From 8afc7e471ad3c92a9c96adc62d1b67de77378bb6 Mon Sep 17 00:00:00 2001 From: Alex Elder Date: Mon, 22 Nov 2021 18:15:55 -0600 Subject: net: ipa: separate disabling setup from modem stop The IPA setup_complete flag is set at the end of ipa_setup(), when the setup phase of initialization has completed successfully. This occurs as part of driver probe processing, or (if "modem-init" is specified in the DTS file) it is triggered by the "ipa-setup-ready" SMP2P interrupt generated by the modem. In the latter case, it's possible for driver shutdown (or remove) to begin while setup processing is underway, and this can't be allowed. The problem is that the setup_complete flag is not adequate to signal that setup is underway. If setup_complete is set, it will never be un-set, so that case is not a problem. But if setup_complete is false, there's a chance setup is underway. Because setup is triggered by an interrupt on a "modem-init" system, there is a simple way to ensure the value of setup_complete is safe to read. The threaded handler--if it is executing--will complete as part of a request to disable the "ipa-modem-ready" interrupt. This means that ipa_setup() (which is called from the handler) will run to completion if it was underway, or will never be called otherwise. The request to disable the "ipa-setup-ready" interrupt is currently made within ipa_modem_stop(). Instead, disable the interrupt outside that function in the two places it's called. In the case of ipa_remove(), this ensures the setup_complete flag is safe to read before we read it. Rename ipa_smp2p_disable() to be ipa_smp2p_irq_disable_setup(), to be more specific about its effect. Fixes: 530f9216a953 ("soc: qcom: ipa: AP/modem communications") Signed-off-by: Alex Elder Signed-off-by: David S. Miller --- drivers/net/ipa/ipa_main.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'drivers/net/ipa/ipa_main.c') diff --git a/drivers/net/ipa/ipa_main.c b/drivers/net/ipa/ipa_main.c index cdfa98a76e1f..a448ec198bee 100644 --- a/drivers/net/ipa/ipa_main.c +++ b/drivers/net/ipa/ipa_main.c @@ -28,6 +28,7 @@ #include "ipa_reg.h" #include "ipa_mem.h" #include "ipa_table.h" +#include "ipa_smp2p.h" #include "ipa_modem.h" #include "ipa_uc.h" #include "ipa_interrupt.h" @@ -801,6 +802,11 @@ static int ipa_remove(struct platform_device *pdev) struct device *dev = &pdev->dev; int ret; + /* Prevent the modem from triggering a call to ipa_setup(). This + * also ensures a modem-initiated setup that's underway completes. + */ + ipa_smp2p_irq_disable_setup(ipa); + ret = pm_runtime_get_sync(dev); if (WARN_ON(ret < 0)) goto out_power_put; -- cgit v1.2.3