linux-kernel - Re: [PATCH V7 2/3] dma: add Qualcomm Technologies HIDMA management driver

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Date:	Mon, 30 Nov 2015 13:51:41 +0530
From:	Vinod Koul <vinod.koul@...el.com>
To:	Sinan Kaya <okaya@...eaurora.org>
Cc:	dmaengine@...r.kernel.org, timur@...eaurora.org,
	cov@...eaurora.org, jcm@...hat.com, agross@...eaurora.org,
	arnd@...db.de, linux-arm-msm@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V7 2/3] dma: add Qualcomm Technologies HIDMA management
 driver

On Sun, Nov 22, 2015 at 09:28:24PM -0500, Sinan Kaya wrote:

> +++ b/Documentation/ABI/testing/sysfs-platform-hidma-mgmt
> @@ -0,0 +1,97 @@
> +What:		/sys/devices/platform/hidma-mgmt*/chan*/priority
> +		/sys/devices/platform/QCOM8060:*/chan*/priority
> +Date:		Nov 2015
> +KernelVersion:	4.4
> +Contact:	"Sinan Kaya <okaya@...eaurora.org>"
> +Description:
> +		Contains either 0 or 1 and indicates if the DMA channel is a
> +		low priority (0) or high priority (1) channel.

What is purpose of adding sysfs entries here ?

> +
> +#define QOS_N_OFFSET			0x300
> +#define CFG_OFFSET			0x400
> +#define MAX_BUS_REQ_LEN_OFFSET		0x41C
> +#define MAX_XACTIONS_OFFSET		0x420
> +#define HW_VERSION_OFFSET		0x424
> +#define CHRESET_TIMEOUT_OFFSET		0x418
> +
> +#define MAX_WR_XACTIONS_MASK		GENMASK(4, 0)
> +#define MAX_RD_XACTIONS_MASK		GENMASK(4, 0)
> +#define WEIGHT_MASK			GENMASK(6, 0)
> +#define MAX_BUS_REQ_LEN_MASK		GENMASK(15, 0)
> +#define CHRESET_TIMEOUUT_MASK		GENMASK(19, 0)
> +
> +#define MAX_WR_XACTIONS_BIT_POS	16
> +#define MAX_BUS_WR_REQ_BIT_POS		16
> +#define WRR_BIT_POS			8
> +#define PRIORITY_BIT_POS		15
> +
> +#define AUTOSUSPEND_TIMEOUT		2000
> +#define MAX_CHANNEL_WEIGHT		15

These names are quite generic and prone to collide with generic names,
please prefix them with your driver name

> +}
> +EXPORT_SYMBOL_GPL(hidma_mgmt_setup);

Why is this exported or rather who would be users of this?

> +static int hidma_mgmt_probe(struct platform_device *pdev)
> +{
> +	struct hidma_mgmt_dev *mgmtdev;
> +	struct resource *res;
> +	void __iomem *virtaddr;
> +	int irq;
> +	int rc;
> +	u32 val;
> +
> +	pm_runtime_set_autosuspend_delay(&pdev->dev, AUTOSUSPEND_TIMEOUT);
> +	pm_runtime_use_autosuspend(&pdev->dev);
> +	pm_runtime_set_active(&pdev->dev);
> +	pm_runtime_enable(&pdev->dev);

at this time pm core will treat device as fully enabled and pm methods can
be invoked, but you are not ready yet right. Typically these are done at the
end of the probe unless you have a reason... 

> +static ssize_t show_values(struct device *dev, struct device_attribute *attr,
> +				char *buf)

Please fix the coding style here and other places as well. Specifically
please read Chapter 2

-- 
~Vinod
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