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

[Hans de Goede <hdegoede@redhat.com>]

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@redhat.com>
>> ---
>> 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);
>>
>