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Message-ID: <2ec29f46-9e0d-7387-6744-a165917fcad4@ti.com>
Date:   Wed, 14 Dec 2022 16:30:57 +0530
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Subject: Re: [PATCH v2 2/2] remoteproc: k3-r5: Use separate compatible string
 for TI AM62 SoC family
To:     Tanmay Shah <tanmays@amd.com>, <andersson@kernel.org>,
        <mathieu.poirier@linaro.org>, <p.zabel@pengutronix.de>,
        <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <devicetree@vger.kernel.org>, <s-anna@ti.com>
CC:     <robh+dt@kernel.org>, <krzysztof.kozlowski+dt@linaro.org>,
        <hnagalla@ti.com>, <praneeth@ti.com>, <nm@ti.com>,
        <vigneshr@ti.com>, <a-bhatia1@ti.com>, <j-luthra@ti.com>
References: <20221130134052.7513-1-devarsht@ti.com>
 <20221130134052.7513-3-devarsht@ti.com>
 <d95ee066-424c-1a0b-cffd-45e16bc7f8da@amd.com>
Content-Language: en-US
From:   Devarsh Thakkar <devarsht@ti.com>
In-Reply-To: <d95ee066-424c-1a0b-cffd-45e16bc7f8da@amd.com>
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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@ti.com>
>> ---
>> 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
>>