qcom: battery: Fix using stale votable pointers

The code flow between battery.c and smblib.c could end up with
stale references in smblib. This is when if pl_init fails for
some reason after creating the votables, while smblib obtains
references to them, those references become invalid.

Fix this by calling pl_init early in smb2 driver's probe such that if
it fails smb2 driver exits early.

Also change the name of pl_(de)init() functions to more appropriate
name - qcom_batt_(de)init().

Change-Id: I58f79d26e6cc8524e792a23185ff6fc8cfdffa75
Signed-off-by: Harry Yang <harryy@codeaurora.org>
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>

drivers/power/supply/qcom/battery.c

@@ -930,11 +930,17 @@ static int pl_determine_initial_status(struct pl_data *chip)
 }
 
 #define DEFAULT_RESTRICTED_CURRENT_UA	1000000
-static int pl_init(void)
+int qcom_batt_init(void)
 {
 	struct pl_data *chip;
 	int rc = 0;
 
+	/* initialize just once */
+	if (the_chip) {
+		pr_err("was initialized earlier Failing now\n");
+		return -EINVAL;
+	}
+
 	chip = kzalloc(sizeof(*chip), GFP_KERNEL);
 	if (!chip)
 		return -ENOMEM;
@@ -1014,7 +1020,9 @@ static int pl_init(void)
 		goto unreg_notifier;
 	}
 
-	return rc;
+	the_chip = chip;
+
+	return 0;
 
 unreg_notifier:
 	power_supply_unreg_notifier(&chip->nb);
@@ -1031,21 +1039,23 @@ cleanup:
 	return rc;
 }
 
-static void pl_deinit(void)
+void qcom_batt_deinit(void)
 {
 	struct pl_data *chip = the_chip;
 
+	if (chip == NULL)
+		return;
+
+	cancel_work_sync(&chip->status_change_work);
+	cancel_delayed_work_sync(&chip->pl_taper_work);
+	cancel_work_sync(&chip->pl_disable_forever_work);
+
 	power_supply_unreg_notifier(&chip->nb);
 	destroy_votable(chip->pl_awake_votable);
 	destroy_votable(chip->pl_disable_votable);
 	destroy_votable(chip->fv_votable);
 	destroy_votable(chip->fcc_votable);
 	wakeup_source_unregister(chip->pl_ws);
+	the_chip = NULL;
 	kfree(chip);
 }
-
-module_init(pl_init);
-module_exit(pl_deinit)
-
-MODULE_DESCRIPTION("");
-MODULE_LICENSE("GPL v2");

drivers/power/supply/qcom/battery.h

@@ -0,0 +1,17 @@
+/* Copyright (c) 2017 The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __BATTERY_H
+#define __BATTERY_H
+int qcom_batt_init(void);
+void qcom_batt_deinit(void);
+#endif /* __BATTERY_H */

drivers/power/supply/qcom/smb-lib.c

@@ -19,10 +19,11 @@
 #include <linux/qpnp/qpnp-revid.h>
 #include <linux/input/qpnp-power-on.h>
 #include <linux/irq.h>
+#include <linux/pmic-voter.h>
 #include "smb-lib.h"
 #include "smb-reg.h"
+#include "battery.h"
 #include "storm-watch.h"
-#include <linux/pmic-voter.h>
 
 #define smblib_err(chg, fmt, ...)		\
 	pr_err("%s: %s: " fmt, chg->name,	\
@@ -4268,26 +4269,30 @@ static int smblib_create_votables(struct smb_charger *chg)
 	int rc = 0;
 
 	chg->fcc_votable = find_votable("FCC");
-	if (!chg->fcc_votable) {
-		rc = -EPROBE_DEFER;
+	if (chg->fcc_votable == NULL) {
+		rc = -EINVAL;
+		smblib_err(chg, "Couldn't find FCC votable rc=%d\n", rc);
 		return rc;
 	}
 
 	chg->fv_votable = find_votable("FV");
-	if (!chg->fv_votable) {
-		rc = -EPROBE_DEFER;
+	if (chg->fv_votable == NULL) {
+		rc = -EINVAL;
+		smblib_err(chg, "Couldn't find FV votable rc=%d\n", rc);
 		return rc;
 	}
 
 	chg->usb_icl_votable = find_votable("USB_ICL");
 	if (!chg->usb_icl_votable) {
-		rc = -EPROBE_DEFER;
+		rc = -EINVAL;
+		smblib_err(chg, "Couldn't find USB_ICL votable rc=%d\n", rc);
 		return rc;
 	}
 
 	chg->pl_disable_votable = find_votable("PL_DISABLE");
-	if (!chg->pl_disable_votable) {
-		rc = -EPROBE_DEFER;
+	if (chg->pl_disable_votable == NULL) {
+		rc = -EINVAL;
+		smblib_err(chg, "Couldn't find votable PL_DISABLE rc=%d\n", rc);
 		return rc;
 	}
 	vote(chg->pl_disable_votable, PL_INDIRECT_VOTER, true, 0);
@@ -4471,6 +4476,14 @@ int smblib_init(struct smb_charger *chg)
 	case PARALLEL_MASTER:
 		chg->qnovo_fcc_ua = -EINVAL;
 		chg->qnovo_fv_uv = -EINVAL;
+
+		rc = qcom_batt_init();
+		if (rc < 0) {
+			smblib_err(chg, "Couldn't init qcom_batt_init rc=%d\n",
+				rc);
+			return rc;
+		}
+
 		rc = smblib_create_votables(chg);
 		if (rc < 0) {
 			smblib_err(chg, "Couldn't create votables rc=%d\n",
@@ -4502,8 +4515,20 @@ int smblib_deinit(struct smb_charger *chg)
 {
 	switch (chg->mode) {
 	case PARALLEL_MASTER:
+		cancel_work_sync(&chg->bms_update_work);
+		cancel_work_sync(&chg->rdstd_cc2_detach_work);
+		cancel_delayed_work_sync(&chg->hvdcp_detect_work);
+		cancel_delayed_work_sync(&chg->step_soc_req_work);
+		cancel_delayed_work_sync(&chg->clear_hdc_work);
+		cancel_work_sync(&chg->otg_oc_work);
+		cancel_work_sync(&chg->vconn_oc_work);
+		cancel_delayed_work_sync(&chg->otg_ss_done_work);
+		cancel_delayed_work_sync(&chg->icl_change_work);
+		cancel_delayed_work_sync(&chg->pl_enable_work);
+		cancel_work_sync(&chg->legacy_detection_work);
 		power_supply_unreg_notifier(&chg->nb);
 		smblib_destroy_votables(chg);
+		qcom_batt_deinit();
 		break;
 	case PARALLEL_SLAVE:
 		break;