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Date:   Wed, 19 Sep 2018 23:25:01 +0530
From:   Vikash Garodia <vgarodia@codeaurora.org>
To:     Stanimir Varbanov <stanimir.varbanov@linaro.org>
Cc:     Alexandre Courbot <acourbot@chromium.org>,
        Hans Verkuil <hverkuil@xs4all.nl>,
        Mauro Carvalho Chehab <mchehab@kernel.org>, robh@kernel.org,
        mark.rutland@arm.com, Andy Gross <andy.gross@linaro.org>,
        Arnd Bergmann <arnd@arndb.de>, bjorn.andersson@linaro.org,
        Linux Media Mailing List <linux-media@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
        devicetree@vger.kernel.org, linux-media-owner@vger.kernel.org
Subject: Re: [PATCH v9 1/5] venus: firmware: add routine to reset ARM9
In-Reply-To: <97b94b9b-f028-cb8b-a3db-67626dc517ab@linaro.org>
References: <1537314192-26892-1-git-send-email-vgarodia@codeaurora.org>
 <1537314192-26892-2-git-send-email-vgarodia@codeaurora.org>
 <CAPBb6MXMv_TD2dbxyM+D2p3pWfCJpQ-_FHK6WdkAEgBhwTdL6g@mail.gmail.com>
 <97b94b9b-f028-cb8b-a3db-67626dc517ab@linaro.org>
Message-ID: <175fcecf3be715d2a20b71746c648f1e@codeaurora.org>
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On 2018-09-19 20:30, Stanimir Varbanov wrote:
> Hi Alex,
> 
> On 09/19/2018 10:32 AM, Alexandre Courbot wrote:
>> On Wed, Sep 19, 2018 at 8:43 AM Vikash Garodia 
>> <vgarodia@codeaurora.org> wrote:
>>> 
>>> Add routine to reset the ARM9 and brings it out of reset. Also
>>> abstract the Venus CPU state handling with a new function. This
>>> is in preparation to add PIL functionality in venus driver.
>>> 
>>> Signed-off-by: Vikash Garodia <vgarodia@codeaurora.org>
>>> ---
>>>  drivers/media/platform/qcom/venus/core.h         |  2 ++
>>>  drivers/media/platform/qcom/venus/firmware.c     | 33 
>>> ++++++++++++++++++++++++
>>>  drivers/media/platform/qcom/venus/firmware.h     | 11 ++++++++
>>>  drivers/media/platform/qcom/venus/hfi_venus.c    | 13 +++-------
>>>  drivers/media/platform/qcom/venus/hfi_venus_io.h |  7 +++++
>>>  5 files changed, 57 insertions(+), 9 deletions(-)
>>> 
>>> diff --git a/drivers/media/platform/qcom/venus/core.h 
>>> b/drivers/media/platform/qcom/venus/core.h
>>> index 2f02365..dfd5c10 100644
>>> --- a/drivers/media/platform/qcom/venus/core.h
>>> +++ b/drivers/media/platform/qcom/venus/core.h
>>> @@ -98,6 +98,7 @@ struct venus_caps {
>>>   * @dev:               convenience struct device pointer
>>>   * @dev_dec:   convenience struct device pointer for decoder device
>>>   * @dev_enc:   convenience struct device pointer for encoder device
>>> + * @no_tz:     a flag that suggests presence of trustzone
>> 
>> Looks like it suggests the absence of trustzone?
>> 
>> Actually I would rename it as use_tz and set it if TrustZone is used.
>> This would avoid double-negative statements like what we see below.
> 
> I find this suggestion reasonable.

Initially i planned to keep it as a positive flag. The reason behind 
keeping it
as no_tz was to keep the default value of this flag to 0 indicating tz 
is present
by default.
I can switch it to use_tz though and set it in firmware_init after the 
presence of
firmware node is checked.

>> 
>>>   * @lock:      a lock for this strucure
>>>   * @instances: a list_head of all instances
>>>   * @insts_count:       num of instances
>>> @@ -129,6 +130,7 @@ struct venus_core {
>>>         struct device *dev;
>>>         struct device *dev_dec;
>>>         struct device *dev_enc;
>>> +       bool no_tz;
>>>         struct mutex lock;
>>>         struct list_head instances;
>>>         atomic_t insts_count;
>>> diff --git a/drivers/media/platform/qcom/venus/firmware.c 
>>> b/drivers/media/platform/qcom/venus/firmware.c
>>> index c4a5778..f2ae2f0 100644
>>> --- a/drivers/media/platform/qcom/venus/firmware.c
>>> +++ b/drivers/media/platform/qcom/venus/firmware.c
>>> @@ -22,10 +22,43 @@
>>>  #include <linux/sizes.h>
>>>  #include <linux/soc/qcom/mdt_loader.h>
>>> 
>>> +#include "core.h"
>>>  #include "firmware.h"
>>> +#include "hfi_venus_io.h"
>>> 
>>>  #define VENUS_PAS_ID                   9
>>>  #define VENUS_FW_MEM_SIZE              (6 * SZ_1M)
>>> +#define VENUS_FW_START_ADDR            0x0
>>> +
>>> +static void venus_reset_cpu(struct venus_core *core)
>>> +{
>>> +       void __iomem *base = core->base;
>>> +
>>> +       writel(0, base + WRAPPER_FW_START_ADDR);
>>> +       writel(VENUS_FW_MEM_SIZE, base + WRAPPER_FW_END_ADDR);
>>> +       writel(0, base + WRAPPER_CPA_START_ADDR);
>>> +       writel(VENUS_FW_MEM_SIZE, base + WRAPPER_CPA_END_ADDR);
>>> +       writel(VENUS_FW_MEM_SIZE, base + WRAPPER_NONPIX_START_ADDR);
>>> +       writel(VENUS_FW_MEM_SIZE, base + WRAPPER_NONPIX_END_ADDR);
>>> +       writel(0x0, base + WRAPPER_CPU_CGC_DIS);
>>> +       writel(0x0, base + WRAPPER_CPU_CLOCK_CONFIG);
>>> +
>>> +       /* Bring ARM9 out of reset */
>>> +       writel(0, base + WRAPPER_A9SS_SW_RESET);
>>> +}
>>> +
>>> +int venus_set_hw_state(struct venus_core *core, bool resume)
>>> +{
>>> +       if (!core->no_tz)
>> 
>> This is the kind of double negative statement I was referring do
>> above: "if we do not not have TrustZone". Turning it into
>> 
>>     if (core->use_tz)
>> 
>> would save the reader a few neurons. :)
>> 
>>> +               return qcom_scm_set_remote_state(resume, 0);
>>> +
>>> +       if (resume)
>>> +               venus_reset_cpu(core);
>>> +       else
>>> +               writel(1, core->base + WRAPPER_A9SS_SW_RESET);
>>> +
>>> +       return 0;
>>> +}
>>> 
>>>  int venus_boot(struct device *dev, const char *fwname)
>>>  {
>>> diff --git a/drivers/media/platform/qcom/venus/firmware.h 
>>> b/drivers/media/platform/qcom/venus/firmware.h
>>> index 428efb5..397570c 100644
>>> --- a/drivers/media/platform/qcom/venus/firmware.h
>>> +++ b/drivers/media/platform/qcom/venus/firmware.h
>>> @@ -18,5 +18,16 @@
>>> 
>>>  int venus_boot(struct device *dev, const char *fwname);
>>>  int venus_shutdown(struct device *dev);
>>> +int venus_set_hw_state(struct venus_core *core, bool suspend);
>>> +
>>> +static inline int venus_set_hw_state_suspend(struct venus_core 
>>> *core)
>>> +{
>>> +       return venus_set_hw_state(core, false);
>>> +}
>>> +
>>> +static inline int venus_set_hw_state_resume(struct venus_core *core)
>>> +{
>>> +       return venus_set_hw_state(core, true);
>>> +}
>> 
>> I think these two venus_set_hw_state_suspend() and
>> venus_set_hw_state_resume() are superfluous, if you want to make the
>> state explicit you can also define an enum { SUSPEND, RESUME } to use
>> as argument of venus_set_hw_state() and call it directly.
> 
> Infact this was by my request, and I wanted to avoid enum and have the
> type of the action in the function name and also avoid one extra
> function argument. Of course it is a matter of taste.