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Subject: Re: [PATCH] bus: mhi: core: Add support MHI EE FP for download
 firmware
To:     Jeffrey Hugo <jhugo@codeaurora.org>, carl.yin@quectel.com,
        manivannan.sadhasivam@linaro.org, sfr@canb.auug.org.au
Cc:     linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
        naveen.kumar@quectel.com
References: <20201027094338.23110-1-carl.yin@quectel.com>
 <937f9236-1c07-d101-a8d7-afad68afdd2b@codeaurora.org>
From:   Hemant Kumar <hemantk@codeaurora.org>
Message-ID: <322cf3df-86f1-7614-62b1-db8594a8062a@codeaurora.org>
Date:   Tue, 27 Oct 2020 16:01:30 -0700
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Hi Jeff,

On 10/27/20 8:11 AM, Jeffrey Hugo wrote:
> On 10/27/2020 3:43 AM, carl.yin@quectel.com wrote:
>> From: "carl.yin" <carl.yin@quectel.com>
>>
>> MHI wwan modems support download firmware to nand or emmc
>> by firehose protocol, process as next:
>> 1. wwan modem normal bootup and enter EE AMSS, create mhi DIAG chan 
>> device
>> 2. send EDL cmd via DIAG chan, then modem enter EE EDL
>> 3. boot.c download 'firehose/prog_firehose_sdx55.mbn' via BHI interface
>> 4. modem enter EE FP, and create mhi EDL chan device
>> 5. user space tool download FW to modem via EDL chan by firehose protocol
>>
>> Signed-off-by: carl.yin <carl.yin@quectel.com>
>> ---
>>   drivers/bus/mhi/core/boot.c     |  4 +++-
>>   drivers/bus/mhi/core/init.c     |  2 ++
>>   drivers/bus/mhi/core/internal.h |  1 +
>>   drivers/bus/mhi/core/main.c     |  3 +++
>>   drivers/bus/mhi/core/pm.c       | 16 +++++++++++++++-
>>   include/linux/mhi.h             |  4 +++-
>>   6 files changed, 27 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/bus/mhi/core/boot.c b/drivers/bus/mhi/core/boot.c
>> index 24422f5..ab39ad6 100644
>> --- a/drivers/bus/mhi/core/boot.c
>> +++ b/drivers/bus/mhi/core/boot.c
>> @@ -460,8 +460,10 @@ void mhi_fw_load_handler(struct mhi_controller 
>> *mhi_cntrl)
>>           return;
>>       }
>> -    if (mhi_cntrl->ee == MHI_EE_EDL)
>> +    if (mhi_cntrl->ee == MHI_EE_EDL) {
>> +        mhi_ready_state_transition(mhi_cntrl);
>>           return;
>> +    }
>>       write_lock_irq(&mhi_cntrl->pm_lock);
>>       mhi_cntrl->dev_state = MHI_STATE_RESET;
>> diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
>> index ac4aa5c..9c2c2f3 100644
>> --- a/drivers/bus/mhi/core/init.c
>> +++ b/drivers/bus/mhi/core/init.c
>> @@ -26,6 +26,7 @@ const char * const mhi_ee_str[MHI_EE_MAX] = {
>>       [MHI_EE_WFW] = "WFW",
>>       [MHI_EE_PTHRU] = "PASS THRU",
>>       [MHI_EE_EDL] = "EDL",
>> +    [MHI_EE_FP] = "FP",
>>       [MHI_EE_DISABLE_TRANSITION] = "DISABLE",
>>       [MHI_EE_NOT_SUPPORTED] = "NOT SUPPORTED",
>>   };
>> @@ -35,6 +36,7 @@ const char * const 
>> dev_state_tran_str[DEV_ST_TRANSITION_MAX] = {
>>       [DEV_ST_TRANSITION_READY] = "READY",
>>       [DEV_ST_TRANSITION_SBL] = "SBL",
>>       [DEV_ST_TRANSITION_MISSION_MODE] = "MISSION_MODE",
>> +    [DEV_ST_TRANSITION_FP] = "FP",
>>       [DEV_ST_TRANSITION_SYS_ERR] = "SYS_ERR",
>>       [DEV_ST_TRANSITION_DISABLE] = "DISABLE",
>>   };
>> diff --git a/drivers/bus/mhi/core/internal.h 
>> b/drivers/bus/mhi/core/internal.h
>> index 4abf0cf..6ae897a 100644
>> --- a/drivers/bus/mhi/core/internal.h
>> +++ b/drivers/bus/mhi/core/internal.h
>> @@ -386,6 +386,7 @@ enum dev_st_transition {
>>       DEV_ST_TRANSITION_READY,
>>       DEV_ST_TRANSITION_SBL,
>>       DEV_ST_TRANSITION_MISSION_MODE,
>> +    DEV_ST_TRANSITION_FP,
>>       DEV_ST_TRANSITION_SYS_ERR,
>>       DEV_ST_TRANSITION_DISABLE,
>>       DEV_ST_TRANSITION_MAX,
>> diff --git a/drivers/bus/mhi/core/main.c b/drivers/bus/mhi/core/main.c
>> index 3950792..e307b58 100644
>> --- a/drivers/bus/mhi/core/main.c
>> +++ b/drivers/bus/mhi/core/main.c
>> @@ -782,6 +782,9 @@ int mhi_process_ctrl_ev_ring(struct mhi_controller 
>> *mhi_cntrl,
>>               case MHI_EE_SBL:
>>                   st = DEV_ST_TRANSITION_SBL;
>>                   break;
>> +            case MHI_EE_FP:
>> +                st = DEV_ST_TRANSITION_FP;
>> +                break;
>>               case MHI_EE_WFW:
>>               case MHI_EE_AMSS:
>>                   st = DEV_ST_TRANSITION_MISSION_MODE;
>> diff --git a/drivers/bus/mhi/core/pm.c b/drivers/bus/mhi/core/pm.c
>> index 3de7b16..3c95a5d 100644
>> --- a/drivers/bus/mhi/core/pm.c
>> +++ b/drivers/bus/mhi/core/pm.c
>> @@ -563,7 +563,15 @@ static void mhi_pm_disable_transition(struct 
>> mhi_controller *mhi_cntrl,
>>       }
>>       if (cur_state == MHI_PM_SYS_ERR_PROCESS) {
>> -        mhi_ready_state_transition(mhi_cntrl);
>> +        if (mhi_get_exec_env(mhi_cntrl) == MHI_EE_EDL
>> +            && mhi_get_mhi_state(mhi_cntrl) == MHI_STATE_RESET) {
>> +            write_lock_irq(&mhi_cntrl->pm_lock);
>> +            cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
>> +            write_unlock_irq(&mhi_cntrl->pm_lock);
>> +            mhi_queue_state_transition(mhi_cntrl, 
>> DEV_ST_TRANSITION_PBL);
>> +        } else {
>> +            mhi_ready_state_transition(mhi_cntrl);
>> +        }
>>       } else {
>>           /* Move to disable state */
>>           write_lock_irq(&mhi_cntrl->pm_lock);
>> @@ -658,6 +666,12 @@ void mhi_pm_st_worker(struct work_struct *work)
>>           case DEV_ST_TRANSITION_MISSION_MODE:
>>               mhi_pm_mission_mode_transition(mhi_cntrl);
>>               break;
>> +        case DEV_ST_TRANSITION_FP:
>> +            write_lock_irq(&mhi_cntrl->pm_lock);
>> +            mhi_cntrl->ee = MHI_EE_FP;
>> +            write_unlock_irq(&mhi_cntrl->pm_lock);
>> +            mhi_create_devices(mhi_cntrl);
>> +            break;
>>           case DEV_ST_TRANSITION_READY:
>>               mhi_ready_state_transition(mhi_cntrl);
>>               break;
>> diff --git a/include/linux/mhi.h b/include/linux/mhi.h
>> index 6e1122c..4620af8 100644
>> --- a/include/linux/mhi.h
>> +++ b/include/linux/mhi.h
>> @@ -120,6 +120,7 @@ struct mhi_link_info {
>>    * @MHI_EE_WFW: WLAN firmware mode
>>    * @MHI_EE_PTHRU: Passthrough
>>    * @MHI_EE_EDL: Embedded downloader
>> + * @MHI_EE_FP, Flash Programmer Environment
>>    */
>>   enum mhi_ee_type {
>>       MHI_EE_PBL,
>> @@ -129,7 +130,8 @@ enum mhi_ee_type {
>>       MHI_EE_WFW,
>>       MHI_EE_PTHRU,
>>       MHI_EE_EDL,
>> -    MHI_EE_MAX_SUPPORTED = MHI_EE_EDL,
>> +    MHI_EE_FP,
>> +    MHI_EE_MAX_SUPPORTED = MHI_EE_FP,
>>       MHI_EE_DISABLE_TRANSITION, /* local EE, not related to mhi spec */
>>       MHI_EE_NOT_SUPPORTED,
>>       MHI_EE_MAX,
>>
> 
> This gets a NACK from me.  I don't see the FP_EE that this patch 
> introduces defined in the spec.  Where did it come from?
> 
There is indeed a FP EE, BHI spec will be updated with this EE next month.

Basically, once device goes to EDL, flash programmer image is downloaded 
using BHI protocol (same as we download SBL image using BHI from PBL in 
current use case). Once it is downloaded intvec sends EE change event 
for FP. Also event is generated for the same which is used to create
EDL channels (34, 35) which is used by flash programmer to flash image
for AMSS.

 >> 2. send EDL cmd via DIAG chan, then modem enter EE EDL
#2 needs to be done in cleaner way. From AMSS when diag cmd is sent to 
switch to EDL, device would send SYS_ERR which we can use to do a call 
back to mhi controller to perform power down and power up. Instead of
moving pm state to POR from disable transition :-

@@ -563,7 +563,15 @@ static void mhi_pm_disable_transition(struct
 >> mhi_controller *mhi_cntrl,
 >>       }
 >>       if (cur_state == MHI_PM_SYS_ERR_PROCESS) {
 >> -        mhi_ready_state_transition(mhi_cntrl);
 >> +        if (mhi_get_exec_env(mhi_cntrl) == MHI_EE_EDL
 >> +            && mhi_get_mhi_state(mhi_cntrl) == MHI_STATE_RESET) {
 >> +            write_lock_irq(&mhi_cntrl->pm_lock);
 >> +            cur_state = mhi_tryset_pm_state(mhi_cntrl, MHI_PM_POR);
 >> +            write_unlock_irq(&mhi_cntrl->pm_lock);
 >> +            mhi_queue_state_transition(mhi_cntrl,
 >> DEV_ST_TRANSITION_PBL);
 >> +        } else {
 >> +            mhi_ready_state_transition(mhi_cntrl);
 >> +        }

Thanks,
Hemant

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