diff mbox

[RFC,03/12] ath10k: htc: Changed order of wait target and ep connect

Message ID 1479141222-8493-4-git-send-email-erik.stromdahl@gmail.com (mailing list archive)
State RFC
Delegated to: Kalle Valo
Headers show

Commit Message

Erik Stromdahl Nov. 14, 2016, 4:33 p.m. UTC
This patch changes the order in which the driver waits for the
target to become ready and the service connect of the HTC
control service.

The HTC control service is connected before the driver starts
waiting for the HTC ready control message.

The reason for this is that the HTC ready control message is
transmitted on EP 0 and that sdio/mbox based systems will ignore
messages received on unconnected endpoints.

Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
---
 drivers/net/wireless/ath/ath10k/htc.c |   32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

Comments

Michal Kazior Nov. 15, 2016, 10:13 a.m. UTC | #1
On 14 November 2016 at 17:33, Erik Stromdahl <erik.stromdahl@gmail.com> wrote:
> This patch changes the order in which the driver waits for the
> target to become ready and the service connect of the HTC
> control service.
>
> The HTC control service is connected before the driver starts
> waiting for the HTC ready control message.
>
> The reason for this is that the HTC ready control message is
> transmitted on EP 0 and that sdio/mbox based systems will ignore
> messages received on unconnected endpoints.
>
> Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
> ---
>  drivers/net/wireless/ath/ath10k/htc.c |   32 ++++++++++++++++----------------
>  1 file changed, 16 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/net/wireless/ath/ath10k/htc.c b/drivers/net/wireless/ath/ath10k/htc.c
> index e3f7bf4..7257366 100644
> --- a/drivers/net/wireless/ath/ath10k/htc.c
> +++ b/drivers/net/wireless/ath/ath10k/htc.c
> @@ -606,6 +606,22 @@ int ath10k_htc_wait_target(struct ath10k_htc *htc)
>         u16 credit_count;
>         u16 credit_size;
>
> +       /* setup our pseudo HTC control endpoint connection */
> +       memset(&conn_req, 0, sizeof(conn_req));
> +       memset(&conn_resp, 0, sizeof(conn_resp));
> +       conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
> +       conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
> +       conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
> +       conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;
> +
> +       /* connect fake service */
> +       status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
> +       if (status) {
> +               ath10k_err(ar, "could not connect to htc service (%d)\n",
> +                          status);
> +               return status;
> +       }
> +

How is this supposed to work? ath10k_htc_connect_service() requires
htc->target_credit_size to compute tx_credits_per_max_message. Or am I
missing something? Applying this patch alone results in:

[    6.680101] divide error: 0000 [#1] SMP
[    6.681342] Modules linked in: ath10k_pci(O) ath10k_core(O) ath
mac80211 cfg80211
[    6.684876] CPU: 3 PID: 823 Comm: kworker/u8:2 Tainted: G        W
O    4.9.0-rc4-wt-ath+ #79
[    6.688051] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
[    6.691644] Workqueue: ath10k_wq ath10k_core_register_work [ath10k_core]
[    6.694309] task: ffff88000a190000 task.stack: ffffc900006d4000
[    6.695458] RIP: 0010:[<ffffffffa01ae46b>]  [<ffffffffa01ae46b>]
ath10k_htc_connect_service+0x21b/0x420 [ath10k_core]


Michał
Erik Stromdahl Nov. 15, 2016, 5:07 p.m. UTC | #2
On 11/15/2016 11:13 AM, Michal Kazior wrote:
> On 14 November 2016 at 17:33, Erik Stromdahl <erik.stromdahl@gmail.com> wrote:
>> This patch changes the order in which the driver waits for the
>> target to become ready and the service connect of the HTC
>> control service.
>>
>> The HTC control service is connected before the driver starts
>> waiting for the HTC ready control message.
>>
>> The reason for this is that the HTC ready control message is
>> transmitted on EP 0 and that sdio/mbox based systems will ignore
>> messages received on unconnected endpoints.
>>
>> Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
>> ---
>>  drivers/net/wireless/ath/ath10k/htc.c |   32 ++++++++++++++++----------------
>>  1 file changed, 16 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath10k/htc.c b/drivers/net/wireless/ath/ath10k/htc.c
>> index e3f7bf4..7257366 100644
>> --- a/drivers/net/wireless/ath/ath10k/htc.c
>> +++ b/drivers/net/wireless/ath/ath10k/htc.c
>> @@ -606,6 +606,22 @@ int ath10k_htc_wait_target(struct ath10k_htc *htc)
>>         u16 credit_count;
>>         u16 credit_size;
>>
>> +       /* setup our pseudo HTC control endpoint connection */
>> +       memset(&conn_req, 0, sizeof(conn_req));
>> +       memset(&conn_resp, 0, sizeof(conn_resp));
>> +       conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
>> +       conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
>> +       conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
>> +       conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;
>> +
>> +       /* connect fake service */
>> +       status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
>> +       if (status) {
>> +               ath10k_err(ar, "could not connect to htc service (%d)\n",
>> +                          status);
>> +               return status;
>> +       }
>> +
> 
> How is this supposed to work? ath10k_htc_connect_service() requires
> htc->target_credit_size to compute tx_credits_per_max_message. Or am I
> missing something? Applying this patch alone results in:
> 
> [    6.680101] divide error: 0000 [#1] SMP
> [    6.681342] Modules linked in: ath10k_pci(O) ath10k_core(O) ath
> mac80211 cfg80211
> [    6.684876] CPU: 3 PID: 823 Comm: kworker/u8:2 Tainted: G        W
> O    4.9.0-rc4-wt-ath+ #79
> [    6.688051] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
> BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
> [    6.691644] Workqueue: ath10k_wq ath10k_core_register_work [ath10k_core]
> [    6.694309] task: ffff88000a190000 task.stack: ffffc900006d4000
> [    6.695458] RIP: 0010:[<ffffffffa01ae46b>]  [<ffffffffa01ae46b>]
> ath10k_htc_connect_service+0x21b/0x420 [ath10k_core]
> 
> 
> Michał
> 

You're right. I have totally missed this. What is strange is that my
compiler (ARM linaro) seems to optimize the code in a way that removes
the tx_credits_per_max_message value.

If I add a printk in ath10k_htc_connect_service (printing the value) I
get a similar oops.

I think it has to do with the fact the this value isn't really used at
all. grepping the code reveals that tx_credits_per_max_message is only
used inside ath10k_htc_connect_service (only written, never read).

Removing it doesn't seem to break anything, so perhaps it should be removed?

Or is there something I have missed?

/Erik
Michal Kazior Nov. 16, 2016, 2:29 p.m. UTC | #3
On 15 November 2016 at 18:07, Erik Stromdahl <erik.stromdahl@gmail.com> wrote:
> On 11/15/2016 11:13 AM, Michal Kazior wrote:
>> On 14 November 2016 at 17:33, Erik Stromdahl <erik.stromdahl@gmail.com> wrote:
>>> This patch changes the order in which the driver waits for the
>>> target to become ready and the service connect of the HTC
>>> control service.
>>>
>>> The HTC control service is connected before the driver starts
>>> waiting for the HTC ready control message.
>>>
>>> The reason for this is that the HTC ready control message is
>>> transmitted on EP 0 and that sdio/mbox based systems will ignore
>>> messages received on unconnected endpoints.
>>>
>>> Signed-off-by: Erik Stromdahl <erik.stromdahl@gmail.com>
>>> ---
>>>  drivers/net/wireless/ath/ath10k/htc.c |   32 ++++++++++++++++----------------
>>>  1 file changed, 16 insertions(+), 16 deletions(-)
>>>
>>> diff --git a/drivers/net/wireless/ath/ath10k/htc.c b/drivers/net/wireless/ath/ath10k/htc.c
>>> index e3f7bf4..7257366 100644
>>> --- a/drivers/net/wireless/ath/ath10k/htc.c
>>> +++ b/drivers/net/wireless/ath/ath10k/htc.c
>>> @@ -606,6 +606,22 @@ int ath10k_htc_wait_target(struct ath10k_htc *htc)
>>>         u16 credit_count;
>>>         u16 credit_size;
>>>
>>> +       /* setup our pseudo HTC control endpoint connection */
>>> +       memset(&conn_req, 0, sizeof(conn_req));
>>> +       memset(&conn_resp, 0, sizeof(conn_resp));
>>> +       conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
>>> +       conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
>>> +       conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
>>> +       conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;
>>> +
>>> +       /* connect fake service */
>>> +       status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
>>> +       if (status) {
>>> +               ath10k_err(ar, "could not connect to htc service (%d)\n",
>>> +                          status);
>>> +               return status;
>>> +       }
>>> +
>>
>> How is this supposed to work? ath10k_htc_connect_service() requires
>> htc->target_credit_size to compute tx_credits_per_max_message. Or am I
>> missing something? Applying this patch alone results in:
>>
>> [    6.680101] divide error: 0000 [#1] SMP
>> [    6.681342] Modules linked in: ath10k_pci(O) ath10k_core(O) ath
>> mac80211 cfg80211
>> [    6.684876] CPU: 3 PID: 823 Comm: kworker/u8:2 Tainted: G        W
>> O    4.9.0-rc4-wt-ath+ #79
>> [    6.688051] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
>> BIOS 1.7.5-20140531_083030-gandalf 04/01/2014
>> [    6.691644] Workqueue: ath10k_wq ath10k_core_register_work [ath10k_core]
>> [    6.694309] task: ffff88000a190000 task.stack: ffffc900006d4000
>> [    6.695458] RIP: 0010:[<ffffffffa01ae46b>]  [<ffffffffa01ae46b>]
>> ath10k_htc_connect_service+0x21b/0x420 [ath10k_core]
>>
>>
>> Michał
>>
>
> You're right. I have totally missed this. What is strange is that my
> compiler (ARM linaro) seems to optimize the code in a way that removes
> the tx_credits_per_max_message value.
>
> If I add a printk in ath10k_htc_connect_service (printing the value) I
> get a similar oops.
>
> I think it has to do with the fact the this value isn't really used at
> all. grepping the code reveals that tx_credits_per_max_message is only
> used inside ath10k_htc_connect_service (only written, never read).
>
> Removing it doesn't seem to break anything, so perhaps it should be removed?

I think it's safe to remove now. This is legacy inherited from the
internal driver.

Otherwise this looks okay except commit log which is a bit unclear.
I'm still not sure *why* you need to reorder this. FWIW this can be a
general clean up thing that ends up moving the if (eid == EP0) {code}
to control endpoint handler in patch 4.


Michał
diff mbox

Patch

diff --git a/drivers/net/wireless/ath/ath10k/htc.c b/drivers/net/wireless/ath/ath10k/htc.c
index e3f7bf4..7257366 100644
--- a/drivers/net/wireless/ath/ath10k/htc.c
+++ b/drivers/net/wireless/ath/ath10k/htc.c
@@ -606,6 +606,22 @@  int ath10k_htc_wait_target(struct ath10k_htc *htc)
 	u16 credit_count;
 	u16 credit_size;
 
+	/* setup our pseudo HTC control endpoint connection */
+	memset(&conn_req, 0, sizeof(conn_req));
+	memset(&conn_resp, 0, sizeof(conn_resp));
+	conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
+	conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
+	conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
+	conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;
+
+	/* connect fake service */
+	status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
+	if (status) {
+		ath10k_err(ar, "could not connect to htc service (%d)\n",
+			   status);
+		return status;
+	}
+
 	time_left = wait_for_completion_timeout(&htc->ctl_resp,
 						ATH10K_HTC_WAIT_TIMEOUT_HZ);
 	if (!time_left) {
@@ -665,22 +681,6 @@  int ath10k_htc_wait_target(struct ath10k_htc *htc)
 
 	ath10k_htc_setup_target_buffer_assignments(htc);
 
-	/* setup our pseudo HTC control endpoint connection */
-	memset(&conn_req, 0, sizeof(conn_req));
-	memset(&conn_resp, 0, sizeof(conn_resp));
-	conn_req.ep_ops.ep_tx_complete = ath10k_htc_control_tx_complete;
-	conn_req.ep_ops.ep_rx_complete = ath10k_htc_control_rx_complete;
-	conn_req.max_send_queue_depth = ATH10K_NUM_CONTROL_TX_BUFFERS;
-	conn_req.service_id = ATH10K_HTC_SVC_ID_RSVD_CTRL;
-
-	/* connect fake service */
-	status = ath10k_htc_connect_service(htc, &conn_req, &conn_resp);
-	if (status) {
-		ath10k_err(ar, "could not connect to htc service (%d)\n",
-			   status);
-		return status;
-	}
-
 	return 0;
 }