linux-kernel - Re: [PATCH v7 4/4] Bluetooth: btqca: inject command complete event during fw download

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Date:   Fri, 28 Dec 2018 11:50:20 -0800
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Balakrishna Godavarthi <bgodavar@...eaurora.org>
Cc:     marcel@...tmann.org, johan.hedberg@...il.com,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        hemantg@...eaurora.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH v7 4/4] Bluetooth: btqca: inject command complete event
 during fw download

On Fri, Dec 28, 2018 at 05:18:19PM +0530, Balakrishna Godavarthi wrote:
> Latest qualcomm chips are not sending an command complete event for
> every firmware packet sent to chip. They only respond with a vendor
> specific event for the last firmware packet. This optimization will
> decrease the BT ON time. Due to this we are seeing a timeout error
> message logs on the console during firmware download. Now we are
> injecting a command complete event once we receive an vendor specific
> event for the last RAM firmware packet.
> 
> Signed-off-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>
> ---
>  drivers/bluetooth/btqca.c | 39 ++++++++++++++++++++++++++++++++++++++-
>  drivers/bluetooth/btqca.h |  3 +++
>  2 files changed, 41 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/bluetooth/btqca.c b/drivers/bluetooth/btqca.c
> index ec9e03a6b778..0b533f65f652 100644
> --- a/drivers/bluetooth/btqca.c
> +++ b/drivers/bluetooth/btqca.c
> @@ -144,6 +144,7 @@ static void qca_tlv_check_data(struct rome_config *config,
>  		 * In case VSE is skipped, only the last segment is acked.
>  		 */
>  		config->dnld_mode = tlv_patch->download_mode;
> +		config->dnld_type = config->dnld_mode;
>  
>  		BT_DBG("Total Length           : %d bytes",
>  		       le32_to_cpu(tlv_patch->total_size));
> @@ -264,6 +265,31 @@ static int qca_tlv_send_segment(struct hci_dev *hdev, int seg_size,
>  	return err;
>  }
>  
> +static int qca_inject_cmd_complete_event(struct hci_dev *hdev)
> +{
> +	struct hci_event_hdr *hdr;
> +	struct hci_ev_cmd_complete *evt;
> +	struct sk_buff *skb;
> +
> +	skb = bt_skb_alloc(sizeof(*hdr) + sizeof(*evt) + 1, GFP_KERNEL);
> +	if (!skb)
> +		return -ENOMEM;
> +
> +	hdr = skb_put(skb, sizeof(*hdr));
> +	hdr->evt = HCI_EV_CMD_COMPLETE;
> +	hdr->plen = sizeof(*evt) + 1;
> +
> +	evt = skb_put(skb, sizeof(*evt));
> +	evt->ncmd = 1;
> +	evt->opcode = HCI_OP_NOP;
> +
> +	skb_put_u8(skb, QCA_HCI_CC_SUCCESS);
> +
> +	hci_skb_pkt_type(skb) = HCI_EVENT_PKT;
> +
> +	return hci_recv_frame(hdev, skb);
> +}
> +
>  static int qca_download_firmware(struct hci_dev *hdev,
>  				  struct rome_config *config)
>  {
> @@ -297,11 +323,22 @@ static int qca_download_firmware(struct hci_dev *hdev,
>  		ret = qca_tlv_send_segment(hdev, segsize, segment,
>  					    config->dnld_mode);
>  		if (ret)
> -			break;
> +			goto out;
>  
>  		segment += segsize;
>  	}
>  
> +	/* Latest qualcomm chipsets are not sending a command complete event
> +	 * for every fw packet sent. They only respond with a vendor specific
> +	 * event for the last packet. This optimization in the chip will
> +	 * decrease the BT in initialization time. Here we will inject a command
> +	 * complete event to avoid a command timeout error message.
> +	 */
> +	if ((config->dnld_type == ROME_SKIP_EVT_VSE_CC ||
> +	    config->dnld_type == ROME_SKIP_EVT_VSE))
> +		return qca_inject_cmd_complete_event(hdev);
> +
> +out:
>  	release_firmware(fw);
>  
>  	return ret;
> diff --git a/drivers/bluetooth/btqca.h b/drivers/bluetooth/btqca.h
> index 0c01f375fe83..5c8fc54133e3 100644
> --- a/drivers/bluetooth/btqca.h
> +++ b/drivers/bluetooth/btqca.h
> @@ -40,6 +40,8 @@
>  #define QCA_WCN3990_POWERON_PULSE	0xFC
>  #define QCA_WCN3990_POWEROFF_PULSE	0xC0
>  
> +#define QCA_HCI_CC_SUCCESS		0x00
> +
>  enum qca_bardrate {
>  	QCA_BAUDRATE_115200 	= 0,
>  	QCA_BAUDRATE_57600,
> @@ -81,6 +83,7 @@ struct rome_config {
>  	char fwname[64];
>  	uint8_t user_baud_rate;
>  	enum rome_tlv_dnld_mode dnld_mode;
> +	enum rome_tlv_dnld_mode dnld_type;

The ->dnld_type vs ->dnld_mode is a bit confusing, I don't have a
better suggestion though.

>  };
>  
>  struct edl_event_hdr {

I'm not an expert in dealing with HCI SKBs, as far as I can tell the
above looks sane to me and I confirmed that it fixes the timeout when
downloading firmware.

Tested-by: Matthias Kaehlcke <mka@...omium.org>
Reviewed-by: Matthias Kaehlcke <mka@...omium.org>