diff mbox series

[v2,1/5] bus: ti-sysc: Move check for no-reset-on-init

Message ID 20240410064010.57142-2-tony@atomide.com (mailing list archive)
State New, archived
Headers show
Series Update ti-sysc description and drop legacy quirk handling | expand

Commit Message

Tony Lindgren April 10, 2024, 6:40 a.m. UTC
We are wrongly checking SYSC_QUIRK_NO_RESET_ON_INIT flag in sysc_reset(),
it can be called also after init from sysc_reinit_module(). Let's fix the
issue by moving the check to the init code.

Fixes: 6a52bc2b81fa ("bus: ti-sysc: Add quirk handling for reset on re-init")
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
 drivers/bus/ti-sysc.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

Comments

Dhruva Gole April 10, 2024, 6:03 p.m. UTC | #1
On Apr 10, 2024 at 09:40:05 +0300, Tony Lindgren wrote:
> We are wrongly checking SYSC_QUIRK_NO_RESET_ON_INIT flag in sysc_reset(),
> it can be called also after init from sysc_reinit_module(). Let's fix the
> issue by moving the check to the init code.

I am not able to understand exactly the potential bug here, what was the
issue exactly?
What I am able to infer is this is more of an improvement than fixing a
bug? Maybe I am missing some context, can you help me understand the
potential bug here?

> 
> Fixes: 6a52bc2b81fa ("bus: ti-sysc: Add quirk handling for reset on re-init")

Fixes tag, you might want to CC stable@vger.kernel.org?

> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
>  drivers/bus/ti-sysc.c | 15 ++++++++-------
>  1 file changed, 8 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
> --- a/drivers/bus/ti-sysc.c
> +++ b/drivers/bus/ti-sysc.c
> @@ -2145,8 +2145,7 @@ static int sysc_reset(struct sysc *ddata)
>  	sysc_offset = ddata->offsets[SYSC_SYSCONFIG];
>  
>  	if (ddata->legacy_mode ||
> -	    ddata->cap->regbits->srst_shift < 0 ||
> -	    ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)
> +	    ddata->cap->regbits->srst_shift < 0)
>  		return 0;
>  
>  	sysc_mask = BIT(ddata->cap->regbits->srst_shift);
> @@ -2240,12 +2239,14 @@ static int sysc_init_module(struct sysc *ddata)
>  			goto err_main_clocks;
>  	}
>  
> -	error = sysc_reset(ddata);
> -	if (error)
> -		dev_err(ddata->dev, "Reset failed with %d\n", error);
> +	if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)) {
> +		error = sysc_reset(ddata);
> +		if (error)
> +			dev_err(ddata->dev, "Reset failed with %d\n", error);
>  
> -	if (error && !ddata->legacy_mode)
> -		sysc_disable_module(ddata->dev);
> +		if (error && !ddata->legacy_mode)
> +			sysc_disable_module(ddata->dev);
> +	}
>
Tony Lindgren April 11, 2024, 4:30 a.m. UTC | #2
* Dhruva Gole <d-gole@ti.com> [240410 18:03]:
> On Apr 10, 2024 at 09:40:05 +0300, Tony Lindgren wrote:
> > We are wrongly checking SYSC_QUIRK_NO_RESET_ON_INIT flag in sysc_reset(),
> > it can be called also after init from sysc_reinit_module(). Let's fix the
> > issue by moving the check to the init code.
> 
> I am not able to understand exactly the potential bug here, what was the
> issue exactly?

With this flag, reset should be skipped on init, for example for an SDRAM
controller during booting or to preserve a boot logo etc. However, if a
reset is requested later on after init, we must ignore this flag.

> What I am able to infer is this is more of an improvement than fixing a
> bug? Maybe I am missing some context, can you help me understand the
> potential bug here?

We are now also calling sysc_reset() during runtime, so in theory some
device would not reset during usage as requested. I don't think we have
such cases in reality though. So yeah this is more cleanup rather than a
fix AFAIK.

> > Fixes: 6a52bc2b81fa ("bus: ti-sysc: Add quirk handling for reset on re-init")
> 
> Fixes tag, you might want to CC stable@vger.kernel.org?

Let's just leave out the fixes tag as there are no known bugs caused
by this.

Regards,

Tony
diff mbox series

Patch

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -2145,8 +2145,7 @@  static int sysc_reset(struct sysc *ddata)
 	sysc_offset = ddata->offsets[SYSC_SYSCONFIG];
 
 	if (ddata->legacy_mode ||
-	    ddata->cap->regbits->srst_shift < 0 ||
-	    ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)
+	    ddata->cap->regbits->srst_shift < 0)
 		return 0;
 
 	sysc_mask = BIT(ddata->cap->regbits->srst_shift);
@@ -2240,12 +2239,14 @@  static int sysc_init_module(struct sysc *ddata)
 			goto err_main_clocks;
 	}
 
-	error = sysc_reset(ddata);
-	if (error)
-		dev_err(ddata->dev, "Reset failed with %d\n", error);
+	if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT)) {
+		error = sysc_reset(ddata);
+		if (error)
+			dev_err(ddata->dev, "Reset failed with %d\n", error);
 
-	if (error && !ddata->legacy_mode)
-		sysc_disable_module(ddata->dev);
+		if (error && !ddata->legacy_mode)
+			sysc_disable_module(ddata->dev);
+	}
 
 err_main_clocks:
 	if (error)