[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Gong Qianyu]

This could avoid executing the code that only applies to i.MX platforms.

The bus_i2c_init() is called before relocation and will assgin value
to a static variable. If U-Boot is then still running in a flash
device, it's theoretically not allowed to write data to flash without
an erasing operation. For i.MX platforms, the U-Boot is always running
in DDR.

Actually it causes asynchronous error when the ARM64 system error
report is enabled and the flash write protect is set.

Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
---
V3:
 - Sorry..Remove an unrelated line in other file.

 drivers/i2c/mxc_i2c.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
index fa4c82f..b2d15c9 100644
--- a/drivers/i2c/mxc_i2c.c
+++ b/drivers/i2c/mxc_i2c.c
@@ -581,8 +581,16 @@ void bus_i2c_init(int index, int speed, int unused,
 		return;
 	}
 
-	mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
-	mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
+	/*
+	 * Warning: Be careful to allow the assignment to a static
+	 * variable here. This function could be called while U-Boot is
+	 * still running in flash memory. So such assignment is equal
+	 * to write data to flash without erasing.
+	 */
+	if (idle_bus_fn)
+		mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
+	if (idle_bus_data)
+		mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
 
 	ret = enable_i2c_clk(1, index);
 	if (ret < 0) {
-- 
2.1.0.27.g96db324

[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Heiko Schocher]

Hello Gong Qianyu,

added Stefano Babic to cc as he is the imx maintainer.

Am 18.12.2015 um 10:38 schrieb Gong Qianyu:
> This could avoid executing the code that only applies to i.MX platforms.
>
> The bus_i2c_init() is called before relocation and will assgin value
> to a static variable. If U-Boot is then still running in a flash
> device, it's theoretically not allowed to write data to flash without
> an erasing operation. For i.MX platforms, the U-Boot is always running
> in DDR.
>
> Actually it causes asynchronous error when the ARM64 system error
> report is enabled and the flash write protect is set.
>
> Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
> ---
> V3:
>   - Sorry..Remove an unrelated line in other file.
>
>   drivers/i2c/mxc_i2c.c | 12 ++++++++++--
>   1 file changed, 10 insertions(+), 2 deletions(-)

Ok, from my side, but it would be better to switch your board(s)
to support DM and get rid of this old stuff from this driver.

Reviewed-by: Heiko Schocher <hs@denx.de>

bye,
Heiko
>
> diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c
> index fa4c82f..b2d15c9 100644
> --- a/drivers/i2c/mxc_i2c.c
> +++ b/drivers/i2c/mxc_i2c.c
> @@ -581,8 +581,16 @@ void bus_i2c_init(int index, int speed, int unused,
>   		return;
>   	}
>
> -	mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> -	mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> +	/*
> +	 * Warning: Be careful to allow the assignment to a static
> +	 * variable here. This function could be called while U-Boot is
> +	 * still running in flash memory. So such assignment is equal
> +	 * to write data to flash without erasing.
> +	 */
> +	if (idle_bus_fn)
> +		mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> +	if (idle_bus_data)
> +		mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
>
>   	ret = enable_i2c_clk(1, index);
>   	if (ret < 0) {
>

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Qianyu Gong]

> -----Original Message-----
> From: Heiko Schocher [mailto:hs at denx.de]
> Sent: Friday, December 18, 2015 6:24 PM
> To: Gong Qianyu-B52263
> Cc: u-boot at lists.denx.de; Stefano Babic
> Subject: Re: [U-Boot] [Patch V3] i2c: mxc: add a condition in case the
> parameter is NULL
> 
> Hello Gong Qianyu,
> 
> added Stefano Babic to cc as he is the imx maintainer.
> 
> Am 18.12.2015 um 10:38 schrieb Gong Qianyu:
> > This could avoid executing the code that only applies to i.MX platforms.
> >
> > The bus_i2c_init() is called before relocation and will assgin value
> > to a static variable. If U-Boot is then still running in a flash
> > device, it's theoretically not allowed to write data to flash without
> > an erasing operation. For i.MX platforms, the U-Boot is always running
> > in DDR.
> >
> > Actually it causes asynchronous error when the ARM64 system error
> > report is enabled and the flash write protect is set.
> >
> > Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
> > ---
> > V3:
> >   - Sorry..Remove an unrelated line in other file.
> >
> >   drivers/i2c/mxc_i2c.c | 12 ++++++++++--
> >   1 file changed, 10 insertions(+), 2 deletions(-)
> 
> Ok, from my side, but it would be better to switch your board(s) to
> support DM and get rid of this old stuff from this driver.
> 
> Reviewed-by: Heiko Schocher <hs@denx.de>
> 
> bye,
> Heiko

Thanks. But I have no control over this driver. Maybe they are considering to 
convert it later.

Regards,
Qianyu

> >
> > diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index
> > fa4c82f..b2d15c9 100644
> > --- a/drivers/i2c/mxc_i2c.c
> > +++ b/drivers/i2c/mxc_i2c.c
> > @@ -581,8 +581,16 @@ void bus_i2c_init(int index, int speed, int unused,
> >   		return;
> >   	}
> >
> > -	mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> > -	mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> > +	/*
> > +	 * Warning: Be careful to allow the assignment to a static
> > +	 * variable here. This function could be called while U-Boot is
> > +	 * still running in flash memory. So such assignment is equal
> > +	 * to write data to flash without erasing.
> > +	 */
> > +	if (idle_bus_fn)
> > +		mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> > +	if (idle_bus_data)
> > +		mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> >
> >   	ret = enable_i2c_clk(1, index);
> >   	if (ret < 0) {
> >
> 
> --
> DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Qianyu Gong]

Hi Stefano,

Could you please help to merge this patch? Thanks very much.

Regards,
Qianyu

> -----Original Message-----
> From: Qianyu Gong
> Sent: Monday, December 21, 2015 1:42 PM
> To: hs at denx.de; Gong Qianyu-B52263 <Qianyu.Gong@freescale.com>
> Cc: u-boot at lists.denx.de; Stefano Babic <sbabic@denx.de>
> Subject: RE: [U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is
> NULL
> 
> 
> 
> > -----Original Message-----
> > From: Heiko Schocher [mailto:hs at denx.de]
> > Sent: Friday, December 18, 2015 6:24 PM
> > To: Gong Qianyu-B52263
> > Cc: u-boot at lists.denx.de; Stefano Babic
> > Subject: Re: [U-Boot] [Patch V3] i2c: mxc: add a condition in case the
> > parameter is NULL
> >
> > Hello Gong Qianyu,
> >
> > added Stefano Babic to cc as he is the imx maintainer.
> >
> > Am 18.12.2015 um 10:38 schrieb Gong Qianyu:
> > > This could avoid executing the code that only applies to i.MX platforms.
> > >
> > > The bus_i2c_init() is called before relocation and will assgin value
> > > to a static variable. If U-Boot is then still running in a flash
> > > device, it's theoretically not allowed to write data to flash
> > > without an erasing operation. For i.MX platforms, the U-Boot is
> > > always running in DDR.
> > >
> > > Actually it causes asynchronous error when the ARM64 system error
> > > report is enabled and the flash write protect is set.
> > >
> > > Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
> > > ---
> > > V3:
> > >   - Sorry..Remove an unrelated line in other file.
> > >
> > >   drivers/i2c/mxc_i2c.c | 12 ++++++++++--
> > >   1 file changed, 10 insertions(+), 2 deletions(-)
> >
> > Ok, from my side, but it would be better to switch your board(s) to
> > support DM and get rid of this old stuff from this driver.
> >
> > Reviewed-by: Heiko Schocher <hs@denx.de>
> >
> > bye,
> > Heiko
> 
> Thanks. But I have no control over this driver. Maybe they are considering to
> convert it later.
> 
> Regards,
> Qianyu
> 
> > >
> > > diff --git a/drivers/i2c/mxc_i2c.c b/drivers/i2c/mxc_i2c.c index
> > > fa4c82f..b2d15c9 100644
> > > --- a/drivers/i2c/mxc_i2c.c
> > > +++ b/drivers/i2c/mxc_i2c.c
> > > @@ -581,8 +581,16 @@ void bus_i2c_init(int index, int speed, int unused,
> > >   		return;
> > >   	}
> > >
> > > -	mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> > > -	mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> > > +	/*
> > > +	 * Warning: Be careful to allow the assignment to a static
> > > +	 * variable here. This function could be called while U-Boot is
> > > +	 * still running in flash memory. So such assignment is equal
> > > +	 * to write data to flash without erasing.
> > > +	 */
> > > +	if (idle_bus_fn)
> > > +		mxc_i2c_buses[index].idle_bus_fn = idle_bus_fn;
> > > +	if (idle_bus_data)
> > > +		mxc_i2c_buses[index].idle_bus_data = idle_bus_data;
> > >
> > >   	ret = enable_i2c_clk(1, index);
> > >   	if (ret < 0) {
> > >
> >
> > --
> > DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
> > HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany

[U-Boot] [Patch V3] i2c: mxc: add a condition in case the parameter is NULL

[Stefano Babic]

On 18/12/2015 10:38, Gong Qianyu wrote:
> This could avoid executing the code that only applies to i.MX platforms.
> 
> The bus_i2c_init() is called before relocation and will assgin value
> to a static variable. If U-Boot is then still running in a flash
> device, it's theoretically not allowed to write data to flash without
> an erasing operation. For i.MX platforms, the U-Boot is always running
> in DDR.
> 
> Actually it causes asynchronous error when the ARM64 system error
> report is enabled and the flash write protect is set.
> 
> Signed-off-by: Gong Qianyu <Qianyu.Gong@freescale.com>
> ---


Applied to u-boot-imx, thanks!

Best regards,
Stefano Babic


-- 
=====================================================================
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: +49-8142-66989-53 Fax: +49-8142-66989-80 Email: sbabic at denx.de
=====================================================================