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    SubjectRe: [PATCH v7 4/4] Bluetooth: btqca: inject command complete event during fw download
    Hi Marcel,

    On 2018-12-31 11:34, Balakrishna Godavarthi wrote:
    > Hi Marcel,
    >
    > On 2018-12-30 13:40, Marcel Holtmann wrote:
    >> Hi Balakrishna,
    >>
    >>>>> 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@codeaurora.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);
    >>>>> +
    >>>> have you actually considered using __hci_cmd_send in that case. It
    >>>> is
    >>>> allowed for vendor OGF to use that command. I see you actually do
    >>>> use
    >>>> it and now I am failing to understand what this is for.
    >>> [Bala]: thanks for reviewing the change.
    >>>
    >>> __hci_cmd_send() can be used only to send the command to the chip. it
    >>> will not wait for the response for the command sent.
    >>>
    >>> as you know that every vendor command sent to chip will respond with
    >>> vendor specific event and command complete event.
    >>> but in our case chip will only respond with vendor specific event
    >>> only. so we are injecting command complete event.
    >>
    >> and __hci_cmd_sync_ev is also not working for you? However since you
    >> are not waiting for the vendor event anyway and just injecting
    >> cmd_complete, I wonder what’s the difference in just using
    >> __hci_cmd_send and not bothering to wait or inject at all. I am
    >> failing to see where this injection makes a difference.
    >>
    >> For me it is a big difference if we are injecting one event like in
    >> the case of Intel compared to injecting one for every command. It will
    >> show a wrong picture in btmon and that is a bad idea.
    >>
    >> Regards
    >>
    >> Marcel
    >
    > [Bala]: here is the use case, when ever we download the fw packets
    > i.e. RAM image, for every command sent(i.e. fw packet) from
    > the host chip will respond with an vendor specific event and command
    > complete event.
    >
    > the above is taking more time to setup the BT device. then we came up
    > with solution where we enable flags in fw file (i.e. RAM image header)
    > whether to wait for event to be received or sent the total packets and
    > wait for the events for the last packet.
    >
    > So currently we are handling both the cases in the code. i.e wait for
    > event for all packet or wait for an event for the last packet.
    >
    > but in the second case i.e. wait for event for the last packet sent,
    > we are only receiving an vendor specific event from chip which holds
    > the status of fw download.
    >
    > so as __hci_cmd_sync_ev() requires an command complete event. so we
    > are injecting it after the vendor specific event received for the last
    > packet.
    >
    > This helps to overcome 0xfc00 timeout error logging on console.

    [Bala]: one more point to add
    command complete injection is done for only 1 Vendor Specific command
    which is used repeatedly only during firmware download phase
    to download firmware chunks. It is not used generically for all Vendor
    Specific commands.

    --
    Regards
    Balakrishna.

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