Re: [PATCH 1/3] usb: typec: Determine common SVDM Versions

From: Guenter Roeck
Date: Tue Jan 26 2021 - 10:11:06 EST

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In reply to: Kyle Tso: "[PATCH 1/3] usb: typec: Determine common SVDM Versions"
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On 1/26/21 12:45 AM, Kyle Tso wrote:
> PD Spec Revision 3.0 Version 2.0 + ECNs 2020-12-10
> 6.4.4.2.3 Structured VDM Version
> "The Structured VDM Version field of the Discover Identity Command
> sent and received during VDM discovery Shall be used to determine the
> lowest common Structured VDM Version supported by the Port Partners or
> Cable Plug and Shall continue to operate using this Specification
> Revision until they are Detached."
>
> Also clear the fields newly defined in SVDM version 2.0 for
> compatibilities. And fix some ID Header fields changed in the Spec.
>

Couple of concerns:
- svdm_ver is kept in three different data structures. I'd like to understand
why there isn't a single version associated with the port.
- Version comparisons are against SVDM_MAX_VER, not against svdm_ver.
That makes me slightly uncomfortable. Is there a reason for doing that
(other than "it should not matter") ?

Thanks,
Guenter

> Signed-off-by: Kyle Tso <kyletso@xxxxxxxxxx>
> ---
> drivers/usb/typec/altmodes/displayport.c | 6 +++-
> drivers/usb/typec/class.c | 8 ++---
> drivers/usb/typec/tcpm/tcpm.c | 44 +++++++++++++++++++-----
> drivers/usb/typec/ucsi/displayport.c | 12 +++++--
> include/linux/usb/pd_vdo.h | 40 +++++++++++++++------
> 5 files changed, 83 insertions(+), 27 deletions(-)
>
> diff --git a/drivers/usb/typec/altmodes/displayport.c b/drivers/usb/typec/altmodes/displayport.c
> index e62e5e3da01e..baf289acf707 100644
> --- a/drivers/usb/typec/altmodes/displayport.c
> +++ b/drivers/usb/typec/altmodes/displayport.c
> @@ -15,7 +15,7 @@
> #include <linux/usb/typec_dp.h>
> #include "displayport.h"
>
> -#define DP_HEADER(_dp, cmd) (VDO((_dp)->alt->svid, 1, cmd) | \
> +#define DP_HEADER(_dp, cmd) (VDO((_dp)->alt->svid, 1, (_dp)->svdm_ver, cmd) | \
> VDO_OPOS(USB_TYPEC_DP_MODE))
>
> enum {
> @@ -57,6 +57,7 @@ struct dp_altmode {
> struct typec_displayport_data data;
>
> enum dp_state state;
> + u32 svdm_ver;
>
> struct mutex lock; /* device lock */
> struct work_struct work;
> @@ -266,6 +267,8 @@ static int dp_altmode_vdm(struct typec_altmode *alt,
> case CMDT_RSP_ACK:
> switch (cmd) {
> case CMD_ENTER_MODE:
> + if (PD_VDO_SVDM_VER(hdr) < SVDM_MAX_VER)
> + dp->svdm_ver = PD_VDO_SVDM_VER(hdr);
> dp->state = DP_STATE_UPDATE;
> break;
> case CMD_EXIT_MODE:
> @@ -536,6 +539,7 @@ int dp_altmode_probe(struct typec_altmode *alt)
> mutex_init(&dp->lock);
> dp->port = port;
> dp->alt = alt;
> + dp->svdm_ver = SVDM_MAX_VER;
>
> alt->desc = "DisplayPort";
> alt->ops = &dp_altmode_ops;
> diff --git a/drivers/usb/typec/class.c b/drivers/usb/typec/class.c
> index 8f77669f9cf4..862afb377752 100644
> --- a/drivers/usb/typec/class.c
> +++ b/drivers/usb/typec/class.c
> @@ -86,7 +86,7 @@ static const char * const typec_accessory_modes[] = {
>
> /* Product types defined in USB PD Specification R3.0 V2.0 */
> static const char * const product_type_ufp[8] = {
> - [IDH_PTYPE_UNDEF] = "undefined",
> + [IDH_PTYPE_NOT_UFP] = "not_ufp",
> [IDH_PTYPE_HUB] = "hub",
> [IDH_PTYPE_PERIPH] = "peripheral",
> [IDH_PTYPE_PSD] = "psd",
> @@ -94,17 +94,17 @@ static const char * const product_type_ufp[8] = {
> };
>
> static const char * const product_type_dfp[8] = {
> - [IDH_PTYPE_DFP_UNDEF] = "undefined",
> + [IDH_PTYPE_NOT_DFP] = "not_dfp",
> [IDH_PTYPE_DFP_HUB] = "hub",
> [IDH_PTYPE_DFP_HOST] = "host",
> [IDH_PTYPE_DFP_PB] = "power_brick",
> - [IDH_PTYPE_DFP_AMC] = "amc",
> };
>
> static const char * const product_type_cable[8] = {
> - [IDH_PTYPE_UNDEF] = "undefined",
> + [IDH_PTYPE_NOT_CABLE] = "not_cable",
> [IDH_PTYPE_PCABLE] = "passive",
> [IDH_PTYPE_ACABLE] = "active",
> + [IDH_PTYPE_VPD] = "vpd",
> };
>
> static struct usb_pd_identity *get_pd_identity(struct device *dev)
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 0afd8ef692e8..c14cf7842520 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -408,6 +408,7 @@ struct tcpm_port {
> u8 vdo_count;
> /* VDO to retry if UFP responder replied busy */
> u32 vdo_retry;
> + unsigned int svdm_version;
>
> /* PPS */
> struct pd_pps_data pps_data;
> @@ -1500,10 +1501,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> if (PD_VDO_VID(p[0]) != USB_SID_PD)
> break;
>
> + if (PD_VDO_SVDM_VER(p[0]) <= SVDM_MAX_VER)
> + port->svdm_version = PD_VDO_SVDM_VER(p[0]);
> /* 6.4.4.3.1: Only respond as UFP (device) */
> if (port->data_role == TYPEC_DEVICE &&
> port->nr_snk_vdo) {
> - for (i = 0; i < port->nr_snk_vdo; i++)
> + /*
> + * Product Type DFP and Connector Type are not defined in SVDM
> + * version 1.0 and shall be set to zero.
> + */
> + if (port->svdm_version < SVDM_V20)
> + response[1] = port->snk_vdo[0] & ~IDH_DFP_MASK
> + & ~IDH_CONN_MASK;
> + else
> + response[1] = port->snk_vdo[0];
> + for (i = 1; i < port->nr_snk_vdo; i++)
> response[i + 1] = port->snk_vdo[i];
> rlen = port->nr_snk_vdo + 1;
> }
> @@ -1532,6 +1544,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
> rlen = 1;
> }
> + response[0] = (response[0] & ~VDO_SVDM_VERS_MASK) |
> + (VDO_SVDM_VERS(port->svdm_version));
> break;
> case CMDT_RSP_ACK:
> /* silently drop message if we are not connected */
> @@ -1542,19 +1556,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
>
> switch (cmd) {
> case CMD_DISCOVER_IDENT:
> + if (PD_VDO_SVDM_VER(p[0]) <= SVDM_MAX_VER)
> + port->svdm_version = PD_VDO_SVDM_VER(p[0]);
> /* 6.4.4.3.1 */
> svdm_consume_identity(port, p, cnt);
> - response[0] = VDO(USB_SID_PD, 1, CMD_DISCOVER_SVID);
> + response[0] = VDO(USB_SID_PD, 1, port->svdm_version, CMD_DISCOVER_SVID);
> rlen = 1;
> break;
> case CMD_DISCOVER_SVID:
> /* 6.4.4.3.2 */
> if (svdm_consume_svids(port, p, cnt)) {
> - response[0] = VDO(USB_SID_PD, 1,
> + response[0] = VDO(USB_SID_PD, 1, port->svdm_version,
> CMD_DISCOVER_SVID);
> rlen = 1;
> } else if (modep->nsvids && supports_modal(port)) {
> - response[0] = VDO(modep->svids[0], 1,
> + response[0] = VDO(modep->svids[0], 1, port->svdm_version,
> CMD_DISCOVER_MODES);
> rlen = 1;
> }
> @@ -1565,7 +1581,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> modep->svid_index++;
> if (modep->svid_index < modep->nsvids) {
> u16 svid = modep->svids[modep->svid_index];
> - response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
> + response[0] = VDO(svid, 1, port->svdm_version,
> + CMD_DISCOVER_MODES);
> rlen = 1;
> } else {
> tcpm_register_partner_altmodes(port);
> @@ -1592,6 +1609,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> /* Unrecognized SVDM */
> response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> rlen = 1;
> + response[0] = (response[0] & ~VDO_SVDM_VERS_MASK) |
> + (VDO_SVDM_VERS(port->svdm_version));
> break;
> }
> break;
> @@ -1611,6 +1630,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> /* Unrecognized SVDM */
> response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> rlen = 1;
> + response[0] = (response[0] & ~VDO_SVDM_VERS_MASK) |
> + (VDO_SVDM_VERS(port->svdm_version));
> break;
> }
> port->vdm_sm_running = false;
> @@ -1618,6 +1639,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
> default:
> response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> rlen = 1;
> + response[0] = (response[0] & ~VDO_SVDM_VERS_MASK) |
> + (VDO_SVDM_VERS(port->svdm_version));
> port->vdm_sm_running = false;
> break;
> }
> @@ -1695,7 +1718,7 @@ static void tcpm_handle_vdm_request(struct tcpm_port *port,
> 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(adev->svid, 1, port->svdm_version, CMD_EXIT_MODE);
> response[0] |= VDO_OPOS(adev->mode);
> rlen = 1;
> }
> @@ -1729,7 +1752,8 @@ static void tcpm_send_vdm(struct tcpm_port *port, u32 vid, int cmd,
>
> /* set VDM header with VID & CMD */
> header = VDO(vid, ((vid & USB_SID_PD) == USB_SID_PD) ?
> - 1 : (PD_VDO_CMD(cmd) <= CMD_ATTENTION), cmd);
> + 1 : (PD_VDO_CMD(cmd) <= CMD_ATTENTION),
> + port->svdm_version, cmd);
> tcpm_queue_vdm(port, header, data, count);
> }
>
> @@ -2024,7 +2048,7 @@ static int tcpm_altmode_enter(struct typec_altmode *altmode, u32 *vdo)
> struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> u32 header;
>
> - header = VDO(altmode->svid, vdo ? 2 : 1, CMD_ENTER_MODE);
> + header = VDO(altmode->svid, vdo ? 2 : 1, port->svdm_version, CMD_ENTER_MODE);
> header |= VDO_OPOS(altmode->mode);
>
> tcpm_queue_vdm_unlocked(port, header, vdo, vdo ? 1 : 0);
> @@ -2036,7 +2060,7 @@ static int tcpm_altmode_exit(struct typec_altmode *altmode)
> struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> u32 header;
>
> - header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> + header = VDO(altmode->svid, 1, port->svdm_version, CMD_EXIT_MODE);
> header |= VDO_OPOS(altmode->mode);
>
> tcpm_queue_vdm_unlocked(port, header, NULL, 0);
> @@ -3716,6 +3740,7 @@ static void run_state_machine(struct tcpm_port *port)
> port->pwr_opmode = TYPEC_PWR_MODE_USB;
> port->caps_count = 0;
> port->negotiated_rev = PD_MAX_REV;
> + port->svdm_version = SVDM_MAX_VER;
> port->message_id = 0;
> port->rx_msgid = -1;
> port->explicit_contract = false;
> @@ -3938,6 +3963,7 @@ static void run_state_machine(struct tcpm_port *port)
> typec_set_pwr_opmode(port->typec_port, opmode);
> port->pwr_opmode = TYPEC_PWR_MODE_USB;
> port->negotiated_rev = PD_MAX_REV;
> + port->svdm_version = SVDM_MAX_VER;
> port->message_id = 0;
> port->rx_msgid = -1;
> port->explicit_contract = false;
> diff --git a/drivers/usb/typec/ucsi/displayport.c b/drivers/usb/typec/ucsi/displayport.c
> index 261131c9e37c..421ad3e0d976 100644
> --- a/drivers/usb/typec/ucsi/displayport.c
> +++ b/drivers/usb/typec/ucsi/displayport.c
> @@ -28,6 +28,7 @@ struct ucsi_dp {
> u32 header;
> u32 *vdo_data;
> u8 vdo_size;
> + u32 svdm_ver;
> };
>
> /*
> @@ -83,7 +84,7 @@ static int ucsi_displayport_enter(struct typec_altmode *alt, u32 *vdo)
> * mode, and letting the alt mode driver continue.
> */
>
> - dp->header = VDO(USB_TYPEC_DP_SID, 1, CMD_ENTER_MODE);
> + dp->header = VDO(USB_TYPEC_DP_SID, 1, dp->svdm_ver, CMD_ENTER_MODE);
> dp->header |= VDO_OPOS(USB_TYPEC_DP_MODE);
> dp->header |= VDO_CMDT(CMDT_RSP_ACK);
>
> @@ -120,7 +121,7 @@ static int ucsi_displayport_exit(struct typec_altmode *alt)
> if (ret < 0)
> goto out_unlock;
>
> - dp->header = VDO(USB_TYPEC_DP_SID, 1, CMD_EXIT_MODE);
> + dp->header = VDO(USB_TYPEC_DP_SID, 1, dp->svdm_ver, CMD_EXIT_MODE);
> dp->header |= VDO_OPOS(USB_TYPEC_DP_MODE);
> dp->header |= VDO_CMDT(CMDT_RSP_ACK);
>
> @@ -200,7 +201,11 @@ static int ucsi_displayport_vdm(struct typec_altmode *alt,
>
> switch (cmd_type) {
> case CMDT_INIT:
> - dp->header = VDO(USB_TYPEC_DP_SID, 1, cmd);
> + if (PD_VDO_SVDM_VER(header) != dp->svdm_ver &&
> + PD_VDO_SVDM_VER(header) < SVDM_MAX_VER)
> + dp->svdm_ver = PD_VDO_SVDM_VER(header);
> +
> + dp->header = VDO(USB_TYPEC_DP_SID, 1, dp->svdm_ver, cmd);
> dp->header |= VDO_OPOS(USB_TYPEC_DP_MODE);
>
> switch (cmd) {
> @@ -310,6 +315,7 @@ struct typec_altmode *ucsi_register_displayport(struct ucsi_connector *con,
> dp->offset = offset;
> dp->con = con;
> dp->alt = alt;
> + dp->svdm_ver = SVDM_MAX_VER;
>
> alt->ops = &ucsi_displayport_ops;
> typec_altmode_set_drvdata(alt, dp);
> diff --git a/include/linux/usb/pd_vdo.h b/include/linux/usb/pd_vdo.h
> index 8c08eeb9a74b..5283a08527ce 100644
> --- a/include/linux/usb/pd_vdo.h
> +++ b/include/linux/usb/pd_vdo.h
> @@ -16,27 +16,33 @@
> #define VDO_MAX_OBJECTS 6
> #define VDO_MAX_SIZE (VDO_MAX_OBJECTS + 1)
>
> +#define SVDM_V10 0
> +#define SVDM_V20 1
> +#define SVDM_MAX_VER SVDM_V20
> +
> /*
> * VDM header
> * ----------
> * <31:16> :: SVID
> * <15> :: VDM type ( 1b == structured, 0b == unstructured )
> - * <14:13> :: Structured VDM version (can only be 00 == 1.0 currently)
> + * <14:13> :: Structured VDM version
> * <12:11> :: reserved
> * <10:8> :: object position (1-7 valid ... used for enter/exit mode only)
> * <7:6> :: command type (SVDM only?)
> * <5> :: reserved (SVDM), command type (UVDM)
> * <4:0> :: command
> */
> -#define VDO(vid, type, custom) \
> +#define VDO(vid, type, ver, custom) \
> (((vid) << 16) | \
> ((type) << 15) | \
> + ((ver) << 13) | \
> ((custom) & 0x7FFF))
>
> #define VDO_SVDM_TYPE (1 << 15)
> #define VDO_SVDM_VERS(x) ((x) << 13)
> #define VDO_OPOS(x) ((x) << 8)
> #define VDO_CMDT(x) ((x) << 6)
> +#define VDO_SVDM_VERS_MASK VDO_SVDM_VERS(0x3)
> #define VDO_OPOS_MASK VDO_OPOS(0x7)
> #define VDO_CMDT_MASK VDO_CMDT(0x3)
>
> @@ -74,6 +80,7 @@
>
> #define PD_VDO_VID(vdo) ((vdo) >> 16)
> #define PD_VDO_SVDM(vdo) (((vdo) >> 15) & 1)
> +#define PD_VDO_SVDM_VER(vdo) (((vdo) >> 13) & 0x3)
> #define PD_VDO_OPOS(vdo) (((vdo) >> 8) & 0x7)
> #define PD_VDO_CMD(vdo) ((vdo) & 0x1f)
> #define PD_VDO_CMDT(vdo) (((vdo) >> 6) & 0x3)
> @@ -103,34 +110,46 @@
> * --------------------
> * <31> :: data capable as a USB host
> * <30> :: data capable as a USB device
> - * <29:27> :: product type (UFP / Cable)
> + * <29:27> :: product type (UFP / Cable / VPD)
> * <26> :: modal operation supported (1b == yes)
> - * <25:16> :: product type (DFP)
> + * <25:23> :: product type (DFP) (SVDM version 2.0+ only; set to zero in version 1.0)
> + * <22:21> :: connector type (SVDM version 2.0+ only; set to zero in version 1.0)
> + * <20:16> :: Reserved, Shall be set to zero
> * <15:0> :: USB-IF assigned VID for this cable vendor
> */
> -#define IDH_PTYPE_UNDEF 0
> +/* SOP Product Type (UFP) */
> +#define IDH_PTYPE_NOT_UFP 0
> #define IDH_PTYPE_HUB 1
> #define IDH_PTYPE_PERIPH 2
> #define IDH_PTYPE_PSD 3
> #define IDH_PTYPE_AMA 5
>
> +/* SOP' Product Type (Cable Plug / VPD) */
> +#define IDH_PTYPE_NOT_CABLE 0
> #define IDH_PTYPE_PCABLE 3
> #define IDH_PTYPE_ACABLE 4
> +#define IDH_PTYPE_VPD 6
>
> -#define IDH_PTYPE_DFP_UNDEF 0
> +/* SOP Product Type (DFP) */
> +#define IDH_PTYPE_NOT_DFP 0
> #define IDH_PTYPE_DFP_HUB 1
> #define IDH_PTYPE_DFP_HOST 2
> #define IDH_PTYPE_DFP_PB 3
> -#define IDH_PTYPE_DFP_AMC 4
>
> -#define VDO_IDH(usbh, usbd, ptype, is_modal, vid) \
> - ((usbh) << 31 | (usbd) << 30 | ((ptype) & 0x7) << 27 \
> - | (is_modal) << 26 | ((vid) & 0xffff))
> +/* ID Header Mask */
> +#define IDH_DFP_MASK GENMASK(25, 23)
> +#define IDH_CONN_MASK GENMASK(22, 21)
> +
> +#define VDO_IDH(usbh, usbd, ufp_cable, is_modal, dfp, conn, vid) \
> + ((usbh) << 31 | (usbd) << 30 | ((ufp_cable) & 0x7) << 27 \
> + | (is_modal) << 26 | ((dfp) & 0x7) << 23 | ((conn) & 0x3) << 21 \
> + | ((vid) & 0xffff))
>
> #define PD_IDH_PTYPE(vdo) (((vdo) >> 27) & 0x7)
> #define PD_IDH_VID(vdo) ((vdo) & 0xffff)
> #define PD_IDH_MODAL_SUPP(vdo) ((vdo) & (1 << 26))
> #define PD_IDH_DFP_PTYPE(vdo) (((vdo) >> 23) & 0x7)
> +#define PD_IDH_CONN_TYPE(vdo) (((vdo) >> 21) & 0x3)
>
> /*
> * Cert Stat VDO
> @@ -138,6 +157,7 @@
> * <31:0> : USB-IF assigned XID for this cable
> */
> #define PD_CSTAT_XID(vdo) (vdo)
> +#define VDO_CERT(xid) ((xid) & 0xffffffff)
>
> /*
> * Product VDO
>

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