linux-kernel - Re: [PATCH 1/3] ARM: davinci: da8xx: Create DSP device only when assigned memory

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Message-ID: <098d38ab-4be3-ec01-044d-1fd2e0ac6130@ti.com>
Date:   Thu, 18 May 2017 11:40:19 +0530
From:   Sekhar Nori <nsekhar@...com>
To:     Suman Anna <s-anna@...com>, Kevin Hilman <khilman@...nel.org>
CC:     <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 1/3] ARM: davinci: da8xx: Create DSP device only when
 assigned memory

On Wednesday 17 May 2017 03:43 AM, Suman Anna wrote:
> The DSP device on Davinci platforms does not have an MMU and requires
> specific DDR memory to boot. This memory is reserved using the rproc_mem
> kernel boot parameter and is assigned to the device on non-DT boots.
> The remoteproc core uses the DMA API and so will fall back to assigning
> random memory if this memory is not assigned to the device, but the DSP
> remote processor boot will not be successful in such cases. So, check
> that memory has been reserved and assigned to the device specifically
> before even creating the DSP device.
> 
> Signed-off-by: Suman Anna <s-anna@...com>
> ---
>  arch/arm/mach-davinci/devices-da8xx.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/arch/arm/mach-davinci/devices-da8xx.c b/arch/arm/mach-davinci/devices-da8xx.c
> index 7cf529ffbe5a..1ccf52e49886 100644
> --- a/arch/arm/mach-davinci/devices-da8xx.c
> +++ b/arch/arm/mach-davinci/devices-da8xx.c
> @@ -814,6 +814,8 @@ static struct platform_device da8xx_dsp = {
>  	.resource	= da8xx_rproc_resources,
>  };
>  
> +static bool rproc_mem_inited __initdata;
> +
>  #if IS_ENABLED(CONFIG_DA8XX_REMOTEPROC)
>  
>  static phys_addr_t rproc_base __initdata;
> @@ -852,6 +854,8 @@ void __init da8xx_rproc_reserve_cma(void)
>  	ret = dma_declare_contiguous(&da8xx_dsp.dev, rproc_size, rproc_base, 0);
>  	if (ret)
>  		pr_err("%s: dma_declare_contiguous failed %d\n", __func__, ret);
> +	else
> +		rproc_mem_inited = true;
>  }
>  
>  #else
> @@ -866,6 +870,12 @@ int __init da8xx_register_rproc(void)
>  {
>  	int ret;
>  
> +	if (!rproc_mem_inited) {
> +		pr_warn("%s: memory not reserved for DSP, not registering DSP device\n",
> +			__func__);

We now have a warning and an error if dma_declare_contiguous() fails. I
like this message better. So can you replace the existing error message
with this text instead ?

Thanks,
Sekhar