linux-kernel - Re: [PATCH] spi: spi-fsl-qspi: Reduce devm_ioremap size to 4 times AHB buffer size

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Message-ID: <95c90219-0fd9-c0b4-5c1a-6abb321ef2e3@kontron.de>
Date:   Thu, 16 Apr 2020 09:36:20 +0000
From:   Schrempf Frieder <frieder.schrempf@...tron.de>
To:     Ashish Kumar <Ashish.Kumar@....com>,
        "broonie@...nel.org" <broonie@...nel.org>,
        "boris.brezillon@...labora.com" <boris.brezillon@...labora.com>
CC:     "linux-spi@...r.kernel.org" <linux-spi@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Kuldeep Singh <kuldeep.singh@....com>
Subject: Re: [PATCH] spi: spi-fsl-qspi: Reduce devm_ioremap size to 4 times
 AHB buffer size

Hi Ashish,

On 16.04.20 10:33, Ashish Kumar wrote:
> Reduce devm_ioremap size to (4 * AHB_BUFER_SIZE) rather than mapping
> complete QSPI-Memmory as driver is now independent of flash size.
> Flash of any size can be accessed.
> 
> Issue was reported on platform where devm_ioremap failure is observed
> with size > 256M.
> Error log on LS1021ATWR :
>   fsl-quadspi 1550000.spi: ioremap failed for resource [mem 0x40000000-0x7fffffff]
>   fsl-quadspi 1550000.spi: Freescale QuadSPI probe failed
>   fsl-quadspi: probe of 1550000.spi failed with error -12
> 
> This change was also suggested previously:
> https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fpatchwork.kernel.org%2Fpatch%2F10508753%2F%2322166385&amp;data=02%7C01%7Cfrieder.schrempf%40kontron.de%7Cba26817e759b460819a708d7e1e0d083%7C8c9d3c973fd941c8a2b1646f3942daf1%7C0%7C0%7C637226228543132272&amp;sdata=z7wekDTg%2FN7CZUy7ikM%2BVHOKT95YbDJ0cr2JE62Wgzw%3D&amp;reserved=0

So if you want you could add a "Suggested-by" tag referring to Boris.

> 
> Signed-off-by: Kuldeep Singh <kuldeep.singh@....com>
> Signed-off-by: Ashish Kumar <Ashish.kumar@....com>
> ---
>   drivers/spi/spi-fsl-qspi.c | 10 +++++++---
>   1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/spi/spi-fsl-qspi.c b/drivers/spi/spi-fsl-qspi.c
> index 63c9f7e..a41ce81 100644
> --- a/drivers/spi/spi-fsl-qspi.c
> +++ b/drivers/spi/spi-fsl-qspi.c
> @@ -859,14 +859,15 @@ static int fsl_qspi_probe(struct platform_device *pdev)
>   
>   	res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
>   					"QuadSPI-memory");
> -	q->ahb_addr = devm_ioremap_resource(dev, res);
> +	q->memmap_phy = res->start;
> +	/* Since there are 4 CS max MAP required is 4 time ahb_buf_size */

/* Since there are 4 cs, map size required is 4 times ahb_buf_size */

> +	q->ahb_addr = devm_ioremap(dev, q->memmap_phy,
> +				   (q->devtype_data->ahb_buf_size * 4));
>   	if (IS_ERR(q->ahb_addr)) {
>   		ret = PTR_ERR(q->ahb_addr);
>   		goto err_put_ctrl;
>   	}
>   
> -	q->memmap_phy = res->start;
> -
>   	/* find the clocks */
>   	q->clk_en = devm_clk_get(dev, "qspi_en");
>   	if (IS_ERR(q->clk_en)) {
> @@ -939,6 +940,9 @@ static int fsl_qspi_remove(struct platform_device *pdev)
>   
>   	mutex_destroy(&q->lock);
>   
> +	if (q->ahb_addr)
> +		devm_iounmap(q->dev, q->ahb_addr);

You don't need to unmap explicitly. Using devm_*(), lifetime of the 
resource is already tied to the device.

Thanks,
Frieder

> +
>   	return 0;
>   }
>   
>