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Commit 3bf9e384 authored by Jack Pham's avatar Jack Pham
Browse files

usb: pd: Simplify VDM tx handling 



VDMs, especially structured ones, are almost always handled
as requests and responses. Hence it does not make sense to
allow more than one outgoing VDM at a time, so get rid of the
vdm_tx_queue list and simplify it to a single-issued packet.

Because port partners can only have one VDM request/response in
flight, also handle the case when a new structured request is
received before the previous response has been sent. In that
case we simply discard the queued message as it's now invalid.

Change-Id: I144f8158dbf8be0babf5516b01d084fd053413c3
Signed-off-by: default avatarJack Pham <jackp@codeaurora.org>
parent 7ce154ad

drivers/usb/pd/policy_engine.c

+30 −25
Original line number Diff line number Diff line
@@ -259,7 +259,6 @@ static const u32 default_snk_caps[] = { 0x2601905A }; /* 5V @ 900mA */ 
struct vdm_tx {

	u32			data[7];

	int			size;

	struct list_head	entry;

};



struct usbpd {
@@ -314,8 +313,8 @@ struct usbpd { 
	enum vdm_state		vdm_state;

	u16			*discovered_svids;

	int			num_svids;

	struct vdm_tx		*vdm_tx;

	struct vdm_tx		*vdm_tx_retry;

	struct list_head	vdm_tx_queue;

	struct list_head	svid_handlers;



	struct list_head	instance;
@@ -975,7 +974,7 @@ int usbpd_send_vdm(struct usbpd *pd, u32 vdm_hdr, const u32 *vdos, int num_vdos) 
{

	struct vdm_tx *vdm_tx;



	if (!pd->in_explicit_contract)

	if (!pd->in_explicit_contract || pd->vdm_tx)

		return -EBUSY;



	vdm_tx = kzalloc(sizeof(*vdm_tx), GFP_KERNEL);
@@ -988,8 +987,10 @@ int usbpd_send_vdm(struct usbpd *pd, u32 vdm_hdr, const u32 *vdos, int num_vdos) 
	vdm_tx->size = num_vdos + 1; /* include the header */



	/* VDM will get sent in PE_SRC/SNK_READY state handling */

	list_add_tail(&vdm_tx->entry, &pd->vdm_tx_queue);

	queue_work(pd->wq, &pd->sm_work);

	pd->vdm_tx = vdm_tx;



	/* slight delay before queuing to prioritize handling of incoming VDM */

	hrtimer_start(&pd->timer, ms_to_ktime(5), HRTIMER_MODE_REL);



	return 0;

}
@@ -1037,6 +1038,18 @@ static void handle_vdm_rx(struct usbpd *pd) 


	switch (cmd_type) {

	case SVDM_CMD_TYPE_INITIATOR:

		/*

		 * if this interrupts a previous exchange, abort the previous

		 * outgoing response

		 */

		if (pd->vdm_tx) {

			usbpd_dbg(&pd->dev, "Discarding previously queued SVDM tx (SVID:0x%04x)\n",

					VDM_HDR_SVID(pd->vdm_tx->data[0]));



			kfree(pd->vdm_tx);

			pd->vdm_tx = NULL;

		}



		if (svid == USBPD_SID && cmd == USBPD_SVDM_DISCOVER_IDENTITY) {

			u32 tx_vdos[3] = {

				ID_HDR_USB_HOST | ID_HDR_USB_DEVICE |
@@ -1201,7 +1214,7 @@ static void handle_vdm_rx(struct usbpd *pd) 
			}



			/* wait tVDMBusy, then retry */

			list_move(&pd->vdm_tx_retry->entry, &pd->vdm_tx_queue);

			pd->vdm_tx = pd->vdm_tx_retry;

			pd->vdm_tx_retry = NULL;

			hrtimer_start(&pd->timer, ms_to_ktime(VDM_BUSY_TIME),

					HRTIMER_MODE_REL);
@@ -1218,16 +1231,14 @@ static void handle_vdm_tx(struct usbpd *pd) 
	int ret;



	/* only send one VDM at a time */

	if (!list_empty(&pd->vdm_tx_queue)) {

		struct vdm_tx *vdm_tx = list_first_entry(&pd->vdm_tx_queue,

				struct vdm_tx, entry);

		u32 vdm_hdr = vdm_tx->data[0];

	if (pd->vdm_tx) {

		u32 vdm_hdr = pd->vdm_tx->data[0];



		ret = pd_send_msg(pd, MSG_VDM, vdm_tx->data, vdm_tx->size,

				SOP_MSG);

		ret = pd_send_msg(pd, MSG_VDM, pd->vdm_tx->data,

				pd->vdm_tx->size, SOP_MSG);

		if (ret) {

			usbpd_err(&pd->dev, "Error sending VDM command %d\n",

					SVDM_HDR_CMD(vdm_tx->data[0]));

					SVDM_HDR_CMD(pd->vdm_tx->data[0]));

			usbpd_set_state(pd, pd->current_pr == PR_SRC ?

					PE_SRC_SEND_SOFT_RESET :

					PE_SNK_SEND_SOFT_RESET);
@@ -1236,8 +1247,6 @@ static void handle_vdm_tx(struct usbpd *pd) 
			return;

		}



		list_del(&vdm_tx->entry);



		/*

		 * special case: keep initiated Discover ID/SVIDs

		 * around in case we need to re-try when receiving BUSY
@@ -1251,10 +1260,12 @@ static void handle_vdm_tx(struct usbpd *pd) 
						pd->vdm_tx_retry->data[0]));

				kfree(pd->vdm_tx_retry);

			}

			pd->vdm_tx_retry = vdm_tx;

			pd->vdm_tx_retry = pd->vdm_tx;

		} else {

			kfree(vdm_tx);

			kfree(pd->vdm_tx);

		}



		pd->vdm_tx = NULL;

	}

}
@@ -1271,13 +1282,8 @@ static void reset_vdm_state(struct usbpd *pd) 
	kfree(pd->discovered_svids);

	pd->discovered_svids = NULL;

	pd->num_svids = 0;

	while (!list_empty(&pd->vdm_tx_queue)) {

		struct vdm_tx *vdm_tx =

			list_first_entry(&pd->vdm_tx_queue,

				struct vdm_tx, entry);

		list_del(&vdm_tx->entry);

		kfree(vdm_tx);

	}

	kfree(pd->vdm_tx);

	pd->vdm_tx = NULL;

}



static void dr_swap(struct usbpd *pd)
@@ -2497,7 +2503,6 @@ struct usbpd *usbpd_create(struct device *parent) 
	pd->current_dr = DR_NONE;

	list_add_tail(&pd->instance, &_usbpd);



	INIT_LIST_HEAD(&pd->vdm_tx_queue);

	INIT_LIST_HEAD(&pd->svid_handlers);



	/* force read initial power_supply values */