[PATCH 5.15 161/171] bus: mhi: core: Add support for forced PM resume

Greg Kroah-Hartman
2021-12-13T10:29:42Z

From: Loic Poulain <loic.poulain@linaro.org>

commit cab2d3fd6866e089b5c50db09dece131f85bfebd upstream.

For whatever reason, some devices like QCA6390, WCN6855 using ath11k
are not in M3 state during PM resume, but still functional. The
mhi_pm_resume should then not fail in those cases, and let the higher
level device specific stack continue resuming process.

Add an API mhi_pm_resume_force(), to force resuming irrespective of the
current MHI state. This fixes a regression with non functional ath11k WiFi
after suspend/resume cycle on some machines.

Bug report: https://bugzilla.kernel.org/show_bug.cgi?id=214179

Link: https://lore.kernel.org/regressions/871r5p0x2u.fsf@codeaurora.org/
Fixes: 020d3b26c07a ("bus: mhi: Early MHI resume failure in non M3 state")
Cc: stable@vger.kernel.org #5.13
Reported-by: Kalle Valo <kvalo@codeaurora.org>
Reported-by: Pengyu Ma <mapengyu@gmail.com>
Tested-by: Kalle Valo <kvalo@kernel.org>
Acked-by: Kalle Valo <kvalo@kernel.org>
Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
[mani: Switched to API, added bug report, reported-by tags and CCed stable]
Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Link: https://lore.kernel.org/r/20211209131633.4168-1-manivannan.sadhasivam@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/bus/mhi/core/pm.c | 21 ++++++++++++++++++---
drivers/net/wireless/ath/ath11k/mhi.c | 6 +++++-
include/linux/mhi.h | 13 +++++++++++++
3 files changed, 36 insertions(+), 4 deletions(-)

--- a/drivers/bus/mhi/core/pm.c
+++ b/drivers/bus/mhi/core/pm.c
@@ -881,7 +881,7 @@ int mhi_pm_suspend(struct mhi_controller
}
EXPORT_SYMBOL_GPL(mhi_pm_suspend);

-int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
+static int __mhi_pm_resume(struct mhi_controller *mhi_cntrl, bool force)
{
struct mhi_chan *itr, *tmp;
struct device *dev = &mhi_cntrl->mhi_dev->dev;
@@ -898,8 +898,12 @@ int mhi_pm_resume(struct mhi_controller
if (MHI_PM_IN_ERROR_STATE(mhi_cntrl->pm_state))
return -EIO;

- if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3)
- return -EINVAL;
+ if (mhi_get_mhi_state(mhi_cntrl) != MHI_STATE_M3) {
+ dev_warn(dev, "Resuming from non M3 state (%s)\n",
+ TO_MHI_STATE_STR(mhi_get_mhi_state(mhi_cntrl)));
+ if (!force)
+ return -EINVAL;
+ }

/* Notify clients about exiting LPM */
list_for_each_entry_safe(itr, tmp, &mhi_cntrl->lpm_chans, node) {
@@ -940,8 +944,19 @@ int mhi_pm_resume(struct mhi_controller

return 0;
}
+
+int mhi_pm_resume(struct mhi_controller *mhi_cntrl)
+{
+ return __mhi_pm_resume(mhi_cntrl, false);
+}
EXPORT_SYMBOL_GPL(mhi_pm_resume);

+int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl)
+{
+ return __mhi_pm_resume(mhi_cntrl, true);
+}
+EXPORT_SYMBOL_GPL(mhi_pm_resume_force);
+
int __mhi_device_get_sync(struct mhi_controller *mhi_cntrl)
{
int ret;
--- a/drivers/net/wireless/ath/ath11k/mhi.c
+++ b/drivers/net/wireless/ath/ath11k/mhi.c
@@ -533,7 +533,11 @@ static int ath11k_mhi_set_state(struct a
ret = mhi_pm_suspend(ab_pci->mhi_ctrl);
break;
case ATH11K_MHI_RESUME:
- ret = mhi_pm_resume(ab_pci->mhi_ctrl);
+ /* Do force MHI resume as some devices like QCA6390, WCN6855
+ * are not in M3 state but they are functional. So just ignore
+ * the MHI state while resuming.
+ */
+ ret = mhi_pm_resume_force(ab_pci->mhi_ctrl);
break;
case ATH11K_MHI_TRIGGER_RDDM:
ret = mhi_force_rddm_mode(ab_pci->mhi_ctrl);
--- a/include/linux/mhi.h
+++ b/include/linux/mhi.h
@@ -664,6 +664,19 @@ int mhi_pm_suspend(struct mhi_controller
int mhi_pm_resume(struct mhi_controller *mhi_cntrl);

/**
+ * mhi_pm_resume_force - Force resume MHI from suspended state
+ * @mhi_cntrl: MHI controller
+ *
+ * Resume the device irrespective of its MHI state. As per the MHI spec, devices
+ * has to be in M3 state during resume. But some devices seem to be in a
+ * different MHI state other than M3 but they continue working fine if allowed.
+ * This API is intented to be used for such devices.
+ *
+ * Return: 0 if the resume succeeds, a negative error code otherwise
+ */
+int mhi_pm_resume_force(struct mhi_controller *mhi_cntrl);
+
+/**
* mhi_download_rddm_image - Download ramdump image from device for
* debugging purpose.
* @mhi_cntrl: MHI controller