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Commit b29669b7 authored by Sagar Dharia's avatar Sagar Dharia
Browse files

slim_ngd: Fix logical address notification mechanism 



It's possible that multiple slaves report present/absent and expect
corresponding notifications concurrently. Avoid using controller
resources where possible, and use list_for_each_safe to allow
changes to the device-list during list traversal.

Change-Id: I371c48d25a0953f5f1909c904e8fd80b599d16b3
Signed-off-by: default avatarSagar Dharia <sdharia@codeaurora.org>
parent 02983880

drivers/slimbus/slim-msm-ngd.c

+5 −3
Original line number Diff line number Diff line 
/* Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.

/* Copyright (c) 2011-2014, 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
@@ -318,7 +318,7 @@ static int ngd_xfer_msg(struct slim_controller *ctrl, struct slim_msg_txn *txn) 
				return -EREMOTEIO;

			timeout = wait_for_completion_timeout(&dev->ctrl_up,

							HZ);

			if (!timeout)

			if (!timeout && dev->state == MSM_CTRL_DOWN)

				return -ETIMEDOUT;

		}

		ret = msm_slim_get_ctrl(dev);
@@ -1046,11 +1046,13 @@ static void ngd_laddr_lookup(struct work_struct *work) 
		container_of(work, struct msm_slim_ctrl, slave_notify);

	struct slim_controller *ctrl = &dev->ctrl;

	struct slim_device *sbdev;

	struct list_head *pos, *next;

	int i;

	slim_framer_booted(ctrl);

	mutex_lock(&ctrl->m_ctrl);

	list_for_each_entry(sbdev, &ctrl->devs, dev_list) {

	list_for_each_safe(pos, next, &ctrl->devs) {

		int ret = 0;

		sbdev = list_entry(pos, struct slim_device, dev_list);

		mutex_unlock(&ctrl->m_ctrl);

		for (i = 0; i < LADDR_RETRY; i++) {

			ret = slim_get_logical_addr(sbdev, sbdev->e_addr,

drivers/slimbus/slimbus.c

+18 −23
Original line number Diff line number Diff line 
/* Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.

/* Copyright (c) 2011-2014, 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
@@ -288,36 +288,26 @@ static struct device_type slim_dev_type = { 


static void slim_report(struct work_struct *work)

{

	u8 laddr;

	int ret, i;

	struct slim_driver *sbdrv;

	struct slim_device *sbdev =

			container_of(work, struct slim_device, wd);

	struct slim_controller *ctrl = sbdev->ctrl;

	if (!sbdev->dev.driver)

		return;

	/* check if device-up or down needs to be called */

	mutex_lock(&ctrl->m_ctrl);

	/* address no longer valid, means device reported absent */

	for (i = 0; i < ctrl->num_dev; i++) {

		if (sbdev->laddr == ctrl->addrt[i].laddr &&

			ctrl->addrt[i].valid == false &&

			sbdev->notified)

			break;

	}

	mutex_unlock(&ctrl->m_ctrl);

	if ((!sbdev->reported && !sbdev->notified) ||

			(sbdev->reported && sbdev->notified))

		return;



	sbdrv = to_slim_driver(sbdev->dev.driver);

	if (i < ctrl->num_dev) {

	/*

	 * address no longer valid, means device reported absent, whereas

	 * address valid, means device reported present

	 */

	if (sbdev->notified && !sbdev->reported) {

		sbdev->notified = false;

		if (sbdrv->device_down)

			sbdrv->device_down(sbdev);

		return;

	}

	if (sbdev->notified)

		return;

	ret = slim_get_logical_addr(sbdev, sbdev->e_addr, 6, &laddr);

	if (!ret) {

		if (sbdrv)

	} else if (!sbdev->notified && sbdev->reported) {

		sbdev->notified = true;

		if (sbdrv->device_up)

			sbdrv->device_up(sbdev);
@@ -633,6 +623,7 @@ void slim_report_absent(struct slim_device *sbdev) 
			ctrl->addrt[i].valid = false;

	}

	mutex_unlock(&ctrl->m_ctrl);

	sbdev->reported = false;

	queue_work(ctrl->wq, &sbdev->wd);

}

EXPORT_SYMBOL(slim_report_absent);
@@ -791,6 +782,8 @@ int slim_assign_laddr(struct slim_controller *ctrl, const u8 *e_addr, 
	u8 i = 0;

	bool exists = false;

	struct slim_device *sbdev;

	struct list_head *pos, *next;



	mutex_lock(&ctrl->m_ctrl);

	/* already assigned */

	if (ctrl_getlogical_addr(ctrl, e_addr, e_len, &i) == 0) {
@@ -840,10 +833,12 @@ ret_assigned_laddr: 
	pr_info("slimbus:%d laddr:0x%x, EAPC:0x%x:0x%x", ctrl->nr, *laddr,

				e_addr[1], e_addr[2]);

	mutex_lock(&ctrl->m_ctrl);

	list_for_each_entry(sbdev, &ctrl->devs, dev_list) {

	list_for_each_safe(pos, next, &ctrl->devs) {

		sbdev = list_entry(pos, struct slim_device, dev_list);

		if (memcmp(sbdev->e_addr, e_addr, 6) == 0) {

			struct slim_driver *sbdrv;

			sbdev->laddr = *laddr;

			sbdev->reported = true;

			if (sbdev->dev.driver) {

				sbdrv = to_slim_driver(sbdev->dev.driver);

				if (sbdrv->device_up)

include/linux/slimbus/slimbus.h

+6 −1
Original line number Diff line number Diff line 
/* Copyright (c) 2011-2013, The Linux Foundation. All rights reserved.

/* Copyright (c) 2011-2014, 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
@@ -634,6 +634,10 @@ struct slim_pending_ch { 
 *  @driver: Device's driver. Pointer to access routines.

 *  @ctrl: Slimbus controller managing the bus hosting this device.

 *  @laddr: 1-byte Logical address of this device.

 *  @reported: Flag to indicate whether this device reported present. The flag

 *	is set when device reports present, and is reset when it reports

 *	absent. This flag alongwith notified flag below is used to call

 *	device_up, or device_down callbacks for driver of this device.

 *  @mark_define: List of channels pending definition/activation.

 *  @mark_suspend: List of channels pending suspend.

 *  @mark_removal: List of channels pending removal.
@@ -657,6 +661,7 @@ struct slim_device { 
	struct slim_driver	*driver;

	struct slim_controller	*ctrl;

	u8			laddr;

	bool			reported;

	struct list_head	mark_define;

	struct list_head	mark_suspend;

	struct list_head	mark_removal;