wake_irq(dev, smem->irq); enable_irq(smem->irq); return smem;@@ -365,6 +367,8 @@ void qcom_glink_smem_unregister(struct qcom_glink_smem *smem)struct qcom_glink *glink = smem->glink; disable_irq(smem->irq); + dev_pm_clear_wake_irq(&smem->dev); + device_init_wakeup(&smem->dev, false); qcom_glink_native_remove(glink);
