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Date: Fri, 1 Mar 2024 11:37:37 -0800
From: Prashant Malani <pmalani@...omium.org>
To: Jameson Thies <jthies@...gle.com>
Cc: heikki.krogerus@...ux.intel.com, linux-usb@...r.kernel.org,
bleung@...gle.com, abhishekpandit@...omium.org, andersson@...nel.org,
dmitry.baryshkov@...aro.org, fabrice.gasnier@...s.st.com,
gregkh@...uxfoundation.org, hdegoede@...hat.com, neil.armstrong@...aro.org,
rajaram.regupathy@...el.com, saranya.gopal@...el.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/4] usb: typec: ucsi: Register SOP/SOP' Discover
Identity Responses
On Thu, Feb 29, 2024 at 3:28 PM Jameson Thies <jthies@...gle.com> wrote:
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index 7c84687b5d1a3..4088422b33c74 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -646,6 +646,121 @@ static int ucsi_get_src_pdos(struct ucsi_connector *con)
> return ret;
> }
>
> +static int ucsi_read_identity(struct ucsi_connector *con, u8 recipient,
> + struct usb_pd_identity *id)
> +{
> + struct ucsi *ucsi = con->ucsi;
> + struct ucsi_pd_message_disc_id resp = {};
> + u64 command;
> + int ret;
> +
> + if (ucsi->version < UCSI_VERSION_2_0) {
> + /*
> + * Before UCSI v2.0, MESSAGE_IN is 16 bytes which cannot fit
> + * the 28 byte identity response including the VDM header.
> + * First request the VDM header, ID Header VDO, Cert Stat VDO
> + * and Product VDO.
> + */
> + command = UCSI_COMMAND(UCSI_GET_PD_MESSAGE) |
> + UCSI_CONNECTOR_NUMBER(con->num);
> + command |= UCSI_GET_PD_MESSAGE_RECIPIENT(recipient);
> + command |= UCSI_GET_PD_MESSAGE_OFFSET(0);
> + command |= UCSI_GET_PD_MESSAGE_BYTES(0x10);
> + command |= UCSI_GET_PD_MESSAGE_TYPE(
> + UCSI_GET_PD_MESSAGE_TYPE_IDENTITY);
> +
> + ret = ucsi_send_command(ucsi, command, &resp, 0x10);
> + if (ret < 0) {
> + dev_err(ucsi->dev,
> + "UCSI_GET_PD_MESSAGE v1.2 failed first request (%d)\n",
> + ret);
> + return ret;
> + }
> +
> + /* Then request Product Type VDO1 through Product Type VDO3. */
> + command = UCSI_COMMAND(UCSI_GET_PD_MESSAGE) |
> + UCSI_CONNECTOR_NUMBER(con->num);
> + command |= UCSI_GET_PD_MESSAGE_RECIPIENT(recipient);
> + command |= UCSI_GET_PD_MESSAGE_OFFSET(0x10);
> + command |= UCSI_GET_PD_MESSAGE_BYTES(0xc);
> + command |= UCSI_GET_PD_MESSAGE_TYPE(
> + UCSI_GET_PD_MESSAGE_TYPE_IDENTITY);
> +
> + ret = ucsi_send_command(ucsi, command, &resp.vdo[0], 0xc);
> + if (ret < 0) {
> + dev_err(ucsi->dev,
> + "UCSI_GET_PD_MESSAGE v1.2 failed second request (%d)\n",
> + ret);
> + return ret;
> + }
> + } else {
> + /*
> + * In UCSI v2.0 and after, MESSAGE_IN is large enough to request
> + * the large enough to request the full Discover Identity
> + * response at once.
> + */
> + command = UCSI_COMMAND(UCSI_GET_PD_MESSAGE) |
> + UCSI_CONNECTOR_NUMBER(con->num);
> + command |= UCSI_GET_PD_MESSAGE_RECIPIENT(recipient);
> + /* VDM Header + 6 VDOs (0x1c bytes) without an offset */
> + command |= UCSI_GET_PD_MESSAGE_OFFSET(0);
> + command |= UCSI_GET_PD_MESSAGE_BYTES(0x1c);
> + command |= UCSI_GET_PD_MESSAGE_TYPE(
> + UCSI_GET_PD_MESSAGE_TYPE_IDENTITY);
> +
> + ret = ucsi_send_command(ucsi, command, &resp, sizeof(resp));
> + if (ret < 0) {
> + dev_err(ucsi->dev, "UCSI_GET_PD_MESSAGE failed (%d)\n",
> + ret);
> + return ret;
> + }
> + }
> +
> + id->id_header = resp.id_header;
> + id->cert_stat = resp.cert_stat;
> + id->product = resp.product;
> + id->vdo[0] = resp.vdo[0];
> + id->vdo[1] = resp.vdo[1];
> + id->vdo[2] = resp.vdo[2];
> + return 0;
> +}
There is some repetition here, both with the "if" block and the
UCSI command itself. You can factor out the command setup code into a separate
function (it can take offset and size as arguments). Then, factor out
common parts in the "if" block. For example:
int ucsi_pd_message_get_identity(struct *ucsi, u8 offset, u8 size, u8 recipient,
void *data) {
u64 command = UCSI_COMMAND(UCSI_GET_PD_MESSAGE) |
UCSI_CONNECTOR_NUMBER(ucsi->con->num) |
UCSI_GET_PD_MESSAGE_RECIPIENT(recipient) |
UCSI_GET_PD_MESSAGE_OFFSET(offset) |
UCSI_GET_PD_MESSAGE_BYTES(size) |
UCSI_GET_PD_MESSAGE_TYPE(UCSI_GET_PD_MESSAGE_TYPE_IDENTITY);
return ucsi_send_command(ucsi, command, data, size);
}
Then in the ucsi_read_identity() :
u8 offset = 0;
u8 size;
/*
* In UCSI v2.0 and after, MESSAGE_IN is large enough to request
* the large enough to request the full Discover Identity
* response at once.
*/
if (ucsi->version >= UCSI_VERSION_2_0) {
size = 0x1c;
else
size = 0x10;
ret = ucsi_pd_message_get_identity(ucsi, offset, size, &resp);
if (ret < 0) {
/* Handle error */
}
/* Request Product Type VDO1 through Product Type VDO3. */
if (ucsi->version < UCSI_VERSION_2_0) {
offset = 0x10;
size = 0xC;
ret = ucsi_pd_message_get_identity(ucsi, offset, size,
&resp.vdo[0]);
if (ret < 0) {
/* Handle error */
}
}
BR,
-Prashant
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