[PATCH 3/4] wifi: brcmfmac: pcie: probe again after a resume through firmware

[Andre Eikmeyer <dev@deq.rocks>]

After ACPI S3 the chip comes back without its firmware, but the
interrupt mask can read back nonzero, so brcmf_pcie_pm_leave_D3()
takes the hot resume path and every command times out afterwards.
Seen on the BCM4377 and BCM4364 of the T2 Macs.

When the platform firmware handled the resume and WoWL is off, go
straight to the existing remove and re-probe path.

Signed-off-by: Andre Eikmeyer <dev@deq.rocks>
---
 .../net/wireless/broadcom/brcm80211/brcmfmac/pcie.c    | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
index fc0f23477eb..faa1e16ed4f 100644
--- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
+++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/pcie.c
@@ -7,6 +7,7 @@
 #include <linux/module.h>
 #include <linux/firmware.h>
 #include <linux/pci.h>
+#include <linux/suspend.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
@@ -2844,6 +2845,15 @@ static int brcmf_pcie_pm_leave_D3(struct device *dev)
 	devinfo = bus->bus_priv.pcie->devinfo;
 	brcmf_dbg(PCIE, "Enter, dev=%p, bus=%p\n", dev, bus);
 
+	/*
+	 * Without WoWL the device is powered off when the platform firmware
+	 * handles the system sleep, as with ACPI S3, and comes back without
+	 * its firmware. Its registers can still read back nonzero, so probe
+	 * it again.
+	 */
+	if (pm_resume_via_firmware() && !devinfo->wowl_enabled)
+		goto cleanup;
+
 	/* Check if device is still up and running, if so we are ready */
 	if (brcmf_pcie_read_pcie32(devinfo, devinfo->reginfo->intmask) != 0) {
 		brcmf_dbg(PCIE, "Try to wakeup device....\n");