Re: [PATCH v2 2/2] remoteproc: k3-r5: Use separate compatible string for TI AM62 SoC family

[Devarsh Thakkar <devarsht@xxxxxx>]

Hi Tanmay,

Thanks for the review and sorry for the delay. Please find my response 
inline.
On 30/11/22 23:27, Tanmay Shah wrote:
> Hi Devarsh,
>
> Please find my comments below.
>
> On 11/30/22 6:40 PM, Devarsh Thakkar wrote:
> > AM62 and AM62A SoCs use single core R5F which is a new scenario
> > different than the one being used with CLUSTER_MODE_SINGLECPU
> > which is for utilizing a single core from a set of cores available
> > in R5F cluster present in the SoC.
> >
> > To support this single core scenario map it with
> > newly defined CLUSTER_MODE_NONE and use it when
> > compatible is set to ti,am62-r5fss.
> >
> > Signed-off-by: Devarsh Thakkar <devarsht@xxxxxx>
> > ---
> > V2: Fix indentation and ordering issues as per review comments
> > ---
> >   drivers/remoteproc/ti_k3_r5_remoteproc.c | 55 ++++++++++++++++++------
> >   1 file changed, 43 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c 
> > b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > index 0481926c6975..9698b29a0b56 100644
> > --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> > @@ -74,11 +74,13 @@ struct k3_r5_mem {
> >    *   Split mode      : AM65x, J721E, J7200 and AM64x SoCs
> >    *   LockStep mode   : AM65x, J721E and J7200 SoCs
> >    *   Single-CPU mode : AM64x SoCs only
> > + *   None            : AM62x, AM62A SoCs
> >    */
> >   enum cluster_mode {
> >          CLUSTER_MODE_SPLIT = 0,
> >          CLUSTER_MODE_LOCKSTEP,
> >          CLUSTER_MODE_SINGLECPU,
> > +       CLUSTER_MODE_NONE,
> >   };
> >
> >   /**
> > @@ -86,11 +88,13 @@ enum cluster_mode {
> >    * @tcm_is_double: flag to denote the larger unified TCMs in certain 
> > modes
> >    * @tcm_ecc_autoinit: flag to denote the auto-initialization of TCMs 
> > for ECC
> >    * @single_cpu_mode: flag to denote if SoC/IP supports Single-CPU mode
> > + * @is_single_core: flag to denote if SoC/IP has only single core R5
> >    */
> >   struct k3_r5_soc_data {
> >          bool tcm_is_double;
> >          bool tcm_ecc_autoinit;
> >          bool single_cpu_mode;
> > +       bool is_single_core;
>
>
> If you are providing this data, then ignore parsing cluster-mode 
> property. This will make change very simple.
Yes, I think we are doing the same thing here. AM62x is modeled as a 
cluster with a single core child but since it is single core there is no 
cluster mode applicable as such and hence no cluster-mode required to be 
set in device-tree for AM62x.


> I believe this would save you any modification in bindings as well as 
> cluster-mode property is optional anyway.
>
> Also, "enum cluster_mode" reflects cluster-mode values from bindings 
> document except proper soc compatible. I don't see new value added in 
> bindings document i.e. only
>
> [0 -> split, 1 -> lockstep, 2 -> single cpu] are defined. If new enum is 
> introduced in driver, it is expected to reflect in bindings i.e. [3 -> 
> cluster-mode none] to avoid any confusion.
To support backward compatibility we introduced CLUSTER_MODE_NONE at 3, 
but I think we can use -1 index and maybe another name say 
CLUSTER_MODE_INVALID to make it less confusing. The cluster-mode 
property doesn't apply to AM62x since it uses CLUSTER_MODE_INVALID, my 
understanding is we don't need to describe CLUSTER_MODE_INVALID in 
dt-binding since it will be only used internally by driver as -1 and need
not be set at all in device-tree since for AM62x there won't be any 
cluster-mode property required to be set in the devicetree.

> I believe it is duplicate logic if you are providing "is_single_core" 
> information here and introduce CLUSTER_MODE_NONE as well.
>
> May be I am missing something, but I don't see any use of providing 
> extra value CLUSTER_MODE_NONE if "is_single_core" is set in the driver. 
> So, simple solutions is just to avoid parsing cluster-mode property if 
> is_single_core is set in the driver. Hope this helps.
Fair point, we could have used soc data's is_single_core check instead 
of adding a new enum and used that check and that would have worked too. 
But in that case, cluster-mode by default would be set to 0 with  as 
part of allocation of k3_r5_cluster struct during probe which would 
imply incorrectly CLUSTER_MODE_SPLIT for AM62x. I think it is better
to have another enum say CLUSTER_MODE_INVALID and use it for SoC's like 
AM62x to make it less confusing.

Regards,
Devarsh
> Thanks,
>
> Tanmay
>
>
> >   };
> >
> >   /**
> > @@ -838,7 +842,8 @@ static int k3_r5_rproc_configure(struct 
> > k3_r5_rproc *kproc)
> >
> >          core0 = list_first_entry(&cluster->cores, struct k3_r5_core, 
> > elem);
> >          if (cluster->mode == CLUSTER_MODE_LOCKSTEP ||
> > -           cluster->mode == CLUSTER_MODE_SINGLECPU) {
> > +           cluster->mode == CLUSTER_MODE_SINGLECPU ||
> > +           cluster->mode == CLUSTER_MODE_NONE) {
> >                  core = core0;
> >          } else {
> >                  core = kproc->core;
> > @@ -853,7 +858,7 @@ static int k3_r5_rproc_configure(struct 
> > k3_r5_rproc *kproc)
> >                  boot_vec, cfg, ctrl, stat);
> >
> >          /* check if only Single-CPU mode is supported on applicable 
> > SoCs */
> > -       if (cluster->soc_data->single_cpu_mode) {
> > +       if (cluster->soc_data->single_cpu_mode || 
> > cluster->soc_data->is_single_core) {
> >                  single_cpu =
> >                          !!(stat & 
> > PROC_BOOT_STATUS_FLAG_R5_SINGLECORE_ONLY);
> >                  if (single_cpu && cluster->mode == CLUSTER_MODE_SPLIT) {
> > @@ -1074,6 +1079,7 @@ static void k3_r5_adjust_tcm_sizes(struct 
> > k3_r5_rproc *kproc)
> >
> >          if (cluster->mode == CLUSTER_MODE_LOCKSTEP ||
> >              cluster->mode == CLUSTER_MODE_SINGLECPU ||
> > +           cluster->mode == CLUSTER_MODE_NONE ||
> >              !cluster->soc_data->tcm_is_double)
> >                  return;
> >
> > @@ -1147,7 +1153,9 @@ static int k3_r5_rproc_configure_mode(struct 
> > k3_r5_rproc *kproc)
> >          atcm_enable = cfg & PROC_BOOT_CFG_FLAG_R5_ATCM_EN ?  1 : 0;
> >          btcm_enable = cfg & PROC_BOOT_CFG_FLAG_R5_BTCM_EN ?  1 : 0;
> >          loczrama = cfg & PROC_BOOT_CFG_FLAG_R5_TCM_RSTBASE ?  1 : 0;
> > -       if (cluster->soc_data->single_cpu_mode) {
> > +       if (cluster->soc_data->is_single_core) {
> > +               mode = CLUSTER_MODE_NONE;
> > +       } else if (cluster->soc_data->single_cpu_mode) {
> >                  mode = cfg & PROC_BOOT_CFG_FLAG_R5_SINGLE_CORE ?
> >                                  CLUSTER_MODE_SINGLECPU : 
> > CLUSTER_MODE_SPLIT;
> >          } else {
> > @@ -1271,7 +1279,8 @@ static int k3_r5_cluster_rproc_init(struct 
> > platform_device *pdev)
> >
> >                  /* create only one rproc in lockstep mode or 
> > single-cpu mode */
> >                  if (cluster->mode == CLUSTER_MODE_LOCKSTEP ||
> > -                   cluster->mode == CLUSTER_MODE_SINGLECPU)
> > +                   cluster->mode == CLUSTER_MODE_SINGLECPU ||
> > +                   cluster->mode == CLUSTER_MODE_NONE)
> >                          break;
> >          }
> >
> > @@ -1704,21 +1713,32 @@ static int k3_r5_probe(struct platform_device 
> > *pdev)
> >           * default to most common efuse configurations - Split-mode 
> > on AM64x
> >           * and LockStep-mode on all others
> >           */
> > -       cluster->mode = data->single_cpu_mode ?
> > +       if (!data->is_single_core)
> > +               cluster->mode = data->single_cpu_mode ?
> >                                  CLUSTER_MODE_SPLIT : 
> > CLUSTER_MODE_LOCKSTEP;
> > +       else
> > +               cluster->mode = CLUSTER_MODE_NONE;
> > +
> >          cluster->soc_data = data;
> >          INIT_LIST_HEAD(&cluster->cores);
> >
> > -       ret = of_property_read_u32(np, "ti,cluster-mode", 
> > &cluster->mode);
> > -       if (ret < 0 && ret != -EINVAL) {
> > -               dev_err(dev, "invalid format for ti,cluster-mode, ret 
> > = %d\n",
> > -                       ret);
> > -               return ret;
> > +       if (!data->is_single_core) {
> > +               ret = of_property_read_u32(np, "ti,cluster-mode", 
> > &cluster->mode);
> > +               if (ret < 0 && ret != -EINVAL) {
> > +                       dev_err(dev, "invalid format for 
> > ti,cluster-mode, ret = %d\n", ret);
> > +                       return ret;
> > +               }
> >          }
> >
> >          num_cores = of_get_available_child_count(np);
> > -       if (num_cores != 2) {
> > -               dev_err(dev, "MCU cluster requires both R5F cores to 
> > be enabled, num_cores = %d\n",
> > +       if (num_cores != 2 && !data->is_single_core) {
> > +               dev_err(dev, "MCU cluster requires both R5F cores to 
> > be enabled but num_cores is set to = %d\n",
> > +                       num_cores);
> > +               return -ENODEV;
> > +       }
> > +
> > +       if (num_cores != 1 && data->is_single_core) {
> > +               dev_err(dev, "SoC supports only single core R5 but 
> > num_cores is set to %d\n",
> >                          num_cores);
> >                  return -ENODEV;
> >          }
> > @@ -1760,18 +1780,28 @@ static const struct k3_r5_soc_data 
> > am65_j721e_soc_data = {
> >          .tcm_is_double = false,
> >          .tcm_ecc_autoinit = false,
> >          .single_cpu_mode = false,
> > +       .is_single_core = false,
> >   };
> >
> >   static const struct k3_r5_soc_data j7200_j721s2_soc_data = {
> >          .tcm_is_double = true,
> >          .tcm_ecc_autoinit = true,
> >          .single_cpu_mode = false,
> > +       .is_single_core = false,
> >   };
> >
> >   static const struct k3_r5_soc_data am64_soc_data = {
> >          .tcm_is_double = true,
> >          .tcm_ecc_autoinit = true,
> >          .single_cpu_mode = true,
> > +       .is_single_core = false,
> > +};
> > +
> > +static const struct k3_r5_soc_data am62_soc_data = {
> > +       .tcm_is_double = false,
> > +       .tcm_ecc_autoinit = true,
> > +       .single_cpu_mode = false,
> > +       .is_single_core = true,
> >   };
> >
> >   static const struct of_device_id k3_r5_of_match[] = {
> > @@ -1779,6 +1809,7 @@ static const struct of_device_id 
> > k3_r5_of_match[] = {
> >          { .compatible = "ti,j721e-r5fss", .data = 
> > &am65_j721e_soc_data, },
> >          { .compatible = "ti,j7200-r5fss", .data = 
> > &j7200_j721s2_soc_data, },
> >          { .compatible = "ti,am64-r5fss",  .data = &am64_soc_data, },
> > +       { .compatible = "ti,am62-r5fss",  .data = &am62_soc_data, },
> >          { .compatible = "ti,j721s2-r5fss",  .data = 
> > &j7200_j721s2_soc_data, },
> >          { /* sentinel */ },
> >   };
> > --
> > 2.17.1