Re: [PATCH v2 03/17] firmware: turris-mox-rwtm: Use macro constant instead of hardcoded 4096

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

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On Thu, 13 Jun 2024, Marek Behún wrote:

> The 4096 bytes limit in mox_hwrng_read() is due to the DMA buffer being
> allocated to one PAGE_SIZE bytes. Use new local macro constant
> RWTM_DMA_BUFFER_SIZE at allocation time and when used in mox_hwrng_read().
> 
> Signed-off-by: Marek Behún <kabel@kernel.org>
> ---
>  drivers/firmware/turris-mox-rwtm.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/firmware/turris-mox-rwtm.c b/drivers/firmware/turris-mox-rwtm.c
> index 3f4758e03c81..b8deb13aed98 100644
> --- a/drivers/firmware/turris-mox-rwtm.c
> +++ b/drivers/firmware/turris-mox-rwtm.c
> @@ -19,6 +19,8 @@
>  
>  #define DRIVER_NAME		"turris-mox-rwtm"
>  
> +#define RWTM_DMA_BUFFER_SIZE	PAGE_SIZE
> +
>  /*
>   * The macros and constants below come from Turris Mox's rWTM firmware code.
>   * This firmware is open source and it's sources can be found at
> @@ -287,8 +289,8 @@ static int mox_hwrng_read(struct hwrng *rng, void *data, size_t max, bool wait)
>  	struct armada_37xx_rwtm_tx_msg msg;
>  	int ret;
>  
> -	if (max > 4096)
> -		max = 4096;
> +	if (max > RWTM_DMA_BUFFER_SIZE)
> +		max = RWTM_DMA_BUFFER_SIZE;
>  
>  	msg.command = MBOX_CMD_GET_RANDOM;
>  	msg.args[0] = 1;
> @@ -479,8 +481,8 @@ static int turris_mox_rwtm_probe(struct platform_device *pdev)
>  		return -ENOMEM;
>  
>  	rwtm->dev = dev;
> -	rwtm->buf = dmam_alloc_coherent(dev, PAGE_SIZE, &rwtm->buf_phys,
> -					GFP_KERNEL);
> +	rwtm->buf = dmam_alloc_coherent(dev, RWTM_DMA_BUFFER_SIZE,
> +					&rwtm->buf_phys, GFP_KERNEL);
>  	if (!rwtm->buf)
>  		return -ENOMEM;

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

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