Re: [PATCH v2] usb: typec: tcpm: Pass down negotiated rev to update retry count

From: Heikki Krogerus
Date: Tue Dec 08 2020 - 04:42:43 EST

On Tue, Dec 01, 2020 at 07:17:33PM -0800, Badhri Jagan Sridharan wrote:
> nRetryCount was updated from 3 to 2 between PD2.0 and PD3.0 spec.
> nRetryCount in "Table 6-34 Counter parameters" of the PD 2.0
> spec is set to 3, whereas, nRetryCount in "Table 6-59 Counter
> parameters" is set to 2.
>
> Pass down negotiated rev in pd_transmit so that low level chip
> drivers can update the retry count accordingly before attempting
> packet transmission.
>
> This helps in passing "TEST.PD.PORT.ALL.02" of the
> "Power Delivery Merged" test suite which was initially failing
> with "The UUT did not retransmit the message nReryCount times"
>
> In fusb302 & tcpci drivers, by default the driver sets the retry
> count to 3 (Default for PD 2.0). Update this to 2,
> if the negotiated rev is PD 3.0.
>
> In wcove, since the retry count is intentionally set to max, leaving
> it as is.
>
> Signed-off-by: Badhri Jagan Sridharan <badhri@xxxxxxxxxx>

Acked-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
> Changes since V1:
> -Squashed tcpm and client patches to one as suggested by Heikki.
> ---
> drivers/usb/typec/tcpm/fusb302.c | 16 +++++++++++-----
> drivers/usb/typec/tcpm/tcpci.c | 12 +++++++-----
> drivers/usb/typec/tcpm/tcpm.c | 2 +-
> drivers/usb/typec/tcpm/wcove.c | 3 ++-
> include/linux/usb/tcpm.h | 2 +-
> 5 files changed, 22 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm/fusb302.c b/drivers/usb/typec/tcpm/fusb302.c
> index 99562cc65ca6..ebc46b9f776c 100644
> --- a/drivers/usb/typec/tcpm/fusb302.c
> +++ b/drivers/usb/typec/tcpm/fusb302.c
> @@ -343,12 +343,11 @@ static int fusb302_sw_reset(struct fusb302_chip *chip)
> return ret;
> }
>
> -static int fusb302_enable_tx_auto_retries(struct fusb302_chip *chip)
> +static int fusb302_enable_tx_auto_retries(struct fusb302_chip *chip, u8 retry_count)
> {
> int ret = 0;
>
> - ret = fusb302_i2c_set_bits(chip, FUSB_REG_CONTROL3,
> - FUSB_REG_CONTROL3_N_RETRIES_3 |
> + ret = fusb302_i2c_set_bits(chip, FUSB_REG_CONTROL3, retry_count |
> FUSB_REG_CONTROL3_AUTO_RETRY);
>
> return ret;
> @@ -399,7 +398,7 @@ static int tcpm_init(struct tcpc_dev *dev)
> ret = fusb302_sw_reset(chip);
> if (ret < 0)
> return ret;
> - ret = fusb302_enable_tx_auto_retries(chip);
> + ret = fusb302_enable_tx_auto_retries(chip, FUSB_REG_CONTROL3_N_RETRIES_3);
> if (ret < 0)
> return ret;
> ret = fusb302_init_interrupt(chip);
> @@ -1017,7 +1016,7 @@ static const char * const transmit_type_name[] = {
> };
>
> static int tcpm_pd_transmit(struct tcpc_dev *dev, enum tcpm_transmit_type type,
> - const struct pd_message *msg)
> + const struct pd_message *msg, unsigned int negotiated_rev)
> {
> struct fusb302_chip *chip = container_of(dev, struct fusb302_chip,
> tcpc_dev);
> @@ -1026,6 +1025,13 @@ static int tcpm_pd_transmit(struct tcpc_dev *dev, enum tcpm_transmit_type type,
> mutex_lock(&chip->lock);
> switch (type) {
> case TCPC_TX_SOP:
> + /* nRetryCount 3 in P2.0 spec, whereas 2 in PD3.0 spec */
> + ret = fusb302_enable_tx_auto_retries(chip, negotiated_rev > PD_REV20 ?
> + FUSB_REG_CONTROL3_N_RETRIES_2 :
> + FUSB_REG_CONTROL3_N_RETRIES_3);
> + if (ret < 0)
> + fusb302_log(chip, "Cannot update retry count ret=%d", ret);
> +
> ret = fusb302_pd_send_message(chip, msg);
> if (ret < 0)
> fusb302_log(chip,
> diff --git a/drivers/usb/typec/tcpm/tcpci.c b/drivers/usb/typec/tcpm/tcpci.c
> index 12d983a75510..98a2455f779f 100644
> --- a/drivers/usb/typec/tcpm/tcpci.c
> +++ b/drivers/usb/typec/tcpm/tcpci.c
> @@ -18,7 +18,8 @@
>
> #include "tcpci.h"
>
> -#define PD_RETRY_COUNT 3
> +#define PD_RETRY_COUNT_DEFAULT 3
> +#define PD_RETRY_COUNT_3_0_OR_HIGHER 2
> #define AUTO_DISCHARGE_DEFAULT_THRESHOLD_MV 3500
> #define AUTO_DISCHARGE_PD_HEADROOM_MV 850
> #define AUTO_DISCHARGE_PPS_HEADROOM_MV 1250
> @@ -447,9 +448,8 @@ static int tcpci_set_vbus(struct tcpc_dev *tcpc, bool source, bool sink)
> return 0;
> }
>
> -static int tcpci_pd_transmit(struct tcpc_dev *tcpc,
> - enum tcpm_transmit_type type,
> - const struct pd_message *msg)
> +static int tcpci_pd_transmit(struct tcpc_dev *tcpc, enum tcpm_transmit_type type,
> + const struct pd_message *msg, unsigned int negotiated_rev)
> {
> struct tcpci *tcpci = tcpc_to_tcpci(tcpc);
> u16 header = msg ? le16_to_cpu(msg->header) : 0;
> @@ -497,7 +497,9 @@ static int tcpci_pd_transmit(struct tcpc_dev *tcpc,
> }
> }
>
> - reg = (PD_RETRY_COUNT << TCPC_TRANSMIT_RETRY_SHIFT) | (type << TCPC_TRANSMIT_TYPE_SHIFT);
> + /* nRetryCount is 3 in PD2.0 spec where 2 in PD3.0 spec */
> + reg = ((negotiated_rev > PD_REV20 ? PD_RETRY_COUNT_3_0_OR_HIGHER : PD_RETRY_COUNT_DEFAULT)
> + << TCPC_TRANSMIT_RETRY_SHIFT) | (type << TCPC_TRANSMIT_TYPE_SHIFT);
> ret = regmap_write(tcpci->regmap, TCPC_TRANSMIT, reg);
> if (ret < 0)
> return ret;
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 3bbc1f10af49..c73bc3a8356a 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -667,7 +667,7 @@ static int tcpm_pd_transmit(struct tcpm_port *port,
> tcpm_log(port, "PD TX, type: %#x", type);
>
> reinit_completion(&port->tx_complete);
> - ret = port->tcpc->pd_transmit(port->tcpc, type, msg);
> + ret = port->tcpc->pd_transmit(port->tcpc, type, msg, port->negotiated_rev);
> if (ret < 0)
> return ret;
>
> diff --git a/drivers/usb/typec/tcpm/wcove.c b/drivers/usb/typec/tcpm/wcove.c
> index 9b745f432c91..79ae63950050 100644
> --- a/drivers/usb/typec/tcpm/wcove.c
> +++ b/drivers/usb/typec/tcpm/wcove.c
> @@ -356,7 +356,8 @@ static int wcove_set_pd_rx(struct tcpc_dev *tcpc, bool on)
>
> static int wcove_pd_transmit(struct tcpc_dev *tcpc,
> enum tcpm_transmit_type type,
> - const struct pd_message *msg)
> + const struct pd_message *msg,
> + unsigned int negotiated_rev)
> {
> struct wcove_typec *wcove = tcpc_to_wcove(tcpc);
> unsigned int info = 0;
> diff --git a/include/linux/usb/tcpm.h b/include/linux/usb/tcpm.h
> index e68aaa12886f..efaedd7e8a18 100644
> --- a/include/linux/usb/tcpm.h
> +++ b/include/linux/usb/tcpm.h
> @@ -121,7 +121,7 @@ struct tcpc_dev {
> enum typec_cc_status cc);
> int (*try_role)(struct tcpc_dev *dev, int role);
> int (*pd_transmit)(struct tcpc_dev *dev, enum tcpm_transmit_type type,
> - const struct pd_message *msg);
> + const struct pd_message *msg, unsigned int negotiated_rev);
> int (*set_bist_data)(struct tcpc_dev *dev, bool on);
> int (*enable_frs)(struct tcpc_dev *dev, bool enable);
> void (*frs_sourcing_vbus)(struct tcpc_dev *dev);
> --
> 2.29.2.576.ga3fc446d84-goog

--
heikki