Re: [PATCH v2 4/6] usb: typec: tcpm: Refactor tcpm_handle_vdm_request

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Hi,

On 7/25/20 4:45 PM, Guenter Roeck wrote:
On 7/24/20 10:47 AM, Hans de Goede wrote:
Refactor tcpm_handle_vdm_request and its tcpm_pd_svdm helper function so
that reporting the results of the vdm to the altmode-driver is separated
out into a clear separate step inside tcpm_handle_vdm_request, instead
of being scattered over various places inside the tcpm_pd_svdm helper.

This is a preparation patch for fixing an AB BA lock inversion between the
tcpm code and some altmode drivers.

Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
---
Changes in v2:
- Keep "if (adev && pdev)" checks as is instead of modifying them
---
  drivers/usb/typec/tcpm/tcpm.c | 76 ++++++++++++++++++++++-------------
  1 file changed, 48 insertions(+), 28 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index ee239b54bcd8..03a0c083ee9a 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -159,6 +159,14 @@ enum pd_msg_request {
  	PD_MSG_DATA_SOURCE_CAP,
  };
+enum adev_actions {
+	ADEV_NONE = 0,
+	ADEV_NOTIFY_USB_AND_QUEUE_VDM,
+	ADEV_QUEUE_VDM,
+	ADEV_QUEUE_VDM_SEND_EXIT_MODE_ON_FAIL,
+	ADEV_ATTENTION,
+};
+
  /* Events from low level driver */
#define TCPM_CC_EVENT BIT(0)
@@ -1078,10 +1086,10 @@ static void tcpm_register_partner_altmodes(struct tcpm_port *port)
#define supports_modal(port) PD_IDH_MODAL_SUPP((port)->partner_ident.id_header) -static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
-			u32 *response)
+static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
+			const u32 *p, int cnt, u32 *response,
+			enum adev_actions *adev_action)
  {
-	struct typec_altmode *adev;
  	struct typec_altmode *pdev;
  	struct pd_mode_data *modep;
  	int rlen = 0;
@@ -1097,9 +1105,6 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
modep = &port->mode_data; - adev = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
-				   PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
-
  	pdev = typec_match_altmode(port->partner_altmode, ALTMODE_DISCOVERY_MAX,
  				   PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
@@ -1125,8 +1130,7 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
  			break;
  		case CMD_ATTENTION:
  			/* Attention command does not have response */
-			if (adev)
-				typec_altmode_attention(adev, p[1]);
+			*adev_action = ADEV_ATTENTION;
  			return 0;
  		default:
  			break;
@@ -1180,23 +1184,15 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
  		case CMD_ENTER_MODE:
  			if (adev && pdev) {

I must be missing something. Does this compile ? The 'adev' variable was removed above.
Maybe move the call to typec_altmode_update_active() into tcpm_handle_vdm_request()
instead ?

Yes it compiles. The adev variable is now a function parameter, since
we already to the lookup for it in tcpm_handle_vdm_request() now,
I'm simply passing it along here.

Regards,

Hans



  				typec_altmode_update_active(pdev, true);
-
-				if (typec_altmode_vdm(adev, p[0], &p[1], cnt)) {
-					response[0] = VDO(adev->svid, 1,
-							  CMD_EXIT_MODE);
-					response[0] |= VDO_OPOS(adev->mode);
-					return 1;
-				}
+				*adev_action = ADEV_QUEUE_VDM_SEND_EXIT_MODE_ON_FAIL;
  			}
  			return 0;
  		case CMD_EXIT_MODE:
  			if (adev && pdev) {
  				typec_altmode_update_active(pdev, false);
-
  				/* Back to USB Operation */
-				WARN_ON(typec_altmode_notify(adev,
-							     TYPEC_STATE_USB,
-							     NULL));
+				*adev_action = ADEV_NOTIFY_USB_AND_QUEUE_VDM;
+				return 0;
  			}
  			break;
  		default:
@@ -1207,11 +1203,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
  		switch (cmd) {
  		case CMD_ENTER_MODE:
  			/* Back to USB Operation */
-			if (adev)
-				WARN_ON(typec_altmode_notify(adev,
-							     TYPEC_STATE_USB,
-							     NULL));
-			break;
+			*adev_action = ADEV_NOTIFY_USB_AND_QUEUE_VDM;
+			return 0;
  		default:
  			break;
  		}
@@ -1221,15 +1214,15 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const u32 *p, int cnt,
  	}
/* Informing the alternate mode drivers about everything */
-	if (adev)
-		typec_altmode_vdm(adev, p[0], &p[1], cnt);
-
+	*adev_action = ADEV_QUEUE_VDM;
  	return rlen;
  }
static void tcpm_handle_vdm_request(struct tcpm_port *port,
  				    const __le32 *payload, int cnt)
  {
+	enum adev_actions adev_action = ADEV_NONE;
+	struct typec_altmode *adev;
  	u32 p[PD_MAX_PAYLOAD];
  	u32 response[8] = { };
  	int i, rlen = 0;
@@ -1237,6 +1230,9 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port,
  	for (i = 0; i < cnt; i++)
  		p[i] = le32_to_cpu(payload[i]);
+ adev = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
+				   PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));
+
  	if (port->vdm_state == VDM_STATE_BUSY) {
  		/* If UFP responded busy retry after timeout */
  		if (PD_VDO_CMDT(p[0]) == CMDT_RSP_BUSY) {
@@ -1251,7 +1247,31 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port,
  	}
if (PD_VDO_SVDM(p[0]))
-		rlen = tcpm_pd_svdm(port, p, cnt, response);
+		rlen = tcpm_pd_svdm(port, adev, p, cnt, response, &adev_action);
+
+	if (adev) {
+		switch (adev_action) {
+		case ADEV_NONE:
+			break;
+		case ADEV_NOTIFY_USB_AND_QUEUE_VDM:
+			WARN_ON(typec_altmode_notify(adev, TYPEC_STATE_USB, NULL));
+			typec_altmode_vdm(adev, p[0], &p[1], cnt);
+			break;
+		case ADEV_QUEUE_VDM:
+			typec_altmode_vdm(adev, p[0], &p[1], cnt);
+			break;
+		case ADEV_QUEUE_VDM_SEND_EXIT_MODE_ON_FAIL:
+			if (typec_altmode_vdm(adev, p[0], &p[1], cnt)) {
+				response[0] = VDO(adev->svid, 1, CMD_EXIT_MODE);
+				response[0] |= VDO_OPOS(adev->mode);
+				rlen = 1;
+			}
+			break;
+		case ADEV_ATTENTION:
+			typec_altmode_attention(adev, p[1]);
+			break;
+		}
+	}
if (rlen > 0)
  		tcpm_queue_vdm(port, response[0], &response[1], rlen - 1);






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