Re: [PATCH 1/3] firmware: qcom_scm: Add support for tsens reinit workaround

[Bhupesh Sharma <bhupesh.sharma@linaro.org>]

Hi Bjorn,

Thanks for your review.

On 7/19/22 8:28 AM, Bjorn Andersson wrote:
> On Fri 01 Jul 09:58 CDT 2022, Bhupesh Sharma wrote:
> 
> Please update $subject to match the most uses prefix for the qcom_scm
> driver.
> 
>> Some versions of QCoM tsens controller might enter a
> 
> s/QCoM/Qualcomm/ please.

Ok.

>> 'bad state' while running stability tests causing sensor
>> temperatures/interrupts status to be in an 'invalid' state.
>>
>> It is recommended to re-initialize the tsens controller
>> via trustzone (secure registers) using scm call(s) when that
>> happens.
>>
>> Add support for the same in the qcom_scm driver.
>>
>> Cc: Amit Kucheria <amitk@kernel.org>
>> Cc: Thara Gopinath <thara.gopinath@gmail.com>
>> Cc: linux-pm@vger.kernel.org
>> Cc: linux-arm-msm@vger.kernel.org
>> Signed-off-by: Bhupesh Sharma <bhupesh.sharma@linaro.org>
>> ---
>>   drivers/firmware/qcom_scm.c | 17 +++++++++++++++++
>>   drivers/firmware/qcom_scm.h |  4 ++++
>>   include/linux/qcom_scm.h    |  2 ++
>>   3 files changed, 23 insertions(+)
>>
>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>> index 3163660fa8e2..0bc7cc466218 100644
>> --- a/drivers/firmware/qcom_scm.c
>> +++ b/drivers/firmware/qcom_scm.c
>> @@ -796,6 +796,23 @@ int qcom_scm_mem_protect_video_var(u32 cp_start, u32 cp_size,
>>   }
>>   EXPORT_SYMBOL(qcom_scm_mem_protect_video_var);
>>   
>> +int qcom_scm_tsens_reinit(int *tsens_ret)
>> +{
>> +	unsigned int ret;
> 
> qcom_scm_call() returns negative numbers on error, so this should be
> signed.

Ok.

>> +	struct qcom_scm_desc desc = {
> 
> const?

Sure.

>> +		.svc = QCOM_SCM_SVC_TSENS,
>> +		.cmd = QCOM_SCM_TSENS_INIT_ID,
>> +	};
>> +	struct qcom_scm_res res;
>> +
>> +	ret = qcom_scm_call(__scm->dev, &desc, &res);
>> +	if (tsens_ret)
>> +		*tsens_ret = res.result[0];
> 
> Most similar qcom_scm functions use negative return value for errors and
> positive (including 0) values for the returned data.
> 
> Looking at patch 3, the only thing you seem to care about is tsens_ret
> being 0 or not, so I do think you would be fine returning both using the
> return value.

Ok, let me double check the same and fix the same in v2.

Regards,
Bhupesh


>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL(qcom_scm_tsens_reinit);
>> +
>>   static int __qcom_scm_assign_mem(struct device *dev, phys_addr_t mem_region,
>>   				 size_t mem_sz, phys_addr_t src, size_t src_sz,
>>   				 phys_addr_t dest, size_t dest_sz)
>> diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
>> index 0d51eef2472f..495fa00230c7 100644
>> --- a/drivers/firmware/qcom_scm.h
>> +++ b/drivers/firmware/qcom_scm.h
>> @@ -94,6 +94,10 @@ extern int scm_legacy_call(struct device *dev, const struct qcom_scm_desc *desc,
>>   #define QCOM_SCM_PIL_PAS_IS_SUPPORTED	0x07
>>   #define QCOM_SCM_PIL_PAS_MSS_RESET	0x0a
>>   
>> +/* TSENS Services and Function IDs */
>> +#define QCOM_SCM_SVC_TSENS		0x1E
>> +#define QCOM_SCM_TSENS_INIT_ID		0x5
>> +
>>   #define QCOM_SCM_SVC_IO			0x05
>>   #define QCOM_SCM_IO_READ		0x01
>>   #define QCOM_SCM_IO_WRITE		0x02
>> diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
>> index f8335644a01a..f8c9eb739df1 100644
>> --- a/include/linux/qcom_scm.h
>> +++ b/include/linux/qcom_scm.h
>> @@ -124,4 +124,6 @@ extern int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
>>   extern int qcom_scm_lmh_profile_change(u32 profile_id);
>>   extern bool qcom_scm_lmh_dcvsh_available(void);
>>   
>> +extern int qcom_scm_tsens_reinit(int *tsens_ret);
>> +
>>   #endif
>> -- 
>> 2.35.3
>>