Re: [PATCH V5 5/5] firmware: scm: Modify only the DLOAD bit in TCSR register for download mode

[POOVENDHAN SELVARAJ <quic_poovendh@quicinc.com>]

On 2/18/2023 1:19 AM, Mukesh Ojha wrote:
>
>
> On 2/16/2023 7:30 PM, Mukesh Ojha wrote:
>>
>>
>> On 2/16/2023 5:30 PM, Poovendhan Selvaraj wrote:
>>> CrashDump collection is based on the DLOAD bit of TCSR register.
>>> To retain other bits, we read the register and modify only the DLOAD 
>>> bit as
>>> the other bits have their own significance.
>>>
>>> Co-developed-by: Anusha Rao <quic_anusha@quicinc.com>
>>> Signed-off-by: Anusha Rao <quic_anusha@quicinc.com>
>>> Co-developed-by: Kathiravan Thirumoorthy <quic_kathirav@quicinc.com>
>>> Signed-off-by: Kathiravan Thirumoorthy <quic_kathirav@quicinc.com>
>>> Signed-off-by: Poovendhan Selvaraj <quic_poovendh@quicinc.com>
>>> ---
>>>   Changes in V5:
>>>     - checking the return value in qcom_scm_set_download_mode 
>>> function as
>>>       suggested by Srinivas Kandagatla
>>>
>>>   Changes in V4:
>>>     - retain the orginal value of tcsr register when download mode
>>>       is not set
>>>
>>>   drivers/firmware/qcom_scm.c | 21 ++++++++++++++++-----
>>>   1 file changed, 16 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>>> index 468d4d5ab550..d88c5f14bd54 100644
>>> --- a/drivers/firmware/qcom_scm.c
>>> +++ b/drivers/firmware/qcom_scm.c
>>> @@ -407,7 +407,7 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
>>>   }
>>>   EXPORT_SYMBOL(qcom_scm_set_remote_state);
>>> -static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>>> +static int __qcom_scm_set_dload_mode(struct device *dev, u32 val, 
>>> bool enable)
>>>   {
>>>       struct qcom_scm_desc desc = {
>>>           .svc = QCOM_SCM_SVC_BOOT,
>>> @@ -417,7 +417,8 @@ static int __qcom_scm_set_dload_mode(struct 
>>> device *dev, bool enable)
>>>           .owner = ARM_SMCCC_OWNER_SIP,
>>>       };
>>> -    desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
>>> +    desc.args[1] = enable ? val | QCOM_SCM_BOOT_SET_DLOAD_MODE :
>>> +                val & ~(QCOM_SCM_BOOT_SET_DLOAD_MODE);
>>>       return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
>>>   }
>>> @@ -426,15 +427,25 @@ static void qcom_scm_set_download_mode(bool 
>>> enable)
>>>   {
>>>       bool avail;
>>>       int ret = 0;
>>> +    u32 dload_addr_val;
>>>       avail = __qcom_scm_is_call_available(__scm->dev,
>>>                            QCOM_SCM_SVC_BOOT,
>>>                            QCOM_SCM_BOOT_SET_DLOAD_MODE);
>>> +    ret = qcom_scm_io_readl(__scm->dload_mode_addr, &dload_addr_val);
>>> +
>>> +    if (ret) {
>>> +        dev_err(__scm->dev,
>>> +            "failed to read dload mode address value: %d\n", ret);
>>> +        return;
>>> +    }
>>> +
>>>       if (avail) {
>>> -        ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
>>> +        ret = __qcom_scm_set_dload_mode(__scm->dev, dload_addr_val, 
>>> enable);
>>
>> Did you test this on a target where it comes under this if statement? 
>> does it really need to know dload_mode_addr for this target ?
>
>
> Can we do something like this? I would let other review as well.
>
> --------------------------------------->0------------------------------------------- 
>
> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
> index cdbfe54..26b7eda 100644
> --- a/drivers/firmware/qcom_scm.c
> +++ b/drivers/firmware/qcom_scm.c
> @@ -419,6 +419,7 @@ static void qcom_scm_set_download_mode(bool enable)
>  {
>         bool avail;
>         int ret = 0;
> +       u32 dload_addr_val;
>
>         avail = __qcom_scm_is_call_available(__scm->dev,
>                                              QCOM_SCM_SVC_BOOT,
> @@ -426,8 +427,16 @@ static void qcom_scm_set_download_mode(bool enable)
>         if (avail) {
>                 ret = __qcom_scm_set_dload_mode(__scm->dev, enable);
>         } else if (__scm->dload_mode_addr) {
> -               ret = qcom_scm_io_writel(__scm->dload_mode_addr,
> -                               enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE 
> : 0);
> +               ret = qcom_scm_io_readl(__scm->dload_mode_addr, 
> &dload_addr_val);
> +               if (ret) {
> +                       dev_err(__scm->dev,
> +                               "failed to read dload mode address 
> value: %d\n", ret);
> +                       return;
> +               }
> +
> +               ret = qcom_scm_io_writel(__scm->dload_mode_addr, enable ?
> +                               dload_addr_val | 
> QCOM_SCM_BOOT_SET_DLOAD_MODE :
> +                               dload_addr_val & 
> ~(QCOM_SCM_BOOT_SET_DLOAD_MODE));
>         } else {
>                 dev_err(__scm->dev,
>                         "No available mechanism for setting download 
> mode\n");
>
> -Mukesh

Okay sure..Agreed, will address this in the next patch.

>>
>> -Mukesh
>>>       } else if (__scm->dload_mode_addr) {
>>> -        ret = qcom_scm_io_writel(__scm->dload_mode_addr,
>>> -                enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0);
>>> +        ret = qcom_scm_io_writel(__scm->dload_mode_addr, enable ?
>>> +                dload_addr_val | QCOM_SCM_BOOT_SET_DLOAD_MODE :
>>> +                dload_addr_val & ~(QCOM_SCM_BOOT_SET_DLOAD_MODE));
>>>       } else {
>>>           dev_err(__scm->dev,
>>>               "No available mechanism for setting download mode\n");

Best Regards,
Poovendhan S