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Commit a057cc3b authored by Dov Levenglick's avatar Dov Levenglick
Browse files

usb: bam: fix race condition between usb bam and controller 



When waking up with the USB cable disconnected, the DWC3 driver
invokes its set_suspend function, which calls
msm_bam_device_lpm_ok. If the usb_bam_probe function hasn't
finished, this results an an attempt to call spin_lock on an
uninitialized lock.
Adding an automatic successful return from msm_bam_device_lpm_ok
if the probe hasn't finished, since this function should return 0
whenever the bam is not a blocking factor to the suspend flow.

Change-Id: Ief52bf12877124281dfd41d5639e72da8055ee5b
Signed-off-by: default avatarDov Levenglick <dovl@codeaurora.org>
parent 4f7295be

drivers/platform/msm/usb_bam.c

+10 −0
Original line number Diff line number Diff line
@@ -212,6 +212,7 @@ static struct usb_bam_pipe_connect *usb_bam_connections; 
static struct usb_bam_ctx_type ctx;

static struct usb_bam_host_info host_info[MAX_BAMS];

static struct device *usb_device;

static bool probe_finished;



static int __usb_bam_register_wake_cb(int idx, int (*callback)(void *user),

	void *param, bool trigger_cb_per_pipe);
@@ -3184,6 +3185,7 @@ static int usb_bam_probe(struct platform_device *pdev) 
	spin_lock_init(&usb_bam_ipa_handshake_info_lock);

	usb_bam_ipa_create_resources();

	spin_lock_init(&usb_bam_lock);

	probe_finished = true;



	return ret;

}
@@ -3271,6 +3273,14 @@ bool msm_bam_device_lpm_ok(enum usb_bam bam_type) 
{

	pr_debug("%s: enter bam%s\n", __func__, bam_enable_strings[bam_type]);



	/*

	 * There is the possibility of a race between the usb_bam_probe()

	 * function initializing the relevant spinlocks and structures, vs. the

	 * USB controller's suspend function being invoked by the pm module.

	 */

	if (!probe_finished)

		return 0;



	spin_lock(&usb_bam_ipa_handshake_info_lock);

	if (info[bam_type].lpm_wait_handshake ||

		info[bam_type].lpm_wait_pipes) {