diff mbox

tty: serial: msm_serial: Use DT aliases

Message ID 5461150B.2010907@codeaurora.org (mailing list archive)
State Superseded, archived
Headers show

Commit Message

Stephen Boyd Nov. 10, 2014, 7:42 p.m. UTC
On 11/10/2014 10:54 AM, Kevin Hilman wrote:
> On Wed, Oct 22, 2014 at 5:33 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
>> We rely on probe order of this driver to determine the line number for
>> the uart port. This makes it impossible to know the line number
>> when these devices are populated via DT. Use the DT alias
>> mechanism to assign the line based on the aliases node.
>>
>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> FYI... this patch hit linux-next and caused multiple boot failures on
> qcom platforms[1] as of next-20141110.  I'm assuming this is because
> the corresponding DTS changes have not hit linux-next yet.
>
> Kevin
>
> [1] http://status.armcloud.us/boot/?qcom

Hmm the intention was to make it optional so that dts changes aren't
necessary unless you want deterministic numbering. I screwed that up
badly :/ Thanks for finding this.

Greg, can you also apply this patch or squash it into the bad one?

----8<-----

From: Stephen Boyd <sboyd@codeaurora.org>
Subject: [PATCH] tty: serial: msm_serial: Don't required DT aliases

If there isn't a DT alias then of_alias_get_id() will return
-ENODEV. This will cause the msm_serial driver to fail probe,
when we want to keep the previous behavior where we generated a
dynamic line number at probe time. Restore this behavior by
generating a dynamic id if the line number is still negative
after checking for an alias or (in the non-DT case) looking at the
.id field of the platform device.

Reported-by: Kevin Hilman <khilman@kernel.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
---
 drivers/tty/serial/msm_serial.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

Comments

Frank Rowand Nov. 11, 2014, 1:56 a.m. UTC | #1
On 11/10/2014 11:42 AM, Stephen Boyd wrote:
> On 11/10/2014 10:54 AM, Kevin Hilman wrote:
>> On Wed, Oct 22, 2014 at 5:33 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
>>> We rely on probe order of this driver to determine the line number for
>>> the uart port. This makes it impossible to know the line number
>>> when these devices are populated via DT. Use the DT alias
>>> mechanism to assign the line based on the aliases node.
>>>
>>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>> FYI... this patch hit linux-next and caused multiple boot failures on
>> qcom platforms[1] as of next-20141110.  I'm assuming this is because
>> the corresponding DTS changes have not hit linux-next yet.
>>
>> Kevin
>>
>> [1] http://status.armcloud.us/boot/?qcom
> 
> Hmm the intention was to make it optional so that dts changes aren't
> necessary unless you want deterministic numbering. I screwed that up
> badly :/ Thanks for finding this.
> 
> Greg, can you also apply this patch or squash it into the bad one?
> 
> ----8<-----
> 
> From: Stephen Boyd <sboyd@codeaurora.org>
> Subject: [PATCH] tty: serial: msm_serial: Don't required DT aliases
> 
> If there isn't a DT alias then of_alias_get_id() will return
> -ENODEV. This will cause the msm_serial driver to fail probe,
> when we want to keep the previous behavior where we generated a
> dynamic line number at probe time. Restore this behavior by
> generating a dynamic id if the line number is still negative
> after checking for an alias or (in the non-DT case) looking at the
> .id field of the platform device.
> 
> Reported-by: Kevin Hilman <khilman@kernel.org>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
> ---
>  drivers/tty/serial/msm_serial.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
> index 09364dd8cf3a..d1bc6b6cbc70 100644
> --- a/drivers/tty/serial/msm_serial.c
> +++ b/drivers/tty/serial/msm_serial.c
> @@ -1046,14 +1046,14 @@ static int msm_serial_probe(struct platform_device *pdev)
>  	const struct of_device_id *id;
>  	int irq, line;
>  
> -	if (pdev->id == -1)
> -		pdev->id = atomic_inc_return(&msm_uart_next_id) - 1;
> -
>  	if (pdev->dev.of_node)
>  		line = of_alias_get_id(pdev->dev.of_node, "serial");
>  	else
>  		line = pdev->id;
>  
> +	if (line < 0)
> +		line = atomic_inc_return(&msm_uart_next_id) - 1;
> +
>  	if (unlikely(line < 0 || line >= UART_NR))

Then this original check for "line < 0" can also be removed.


>  		return -ENXIO;
>  
> 

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Stephen Boyd Nov. 11, 2014, 2:07 a.m. UTC | #2
On 11/10/2014 05:56 PM, Frank Rowand wrote:
> On 11/10/2014 11:42 AM, Stephen Boyd wrote:
>> diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
>> index 09364dd8cf3a..d1bc6b6cbc70 100644
>> --- a/drivers/tty/serial/msm_serial.c
>> +++ b/drivers/tty/serial/msm_serial.c
>> @@ -1046,14 +1046,14 @@ static int msm_serial_probe(struct platform_device *pdev)
>>  	const struct of_device_id *id;
>>  	int irq, line;
>>  
>> -	if (pdev->id == -1)
>> -		pdev->id = atomic_inc_return(&msm_uart_next_id) - 1;
>> -
>>  	if (pdev->dev.of_node)
>>  		line = of_alias_get_id(pdev->dev.of_node, "serial");
>>  	else
>>  		line = pdev->id;
>>  
>> +	if (line < 0)
>> +		line = atomic_inc_return(&msm_uart_next_id) - 1;
>> +
>>  	if (unlikely(line < 0 || line >= UART_NR))
> Then this original check for "line < 0" can also be removed.
>
>

Well this matches what was there before. It would do atomic_inc_return
if the line was negative and then still check for a negative value. I
don't mind removing it though. Perhaps we should use an ida?
Kevin Hilman Nov. 11, 2014, 3:31 p.m. UTC | #3
Stephen Boyd <sboyd@codeaurora.org> writes:

> On 11/10/2014 10:54 AM, Kevin Hilman wrote:
>> On Wed, Oct 22, 2014 at 5:33 PM, Stephen Boyd <sboyd@codeaurora.org> wrote:
>>> We rely on probe order of this driver to determine the line number for
>>> the uart port. This makes it impossible to know the line number
>>> when these devices are populated via DT. Use the DT alias
>>> mechanism to assign the line based on the aliases node.
>>>
>>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>> FYI... this patch hit linux-next and caused multiple boot failures on
>> qcom platforms[1] as of next-20141110.  I'm assuming this is because
>> the corresponding DTS changes have not hit linux-next yet.
>>
>> Kevin
>>
>> [1] http://status.armcloud.us/boot/?qcom
>
> Hmm the intention was to make it optional so that dts changes aren't
> necessary unless you want deterministic numbering. I screwed that up
> badly :/ Thanks for finding this.
>
> Greg, can you also apply this patch or squash it into the bad one?
>
> ----8<-----
>
> From: Stephen Boyd <sboyd@codeaurora.org>
> Subject: [PATCH] tty: serial: msm_serial: Don't required DT aliases
>
> If there isn't a DT alias then of_alias_get_id() will return
> -ENODEV. This will cause the msm_serial driver to fail probe,
> when we want to keep the previous behavior where we generated a
> dynamic line number at probe time. Restore this behavior by
> generating a dynamic id if the line number is still negative
> after checking for an alias or (in the non-DT case) looking at the
> .id field of the platform device.
>
> Reported-by: Kevin Hilman <khilman@kernel.org>
> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

Tested-by: Kevin Hilman <khilman@linaro.org>

I confirm that this patch gets things booting again for the
msm8974/xperia-z1 and the apq8064/ifc6410.

Kevin
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diff mbox

Patch

diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
index 09364dd8cf3a..d1bc6b6cbc70 100644
--- a/drivers/tty/serial/msm_serial.c
+++ b/drivers/tty/serial/msm_serial.c
@@ -1046,14 +1046,14 @@  static int msm_serial_probe(struct platform_device *pdev)
 	const struct of_device_id *id;
 	int irq, line;
 
-	if (pdev->id == -1)
-		pdev->id = atomic_inc_return(&msm_uart_next_id) - 1;
-
 	if (pdev->dev.of_node)
 		line = of_alias_get_id(pdev->dev.of_node, "serial");
 	else
 		line = pdev->id;
 
+	if (line < 0)
+		line = atomic_inc_return(&msm_uart_next_id) - 1;
+
 	if (unlikely(line < 0 || line >= UART_NR))
 		return -ENXIO;