linux-kernel - Re: [PATCH V2 1/2] mmc: sdhci: Let a vendor driver supply and update ADMA descriptor size

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Message-ID: <9cb3dd40-0edd-6e71-bc31-c4bb4a7282c9@intel.com>
Date:   Mon, 20 Jan 2020 14:29:56 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Veerabhadrarao Badiganti <vbadigan@...eaurora.org>,
        ulf.hansson@...aro.org
Cc:     asutoshd@...eaurora.org, stummala@...eaurora.org,
        sayalil@...eaurora.org, cang@...eaurora.org,
        rampraka@...eaurora.org, linux-mmc@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH V2 1/2] mmc: sdhci: Let a vendor driver supply and update
 ADMA descriptor size

On 20/01/20 1:17 pm, Veerabhadrarao Badiganti wrote:
> Let a vendor driver supply the maximum descriptor size that it
> can operate on. ADMA descriptor table would be allocated using this
> supplied size.
> If any SD Host controller is of version prior to v4.10 spec
> but supports 16byte descriptor, this change allows them to supply
> correct descriptor size for ADMA table allocation.
> 
> Also let a vendor driver update the descriptor size by overriding
> sdhc_host->desc_size if it has to operates on a different descriptor
> sizes in different conditions.

A couple of minor tweaks below sorry.

> 
> Suggested-by: Adrian Hunter <adrian.hunter@...el.com>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@...eaurora.org>
> ---
>  drivers/mmc/host/sdhci.c | 13 +++++++------
>  drivers/mmc/host/sdhci.h |  3 ++-
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 3140fe2..44fb446 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3822,14 +3822,15 @@ int sdhci_setup_host(struct sdhci_host *host)
>  		void *buf;
>  
>  		if (host->flags & SDHCI_USE_64_BIT_DMA) {
> -			host->adma_table_sz = host->adma_table_cnt *
> -					      SDHCI_ADMA2_64_DESC_SZ(host);
> -			host->desc_sz = SDHCI_ADMA2_64_DESC_SZ(host);
> +			if (!host->alloc_desc_sz)
> +				host->alloc_desc_sz =
> +					SDHCI_ADMA2_64_DESC_SZ(host);
>  		} else {
> -			host->adma_table_sz = host->adma_table_cnt *
> -					      SDHCI_ADMA2_32_DESC_SZ;
> -			host->desc_sz = SDHCI_ADMA2_32_DESC_SZ;
> +			host->alloc_desc_sz = SDHCI_ADMA2_32_DESC_SZ;
>  		}

The following is simpler:

		if (!(host->flags & SDHCI_USE_64_BIT_DMA))
			host->alloc_desc_sz = SDHCI_ADMA2_32_DESC_SZ;
		else if (!host->alloc_desc_sz)
			host->alloc_desc_sz = SDHCI_ADMA2_64_DESC_SZ(host);

> +		host->desc_sz = host->alloc_desc_sz;
> +		host->adma_table_sz = host->adma_table_cnt *
> +					      host->desc_sz;

Wrap is not needed

>  
>  		host->align_buffer_sz = SDHCI_MAX_SEGS * SDHCI_ADMA2_ALIGN;
>  		/*
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 0ed3e0e..10bda3a 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -554,7 +554,8 @@ struct sdhci_host {
>  	dma_addr_t adma_addr;	/* Mapped ADMA descr. table */
>  	dma_addr_t align_addr;	/* Mapped bounce buffer */
>  
> -	unsigned int desc_sz;	/* ADMA descriptor size */
> +	unsigned int desc_sz;	/* ADMA current descriptor size */
> +	unsigned int alloc_desc_sz;	/* ADMA descr. max size host supports */
>  
>  	struct workqueue_struct *complete_wq;	/* Request completion wq */
>  	struct work_struct	complete_work;	/* Request completion work */
>