@@ -6,6 +6,7 @@
#include <linux/acpi.h>
#include <linux/bitfield.h>
#include <linux/module.h>
+#include <linux/suspend.h>
#include <net/rtnetlink.h>
#include "iosm_ipc_imem.h"
@@ -448,7 +449,61 @@ static struct pci_driver iosm_ipc_driver = {
},
.id_table = iosm_ipc_ids,
};
-module_pci_driver(iosm_ipc_driver);
+
+static bool pci_registered;
+
+static int pm_notify(struct notifier_block *nb, unsigned long mode, void *_unused)
+{
+ if (mode == PM_HIBERNATION_PREPARE || mode == PM_RESTORE_PREPARE) {
+ if (pci_registered) {
+ pci_unregister_driver(&iosm_ipc_driver);
+ pci_registered = false;
+ }
+ } else if (mode == PM_POST_HIBERNATION || mode == PM_POST_RESTORE) {
+ if (!pci_registered) {
+ int ret;
+
+ ret = pci_register_driver(&iosm_ipc_driver);
+ if (ret) {
+ pr_err(KBUILD_MODNAME ": unable to re-register PCI driver: %d\n",
+ ret);
+ } else {
+ pci_registered = true;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static struct notifier_block pm_notifier = {
+ .notifier_call = pm_notify,
+};
+
+static int __init iosm_ipc_driver_init(void)
+{
+ int ret;
+
+ ret = pci_register_driver(&iosm_ipc_driver);
+ if (ret)
+ return ret;
+
+ pci_registered = true;
+
+ register_pm_notifier(&pm_notifier);
+
+ return 0;
+}
+module_init(iosm_ipc_driver_init);
+
+static void __exit iosm_ipc_driver_exit(void)
+{
+ if (pci_registered)
+ pci_unregister_driver(&iosm_ipc_driver);
+
+ unregister_pm_notifier(&pm_notifier);
+}
+module_exit(iosm_ipc_driver_exit);
int ipc_pcie_addr_map(struct iosm_pcie *ipc_pcie, unsigned char *data,
size_t size, dma_addr_t *mapping, int direction)
Currently, the driver is seriously broken with respect to the hibernation (S4): after image restore the device is back into IPC_MEM_EXEC_STAGE_BOOT (which AFAIK means bootloader stage) and needs full re-launch of the rest of its firmware, but the driver restore handler treats the device as merely sleeping and just sends it a wake-up command. This wake-up command times out but device nodes (/dev/wwan*) remain accessible. However attempting to use them causes the bootloader to crash and enter IPC_MEM_EXEC_STAGE_CD_READY stage (which apparently means "a crash dump is ready"). It seems that the device cannot be re-initialized from this crashed stage without toggling some reset pin (on my test platform that's apparently what the device _RST ACPI method does). While it would theoretically be possible to rewrite the driver to tear down the whole MUX / IPC layers on hibernation (so the bootloader does not crash from improper access) and then re-launch the device on restore this would require significant refactoring of the driver (believe me, I've tried), since there are quite a few assumptions hard-coded in the driver about the device never being partially de-initialized (like channels other than devlink cannot be closed, for example). Probably this would also need some programming guide for this hardware. Considering that the driver seems orphaned [1] and other people are hitting this issue too [2] fix it by simply unbinding the PCI driver before hibernation and re-binding it after restore, much like USB_QUIRK_RESET_RESUME does for USB devices that exhibit a similar problem. Tested on XMM7360 in HP EliteBook 855 G7 both with s2idle (which uses the existing suspend / resume handlers) and S4 (which uses the new code). [1]: https://lore.kernel.org/all/c248f0b4-2114-4c61-905f-466a786bdebb@leemhuis.info/ [2]: https://github.com/xmm7360/xmm7360-pci/issues/211#issuecomment-1804139413 Signed-off-by: Maciej S. Szmigiero <mail@maciej.szmigiero.name> --- drivers/net/wwan/iosm/iosm_ipc_pcie.c | 57 ++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-)