Re: [PATCH 2/2] platform/chrome: cros_ec_typec: Send mux configuration acknowledgment to EC

[Benson Leung]

Hi Utkarsh,

On Wed, Dec 09, 2020 at 10:09:03PM -0800, Utkarsh Patel wrote:
> In some corner cases downgrade of the superspeed typec device(e.g. Dell
> typec Dock, apple dongle) was seen because before the SOC mux configuration
> finishes, EC starts configuring the next mux state.
> 
> With this change, once the SOC mux is configured, kernel will send an
> acknowledgment to EC via Host command EC_CMD_USB_PD_MUX_ACK [1].
> After sending the host event EC will wait for the acknowledgment from
> kernel before starting the PD negotiation for the next mux state. This
> helps to have a framework to build better error handling along with the
> synchronization of timing sensitive mux states.
> 
> This change also brings in corresponding EC header updates from the EC code
> base [1].
> 
> [1]:
> https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/master/include/ec_commands.h
> 
> Signed-off-by: Utkarsh Patel <utkarsh.h.patel@xxxxxxxxx>
> ---
>  drivers/platform/chrome/cros_ec_typec.c        | 16 ++++++++++++++++
>  include/linux/platform_data/cros_ec_commands.h | 17 +++++++++++++++++
>  2 files changed, 33 insertions(+)
> 
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 650aa5332055..e6abe205890c 100644

I went ahead and staged this commit, but just for your information, applying
this patch was problematic because the sha1 used here didn't match anything
in the upstream kernel.

Here's the error when I try to apply this using git am:
Applying: platform/chrome: cros_ec_typec: Send mux configuration acknowledgment to EC
error: sha1 information is lacking or useless (drivers/platform/chrome/cros_ec_typec.c).
error: could not build fake ancestor
Patch failed at 0001 platform/chrome: cros_ec_typec: Send mux configuration acknowledgment to EC


Please double check when you run git-format-patch that the branch you are
working on comes from publicly available git repos, ideally, based on linus's
tagged releases. This will ensure things apply cleanly on my side.

I've gone ahead and staged this, but could you please sanity check that the
result is as intended?

https://git.kernel.org/pub/scm/linux/kernel/git/chrome-platform/linux.git/commit/?h=cros-ec-typec-for-5.12&id=8553a979fcd03448a4096c7d431b7ee1a52bfca3

Thank you,
Benson

> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -74,6 +74,7 @@ struct cros_typec_data {
>  	struct notifier_block nb;
>  	struct work_struct port_work;
>  	bool typec_cmd_supported;
> +	bool needs_mux_ack;
>  };
>  
>  static int cros_typec_parse_port_props(struct typec_capability *cap,
> @@ -503,6 +504,7 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>  				struct ec_response_usb_pd_control_v2 *pd_ctrl)
>  {
>  	struct cros_typec_port *port = typec->ports[port_num];
> +	struct ec_params_usb_pd_mux_ack mux_ack;
>  	enum typec_orientation orientation;
>  	int ret;
>  
> @@ -543,6 +545,18 @@ static int cros_typec_configure_mux(struct cros_typec_data *typec, int port_num,
>  		ret = -ENOTSUPP;
>  	}
>  
> +	if (!typec->needs_mux_ack)
> +		return ret;
> +
> +	/* Sending Acknowledgment to EC */
> +	mux_ack.port = port_num;
> +
> +	if (cros_typec_ec_command(typec, 0, EC_CMD_USB_PD_MUX_ACK, &mux_ack,
> +				  sizeof(mux_ack), NULL, 0) < 0)
> +		dev_warn(typec->dev,
> +			 "Failed to send Mux ACK to EC for port: %d\n",
> +			 port_num);
> +
>  	return ret;
>  }
>  
> @@ -908,6 +922,8 @@ static int cros_typec_probe(struct platform_device *pdev)
>  
>  	typec->typec_cmd_supported = !!cros_typec_feature_supported(typec,
>  					EC_FEATURE_TYPEC_CMD);
> +	typec->needs_mux_ack = !!cros_typec_feature_supported(typec,
> +					EC_FEATURE_TYPEC_MUX_REQUIRE_AP_ACK);
>  
>  	ret = cros_typec_ec_command(typec, 0, EC_CMD_USB_PD_PORTS, NULL, 0,
>  				    &resp, sizeof(resp));
> diff --git a/include/linux/platform_data/cros_ec_commands.h b/include/linux/platform_data/cros_ec_commands.h
> index 7f54fdcdd8cb..3b53e45cb5a0 100644
> --- a/include/linux/platform_data/cros_ec_commands.h
> +++ b/include/linux/platform_data/cros_ec_commands.h
> @@ -1286,6 +1286,16 @@ enum ec_feature_code {
>  	EC_FEATURE_ISH = 40,
>  	/* New TCPMv2 TYPEC_ prefaced commands supported */
>  	EC_FEATURE_TYPEC_CMD = 41,
> +	/*
> +	 * The EC will wait for direction from the AP to enter Type-C alternate
> +	 * modes or USB4.
> +	 */
> +	EC_FEATURE_TYPEC_REQUIRE_AP_MODE_ENTRY = 42,
> +	/*
> +	 * The EC will wait for an acknowledge from the AP after setting the
> +	 * mux.
> +	 */
> +	EC_FEATURE_TYPEC_MUX_REQUIRE_AP_ACK = 43,
>  };
>  
>  #define EC_FEATURE_MASK_0(event_code) BIT(event_code % 32)
> @@ -6054,6 +6064,13 @@ struct ec_params_charger_control {
>  	uint8_t allow_charging;
>  } __ec_align_size1;
>  
> +/* Get ACK from the USB-C SS muxes */
> +#define EC_CMD_USB_PD_MUX_ACK 0x0603
> +
> +struct ec_params_usb_pd_mux_ack {
> +	uint8_t port; /* USB-C port number */
> +} __ec_align1;
> +
>  /*****************************************************************************/
>  /*
>   * Reserve a range of host commands for board-specific, experimental, or
> -- 
> 2.25.1
> 

-- 
Benson Leung
Staff Software Engineer
Chrome OS Kernel
Google Inc.
bleung@xxxxxxxxxx
Chromium OS Project
bleung@xxxxxxxxxxxx

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