Re: [PATCH v9 1/5] venus: firmware: add routine to reset ARM9

[Vikash Garodia]

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@xxxxxxxxxxxxxx> 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@xxxxxxxxxxxxxx>
> > > ---
> > >  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.