linux-kernel - Re: [PATCH 3/3] remoteproc: k3-r5: Adjust TCM sizes in Split-mode on J7200 SoCs

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Message-ID: <20201123235129.GA529235@xps15>
Date:   Mon, 23 Nov 2020 16:51:29 -0700
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Suman Anna <s-anna@...com>
Cc:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Lokesh Vutla <lokeshvutla@...com>,
        linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/3] remoteproc: k3-r5: Adjust TCM sizes in Split-mode on
 J7200 SoCs

Good afternoon Suman,

On Wed, Nov 18, 2020 at 07:05:31PM -0600, Suman Anna wrote:
> The J7200 SoCs have a revised R5FSS IP that adds a unique feature w.r.t
> TCM sizing. Each R5F core in a cluster typically has 32 KB each of ATCM
> and BTCM, with only the Core0 TCMs usable in LockStep mode. This revised
> IP however doubles the total available TCM in LockStep mode by making the
> Core1 TCM visible immediately after the corresponding Core0 TCM.
> 
> The R5F DT nodes on the J7200 SoCs define double (64 KB) the normal TCM
> size (32 KB) for R5F Core0 for each of ATCM and BTCM to represent the
> above. This increased TCM memory is only usable in LockStep-mode, and
> has to be adjusted to the normal 32 KB size in Split mode. Enhance the
> TI K3 R5F remoteproc for this logic through a new function. The adjustment
> is a no-op on prior SoCs and relies on the correct DTS node sizes in
> LockStep-mode on applicable SoCs.
> 
> Signed-off-by: Suman Anna <s-anna@...com>
> ---
>  drivers/remoteproc/ti_k3_r5_remoteproc.c | 43 ++++++++++++++++++++++++
>  1 file changed, 43 insertions(+)
> 
> diff --git a/drivers/remoteproc/ti_k3_r5_remoteproc.c b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> index 66a32dcdd7d0..62b5a4c29456 100644
> --- a/drivers/remoteproc/ti_k3_r5_remoteproc.c
> +++ b/drivers/remoteproc/ti_k3_r5_remoteproc.c
> @@ -71,9 +71,11 @@ enum cluster_mode {
>  
>  /**
>   * struct k3_r5_soc_data - match data to handle SoC variations
> + * @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
>   */
>  struct k3_r5_soc_data {
> +	bool tcm_is_double;
>  	bool tcm_ecc_autoinit;
>  };
>  
> @@ -886,6 +888,43 @@ static void k3_r5_reserved_mem_exit(struct k3_r5_rproc *kproc)
>  	of_reserved_mem_device_release(kproc->dev);
>  }
>  
> +/*
> + * Each R5F core within a typical R5FSS instance has a total of 64 KB of TCMs,
> + * split equally into two 32 KB banks between ATCM and BTCM. The TCMs from both
> + * cores are usable in Split-mode, but only the Core0 TCMs can be used in
> + * LockStep-mode. The newer revisions of the R5FSS IP maximizes these TCMs by
> + * leveraging the Core1 TCMs as well in certain modes where they would have
> + * otherwise been unusable (Eg: LockStep-mode on J7200 SoCs). This is done by
> + * making a Core1 TCM visible immediately after the corresponding Core0 TCM.
> + * The SoC memory map uses the larger 64 KB sizes for the Core0 TCMs, and the
> + * dts representation reflects this increased size on supported SoCs. The Core0
> + * TCM sizes therefore have to be adjusted to only half the original size in
> + * Split mode.
> + */
> +static void k3_r5_adjust_tcm_sizes(struct k3_r5_rproc *kproc)
> +{
> +	struct k3_r5_cluster *cluster = kproc->cluster;
> +	struct k3_r5_core *core = kproc->core;
> +	struct device *cdev = core->dev;
> +	struct k3_r5_core *core0;
> +
> +	if (cluster->mode == CLUSTER_MODE_LOCKSTEP ||
> +	    !cluster->soc_data->tcm_is_double)
> +		return;

Shouldn't this be:

	if (cluster->mode == CLUSTER_MODE_SPLIT ||
	    !cluster->soc_data->tcm_is_double)
		return;

If am wrong then I'm pretty sure other people will be confused and a comment is
warranted. 

> +
> +	core0 = list_first_entry(&cluster->cores, struct k3_r5_core, elem);
> +	if (core == core0) {
> +		WARN_ON(core->mem[0].size != SZ_64K);
> +		WARN_ON(core->mem[1].size != SZ_64K);
> +
> +		core->mem[0].size /= 2;
> +		core->mem[1].size /= 2;
> +
> +		dev_dbg(cdev, "adjusted TCM sizes, ATCM = 0x%zx BTCM = 0x%zx\n",
> +			core->mem[0].size, core->mem[1].size);
> +	}
> +}
> +
>  static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
>  {
>  	struct k3_r5_cluster *cluster = platform_get_drvdata(pdev);
> @@ -933,6 +972,8 @@ static int k3_r5_cluster_rproc_init(struct platform_device *pdev)
>  			goto err_config;
>  		}
>  
> +		k3_r5_adjust_tcm_sizes(kproc);
> +
>  		ret = k3_r5_reserved_mem_init(kproc);
>  		if (ret) {
>  			dev_err(dev, "reserved memory init failed, ret = %d\n",
> @@ -1407,10 +1448,12 @@ static int k3_r5_probe(struct platform_device *pdev)
>  }
>  
>  static const struct k3_r5_soc_data am65_j721e_soc_data = {
> +	.tcm_is_double = false,
>  	.tcm_ecc_autoinit = false,
>  };
>  
>  static const struct k3_r5_soc_data j7200_soc_data = {
> +	.tcm_is_double = true,
>  	.tcm_ecc_autoinit = true,

With the above and for the set:

Reviewed-by: Mathieu Poirier <mathieu.poirier@...aro.org>

>  };
>  
> -- 
> 2.28.0
>