2019-08-28 11:20:16

by Nagarjuna Kristam

Subject: [PATCH] soc/tegra: fuse: Add clock error check in tegra_fuse_readl

Tegra fuse clock handle is retrieved in tegra_fuse_probe().
tegra_fuse_readl() is exported symbol, which can be called from drivers
at any time. tegra_fuse_readl() enables fuse clock and reads corresponding
fuse register offset.

Calling tegra_fuse_readl() before tegra_fuse_probe(), will cause data
abort. Add DEFER_PROBE error check for fuse clock in tegra_fuse_readl(),
to avoid enabling of fuse clock, before clock is available.

Signed-off-by: Nagarjuna Kristam <[email protected]>
---
drivers/soc/tegra/fuse/fuse-tegra.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/soc/tegra/fuse/fuse-tegra.c b/drivers/soc/tegra/fuse/fuse-tegra.c
index 3eb44e6..21b39b7 100644
--- a/drivers/soc/tegra/fuse/fuse-tegra.c
+++ b/drivers/soc/tegra/fuse/fuse-tegra.c
@@ -186,7 +186,7 @@ u32 __init tegra_fuse_read_early(unsigned int offset)

int tegra_fuse_readl(unsigned long offset, u32 *value)
{
- if (!fuse->read)
+ if (!fuse->read || (PTR_ERR(fuse->clk) == -EPROBE_DEFER))
return -EPROBE_DEFER;

*value = fuse->read(fuse, offset);
--
2.7.4

2019-09-02 11:55:30

by Jon Hunter

Subject: Re: [PATCH] soc/tegra: fuse: Add clock error check in tegra_fuse_readl

On 28/08/2019 12:18, Nagarjuna Kristam wrote:
> Tegra fuse clock handle is retrieved in tegra_fuse_probe().
> tegra_fuse_readl() is exported symbol, which can be called from drivers
> at any time. tegra_fuse_readl() enables fuse clock and reads corresponding
> fuse register offset.
>
> Calling tegra_fuse_readl() before tegra_fuse_probe(), will cause data
> abort. Add DEFER_PROBE error check for fuse clock in tegra_fuse_readl(),
> to avoid enabling of fuse clock, before clock is available.
>
> Signed-off-by: Nagarjuna Kristam <[email protected]>
> ---
> drivers/soc/tegra/fuse/fuse-tegra.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/soc/tegra/fuse/fuse-tegra.c b/drivers/soc/tegra/fuse/fuse-tegra.c
> index 3eb44e6..21b39b7 100644
> --- a/drivers/soc/tegra/fuse/fuse-tegra.c
> +++ b/drivers/soc/tegra/fuse/fuse-tegra.c
> @@ -186,7 +186,7 @@ u32 __init tegra_fuse_read_early(unsigned int offset)
>
> int tegra_fuse_readl(unsigned long offset, u32 *value)
> {
> - if (!fuse->read)
> + if (!fuse->read || (PTR_ERR(fuse->clk) == -EPROBE_DEFER))
> return -EPROBE_DEFER;

What about the case where fuse->clk is NULL or a different error value?

Jon

--
nvpublic

2019-09-03 04:59:02

by Nagarjuna Kristam

Subject: Re: [PATCH] soc/tegra: fuse: Add clock error check in tegra_fuse_readl

On 02-09-2019 16:15, Jon Hunter wrote:
>
> On 28/08/2019 12:18, Nagarjuna Kristam wrote:
>> Tegra fuse clock handle is retrieved in tegra_fuse_probe().
>> tegra_fuse_readl() is exported symbol, which can be called from drivers
>> at any time. tegra_fuse_readl() enables fuse clock and reads corresponding
>> fuse register offset.
>>
>> Calling tegra_fuse_readl() before tegra_fuse_probe(), will cause data
>> abort. Add DEFER_PROBE error check for fuse clock in tegra_fuse_readl(),
>> to avoid enabling of fuse clock, before clock is available.
>>
>> Signed-off-by: Nagarjuna Kristam <[email protected]>
>> ---
>> drivers/soc/tegra/fuse/fuse-tegra.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/soc/tegra/fuse/fuse-tegra.c b/drivers/soc/tegra/fuse/fuse-tegra.c
>> index 3eb44e6..21b39b7 100644
>> --- a/drivers/soc/tegra/fuse/fuse-tegra.c
>> +++ b/drivers/soc/tegra/fuse/fuse-tegra.c
>> @@ -186,7 +186,7 @@ u32 __init tegra_fuse_read_early(unsigned int offset)
>>
>> int tegra_fuse_readl(unsigned long offset, u32 *value)
>> {
>> - if (!fuse->read)
>> + if (!fuse->read || (PTR_ERR(fuse->clk) == -EPROBE_DEFER))
>> return -EPROBE_DEFER;
>
> What about the case where fuse->clk is NULL or a different error value?
>
> Jon
>
Yes, all error checks are needed, will use IS_ERR as a separate condition for clock.

Thanks,
Nagarjuna